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Full text of "Progress in sport fishery research"

/N SPORT FISHERY 



RESEARCH 



R 




United States Department of the Interior 

Fish and Wildlife Service 
Bureau of Sport Fisheries and Wildlife 



UNITED STATES DEPARTMENT OF THE INTERIOR 
Walter J. Hickel, Secretary 

Leslie L. Glasgow, Assistant Secretary for 
Fish and Ifiildlife and Parks 

Fish and Wildlife Service 
Charles H. Meacham, Commissioner 

Bureau of Sport Fisheries and Wildlife 
John S. Gottschalk, Director 

Raymond E. Johnson, Assistant Director - Research 

Division of Fishery Research 
Paul E. Thompson, Chief 



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PROGR ESS 

IN SPORT FISHERY 
RESEARCH/igQg 




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PREPARED IN 

DIVISION OF FISHERY RESEARCH 

BUREAU OF SPORT ^^ISHERIES AND WILDLIFE 

WASHINGTON • JUNE 1970 

Resource Publication 88 



u 



For sale by the Superintendent of Documents, U.S. Government Printing Office 
Washington, D.C., 20402 - Price $2.00 per copy 



CONTENTS 

Page 

ORGANIZATION CHART "■" 

FOREWORD ^ 

PEST CONTROL RESEARCH 

Pest Control and the Aquatic Ecosystem 2 

Fish-Pesticide Research Laboratory 5 

Fish Control Laboratories 22 

FISH HUSBANDRY RESEARCH 

Fish Husbandry Research- -Tomorrow or Today? 47 

Eastern Fish Disease Laboratory 48 

Western Fish Disease Laboratory 62 

Eastern Fish Nutrition Laboratory "76 

Western Fish Nutrition Laboratory 89 

Fish Genetics Laboratory HO 

Salmon-Cultural Laboratory 118 

Sierra Nevada Aquatic Research Laboratory 129 

Warmwater Fish Cultural Laboratories 143 

OCEANIC AND RESERVOIR ECOSYSTEM RESEARCH 

The New Environmental Awareness 166 

Atlantic Marine Game Fish Research 168 

Tiburon Marine Laboratory .' 198 

National Reservoir Research Program 217 

North Central Reservoir Investigations 226 

South Central Reservoir Investigations 246 

TECHNICAL COMMUNICATIONS 262 

LOCATION MAP 284 

DIRECTORY Inside back cover 



Linda W . McGuinn 
Compositor 











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FOREWORD 



SOMEONE HAS SAID that research is a small part inspiration, a large part perspiration. The 
inspiration part is by far the more important, of course. Sometimes it comes from an example and 
that is the purpose of the true story which follows . 

Early in 1969, fishery research lost a man of great character and promise when Clarence E . 
(Ed) Dunbar died suddenly at Leetown, West Virginia. Almost 20 years ago Ed joined the staff of 
the Leetown Laboratory as a fish culturist at $2,450 a year to care for the trout used in disease 

research. He was about 34 years old then. 



married and with two children, and with some- 
thing less than a high school education. 

By 1969, Ed had a high school diploma, a 
college degree. He was a professional histo- 
pathologist occupying a key position on the 
Leetown staff. He had had special courses in 
histochemistry at Kansas University and path- 
ology at Ohio State . He had presented papers at 
technical meetings, published in his specialty, 
and was respected as an authority. He taught in 
the Leetown fish disease courses , and gave 
demonstrations to visiting scientists from all 
over the world . 



From a background in West Virginia coal 
mining to histo pathology in a West Virginia research laboratory took personal career development 
quite beyond the vision of most people. Ed completed high school graduation requirements, 
attended classes and studied on his own time until he received his Bachelor's degree, all the while 
perfecting laboratory techniques and proficiency in separating normal from pathological tissues . 
How in the world did he do it? Of course he had the support and encouragement of his wife, the 
sympathetic urging of the laboratory director and his co-workers. But, in the final analysis, it 
was his own perseverance, personal sacrifices, and ambition to excel in a field of research he 
had grown to love and respect . 

Ed's death has left a large and painful vacancy in the Leetown Laboratory staff, but his life 
example has left so much more that should encourage, motivate, and, yes, inspire those who 
otherwise may feel the road up is too steep, or the toll too costly. It has been done- -it can be 
done. That is Ed Dunbar's memorial and legacy. 




Paul E. Thompson, Chief 
Division of Fishery Research 



PEST CONTROL AND THE AQUATIC ECOSYSTEM 



The value of the sport fishery depends on the quality and quantity of fish taken per unit of 
fishing effort. Fish management requires thorough knowledge of the life history of each fish, 
environmental requirements (and tolerances), relations to other species (predator and prey), analy- 
sis of habitat, and methods to manipulate and control populations. Ecological evaluations of the 
kinetics of energy flow through food chains and greater efficiency in producing sport fishes from 
available energy sources is the key to management success. Thus, as we become committed to 
"priorities for the Seventies," our contribution to society will come through effective research lead- 
ing to good stewardship and wise resource use by improving and maintaining biological systems in 
aquatic environments. 

In the past, we gave high priority to study of the persistent organochlorine insecticides because 
of their acute toxicity, accumulation in food chain organisms, and chronic effects. Typically, 
insecticides in the aquatic ecosystem cause acute toxicity to both fish and aquatic invertebrates. 
Resistant individuals that survive accumulate and transfer pesticide residues to other members of 
the ecosystem and to man. The degradation of the value and production of favored fish is often 
subtle and unnoticed. More recently, our attention has turned to the organophosphorous and car- 
bamate insecticides . We are concerned about their interaction with organochlorine pesticides and 
those compounds commonly called PCBs (polychlorinated biphenyls). Herbicides rate more attention 
suice the controversy on 2,4,5-T and the report that its contaminant dioxin induces abnormal 
fetuses in special strains of mice. Because some phenoxy herbicides are applied directly in water 
for control of aquatic plants to enhance fish production and sport fishing, our investigations center 
on the fate of herbicide residues and effects on fish, fish -food organisms, and other aquatic orga- 
nisms . 

Excessive aquatic weed growth is a universal management problem. It interferes with fish 
culture and angling. The relation of aquatic flora to a fishery is often poorly understood and docu- 
mented even in the most technically detailed studies . Generally, most research on aquatic weeds 
and their control has been focused on chemical, mechanical, or biological removal. Very little 
effort, however, has been made to understand the flow of plant nutrients and energy in the aquatic 
ecosystem and how to manipulate producer and food chain organisms to maximize the harvestable 
yield. Thus, our concern is with aquatic ecology, plant and animal physiology, kinetics of plant 
nutrients in water and soil chemistry, pesticide toxicology, nutritional biochemistry, life history 
of the aquatic food chain species (consumer organisms), and dependent relations with aquatic plants 
and algae (producer organisms) . We know too little about the flow of energy through the food chain 
to fish, the selectivity or preferences of fish for different food organisms and aquatic plants, and 
the interdependence of plants and food organisms . 

We have examined certain pesticides and their effects on the aquatic ecosystem in relation to 
maximizing production of sport fish populations. Antimycin, a short-lived and non -residue produc- 
ing chemical, has been used effectively to alter the structure of bass-bluegill populations . This 
selective pesticide thinned out the stunted bluegUl and reinstituted a desirable predator -prey 



relation to improve angling quality. This chemical affects only the secondary and tertiary consumers . 
Toxaphene, in contrast, has been used in a similar manner except that the primary consumers (fish- 
food organisms) are also destroyed. Toxaphene lingers--the residues are biologically transferred 
up the food chain and accumulate in tissues of fish and other predators . Herbicides are generally 
short-lived but have a much more subtle effect on the aquatic ecosystem (Figure 1). The primary 
producer organisms are directly affected. This is the objective of the management biologists, but 
the changes induced are transferred all the way up the food chain and dramatically alter the flow of 
energy. In this example, sodium endothal is selectively toxic to certain submersed rooted plants 
and eliminates them from the habitat --releases these stored nutrients and energy to decomposer 
organisms (bacteria, etc.) which in turn feed diatoms, rotifers, protozoans, etc. This also 
changes some of the physical features of the habitat - -weed clinging insect larvae and protective 
cover for the invertebrates and small fish are now more vulnerable to predation. Turbidity from 
the plankton is sharply increased but does not adversely affect feeding by predatory fishes at the 
secondary and tertiary trophic level. The net result is a more efficient system for benefiting the 
desirable sport fishes. Removal of excessive plant growth redirects energy flow, improves fish 
growth rates, and increases in production, and catch per unit effort is evidence of improvement in 
the sport fishery. 

Adequate labeling, recommendations, and guidelines for safe and effective use of pesticides 
require appropriate data on toxicity, efficacy, and residues under different conditions. Research 
for evaluation of weed control chemicals must develop the following information: 1) toxicity to the 
target species; 2) relative toxicity to non -target species of plants, invertebrates, fish, other aquatic 
animals, birds, mammals, and man; 3) fate of residues and significance in water, fish, crops, 
livestock and other foods of man; 4) conditions affecting toxicity, efficacy and persistence of resi- 
dues in the proposed pattern of use, e. g., water chemistry, temperature, variations in suscepti- 
bility of species at various life stages and seasons, inflow dilution, contact time, rate of degrada- 
tion, deactivation or detoxification; 5) potentiating or synergizing activity of carriers, formulations, 
or combination with other contaminants and pesticides, metabolites and degradation products. 

An orderly system of toxicological screening and evaluation is required. Pesticides may be 
applied in both standing and flowing situations, and the bioassay methods must be sufficient to 
measure the herbicide concentration and the contact time necessary for aquatic plant control or 
toxicological effects on other aquatic organisms. Thus, our research includes static, intermittent- 
flow or constant -flow bioassay systems depending on the length of the testing and investigator's 
desire to most nearly simulate the lentic or lotic environmental conditions. Temperature, biomass- 
volume rates, water chemistry and light intensity or periodicity are also important considerations 
with regard to the reaction of aquatic organisms or plants to the chemicals. 

Economical considerations are dictated by the effectiveness of the chemical in channelization of 
energy to increased quality or quantity of the harvestable yield. Thus, our research method for 
evaluation of the cost -benefit aspects of pesticide use must include analysis of energy flow limiting 
factors, and biomass produced at each trophic level with respect to the biotic potential of the species 
under management . 

Charles R. Walker, Chief 
Branch of Pest Control Research 



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FISH-PESTICIDE RESEARCH LABORATORY 

Columbia, Missouri 
Richard A. Schoettger, Director 



HIGHLIGHTS 

We completed 320 acute and continuous -flow 
bioassays of insecticides, herbicides, fungicides, 
fish eradicants, a rodenticide and eight PCBs 
(polychlorinated biphenyls) against fish. 

In bioassays on many organophosphate 
insecticides now being suggested as alternatives 
to the more persistent pesticides, we find that 
they are particularly active where combined 
with other chemicals. 

Dichlone was the most toxic of 16 herbicides 
tested against six species of Crustacea. 

Methoxychlor has an adverse effect on 
growth of adult cutthroat trout and ripening of 
females. Progeny of methoxychlor -treated fish 
are more resistant to the insecticide than pro- 
geny of controls. 

Application rates of Dursban or malathion- 
parathion mixtures recommended for mosquito 
control are hazardous to fish and fish -food 
organisms . 

Various crustaceans and immature 
aquatic insects exposed to 100 ng of DDT per 
liter accumulate residues of the insecticide that 
are 1,000 to 100,000 times greater than those in 
water. 

Heptachlor stimulated growth of certain 
microorganisms, inhibited growth in others, but 
had no effect on gram -negative bacteria . 

Rainbow trout exposed to dieldrin and 
subjected to forced swimming, preferentially 



utilize amino acids for energy, whereas DDT- 
treated and control fish use fats and carbohy- 
drates . 

The presence of DDT in a synthetic mixture 
of polychlorinated biphenyls (PCBs) was detected 
by use of a gas chromatograph-mass spectro- 
meter . 

Specific activity of acetyl cholinesterase in 
bluegill brain is correlated with water tempera- 
ture. 

Forced swimming and fasting of DDT -treated 
rainbow trout depleted their mesenteric fats, 
mobilized fat -stored DDT, and elevated DDT 
deposits in their brains. Death ensued and prior 
symptoms suggest DDT poisoning. 

The uptake of 2,4 -D dimethylamine salt 
from water by bluegills and channel catfish 
appears to be a more important source of 2,4 -D 
residues than uptake from food. 

Our analytical capabilities were extended to 
at least 20 other government agencies and 
included pesticide analyses of fish, water, sedi- 
ments , and fish foods . 

ACUTE TOXICITY OF PESTICIDES TO FISH 

We completed 320 acute and chronic bioas- 
says in spite of the loss of approximately 40,000 
fishes resulting from two separate power fail- 
ures, and finally, from the complete breakdown 
of the submersible well pump on December 5. 
Twenty-four-, 48-, and 96-hr TLcq values and 
corresponding 95 percent confidence intervals 
were calculated from tests conducted on toxicity 



of 60 pesticides to coho salmon, rainbow trout, 
channel catfish, bluegUls, redear, and black 
crappie. The pesticides tested included insect- 
icides, herbicides, fungicides, fish eradicants, 
a rodenticide, and polychlorinated biphenyl com- 
pounds (PCBs -industrial chemicals). 

Many of the acute toxicity tests served as 
guidelines for further research. These include 
dieldr in and photo -dieldrin, Dyrene, Akton, 
malathion and its thionate analog, and parathion 
and its thioate analog. Also, many fishes were 
exposed to different pesticides in static and 
continuous -flow systems for use by the analyti- 
cal section in perfecting their methods of resi- 
due analysis . 

We obtained preliminary data on toxicity of 
several herbicides to bluegills. The 96 -hour 
TLcQ value for N,N-dimethyl-2,4-dichlorophen- 
oxyacetamine was 0.9 mg/1 and Igran was 2.7 
mg/1, while Brush Rhap A-2D-2T, Ded Weed 
(2,4, 5-T amine) and 2 A-D/2,4,5-T DMA gave 
96 -hour TLcQ values of over 100 mg/1. Dipotas- 
sium endothall and Kllng Tite 800 (naphthalene- 
acetic acid) were relatively non-toxic to coho 
salmon with 96 -hour TLcq values of 100 and 75 .7 
mg/1, respectively. Weed and Brush-off 400 
(diethylethanolamine salt) of two specific gravi- 
ties (0.92 and 1.00) are relatively toxic to blue- 
gills: 96 -hour TL^q values for the 0.92 formula- 
tion was 0.16 mg/1, whereas the value of the 
other formulation was 0.28 mg/1. Two other 
herbicides, Veon and 2,4-D/2,4,5-T amuie, 
gave 96-hour TLjq values of 40.9 and 22.6 mg/1, 
respectively. 

Two PCBs were bioassayed for toxicity 
against channel catfish. The toxicity of Aroclor 
1254 at 18 C. was 7.0 mg/1, whereas Aroclor 
1248 was slightly more toxic. Definitive tests 
with 1254 and 1248 against bluegUls gave 96 -hour 
TL50 values of 2.7 and 0.3 mg/1, respectively. 
We also tested nine other PCBs , but because of 
failure in our water system these tests were 
discontinued after 24 hours . Little activity at 
either 24 or 48 hours for all 11 of these com- 
pounds was indicated. Consequently, these 
compoimds should be tested in constant -flow 
systems longer than 96 hours to fully evaluate 
theur toxicity to fishes. 



We completed research on the toxicities of 
different pesticide combinations against rainbow 
trout and bluegills; a manuscript dealing with a 
portion of this work by Dr . Kenneth Macek is 
in review. General conclusions of this study 
were as follows: 1) m each case the results 
were the same whether the particular combina- 
tion was tested against rainbow trout or blue- 
gills; 2) malathion and copper sulfate Interacted 
synergistically; 3) 18 combinations were addi- 
tive; 4) DDT did not interact with any of the pest- 
icides tested except BHC; 5) many organophos- 
phorus insecticides being suggested as alterna- 
tives to the more persistent pesticides are 
particularly active when combined with other 
chemicals; and 6) several combinations cur- 
rently recommended by the U.S. Department 
of Agriculture are synergistic In their toxicity 
to rainbow trout and bluegUls (Table 1) . 

The influences of tune and temperature on 
the toxicity of four pesticides to rainbow trout 
were established In static and continuous -flow 
bioassays . Preliminary tests against rainbow 
trout were completed under static conditions for 
dieldrin, DDT, Dursban, and Zectran. DDT, 
dieldr ui, and Dursban were tested against rain- 
bow trout under continuous -flow conditions . DDT 
exhibited a negative temperature coefficient of 
activity, being approximately twice as toxic at 
4 .4 C . as at 12 .8 C . Dieldrin and Dursban both 
exhibited a positive temperature coefficient of 
activity. Dursban was three times as toxic at 
12.8 C. than at 4.4 C. Dieldrin was only 
slightly more toxic at 12 .8 C . 

Several attempts were made to bioassay 
Guthion, carbaryl and DDT against various life 
stages of coho salmon, rainbow trout, channel 
catfish, bluegUls, and black crappie to determine 
relative susceptibilities. As each lot offish 
arrived at the- laboratory, they were held until 
Individual weights reached approximately one 
gram. At these tunes, static trials were begun 
and continued as each group reached weight Incre- 
ments of 5, 10, 20, 40, and 80 grams. Some 
species reached 20 grams , but because of loss of 
the original stocks of fishes , none of the tests 
was completed. 

Harry D . Kennedy 



ACUTE TOXICITY OF PESTICIDES 
TO FRESHWATER INVERTEBRATES 

We determined the median tolerance limits 
(TL50) of 16 herbicides by static bioassay to 
scud, Gammarus fasciatus , glass shrimp, 
Palaemonetes kadiakensis , crayfish, Orconectes 
nais, seed shrimp, Cypridoposis vidua, water 
fleas , Daphnia magna , and sowbugs , As ellus 
brevicaudus . Dichlone was the most toxic 
herbicide tested against the six species of 
Crustacea with 48 -hour TLrn values of 0.025 
mg/1 for water fleas to 3.2 mg/1 for crayfish. 
The propylene glycol butyl ether esters of 2,4- 
D and silvex are more toxic to the Crustacea 
than is the butoxyethanol ester . 



Static bioassays with naiads of damselflies , 
Ischnura verticalis , and burrowing mayflies, 
Hexagenia bilineata , and a midge larvae, Tany - 
tarsus diisimilus provided TL^q values for 25 
insecticides. Toxicities of the insecticides to 
damselflies ranged from highly toxic methyl 
parathion (96-hour TL^q value of 0.00064 mg/1) 
to much less toxic Zectran (96 -hour TL^q value 
of 0.1 mg/1). The most toxic insecticide to may- 
flies was carbophenothion (96 -hour TLcq value of 
0.006 mg/1), and the least toxic was malathion 
(96-hour TL5Q value of 0.32 mg/1) . Dursban 
and malathion are more toxic to midge larvae 
than DDT or aldrin . 



Table 1. — Acute toxic interaction of pesticide combinations to 
rainbow trout and bluegills. 



Pesticide combination 
Compound A 



Compound B 



Toxic interaction 



DDT 



Malathion 



Carbaryl 



Methyl parathion 



Vapona 

Endrin 

Dieldrin 

Azinphosmethyl 

Toxaphene 

Zectran 

BHC 

Copper sulfate 

Diazinon 

DDT 

Endosulfan 

Methoxychlor 

Baytex 

Copper sulfate 

DDT 

EPN 

Parathion 

Perthane 

Carbaryl 

Toxaphene 

Copper sulfate 

DDT 

Azinphosmethyl 

Methoxychlor 

Parathion 

DDT 

Endosulfan 

Carbaryl 

Sumithion 



Addi t i ve 
Additive 

Additive 
Addi tive 
Additive!./ 
Additive 
Synergistic 
Synergist ic 
Synergistic 
Additive- 
Additive 
Synergistic 
Synergistic 
Antagonistic 
Addi tive 
Synergistic 
Synergistic 

Synergistic— 

1 

Synergistic— 

Additive!-^ 
Synergistic 
Additive 
Additivei"^ 
Additive 
Additivei'' 
Additive 
Additivey'^ 
Additive- 
Additive 



1/ 



1/ 



— This combination recommended for control of insect pests by the 
U. S. Department of Agriculture. 

Note: Mention of trade names does not constitute endorsement. 



We conducted continuous -flow bioassays 
for 30 days to determine extended -term toxi- 
cities of DDT, endrin, and malathion to cray- 
fish. The TLcQ values for the three insecticides 
decreased rapidly with time of exposure for the 
first 5 days, but decreased less rapidly for the 
subsequent 10 days. However, no further 
decrease in TL^q values occurred during an 
additional 15 days of exposure . 

We exposed late instar burrowing mayfly 
naiads to malathion for 20 days in a continuous - 
flow bioassay. The toxicity of malathion in- 
creased with time of exposure from 0.55 mg/1 
after 24 hours to 0.15 mg/1 after 5 days. This 
was followed by a less rapid decrease for the 
next 5 days (0.10 mg/1) and little change was 
recorded between 10 and 20 days . 

The influence of selected pesticides on 
several species of invertebrates was measured 
in a Warburg respirometer . The study was 
designed to elucidate how pesticides exert lethal 
effects on fish -food organisms . Water fleas 
exposed to DDT and methoxychlor showed an 
immediate increase in oxygen uptake followed by 
a gradual decline until death. However, with 
chlordan we observed a 2 00 -m in. latent period 
followed by an abrupt rise in respiration and 
then a sharp decline In oxygen uptake . In 
general , the rates of oxygen uptake were inf lu - 
enced by variables such as toxicant concentra- 
tion, activity of the animals, body size, and 
stage in their life cycle. 

We shipped stocks of water fleas, seed 
shrimp, scud and glass shrimp to the Depart- 
ment of Forestry, United Kingdom, in the 
Azores to be used in populating a sterile lake. 
Lake Furnas, with fish -food organisms. For- 
tunately, we were able to work out proper 
methods for holding and packaging the animals 
for the long air shipment. We were most con- 
cerned with temperature changes, accumulation 
of metabolic wastes , and other conditions relat - 
ing to organism density and water volume. The 
organisms arrived in good health. We were 
pleased to be able to cooperate with the Division 
of Fishery Services, Department of Forestry, 
U.K., and the U.S. Air Force in this matter . 



CHRONIC TOXICITY OF INSECTICIDES 
TO COLD-WATER FISH 

A study of the long-term effects of methoxy- 
chlor in bath and in the diets of cutthroat trout 
was completed at the NFH, Jackson, Wyo., dur- 
ing 1969. We found a significant relation between 
the concentration of methoxychlor and mortality 
and growth of adults , and the ripening of females . 
In a series of bioassays the progeny from fish in 
the high concentration bath treatment were more 
resistant to methoxychlor than progeny from the 
controls . The latter portion of the experiment 
was terminated prematurely when a bacterial 
epidemic necessitated removing all fish from the 
hatchery. The entire hatchery complex was dis- 
infected on June 25 , 1969 , 

The hatchery disinfection changed our 
experimental designs to use those fish available 
at Jackson for the next year . The wet laboratory 
was converted from an egg-incubating, fry-hold- 
ing facility to a temperature controlled, 22 -jar 
static bioassay facility. In addition, a battery 
of eight, 170-liter aluminum tanks is being con- 
structed for short-term feeding experiments. 
The bioassay facility is operational and is being 
used to determine the relative acute toxicities of 
a variety of compounds to juvenile cutthroat 
trout (Table 2) . 

Dieldrin was approximately 1.75 times more 
toxic to juvenile cutthroat trout than photodiel- 
drin. Many of the PCBs seem to have had a 
delayed effect on trout because most of the 
deaths occurred after 50-60 hours of exposure. 

Our modified facility at Jackson is pro- 
grammed for feeding trials during 1970. We 
have initiated two studies, one with chlordane 
and the other with PCBs, to measure tissue resi- 
dues of these chemicals and their effects on 
serum alpha amino nitrogen, thyroid activity, 
growth, and mortality. 

Don Swedburg 



Herman O . Sanders 



Table 2. --Toxicity of 12 chemicals to cutthroat trout at 8 C. 





L cal 


TL 

24 hrs 


^,^ values and 95 


percent 


confidence 


limits 


in tig/] 


. after- 




Chem: 




48 hrs 






96 hrs. 






Antimycin A 


0.49 


( 0.28- 0.64) 


0.20 


( .09- 


.30) 


0.11 


( .06- , 


.16) 


DDT 




11.7 


( 9.2 -14.1 ) 


9.7 


( 8.3 -11. 


.0 ) 


9.4 


( 7.6 -11, 


.1 ) 


Dieldr in 


12.7 


(11.8 -13. D ) 


8.5 


( 7.0 -10, 


.0 ) 


6.4 


( 5.3 - 7, 


.5 ) 


Photodieldrin 


19.6 


(17.9 -21.2 ) 


14.0 


(12.6 -15, 


.3 ) 


11.1 


t 9.8 -12, 


.3 ) 


Methoxychlor _ 


19.3 


(13.5 -25.0 ) 


14.2 


(10.06-17 


.7 ) 


13.8 


(12.4 -15 


.1 ) 


Aroclor 


1242^./ 












4600 - 


8200 




Aroclor 


1232 


5900 - 


10,3000 


2600 - 


4200 




1900 - 


2500 




Aroclor 


1248 












25,000 






Aroclor 


1254 












25,000 






Aroclor 


5460 












25,000 






Aroclor 


4465 












25,000 






Aroclor 


5442 












25,000 






Aroclor 


1260 












25,000 







— Preliminary data on Aroclor compounds. 



PESTICIDES AND AQUATIC ANIMALS 

IN THE ESTUARINE AND MARINE 

ENVIRONMENT 

Acquisition of suitable bioassay animals 
throughout the year continues to be one of our 
biggest problems. However, we are able to 
collect shiner perch, English sole, and speckled 
sanddab on a fairly regular basis . The Korean 
shrimp proved to be an excellent test animal 
because it is hardy and easy to hold in the lab- 
oratory. Its range appears to be diminishing, 
reportedly because of pesticides . We observed 
these shrimp were susceptible to what were 
normally sub-lethal concentrations of DDT. 
Long-term exposures of shrimp to low concen- 
trations of DDT suggest a correlation between 
susceptibility and molting. In one 38 -day trial 
with 20 individuals, 8 out of 10 dead shrimp 
were molting or had just molted, whereas none 
of the controls died. 

Turbidity and salinity fluctuate widely 
throughout the year in San Francisco Bay. Even 
after filtration we have measured turbidities as 
high as 40 Jackson Turbidity Units in our labora- 
tory water. Therefore, we have tested 10 
organochlorine insecticides for their relative 
sorption on different amounts of sediments at 
th'ree salinities. As expected, pesticide sorp- 
tion increased with turbidity, however, we also 



found that sorption on sediment increased at 
higher salinities . Endrin had the least affinity 
for Bay sediments and aldrin had the highest. 

Sediments in our laboratory water bear 
various amounts of DDT and the DDT complex. 
Because marine fishes drink water, we postu- 
lated that DDT residues in our experimental 
fishes may be related to the degree of turbidity. 
We initiated preliminary research which involved 
maintaining seven species of fish at three levels 
of turbidity. A trend toward higher DDT resi- 
dues in individuals was indicated in these fish 
maintained at higher turbidity. 

Russell Earnest and Pete Benville 

CHRONIC TOXICITY OF PESTICIDES 
TO FISH 

We extended our study of chronic effects of 
pesticides and their fate in fish to include 
carbaryl and channel catfish. Four duplicate 
groups (eight) of fish were exposed to ^^C -car- 
baryl in 500-liter tanks, two by bath and two by 
diet for 56 days. The insecticide was metered 
continuously for the bath treatments to give con- 
centrations of 0.05 or 0.25 mg/1, or fed at the 
rate of 0.4 or 0.04 mg of labeled carbaryl/kg 
of body weight daily. 



Table 3. — Residues of radioactive materials (mg/kg body_weight) accumulated 
by channel catfish exposed by bath or in diet (X +_ SE, N=10) 



Treatment 



Exposure 



3 days 



8 days 



14 days 



28 days 



56 days 



Low-carbaryl bath 
(0.05 mg/1) 

Higji-carbaryl bath 
(0.25 mg/1) 



Low-carbaryl diet 



2/ 



rV 



3 + 0.3 7 + 0.5 



+0.5 9 + 0.6 11 + 0.4 



22 + 2.6 6 + 0.4 7 + 0.7 7+0. 



(0.04 mg/kg per day) 

2/ 
High-carbaryl diet— 

(0.4 mg/kg per day) 

— Trace, less than 1 ng/g. 

2/ 

- The fish were fed 5 hr before the 3-day sampling and 24 hr before the 8-, 14-, 28- 

and 56-day samplings. The stomachs of all fish were cleaned at sampling. 



9 + 0.3 



The uptake, metabolite composition, and 
elimination half -life of radioactive carbaryl 
residues were determined by liquid scintillation 
counting (Table 3) . 

Fish exposed to the high diet concentration 
of carbaryl retained 89 percent of their radio- 
active residues after 25 days on control foods, 
whereas those exposed to the high bath treat - 
ment retained only 18 + 3 percent after the same 
interval . 



We applied 0.01 or 0.05 lb. of Dursban/acre 
to duplicate ponds and two additional ponds 
served as controls . Dursban was applied twice, 
June 9 and July 14 . The mortality of bluegills and 
largemouth bass was 46 and 55 percent, respec- 
tively. Dursban residues in bluegills peaked 
seven days after the first treatment and three 
days after the second treatment. However, the 
maximal concentration of residues after the 
second treatment was twice the maximal residue 
concentration after the first. 



Carbaryl appeared to be excreted or meta- 
bolized at a rapid rate. Presently, we are try- 
ing to elucidate the composition of the radio- 
active metabolites . 



Dursban residues in largemouth bass did not 
follow the bluegill pattern. Both peaks occurred 
three days after application, but the magnitude of 
the first treatment was twice that of the second. 



Sidney Korn 

PESTICIDE -INDUCED CHANGES 
IN POND ECOLOGY 

Mosquito control agencies recommend 
Dursban to control the larval stages. But, our 
static bioassays indicate an adverse effect on 
fish populations if recommended application 
rates are used on ponds . Therefore, we studied 
the chronic effects of multiple treatments of 
Dursban on fish and fish -food organisms . 



Dursban changed population density and 
structure of non -target invertebrates . A density- 
time plot of bottom fauna in the control ponds 
had a cyclic pattern similar to the pattern for 
emergent forms . The sequence of increases and 
decreases in numbers of individuals in the ponds 
treated with 0.01 and 0.05 lb/acre was not simi- 
lar to that of the control ponds . Estimates of 
changes in population structure and density in 
ponds treated at 0.01 lb/acre were intermediate 
between control ponds and those heavily treated. 
Therefore, the effects of Dursban appear to be 
correlated with treatment levels . 



We could not demonstrate conclusive 
evidence of pesticide -induced pathology in our 
microscopial examination of Dursban -exposed 
fish. However, in ponds treated with 0.05 lb/ 
acre, we found a moderate incidence of chronic 
splenomegaly after 28 days of exposure. Both 
species of fish were heavily parasitized at the 
start of the experiment . Mechanical damage to 
the liver, spleen, pancreas, kidney, gonad, 
lobulation of liver parenchyma and eosinophilic 
leucocytes is near or in the abdominal cavity 
characterized tissue responses to trematodes in 
the largemouth bass. The parasite damage to 
tissues and organs may have masked damage 
attributable to Dursban. The number and inci- 
dence of infestation of trichodina, trematodes, 
and mxyospordia in the gills of bluegills declined 
sharply in the 28 -day samples . 



We determined that malathion and para- 
thion acted synergistically (see acute toxicity 
section) in static bioassays, and the pond appli- 
cations appear to support this finding. The 
final report will soon be completed for publica- 
tion. 

Thomas Russell of the Missouri Department 
of Conservation artifically spawned paddlefish 
in one of our tenth-acre ponds. Because of the 
surface swimming habits of very young paddle- 
fish (Figure 1) and heavy predation by a pair of 
green herons and kingfishers, less than 50 
survived. The remaining fish were moved to a 
private pond with a greater mean depth for over- 
wintering. 

David F. Walsh 



Obviously, recommended application rates 
of Dursban for mosquito control are hazardous 
to fish and fish -food organisms . We are now 
better able to predict what effects this insecti- 
cide will have on pond ecosystems . 

Similar to Dursban, our earlier laboratory 
bioassays suggested that a more intensive in- 
vestigation was needed to predict potential haz- 
ards from the promiscuous use of parathion and 
malathion. These trials were conducted in 
ponds with green sunfish and channel catfish. 
Nine quarter -acre ponds were treated with the 
following concentrations: three ponds - 0.5 lb. 
of malathion/acre; three ponds - 0.5 lb. of 
parathion/acre; and three ponds - 0.5 lb/acre of 
each pesticide. Two additional ponds served as 
controls . The ponds were treated twice at 30- 
day intervals. After the second application 
nearly all the fish were killed in ponds treated 
with the pesticide mixture, but there were few 
deaths in ponds treated with only one insecti- 
cide. Samples of water, mud, and fish were 
collected for residue analysis, but the analyses 
are not completed. The invertebrates from 
ponds treated with the insecticide combination 
were unable to repopulate the ponds before the 
second treatment . In contrast, invertebrate 
populations in ponds treated with only one 
insecticide declined immediately after the 
application, but approached densities of the 
"control ponds before the second application. 



INTERACTION BETWEEN MICROORGANISMS 
AND PESTICIDES 

Our efforts to determine the effects of 
pesticides on the biotic communities of an 
aquatic ecosystem involved four specific areas 
of study: the influence of pesticides on primary 
producers; the bioconcentration and biopassage 
of pesticides; the influence of pesticide residues 
on individual trophic levels of a food chain; and 
the degradation of pesticides by members of the 
biotic community. 

In a collaborative study with Dr. Robert 
Campbell and Mr. Lelyn Stadnyk , Department 
of Zoology, University of Missouri, we developed 
a suitable method for studying the effects of 




Figure 1. — Immature paddlefish reared in a 
tenth-acre pond at the Fish-Pesticide 
Research Laboratory. 



11 



pesticide interaction on primary production in 
an aquatic environment . A manuscript entitled 
"The effect of selected pesticides upon growth 
and carbon uptake of Scenedesmus quadricauda" 
is near completion. 

Herman Sanders and I are currently develop- 
ing simple combinations of aquatic food chains 
designed to investigate biopassage and biocon- 
centratlon of pesticides under controlled labora- 
tory conditions . A food -chain sequence of 
algae -daphnia-bluegill -bass shows the most 
promise. The investigation of uptake, reten- 
tion and metabolism of ^c -labeled DDT by 
freshwater invertebrates was completed. The 
Crustacea Daphnia magna (waterflea) , Gammarus 
fasciatus (scud), and Palaemonetes kadikensis 
(glass shrimp), and the immature aquatic 
insects Ischnura (damselfly), Hexagenia (mayfly) 
and Odonata (dragonfly) were exposed to 100 ng/ 
1 C-DDT in a continuous flow system. The 
invertebrates contained residues from 1,000 to 
100,000 times greater than those in water. 
p . magna , for example , accumulated 10 mg of 
DDT per kg withui 48 hours . Sites of ^^c-DDT 
accumulation in this animal are shown in 
Figure 2. Furthermore, D. magna that were 
washed, returned to fresh water and fed, 
retained approximately 50 percent of their ori- 
ginal DDT residues after 7 days. The rapid bio- 
concentration and retention of DDT by D. magna 
demonstrates the significant role many inverte- 
brates may play in the entrance of pesticides 
into an aquatic food chain- -even from a seem- 
ingly insignificant amount of pollution. 

In preliminary investigations heptachlor 
was accumulated rapidly by microorganisms 
suspended in water. In 72 hours, pure cultures 
of Alternaria , Aspergillus , Bacillus , Chaetom - 
ium, Kurthia , Mucor , Mycobacterium , Nocar- 
dia , Rhizopus and Trichoderma concentrated 
over 50 percent of the insecticide contained in a 
concentration of 1 mg/1. Similarly, we found 
that bacteria isolated from uitestinal tracts of 
fish concentrate C -labeled DDT from water. 
DDT is concentrated by a factor of 100 to 1,000 
times in 24 -hour cultures. We feel that reten- 
tion or organochlorine insecticides by micro- 
organisms is essentially a passive adsorption 
phenomenon. 




Figure 2. --Autoradiogram of D. magna 
exposed to ^"'C-DDT. ~ 

We investigated the influence of heptachlor 
(1 mg/1) on growth (biomass) of selected micro- 
organisms . The insecticide had marked effects 
on fungi, actinomycetes and gram positive bac- 
teria. For instance, a 72 -hour culture of 
Aspergillus nigcr increased in biomass by 14 
percent while cultures of Kurthia zopfil de- 
creased by 50 percent . Significantly, the gram- 
negative bacteria Aerobacter, Aeromonas, 
Achromobacter , Flavobacter , and Pseudomonas 
were not affected by heptachlor . 

The degradation of DDT to DDD by bacteria 
isolated from the gastrointestinal tracts of 
channel catfish, bluegills, and largemouth bass 
was reported last year. In recent studies on 
degradation of l^c -labeled DDT by gastrointes- 
tinal microflora of fish, supported by autoradio- 
grams of thin-layer chromatograms, we found 
DDE, DDMU, DDMS, DBF, Kelthane, DDA, DBH, 
and several unidentifiable products in addition 
to DDD. Thus, a relatively broad spectrum of 
bacterial species can readily attack the ethane 
moiety of the DDT molecule under specific 
environmental conditions . The effects of these 
degradation products on the biotic community 
are still unknown. 



12 



I also participated with Dr. Charles O. 
Knowles, toxicologist at the University of 
Missouri, in a joint investigation involving the 
ability of selected microorganisms to degrade 
the acaricide, Galecron. Compounds containing 
an aniline moiety such as Galecron, Karsil, 
Propanil, and some phenylureas are converted 
under certain conditions to azo derivatives . 
The anilines, because of their potential carcino- 
genicity, are of considerable interest as environ- 
mental pollutants . 

Our research on the metabolism of DDT by 
aquatic invertebrates (immature aquatic insects 
and Crustacea) is complete. Basically, we found 
that DDT taken up by these organisms is changed 
within their tissues. Extensive metabolism of 
DDT to DDD, DDE, and Kelthane is indicated by 
all of our residue studies . 

PESTICIDE EFFECTS 
ON FISH ENDOCRINE FUNCTION 

We continued our efforts to elucidate 
possible mechanisms and effective levels of 
insecticide interference with growth and mor- 
phogenesis in fishes by studying thyroidal 
activities of pesticide -exposed rainbow trout. 
Two dietary doses of DDT or dieldrin, 0.145 mg 
and 0.029 mg/kg body weight per day and 
0.145 mg/kg of both compounds in combination 
per day, suppressed thyroidal radioiodine up- 
take. Uptake was reduced 33.6 percent and 
21.7 percent below controls by the high and low 
DDT dosage, 24.5 percent and 30.8 percent 
below controls by the high and low dieldrin 
dosage , and 15 .4 percent below the controls by 
the DDT-dieldrin dosage, respectively. 

We fractionated carp pituitary extract by 
gel filtration to isolate fish thyrotrophin for re- 
injection studies that will hopefully determine 
whether a toxicant acts directly on the thyroid 
gland or whether its effects are mediated 
through the pituitary. We replicated the prepar- 
ative separation four times to attain the neces- 
sary amount of an active thyrotrophin principle 
for repeated injections in a future series of 
experiments . 

The effects of a piscine adrenocorticotro- 
phin (ACTH) on the circulating blood level of 



adrenocorticoids in goldfish are under study. 
ACTH -injected (crude pituitary extract) fish and 
controls were sampled serially at 2, 4, 6, and 
8 hours after injection to determine the time of 
maximal response to a single ACTH injection. 
Serum Cortisol peaked at 2 hours and declined 
linearly to twice the control's Cortisol level at 
8 hours. Then, in a separate experiment, we 
varied the dosage and sampled all groups at the 
2 -hour peak to disclose the response (serum 
Cortisol level) to log dose (ACTH injected) rela- 
tionship. Both experiments were remarkably 
successful and represent a major breakthrough 
in characterizing the stress response in fishes. 
In future experimentation using rainbow trout 
and channel catfish, we shall observe the induced 
response in the presence of selected pesticides to 
test for interrenal (adrenal) dysfunction. Using 
the blood Cortisol response as a bioassay, we 
can follow the activity in isolating piscine ACTH 
by gel filtration. 

We continued research into the effects of 
pesticides and two organic solvents on the 
induced spermiation response in goldfish. Meter- 
ing pumps and flow regulators were installed 
and proved acceptable for continuous -flow ad- 
ministration of toxicants (Figure 3). Adult, 
male goldfish with developed testes were injected 
with the spermiation gonadotrophin (isolated 
from carp pituitary extract by Sephadex G-lOO 
gel filtration). This induced the 24 -hour spermi- 
ation response after the fish had received 6-8 
days of exposure to a toxicant or solvent. 
Individual groups of fish were exposed to the 




Figure 3. — Metering pumps and flow regulators 
for continuous administration of pesticides 
in physiological experiments. 



13 



dimethylamine salt of 2,4-0(700, 300, 150, 70 
i^g/1, and controls) and Dursban(4, 8, 18, 40 
jag/l, and controls). The spermiation response 
occurred in all 2,4 -D-treated groups, but the 
magnitude of response was proportionately less 
in the three highest -treatment groups and un- 
affected in the lowest -treatment group . The 
recommended treatment of 2 to 4 lb. of 2,4 -D 
per acre (0.7 to 1.5 mg/1) may interfere direct- 
ly with spawning in goldfish and could be more 
detrimental to less hardy species. On the other 
hand, Dursban did not affect spermiation even 
though brain acetylcholinesterase in all treat- 
ment groups was inhibited more than 90 percent. 
Classic symptoms of cholinesterase inhibition 
occurred in fish at all levels of treatment: tor- 
por, and protraction of fins, and mouth. This 
demonstrated decidedly that induced spermiation 
was independent of central nervous system con- 
trol. 

The recommended application rate of Abate 
for mosquito control, 40 ng/1, did not affect 
spermiation nor brain acetylcholinesterase. 
Ethanol or acetone in concentration of 0.067 and 
0.05 percent, respectively, also had no effect 
on spermiation nor on brain acetylcholinester- 
ase. We attempted to administer simazine in 
bath exposure, but we were unsuccessful be- 
cause of the compound's extremely low water 
solubility. However, by flowing the bath water 
slowly through a millipore filter containing 
simazine crystals, we hoped to achieve a satur- 
ated solution, but this solution had no effect on 
spermiation. Even toxic concentrations of 
chlordan did not affect induced spermiation. 
Thus , all of the compounds tested to date except 
2,4 -D appear to have no effect on induced 
spermiation. But, to successfully induce sperm- 
iation, fish must have undergone successful 
gametogenesis and we doubt that the gameto- 
genic response is similarly refractory to the 
variety of toxicants we have used on spermia- 
tion. 

In addition to the above bath exposures, we 
also tested injections of DDT and malathion 
against induced spermiation in goldfish . After 
massive, single doses of malathion (0.1, 0.3, 
and 1.0 mg/gm body weight), the fish immedi- 
ately showed considerable distress such as fin 
and mouth distention, lethargy, and slow 



return of sigmoid body flexures to normal. 
By the following morning, the symptoms had dis- 
appeared and the spermiation response was 
similar in the controls and the treated groups. 
Similarly, single injections of 0.1, 0.3, and 
1.0 mg DDT/gm body weight in quota of 10,0 ^1/ 
gm body weight, were given to mature male 
goldfish . These doses were higher than an 
intended sublethal range. Twenty -four hours 
after injection, the 0.3 and 1.0 mg/gm groups of 
seven fish had one and two deaths, respectively, 
and the spermiation assays were not continued. 
However, blood was collected from the surviv- 
ing fish to determine whether death was asso- 
ciated with osmoregulatory failure. For this 
assessment, we analyzed the serum Na, K, and 
blood concentration of DDT . The sodium values 
for the 0.1, 0.3, and 1.0 mg/gm groups were 
143,7, 128.9, and 127,9 milliequivalent/liter 
(mEq/1), respectively. Control goldfish had 
141.5 +3.4 mEq/1 (SD,N=14). The potassium 
values were all high: 5 .0, 6.2, and 5 .3 mEq/1 
respectively. The corresponding concentrations 
of DDT in the serum were 2.5, 7.3, and 11.9 
mg/1 respectively. The depression of serum 
sodium correlated statistically with the concen- 
trations of DDT. 

Immature rainbow trout were tested to 
determine whether ovine prolactin (mammalian 
homologue of piscine paralactin) exerts a diur- 
nal lipogenic effect as previous work has shown 
it to do in sexually mature plains killifish. 
Apparently, a diurnal lipogenic response does 
not exist in immature rainbow trout. Part of 
this study consisted of subjecting the prolactin- 
injected and the control groups to 0,7 jig/l of 
endrin by continuous -flow exposure. The con- 
trol fish all died within 48 hours, but the pro- 
lactin -injected fish lived for over 7 days . 

In previous studies serum amino acid, 
creatinine, and non -protein nitrogen levels in 
fish appeared to be influenced by exposures to 
several insecticides. Therefore, we considered 
the amino acids to be of compelling interest and 
importance in elucidating mechanisms of likely 
pesticide -induced dysfunctions in nitrogen meta- 
bolism. We exposed rainbow trout to 1.0 mg of 
DDT/kg body weight or 1.0 mg of dieldrin/kg 
body weight by diet for 140 days, then subjected 
them to forced -swimming for 24 hr at 2 ft/sec. 



Amino acids in 50tJ.l of serum were quantitated 
by gas -liquid chromatography. Total amino 
acid concentrations were similar in the control, 
DDT, and dieldr in -treated fish, but several 
individual amino acids varied significantly. 
DDT caused serine, methionine, phenylalnine , 
aspartate, glutamate, and tyrosine to increase, 
whereas lysine, valine, trypthophan and cystine 
decreased. Dieldrin caused alanine , glycine, 
isoleucine, proline, threonine, phenylalanine, 
aspartate, and glutamate to increase, whereas 
lysine, histidine, tryptophan, and cystine 
decreased. After 24 hours of forced-swimming, 
total amino acid concentrations in the control 
and DDT-treated fish decreased significantly, 
but total serum amino acids of fish exposed to 
dieldrin did not decrease. 

In addition to the differential analysis of the 
amino acids above, serum glucose, liver gly- 
cogen, serum amino acids, total body lipid, 
total body nitrogen, and pesticide residues were 
determined during continuous forced -swimming 
for four weeks. Utilization of liver glycogen 
was inhibited by dieldrin during the first week of 
forced swimming, but then the glycogen concen- 
tration decreased to the level of the control and 
DDT treated groups for the remaining period of 
forced swimming. After the first week of 
forced swimming, serum amino acids increased 
markedly in the dieldrin group, whereas those 
of the DDT group remained similar to amino 
acids of the control group. Lipid content was 
greater in the dieldrin-treated fish than in the 
DDT-treated and control groups during the first 
week of forced swimming, but total lipids in all 
groups decreased to a similar level for the 
remainder of the forced swimming period. 
Amino acids were apparently utilized preferen- 
tially for energy by dieldrin-treated fish during 
the first week of forced swimming, whereas 
DDT -exposed and control fish preferentially 
utilized fat and carbohydrate during this period. 

We had an opportunity to collect blood from 
spawning paddlefish through cooperation with 
Thomas R. Russell of the Missouri Department 
of Conservation. Pol^odon and related primi- 
tive groups of fishes have not been investigated 
.to any appreciable depth, and we considered 
them of great general interest because of their 
unique phylogenetic position and because of 



their potential economic importance. The 
serum parameters characterized and summar- 
ized in a manuscript are: Na,_ K, Mg, Ca, CI, 
inorganic phosphate, osmolality, cholesterol, 
NPN, total protein, protein electrophoresis, 
lactate, glucose, and Cortisol. 

Blake F . Grant and Paul M . Mehrle 

METABOLISM OF PESTICIDES 

Diuring 1969, we examined the uptake kinetics 
and distribution of two insecticides and a herbi- 
cide. Rainbow trout were exposed to ^"^C-DDT, 
C -dieldrin or to both radioactive insecticides 
in combination. The chemicals were incorpor- 
ated into their diets and fed at the rate of 1 mg/ 
kg/wk over a period of 168 days . Residues of 
the pesticides occurred in all tissues samples 
including brain, liver, pyloric ceaca, megenteric 
fats, lateral -line muscle, striated muscle, gill 
and blood. The concentrations increased during 
exposure, but plateaued before the experiment 
was terminated. The highest residues were found 
in mesenteric fats and pyloric ceaca . 

Individuals from all three of the above types 
of insecticide treatments were entered into two 
additional experiments. In one study, the fish 
were fasted, while in the other the fish were 
stressed by fasting and forced exercise. The 
exercise consisted of 4 weeks of forced swimming 
in a stamina tunnel at a velocity of 2 feet per 
second. Individuals were collected at intervals 
and analyzed to determine what effect the stress 
may have on weight and the distribution of DDT 
and dieldrin within tissues . Stressed dieldrin- 
treated fish lost 32 percent more weight during 
the first two weeks of stress than stressed -con- 
trols or stressed, DDT-treated fish. There 
were no significant differences between the rela- 
tive weight losses of DDT-treated and control 
groups in either the stress or fasting experi- 
ments. However, stressed, DDT-treated fish 
and stressed controls lose 60 percent more 
weight than fasted groups of fish . The fasted 
groups of fish lost about the same amount of 
weight whether or not they were exposed to the 
insecticides. 

The concentration of DDT in mesenteric fats 
of stressed, DDT-treated fish increased 



15 



threefold during the four weeks of exercise, 
suggesting that DDT was not rapidly mobilized 
as fats were consumed. However, when mesen- 
teric fats were nearly depleted, mobilization of 
DDT occurred and residues increased greatly in 
brains and livers. The fish then became im- 
mobile and died. 



paper entitled "Uptake and Elimination of 
Simazine by Green Sunfish ( Lepomis cyanellus )," 
and another, "2,4 -D Butoxyethanol Ester Uptake, 
Distribution, and Elimination by Organs of Rain- 
bow Trout, Channel Catfish, and Bluegill," were 
prepared for the Weed Science Society of 
America . 



We observed that dieldrln -treated fish 
which were fasted and exercised for two weeks 
eliminate some dieldrin from their mesenteric 
fat and other organs . Although these fish lost 
considerable weight, little fat, if any, was 
utilized during this period. Forced exercise of 
dieldrin -treated fish did not accelerate the 
elimination of the pesticide. Elimination pro- 
ceeded at a rate predicted by the elimination 
half -life previously determined to be 40 + 4 days . 
However, the rate of dieldrin elimination from 
stressed fish exposed to combinations of DDT 
and dieldrin was not what we might predict. The 
presence of DDT in the combination treatment 
appeared to block the elimination of dieldrin 
resulting in larger dieldrin residues. In con- 
trast, dieldrin did not cause an increase in DDT 
residues, but it did slow the elimination of DDT. 

The potential of the herbicide 2,4 -D to 
accumulate in fish tissues was investigated by 
exposing bluegills to a radioactive formulation 
of the chemical in water, and in their diets . 
The bath treatment consisted of placing the fish 
in 2 mg/1 of ^'*C -labeled 2,4 -D dimethylamine 
salt (2,4 -D DMA) for up to four weeks . During 
this exposure, we observed a gradual increase 
in whole body residues, and in residues within 
individual organs . Individuals exposed for 28 
days contained up to 0.69 tig/g of radioactive 
material. The gall bladder bile contained as 
much as 55.5 ^ig/g and we measured 0.20 ^g/g 
in muscle. Bluegills fed a diet containing 2 mg/ 
kg/wk of ^4 C -labeled 2,4 -D DMA for 3 weeks 
retained whole body residues of only 0.005 t^g/g 
of radioactive material. Thus, uptake of 2,4 -D 
DMA from water appears more important as a 
source of 2,4 -D residues in fish than does up- 
take from their food. 

Our paper entitled "Uptake, Distribution, 
and Elimination of Dietary '^'^C-DDT in Rainbow 
Trout" has been submitted to the Journal of the 
Fisheries Research Board of Canada. One 



Charles Rodgers and David Stalling 

INTERACTIONS BETWEEN PESTICIDES 
AND FISH ENZYME SYSTEMS 

The inhibition of brain acetylcholinesterase 
(AChE) is used frequently in research and moni- 
toring to evaluate the effect of certain pesticides 
on fish and other aquatic animals . We find a 
controversy concerning the influence of different 
variables on AChE activity, i.e., freezing and 
storage of samples , environmental temperatures , 
species, etc. Investigations of these variables 
were initiated in 1968 and continued in 1969. 

We measured AChE activities in fish brains 
frozen in liquid nitrogen or at -20° C . and then 
stored at -80° C. and -20° C. for periods up to 
six months . Methods of freezing and length of 
storage do not have a statistically significant 
effect on the mean percent inhibition of brain 
AChE activity by an organophosphate pesticide. 
However, brains of control and pesticide- 
treated fish should be stored under similar con- 
ditions . Although freezing and storage have 
little effect on percent of AChE inhibition, these 
preservative techniques do influence specific 
activity of the enzyme. We were able to corre- 
late length of storage with increased specific 
activity. We concluded that under controlled 
laboratory conditions where percent inhibition 
rather than specific activity is under study, 
freezing and storage of fish brains are acceptable 
procedures . 

Sex and water temperature were investi- 
gated as potential sources of variation in AChE 
activity of bluegill brains. Ninty-three female 
and 141 male bluegills were collected from our 
ponds at monthly intervals beginning in May, 
1968, and terminating in July, 1969. Their brain 
AChE activities were estimated and compared 
statistically according to seasonal water and air 
temperatures and sex. A significant exponential 



16 



increase in AChE activity was measured witli 
warmer water and air temperatures , but was 
not correlated with sex. 

Daphnia magna and the crayfish Orconectes 
nais were tested for their exterase activities, 
and central nerve cords of the latter had rela - 
tively high activities . Thus , we measured the 
inhibition of this enzyme in crayfish by selected 
organophosphate pesticides in vitro . Crayfish 
esterase activity is approximately as suscepti- 
ble to organophosphate poisoning as is brain 
AChE in channel catfish and bluegUls . These 
trials were expanded to determine the relative 
in vitro potencies of seven anticholinesterase 
agents on esterases of damselfly naiads , cray- 
fish, channel catfish, and bluegills. We dis- 
covered that the esterase activity of damselfly 
naiads is the most susceptible. For example, 
the inhibition of AChE potency by 50 percent 
(pl50) for 2,2-dichlorovinyldimethyl phosphate 
(DDVP, dichlorvos, or Vapona) was 7.4, 6.3, 
6.1, and 5.6 for damselfly naiads, channel 
catfish, crayfish, and bluegUls , respectively. 

Esterases in fish blood may offer some 
advantages over brain esterases in determining 
the effects of cholinesterase inhibitors. Be- 
cause blood samples could be drawn before and 
after pesticide treatments, each fish could 
serve as its own control. We estimated esterase 
activities in the plasma of 14 species of fish 
representing 10 families . Plasma from chain 
pickerel and channel catfish had the highest rates 
of activity, based on the number of micromoles 
of acetylcholine hydrolyzed per ml of plasma per 
hour. We selected channel catfish for further 
studies of enzymatic properties of their plasma 
esterases. The optimum substrates and sub- 
strate concentrations were determined by using 
various choline and non-choline esters. Also, 
we measured the enzymatic activity of the 
enzyme in the presence of six cations and a 
number of selected anticholinesterase agents . 
Magnesium and manganese increase enzyme 
activity while calcium, copper, and nickel re- 
duce it . Cobalt has no measurable effect . 
When we compared pIcQ values obtained for 
various organophosphate pesticides with channel 
catfish brain and plasma esterases, the latter 
esterase appears to be slightly more resistant 
than the former. For instance, DFP, DDVP, 



and malathion gave pIcQ values of 5 .9 , 6.2, and 
3.2, respectively, for plasma esterase while 
the corresponding values for brain esterase 
were 6.1, 6.3, and 3 .5 . 

James Hogan 

ACETYL CHOLINESTERASE INHZBITION 
AND STAMINA IN SALMONEDS 

Coho salmon and rainbow trout were exposed 
to malathion and subjected to forced swimming 
to determine the correlation between AChE 
inhibition and stamina. We found that 200 g/1 
of malathion inhibited brain AChE by 86 percent 
in coho salmon and their physical activity index 
was reduced by 50 percent. In rainbow trout, 
175 iig/1 of malathion reduced AChE activity by 
68 percent while the activity index is depressed 
by 65 percent . 

George Post 

Colorado State University, 
Contractor 

PESTICIDE INDUCED MINERAL IMBALANCE 
IN FISH 

Comments of both inside and outside review- 
ers on the tentative manuscript entitled, "Poly- 
valent mineral imbalance in organs and organ 
systems of cutthroat trout induced by intermit- 
tent chronic exposures to endrin," are in the 
process of being reconciled and resolved. 

A segment of the above report has been pre- 
pared under the title of "Significant prolongation 
of coagulation time of blood of cutthroat trout 
induced by intermittent chronic exposures to 
endrin." This report has now had its first intern- 
al review and is being revised in preparation for 
its second internal review . 

Eugene T . Oborn 



17 



METHODOLOGY IN CHEMICAL ANALYSIS 
AND SAMPLING 

We made considerable progress in develop- 
ing a promising, easily automated technique for 
cleanup of fish extracts that may bring about 
appreciable savings in money and manpovirer. 
The method uses the gel permeation principle, 
but differs from typical adsorption chromato- 
graphy because separations are based on mole- 
cular size rather than polarity. This eliminates 
the need for strong chemical or physical condi- 
tions, thereby reducing the possibility of com- 
pound degradation. Sample cleanup is accom- 
plished thru the use of a gel permeation column. 
This method will be entirely operational when 
additional data concerning recovery efficiency 
are generated over the next few months . 

Recently, we began to evaluate an analyti- 
cal procedure which gives much greater recov- 
ery efficiencies than classical partition methods. 
This technique is based on liquid/liquid parti- 
tioning, but differs from classical partition 
extracts . One phase is contained in a long tube 
and the other phase is introduced as small drop- 
lets which travel thru the tube . Our work with 
this procedure is in the initial development 
phase. 

An improved method of girinding fish sam- 
ples was devised by Pete Benville, chemist at 
Tiburon. Initially, large samples of fish are 
chopped into pieces , and then blended with dry 
ice in a stainless steel blender cup. This mix- 
ture is stored overnight in a freezer to allow 
the dry ice to sublime and the resulting fish 
powder is extracted. We anticipate that use of 
this procedure will increase the efficiency of 
our analytical section. In addition, it led to 
trials of a new extraction procedure which uses 
1:4 mixture of fish and anhydrous sodium sul- 
fate. The mixture is placed in a chromato- 
graphy column and the pesticides are then 
eluted with an appropriate solvent . Recoveries 
are generally comparable to, or better than, 
those obtained with previous techniques. 

Partition values for different types of fish 
fat were determined with two solvent systems. 



This information, which is of value in method 
design, will be published soon. 

Several procedures described in the liter- 
ature for cleanup of pesticide samples were 
tested and found inadequate for analyses of fish 
tissues . Among the procedures evaluated were 
florisil chromatography, partitioning, channel- 
layer chromatography, several versions of 
forced volatilization techniques ( sweep -codistill- 
ation), and low temperature precipitation. 

Our gas chromatograph-mass spectrometer 
(GC-MS) (Figure 4) was installed in August and 
we were successful in obtaining limited numbers 
of mass spectra of the more commonly used 
pesticides. GC-MS examination of several of 
the polychlorinated biphenyl (PCB) compounds 
revealed they were complex mixtures of biphenyls , 
substituted with 2, 3, 4, 5, or 6 chlorine atoms. 
Using GC-MS we were able to determine the pre- 
sence of DDT in a synthetic mixture of PCB 
compounds . 

Chlordan was also examined by GC-MS, but 
elucidation of the many isomers and compounds 
composing this material is not yet complete. 
This Instrument has greatly increased our abil- 
ity to study the effects of pesticides on fish and 
the breakdown of pesticides in aquatic ecosys- 
tems. 

This year, greater emphasis was placed on 
the development of analytical methods for 
herbicide residues, because as yet, residue 




Gas chromatograph-mass spectro- 



tolerances in fish have not been established 
by Food and Drug Administration. The benzyl 
ester derivative of dalapon was found to be suit- 
able for GLC . However, while working with 
aqueous solutions of this herbicide, we discov- 
ered that it may degrade quite rapidly in water. 
For instance, 60 percent of 1,000 mg of "C- 
dalapon in 1 liter of water was hydrolyzed to 
pyruvic acid after standing 1 month at room 
temperature. Degradation is greatly reduced by 
storing dalapon solutions in the dark at 2 to 3° C . 

We developed a method for analysis of 2,4- 
D dimethylamine salt (2,4 -D DMA) in fish tis- 
sue which gives recoveries of 84 + 3 percent 
with spiked samples. This method uses acidic 
methanol (H3PO4) extraction for cleanup; analy- 
sis is as the methyl ester. Green sunfish were 
exposed for 1 to 3 weeks to a 5 mg/1 bath of ^'^C- 
2,4 -D DMA and analyzed. The free acid form 
of 2,4 -D accounted for approximately 5 percent 
of the total activity. We do not know the identity 
of the remaining radioactive compounds, but the 
radioactivity is distributed between at least 2 
compounds or groups of compounds . One of 
these compounds is relatively non-polar, having 
a polarity which is roughly comparable to the 
polarity of most organochlorine pesticides. The 
other compound, or group, is extremely polar, 
but apparently not charged . We think this group 
may contain different conjugates of 2,4 -D. 

Our work on the preparation of highly puri- 
fied solvents culminated with the publication of 
a paper entitled "Purification Procedure for Low 
Polarity Solvents ." 

We have completed a manuscript entitled 
"A Handbook of Standard Methods of Analysis 
for Pesticide Residues." This manuscript 
will be published as the first issue of Fish - 
Pesticide Research , a proposed new series . 

Roger Tindle, David Stalling, 
Robert Hesselberg, and 
Pete Benville 



HESTOPATHOLOGY SECTION 

Exposure of cutthroat trout ( Salmo clarki) 
to endrin at the Jackson NFH caused lesions in 
their gills, livers, pancreas, and ovaries. 
Extravascular edema, hemorrhage, and possible 
intracapillary congestion causing globe-shaped 
lamellae characterized the gill damage noted in 
fish exposed to the higher concentration of 
endrin. Hepatic lesions in young trout were of 
the type frequently described as preceding the 
development of hepatomas in trout . The 
increased incidence and severity of liver changes 
observed in fish exposed to the greatest amount 
of endrin by bath and in food suggested a nutri- 
tional deficiency enhanced by exposures to en- 
drin. In addition, these individuals had pro- 
nounced pancreatic islet hyperplasia and irre- 
gular, atypical oocytes. 

John A. McCann, biologist. Agricultural 
Research Service, Pesticide Regulation Division, 
Beltsville, Md., alerted our laboratory to a 
macroscopic redness occurring in the caudal 
region of about 60 percent of 5 to 6 cm bluegUls 
( Lepomis macrochirus) after exposure to 0.32 
mg/I Dyrene or 4 .9 mg/1 Akton. We duplicated 
this experiment at Columbia and took photographs 
of a non -exposed control and a bluegill which 
was exposed to 0.32 mg/1 Dyrene (Figure 5). 
In a preliminary microscopial examination of a 
transverse section of the hyperemic area, I 
found a partial recanalization of an occluded 
caudal artery, intermuscular hemorrhage, and 
degeneration of some muscle bundles . 

Lafayette EUer 

PESTICIDE ANALYSIS SECTION 

Our section has made residue analyses 
requiring more than 3,000 pesticide determina- 
tions on 1,500 of our research samples. These 
analyses have provided necessary information to 
determine the effects of pesticide on fish. Con- 
siderable analytical support has been given to 
the chemical methodology section . 



Our analytical capabilities were extended to 
at least 20 other government agencies. These 
agencies submitted 61 fish samples, 28 water 
samples , samples of two fish diets , and 4 



19 



FISH CULTURE SECTION 




The Fish Culture Section was established as 
a separate unit in July, 1969. This section 
acquired 371,185 fish of 21 species in 1969, held 
475,413 fish for research purposes, and assisted 
in planning projects using these fish. Incubation 
of 20,700 channel catfish and 58,172 rainbow 
trout eggs aided established work units . Over a 
ton of food was prepared throughout the year to 
hold these fish. The Division of Fish Hatcheries, 
Regions 3 and 4, the Southeastern Fish Cultural 
Laboratory, Marion, Ala., and the Fish-Farming 
Experimental Station, Stuttgart, Ark., gave us 
splendid cooperation in obtaining these valuable 
fish for research. 




Figure 5. — Non-exposed bluegill (top) and 
a bluegill exposed to 0.32 mg Dyrene''-/1 
for 17 hours (bottom). The encircled 
area on the lower photograph shows the 
grossly visible hyperemic area. 

sediment samples . In addition, 10 National fish 
hatcheries submitted a variety of samples for 
pesticide analysis . Typical results include the 
determination that experimental fish diets were 
highly contaminated with dieldrin at the NFH, 
Spearfish, S. D., saving considerable develop- 
ment time and effort; the NFH, Craigbrook, 
Maine, conceivably saved a year of production 
time by anticipating high mortalities from poten- 
tial pesticide residues in Atlantic salmon eggs. 
These analyses assist the agencies responsible 
for fish production and utilization. 



The appearance of gravid, female channel 
catfish in August provided me with the opportun- 
ity to spawn these fish much later than normal. 
Four pairs of two -year -old channel catfish 
spawned in late August and early November . 
Feeding high -protein diet, holding parent fish at 
low temperatures, and gradually increasing the 
temperature in the proper sequence were criti- 
cal in bringing about spawning at this time . The 
induction of young fish to spawn took less time, 
money and space than spawning large brood 
stock in the IV to X age classes . Use of this 
technique will make gram size channel catfish 
available for mid -winter research and allow 
catfish farmers to delay channel catfish spawn- 
ing until convenient. 

Incubation of paddlefish eggs provided by 
the Missouri Department of Conservation at 
17 .2 C . for 5 days produced 500 sac fry. Some 
of the problems we encountered included egg 
sensitivity to strong light, pronounced adhesive- 
ness of green eggs, and fungus infections . 
Malachite green treatments of the eggs for fun- 
gus at 17 mg/1 for 10 min. has no effect on 
embryo development, but the fry did not accept 
artificial food and died. 

Jim Brauhn 



Robert Hesselberg 



COOPERATIVE RESEARCH STUDIES 

Determination of pesticide residues in fish 
from Lewis and Clark Reservoir assisted a 
study being conducted by the University of South 
Dakota on bald eagle populations . 

We provided bioassay services for testing 
38 compounds from 13 chemical companies, 3 
compounds for the U. S. Coast Guard, Dyrene 
for U . S . D . A . , and additional compounds from 
Fishery Services (Portland, Ore.); States of 
Wisconsin and Colorado; Stauffer Chemical 
Company; FWPCA (Alaska); American Cyanamid 
Company; and Radiant Electric Cooperative, Inc. 
(Kansas) . 



Herman Sanders cooperated with the 
Division of Fishery Services, USAF, and the 
Division of Forestry, U. K., in shipping stocks 
of fish -food Crustacea to be used for populating 
Lake Furnas in the Azores . 

Lafayette Eller contributed photomicrographs 
to Dr. Lawrence Roder, Argonne National 
Laboratories, Inc., to be included in a proposed 
text book, "Diseases of Laboratory Animals , " 
Vol. I. 



Dr. Stalling participated with Dr. Charles 
Gehrke, University of Missouri, in the Organic 
Analysis Consortium, NASA, Ames Research 
Center, in analyzing lunar samples from the 
Apollo 11 space flight. A new class of organic 
compounds, organosiloxanes, was discovered. 



21 



FISH CONTROL LABORATORIES 

La Crosse, Wisconsin 
Robert E. Lennon, Director 



HIGHLIGHTS 



INTRODUCTION 



Research at La Crosse was interrupted for 
the third time in five years by flooding of the 
Mississippi River, but there was no property 
damage . 

Quinaldine sulfate, a water-soluble salt of 
quinaldine, is under development as a fish 
anesthetic. A synergic mixture of MS -222 with 
quinaldine sulfate is a highly effective anesthetic, 
having the quick knockdown rate of MS -222 and 
the extended holding time of quinaldine sulfate . 
Residues of quinaldine in anesthetized fish are 
reduced to background level in less than 24 hours 
after withdrawal . 

Fiel^i trials in Florida indicate that walking 
catfish (Clarias sp.) are not repelled by anti- 
mycin, but the fish are as resistant to the toxi- 
cant as bullheads . 

Bioassays in flowing water revealed that 
fish are killed by much shorter exposures to 
antimyciti than to rotenone . 

Continuing work on the biological activity of 
toxicants and anesthetics shows that the pH of 
the solution is critical in governing passage of 
a chemical through the gUl into the fish. 

The Laboratory at La Crosse hosted the 
Bureau's first Workshop for physiologists and 
biochemists . 

We accepted a contract from FAO to do a 
review of toxicants in fish management . 



The Urban Renewal Authority of La Crosse 
and the Army Corps of Engineers have forced us 
to consider the future of the Laboratory. The 
principal reason for concern is the Harborview 
Plaza Urban Renewal Project that includes a por- 
tion of Riverside Park where we are located. 
Some of our basic utilities, such as municipal 
water, sewage, electricity, and telephone, pass 
through the Project Area . We face interruptions 
of utility service as well as limited capacities. 
The Project got underway in 1969 , properties 
were purchased, some buildings were demolished, 
and accelerated activity is scheduled for early 
1970, There is a possibility that public or com - 
mercial developments peripheral to the UR 
Project Area will impinge further on Laboratory 
property or operations . 

The second major reason for concern is 
the Corps of Engineers' plan to deepen the 
Mississippi River channel from 9 to 12 feet soon, 
and to 15 or more feet later . The City may elect 
to use dredge spoil to raise the level of Riverside 
Park above flood stage or to erect a permanent 
levee to protect the Park. Either approach would 
leave the Laboratory in a hole, literally. 

The City prefers we move the Laboratory to 
another site in La Crosse and will aid us in 
doing so . We prefer this approach because we 
need more laboratory space and experimental 
ponds to study chemical, biological, physical, 
and integrated controls for fish. Then, 
Wisconsin State University --La Crosse proposes 
that the Bureau and University cooperate to ac- 
quire a site and construct a fishery center, to 
include the Fish Control Laboratory, University 



22 



facilities for teaching and research in aquatic 
biology, and a headquarters office for the 
Mississippi River Research Consortium. A 
public aquarium and visitor center may also be 
appropriate. City and State authorities have 
approved the proposal, and Congress appropri- 
ated a small sum for preliminary planning. 
The staff has assembled 129 pages of plans and 
drawings into "A Proposal for Expansion of the 
Fish Control Laboratory," and copies were sub- 
mitted to Washington. 

The third major flood in 5 years occurred 
on the Upper Mississippi in April. The Labora- 
tory began sandbagging and other preventive 
activities on March 31; and arrangements were 
made with the City, Civil Defense, Corps of 
Engineers , and Coast Guard for mutual aid 
(Figure 1). Our experimental work ceased on 
April 14 . The flood crested on April 20 below 
the predicted level, but the water lapped within 
one foot of the Laboratory building (Figures 2, 
3, and 4). The flood receded rapidly which 
enabled us to start restoring the Lab to operable 
condition. Services and equipment were re- 
installed, new supplies of fish obtained, and 
experiments resumed during the second week of 
May. There was no property damage, and the 
only loss was that of research time. This was, 
however, the third flood -related interruption of 
research, and it strengthens arguments for 
relocation of the Laboratory to another site in 
La Crosse. 

We marked the fifth anniversary of research 
and efforts to get MS -222 registered as a fish 
anesthetic. The sponsoring company submitted 
a revised application for registration in July, 
but we have no word on its fate . The mechanics 
and time involved in registering fishery chemi- 
cals are discouraging. 

Six students were employed part-time, 
including four majors in chemistry, one in bio- 
logy, and one in education. Two faculty mem- 
bers were also employed part-time. We 
served as advisors on five research projects 
conducted by non -employee students . 

We renewed a contract with the Biology 
Department, Black Hills State Teachers College, 
Spearfish, S . D. , for a study on "The effects of 




Figure 1. — Black River Falls, Wisconsin 
Boys Camp enrollees, filling sandbags for 
flood protection in the pool area at the 
Laboratory. Photo taken by Bernard L. 
Berger . 




Figure 2. — Water level of 15.4' on the road 
southwest of the Laboratory on April 18. 
This was .4' below the flood crest of 
15.8 which occurred on April 20. Photo 
taken by Bernard L. Berger. 



23 




Figure 3. — Water level of 12.4' at the 
northwest corner of the Laboratory on 
April 18, .4' under the flood crest of 
15.8' which occurred on April 20. Photo 
taken by Bernard L. Berger. 




Figure 4. — Polyethylene and sandbags placed 
to protect loam and levee north of the 
Laboratory and Garage. Water level 15.4' 
on April 18, .4' below the April 20 crest 
of 15.8'. Photo taken by Bernard L. 
Berger. 



magnetism on rainbow trout." We accepted a 
contract from the Food and Agriculture Organi- 
zation of the United Nations to do a review of 
chemical means and methods used in fish control 
throughout the world in the past 30 years . This 
task is to be completed in the first half of 1970. 

We provided advice and reviews on contract 
research by the Wisconsin Alumni Foundation 
for the Wisconsin Department of Natural 



Resources and by Wisconsin State University- 
La Crosse for the Max McGraw Wildlife Founda- 
tion. Antimycin played a large role in both 
studies (Figure 5). 

Sixteen papers were published and 21 are in 
press. Seven special reports were completed. 
Fifteen major talks and many minor talks to 
tour groups and local organizations were pre- 
sented. 

Two staff members were appointed to 
faculty status at Wisconsin State University-La 
Crosse. We also hold appointments to commit- 
tees in the National Academy of Sciences, 
Wisconsin Research Advisory Council, Wisconsin 
Scientific Areas Preservation Council, La Crosse 
County Civil Defense Office, and the American 
Fisheries Society. An appointment to the 
Interior Taconite Study Group was terminated. 
Twelve staff members participated in 19 train- 
mg courses and 8 college courses . 




Figure 5. — A registered fish management tool 
researched by the Fish Control Laboratories 
and now being widely used. Photo by 
Bernard L. Berger. 



24 



Two Reports of Invention were submitted 
to the Department's Solicitor. 

There were 24 tours given to 1,306 people, 
11 talks to 339 people at La Crosse and Warm 
Springs. Two seminars were presented to 60 
people by personnel of both Labs . 

Robert E . Lennon 

SECTION OF CHEMICAL BIOASSAY 

Toxicity of potential control chemicals to fish 

Preliminary static bioassays included 
experimental fungicides, bactericides, avicides, 
insecticides, chemotherapeutants , chemosteril - 
ity compounds, anesthetics, herbicides and a 
few reagent chemicals not designated for any 
specific use. Their activity ranged from lethal 
at 10 ppb to nontoxic at 100 ppm . Many of the 
chemicals show potential as fish toxicants . 
Some show species specificity while others are 
extremely toxic to all species of fish. The po- 
tential preliminary candidates were selected 
for delineation under controlled test conditions 
of water hardness, temperature, and pH. 

Quinaldme sulfate (QdS04) 

Quinaldine is a common fish anesthetic. 
Its advantages include economy and safety to 
fish under long exposure. Its disadvantages are 
insolubility in water, disagreeable odor, slow 
anesthesia, and liquid form. Chemists at the 
Warm Springs Laboratory improved the anes- 
thetic by treating quinaldine with sulfuric acid. 
The result is quinaldine sulfate, a water-solu- 
ble powder easier to use and with far less dis- 
agreeable odor. A product description and 
structure identification have been prepared at 
Warm Springs. The data include UV, infrared, 
and mass spectra of the compound as well as the 
test for sulfates, elemental analysis, melting 
point, and purity as determined by acid equiva- 
lents. Additional work on the toxicity, efficacy, 
and residues of quinaldine sulfate is underway 
at La Crosse and Warm Springs to register the 
compound. 

Quinaldine sulfate was tested against fish 
to establish toxic concentrations . Because 



previous testing at the Laboratory showed 
quinaldine is less toxic and less efficacious in 
acid pH water, we investigated the fate of quinal- 
dine sulfate in different water qualities . The pH 
in very soft water drops from 6.55 to 3.86 with 
80 ppm of quinaldine sulfate. In harder waters 
the pH is more stable and drops only 1 pH unit 
in very hard water (Table 1) . Extremely high 
concentrations are necessary to kill rainbow 
trout in very soft water (Table 2) . The 1-hr . 
LC^Q was not determined because no fish died 
at 140 ppm, the highest concentration tested. 
At this concentration, the pH was 3.35. Thus, 
the toxic effects are diminished in acid water. 
Temperature is not as critical as pH and salt 
content of the test water in altering activity . 
In 1-hr. exposures, QdSO^ is more toxic to fish 
at 7 C. than at other temperatures, but in 96 -hr. 
exposures, it is more toxic at 17 C. 

Salicylanilides as fish toxicants 

High pH in some natural waters limits the 
effectiveness of fish toxicants . We are attempt- 
ing to develop new toxicants that can perform 
satisfactorily in water at pH 6.0 to 10.0. Some 
salicylanilides are biologically active in high, 
low, and neutral pH waters . In our recent bio- 
assays, salicylanilides with phenyl- and tertiary 
butyl- substitutions in addition to hydroxy-, 
nitro-, halo-, and alkyl- groups were highly 
toxic , offering chemical stability in problem pH 
waters . I selected 6 salicylanilides whose 
toxicity and persistence is influenced by differ- 
ent pH conditions (Table 3). All showed poten- 
tial as general toxicants in preliminary tests, but 
in further tests some did not perform acceptably 
at high or low pH's. Persistence of these chemi- 
cals at pH 6.0 to 10.0 was checked by aging a 
series of bioassay solutions for a week before 
adding fish. Another series of fresh reference 
solutions were bioassayed concurrently with the 
aged solutions using bluegills from the same 
source. The LCjq was calculated for each 
series and the deactivation index, a measure of 
inactivation, was derived by dividing the LCcq 
of the aged test by the LC^q of the reference 
test. Index values near 1.0 indicate little deacti- 
vation within 1 week, whereas larger numbers 
such as 10 to 15 indicate more rapid deactivation. 



Table 1. — The influence of quinaldine sulfate on pH in soft 
and hard waters. 



Quinalc 


line 
(ppm) 


pH in 


various wat 


er qualit 


ies 


i/ 


sulfate 


Very soft 


Soft 


Hard 


Ve: 


ry hard 







6.55 


7.10 


7.78 




8.00 


5 




6.29 


6.92 


7.57 




7.82 


20 




5.65 


6.61 


7.30 




7.55 


40 




5.40 


6.22 


7.00 




7.39 


60 




4.02 


6.04 


6.87 




7.19 


80 




3.86 


5.67 


6.61 




7.01 



1/ 



Total hardness as CaCDo ranges from 10 ppm in very soft water 
to 320 ppm in very hard water. 



In Table 3 , the three chemicals on the right 
(Nos. 43489, 44016, and 52790) are p-chloro - 
phenyl -substituted, and their toxicity to bluegills 
is extremely diminished at pH 6. Cpd. 43057 
is toxic at all pH's but more so in acid and neu- 
tral waters. It is also persistent. Cpd. 42317 
is less toxic than most of the other salicylani- 
lides and is deactivated more rapidly at pH 9 
and 10. Cpd, 51294 shows greatest potential as 
a general toxicant. Its LC5o's range from 3.69 
to 13.50 ppb and deactivation indexes range from 
1.06 to 1.70 at pH's 6 to 10. This tertiary butyl- 
salicylanilide provides good killing power and 
persistence at all pH levels. 

These bioassays in chemically buffered 
solutions demonstrate that closely related chemi- 
cals differ significantly in toxic activity and 
persistence--themical structural configurations 
are important to biological activity. The 
studies also demonstrate how potential toxicants 
can be eliminated in the laboratory before use 
in field trials . 



solutions. More resistant fish are exposed to 
fresher solutions of antimycin while more sensi- 
tive species are exposed to aged solutions that 
have become inactivated to some extent. LCcq's 
are determined for the fish in aged solutions and 
also in concurrent reference tests containing a 
known series of concentrations . The percent 
reduction in LCjq's reflects the rate of inactiva- 
tion. The percent concentration remaining in a 
bioassay at a selected exposure is found by sub- 
tracting the percent reduction from 100. The 
procedure is illustrated by the following mathe- 
matical relationship: 

Percent concentration remaining = 100 - 



(^1 



-2)100 



where 



C, = LCcQ of aged solution 

C2 = LC5Q of reference solution 



Antimycin: Half -life of biological activity 

Knowledge on the persistence and degrada- 
tion of antimycin in water is incomplete, 
especially in high pH waters known to influence 
deactivation. Analytical methods do not detect 
very low concentrations of antimycin in water. 
However, we must know how long the antibiotic 
remains at toxic levels In water of different 
pH's . We have developed a method to estimate 
the half -life of biological activity by testing 
differentially sensitive fishes in aging bioassay 



The half -life of biological activity is found by 
plotting the percent concentrations remaining 
against time on cyclic semi -logarithmic graph 
paper . 

We have used this method to estimate half- 
life of antimycin in waters chemically buffered 
to maintain pH's of 6 to 10 (Figure 6). At pH 6, 
the half -life of biological activity is 310 hours, 
but at pH 9, 9 .5 and 10 the half -lives are 8 .7, 
4.6, and 1.5 hours, respectively. Half -lives 
may be even more brief in certain natural waters 



26 





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Figure b. — The half -life of biological 
activity of antimycin at different pH's. 

Antimycin inactivation 

In previous tests antimycin appeared to be 
inactivated rapidly by high pH. They did not 
differentiate, however, between irreversible 
and reversible inactivation. In attempts to 
delineate the type of inactivation, we introduced 
bluegills at different times into bioassays of 
antimycin at pH 9 . Concurrently, in another 
series, bluegills were introduced into bioassays 
in the same manner except that the solutions of 
antimycin were rebuffered from pH 9 to pH 7 
just before adding fish. Figure 7 shows that 
antimycin is rapidly inactivated at pH 9, where- 
as its activity is restored almost completely 
when the solutions are rebuffered down to pH 7 . 
Thus, the antimycin had not decomposed signi- 
ficantly, but the high pH water inhibited its 
killing power. Under conditions of fluctuating 
pH In natural waters, a presumed sublethal con- 
centration of antimycin could become toxic to 
non-target organisms if the pH were to shift 



from basic to acid after the toxicant is 
applied. 



6' 



u 2 




2 

TIME 



IN 



HOURS 



Figure 7. — The toxicity of antimycin to 
bluegills introduced to the bioassays 
from to 6 hours following antimycin 
addition. Reference tests at pH 9 are 
represented by (+) and tests in water 
rebuffered from pH 9 to pH 7 are repre- 
sented by (0) . 

In addition to pH, the ion content of the 
water has been reported to influence the inactiva- 
tion of antimycin. Salts of NaHC03, MgSO^, 
CaSO^ , and KCl were individually eliminated or 
increased by eight tunes their normal concentra- 
tion in the test waters . The pH and alkalinity 
were monitored throughout the tests to more 
accurately assign the influential ions. The pH's 
were controlled with chemical buffers when 
necessary. Results in tests with rainbow trout 
and bluegills showed that deletions of MgSO^, 
CaSO^ , and KCl had very little influence upon 
the toxicity of antimycin, or the pH and alkalinity 
of the solution (Table 4) . By eliminating NaHC03, 
the antimycin became more toxic and the pH and 



29 



Table 4. — Toxicity of antimycin to fish in controlled pH solutions at 12 C. 





Changes in 




Total alkalinity 


96-hour 




routine 




as CaCO, 
(ppm) 


(ppb9 


Species 


test water 


pH 


Rainbow trout 


None 


7.30 


30 


0.048 




Buffered 


7.10 


88 


0.038 


„ 


Eliminated NaHCOj 


5.50 


2 


0.027 


" 


Eliminated NaHCO^ 
and buffered!/ 


7.10 


8 


0.040 










,, 


8 X NaHCOj 


8.18 


220 


0.083 


" 


8 X NaHCOg 

and buffered — 


7.11 


256 


0.040 










Bluegill 


None 


7.30 


30 


0.220 


" 


Buffered 


7.10 


89 


0.208 




Eliminated NaHCOj 


5.30 


1.2 


0.057 


" 


Eliminated NaHC03 


7.15 


65 


0.200 




and buffered^./ 








•• 


8 X NaHC03 


8.15 


220 


0.468 


" 


8 X NaHCOo 

and buffered— 


7.10 


256 


0.258 











1/ 



TRIZMA*-'^-' buffered 



2/ 



Phosphate buffered 



alkalinity dropped significantly. The reverse is 
true when NaHCOo concentrations are increased. 
However, when strong bicarbonate solutions 
were pH buffered to near original levels, they 
regained toxic activity against rainbow trout to 
routine test water. The LC5Q of antimycin in 
water lacking NaHCOo is 0.027 ppb whereas that 
value is 0.040 ppb in buffered tests. The LC5Q 
for rainbow trout in water with eight times the 
NaHCOg is 0.083 ppb, whereas it is 0.040 ppb 
again in buffered tests. Thus, NaHC03 influ- 
ences the toxicity of antimycin against fish 
through pH manipulations only. 

Fish therapeutants 

Furpyrinol, 6 -hydroxymethyl 2 [2-nitro- 
2-furyl) vinyl ] pyridine, a potential bacteri- 
cide from Japan was checked for its toxicity to 
fish. This compound is presently undergoing 
clearance for use in fisheries. The bacteri- 
cide is not very toxic to trout, especially in 
short exposures (Table 5). Few fish died before 
24 hours in saturated solutions (100 ppm) of the 
compound, but rainbow trout, carp, black bull- 
heads and sunfish died within 72 hours. Also, 



compound is less toxic to rainbow trout in colder 
and harder water. The results of the toxicity 
tests are encouraging for eventual use of this 
therapeutant . 

Juglone in different pH waters 

Juglone, an extract of walnut, was tested 
against black bullheads in reconstituted waters 
at pH 6.0, 8.0, 8.5, 9.0, and 9.5 to determine 
its rate of inactivation. The bullheads were 
added to a series of newly prepared solutions of 
juglone and also to identical solutions which had 
aged one week. Juglone is effective against 
bullheads in the fresh solutions at about 100 ppb 
regardless of the pH . In the aged solutions , 
however, approximately double the amount of 
juglone was required to kill the fish at pH 9 ,0. 
At pH 9 .5 , bullheads were not completely 
eliminated at 1.0 ppm. The tests show that jug- 
lone is inactivated much faster at high pH than 
at low pH. The compound continues to show 
promise as an effective toxicant, especially in 
alkaline situations. No company is sponsoring 
this candidate toxicant, the cost for synthesized 
material is extremely high , and only research 
quantities are available or practical at the 
present time. 



Table 5. — Toxicity of 10-percent Furpyrinol (P-7138) to rainbow trout 
in different water qualities and temperatures 



Water 


Temp. 
(C.) 


LC50 and 95- 


-percent confidence 


interval (ppm) at 


hardness 


24 hours 


48 hours 


96 hours 


soft 


7 


61.89 
54.78-69.92 


35.00 
27.47-44. iv 


15.91 
12.51-20.23 


soft 


12 


50.40 
47.45-54.58 


44.00 
40.78-47.48 


15.89 

14.04-17.98 


soft 


17 


31.24 
26.49-36.85 


11.15 
9.87-12.60 


7.32 
6.00- 8.93 


very soft 


12 


1/ 


1/ 


7.40 
5.61- 9.77 


hard 


12 


46.60 
40.63-53.44 


15.89 
13.05-19.34 


8.13 
6.89- 9.59 


very hard 


12 


114.90 
91.49-144.30 


21.25 
18.91-23.88 


12.23 

10.56-14.17 



— Inconsistent mortality prevented data analysis. 



Toxicity of herbicides to fish 

Thirteen potential aquatic herbicides were 
tested against rainbow trout, goldfish, carp, 
black bullheads, channel catfish, green sunfish, 
bluegills and yellow perch. Most of the com- 
pounds are ethers of a Ikyl -substituted amines 
and are not particularly toxic to fish. One 
shows selective toxicity to carp. Several have 
been selected for further delineation. The 
sponsor is also working with the U. S. D. A. 
at Fort Lauderdale, Fla., and other research 
agencies in attempts to develop an aquatic herb- 
icide safe in the presence of fish . 

Toxicity of potential control chemicals to fish 
eggs 

Six chemicals were tested against recently 
spawned rainbow trout eggs in reconstituted 
water at 12 C. Twenty-five eggs were exposed 
to each concentration in 2.5 liters of solution. 
Juglone is the most toxic of the materials tested 
and zinc sulfate is the least toxic (Table 6). In 
additional tests , juglone killed eggs equally well 
in very soft and very hard reconstituted water 
and also in water that was buffered to pH 9 . 



Cadmium sulfate kills the rainbow trout 
eggs at 5 ppm and does not appear as toxic as 
copper sulfate. Our previous tests, however, 
indicate that trout fry are more susceptible to 
cadmium sulfate than to copper sulfate. Fry 
died upon exposure to 5 ppb of cadmium sulfate 
but approximately 0.1 ppm of copper sulfate was 
required to kill them under similar conditions. 

Leif L. Marking 

SECTION OF EFFICACY -- LABORATORY 

Intfensive screening of fish control agents 

Anesthetics 

Salmon and trout . The anesthetic combina- 
tion of MS -222 and quinaldine sulfate was tested 
extensively during the year on 5 salmonids 
(Figure 8) . MS -222 by itself anesthetized fish 
rapidly but exposure times must be brief to avoid 
mortalities . Quinaldine sulfate anesthetizes 
fish slowly, but affords longer holding times 
with safety. The mixture then does provide the 
advantages of quick anesthesia and long holding 
time. 



31 



Table o.--The toxicity of chemicals to recently spawned eggs 
from rainbow trout 





Lethal 


concent rat 


ions (ppm) 


in exposures 


. of 


Chemical 


5 days 


10 days 


15 days 


20 days 


25 days 


Juglone 


0.10 


0.10 


0.07 


0.07 


0.05 


Squaxin 


>1.0 


>1.0 


>1.0 


>1.0 


0.4 


Methyl testosterone 


^20 


5^20 


>20 


>20 


6 


Copper sulfate 


>10 


1.0 


1.0 


0.4 


0.4 


Cadmium sulfate 


>30 


30 


30 


5 


5 


Zinc sulfate 


>30 


>30 


>30 


20 


10 




Figure 8. — Charles Ustby checking the 
effect of the new anesthetic mixture 
quinaldine sulfate and MS-222 on rainbow 
trout. Photo taken by Bernard L. Berger. 

Mixtures of 20 to 60 ppm of MS-222 with 5 
to 20 ppm of quinaldine sulfate demonstrated 
synergism by being 3- to 5 -fold more effective 
on coho salmon, rainbow, brown, brook and 
lake trout than the individual components . Fish 
in concentrations causing complete loss of 
equilibrium within 3 minutes were exposed for 
periods up to 60 minutes in waters of 7 to 17 C. 
with good recovery. Although less chemical is 



required to anesthetize salmonids at increased 
water temperatures , total safe exposure time is 
reduced. Rapid anesthesia, or loss of reflex 
within 2 minutes in rainbow trout requires a 
50:20 ppm of MS-222:QdS04 mixture. 

Water hardnesses from 12 to 350 ppm of 
calcium carbonate had little Influence on the 
anesthetic properties of MS-222:QdS04 to rain- 
bow trout . However , in very soft waters the pH 
is lowered markedly by the addition of eff ica - 
cious concentrations of the mixture which in turn 
render the solution less effective on fish. Buf- 
fering the solutions back to pH 7.0-7.4 with 
sodium bicarbonate produces a normal response . 

hi late fall, MS-222:QdS04 was employed in 
practical applications at 5 State and National 
fish hatcheries . The anesthetic combination 
was incorporated into the spawning operations on 
coho salmon, rainbow, brown, brook and lake 
trout. A desired effect was moderate to rapid 
anesthesia within 3 minutes. Efficacious con- 
centrations ranged from 20 to 40 ppm of MS-222 
in combination with 5 to 10 ppm of quinaldine sul- 
fate to render the spawners manageable (Table 
7). Adult lake and brook trout required the high- 
est concentration of MS-222:QdS04 (40:10 ppm) 
for adequate knockdown while coho salmon suc- 
cumbed at 20:10 ppm . Recovery of all salmonids 
occurred within 2.5 to 8.0 minutes in fresh water 
and the majority of the fish were swimming up- 
right within 4 minutes . 

A 20:10 ppm mixture of MS-222:QdS04 was 
tested on 4 -inch lake trout at the Jordan River 
National Fish Hatchery in Michigan. The object- 
ive was to determine the value of the anesthetic 
mixture in large-scale, fin -clipping operations. 



ni 


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m 


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V a !i 



33 



The fish reached loss of equilibrium within 30 
seconds, a desirable characteristic in fin clip- 
ping, and fish exposed to the solution for 30 
minutes suffered no mortalities . 

Samples of muscle tissue were collected 
from fish exposed to the anesthetics in the lab- 
oratory and in the field. In most cases, the 
fish were exposed for 5 .5 and 15 minutes to 
efficacious concentrations of quinaldine and the 
mixture of MS -222 and quinaldine, and the tis- 
sues were collected after 0, 1, 2, 4, 8, and 24 
hours of withdrawal. On occasion, a 48 -hour 
withdrawal sample was taken. The tissues were 
analyzed for anesthetic residues at Warm 
Springs . 

Warmwater fish . In preliminary testing of 
the anesthetics on warmwater species including 
northern pike , carp, black bullhead, channel 
catfish, bluegill, largemouth bass and walleye, 
species require 50:10 to 75:20 ratios of MS -222: 
QdSO^ , This compares to a concentration of 
150 to 200 ppm of MS -222 when used by itself. 
Again, the duration of permissible exposure is 
increased when using the mixture. 

Toxicants 



The potentiation of antimycin with naled 
was investigated further. In outdoor trials, 
2 to 3 ppm of naled plus 10 ppm of antimycin 
were required to eradicate resistant fish in warm, 
hard and high pH waters . The high concentra- 
tions presented solubility problems, and lack of 
analytical techniques makes further testing of 
the combination doubtful. 

Collecting aid 

Propoxate was tested in outdoor, vinyl pools 
to determine its potential as a fish collecting 
aid. Stupefaction, slow recovery, inverted posi- 
tion, and settling to the bottom were typical 
responses of the fish. No repellency was ob- 
served. A concentration of 2.5 ppm was effi- 
cacious on salmonids, minnows, catfishes and 
centrarchids and compared well with laboratory 
findings. A 5 -minute exposure rendered most 
fish Immobile; however, goldfish and bluegill 
required 20 minutes . Fish exposed for 5 min- 
utes recovered in 30-45 minutes when placed in 
fresh water . 

Propoxate is affected little by high pH , e.g., 
2 .5 ppm in pH 8 .5 well water remained toxic to 
rainbow trout fingerlings for 3 weeks . 



Juglone was advanced in the research pro- 
gram because of its potential in eradicating 
black bullheads . We tested it in outdoor pools 
on 11 fish species. A concentration of 0.4 ppm 
was the minimum amount of juglone necessary 
to eradicate all target species Including the 
most resistant 12-inch black bullheads . Inacti- 
vation of the toxicant was apparent after 3 days 
because fingerling rainbow trout introduced at 
that time survived a minimum of 96 hours . 

A candidate salicylanilide was evaluated 
for its potential as a toxicant in high pH waters 
under outdoor conditions . The chemical was 
applied to 11 fish species at concentrations up to 
60 ppb at pH 8 .5 . It worked well at water temp- 
eratures as low as 40° F. Black bullheads along 
with all other fish were killed in 48 hours by 
40 ppb. No mortality occurred among fingerling 
rainbow trout that were introduced into the pools 
three weeks after the start of the experiments . 



Bernard L. Berger 

Lethal doses of antimycin 

The oral and injected lethal doses (LD50) of 
antimycin to rainbow trout were determined. 
Two groups of adult rainbows ranging in weight 
from 400 to 600 grams and 13 .1 to 13 .9 inches in 
length were used as test animals . One group of 
fish received selected oral doses of antimycin in 
gelatin capsules , and the second group received 
intraperitoneal (ip) injections of a 1 ml. ethanol- 
water solution containing selected doses of anti- 
mycin. After dosing, the fish were placed in 
flowing well water for observation. Results were 
as follows: 

Oral toxicity . The oral, 48 -hour LD50 of 
antimycin to adult rainbow trout was 2.50 mg/kg 
with a 95 -percent confidence interval of 0.76- 
8.25 mg/kg. 



Injected toxicity . The ip 48 -hour LD50 of 
antimycin to adult rainbow trout was 0,105 mg/ 
kg with a 95 -percent confidence interval of 
0.078-0.140 mg/kg. 

Judging from the bioassay immersion toxi- 
city data accumulated at this laboratory, the 
actual dose of antimycin required to kill rain- 
bow trout is in terms of i-ig/kg. The differences 
between immersion, oral and ip toxicity further 
illustrate the efficiency and importance of the 
gill and the role it plays in the entry of chemi- 
cals . 

Wayne A. Willford 

SECTION OF EFFICACY -- FIELD 

Evaluation of fish control agents in the field 

Minimum contact time 

Control of fish populations with toxicants 
requires that the target species be in contact 
with the chemical for a specific length of time. 
Concentration and contact time are equally 
important. In treating a stream, the bolt of 
toxicant moves downstream and the fish are 
exposed for the length of time it takes the bolt 
to p)ass any particular point in the stream. 
Thus , we must know how long an exposure to a 
given concentration is needed to eliminate the 
target species with a particular toxicant. 

We conducted tests in flowing water in a 
stainless steel trough to determine the minimum 
contact time to eliminate 100 percent of selected 
species of fish with antimycin and rotenone. 
The water had a total hardness of 220 to 250 ppm 
and pH of 7.7 to 7.9. The temperature was 
held constant at either 12 or 17 C . , + 1 C . We 
applied the chemical to the entering flow of 29 
liters of water per minute. Groups of fish were 
moved to another trough with flowing, fresh 
water after selected periods of exposure in the 
treated trough, and observed for approximately 
96 hours . 

At 12 C, the minimum contact time for 100 
percent mortality was much less with antimycin 
than with rotenone (Table 8). This was espec- 
ially true for carp and white suckers which are 



often target species. The concentrations of 
rotenone recommended by the manufacturer 
required up to 24 hours of exposure to kill carp 
whereas recommended rates of antimycin took 
only 6 hours , The exposure required for roten- 
one in water at 17 C. was 50 to 67 percent less 
than that needed at 12 C . 

Rotenone is generally considered a fast- 
acting toxicant. This is true if only initial re- 
sponse is the criterion because fish do exhibit 
distress and lose equilibrium rapidly. However, 
fish exposed to rotenone in these tests laid on 
their sides up to 12 hours or more but recovered 
when placed in fresh water. Conversely, many 
fish exposed to antimycin showed no distress 
when placed in fresh water, but died within 24 
hours . In no case did a fish recover after 
exhibiting distress for antimycin. 

Solid formulation of antimycin 

Major problems in treatment of streams 
with toxicants are the application of constant 
concentrations and the manpower needed to 
maintain the application apparatus. 

Ayerst Laboratories has produced experi- 
mental, solid-block formulations of antimycin 
designed to dissolve at a constant rate and 
eliminate the need for constant observation of 
application equipment. The blocks, which look 
like large chocolate bars , are composed of 
antimycin, sodium fluorescein, and a surface 
active agent. The sodium fluorescein inhibits 
the formation of antimycin crystals as the toxi- 
cant dissolves from the bar. 

' The formulations were tested in a river in 
central Wisconsin. Some bars dissolved at a 
constant rate and effectively eliminated caged 
carp in the treatment area. In blocks that did 
not contain enough sodium fluorescein, the anti- 
mycin formed a thick lattice of crystals around 
the bar, keeping it from further dissolution after 
a few hours . Improvements are being made in 
the formulations based on the results of the 
field trial. We think this innovation will consid- 
erably reduce the cost of manpower and equip- 
ment needed for stream treatments . 

Philip A . Gilderhus 



35 



Table 8. — Number of hours of exposure to antimycin 

and rotenone required for total mortality 

of selected species of fish 









Hours in rotenone 


at 




Temp. 


antimycin at 


50 


100 


250i/ 


Species 


(C.) 


10 


ppbi/ 


ppb 


ppb 


ppb 


Rainbow trout 


12 




1 


2 


- 


- 


Carp (small) 


12 




6 


- 


- 


- 


Carp (large) 


12 




6 


24 


18 


15 




17 




- 


10 


9 


5 


White sucker 


12 




4 


18 


15-17 


9 




17 




- 


9 


5 


3 


Black bullhead 


12 




_ 


_ 


21 


15 




17 




- 


9 


- 


3 


Green sunfish 


12 




8 


8 


- 


- 


Largemouth bass 


12 




6 


8 


- 


- 


Yellow perch 


12 




2 


- 


- 


- 



1/ 



2/ 



Fintrol-Concentrate (10 percent antimycin) expressed as active ingredient. 



— Nox-Fish (5 percent rotenone) expressed as active ingredient. 



Toxicants against Tilapia and Clarias 



SECTION OF FISH PHYSIOLOGY 



On-site bioassays of antimycin and rotenone 
were made in Florida against Tilapia aurea and 
T . Mossambica of 2 to 5 inches long . The 
species are more resistant to antimycin than 
largemouth bass and bluegills. 

Attempts to bioassay antimycin against the 
walking catfish ( Clarias batrachus) in Florida 
were thwarted by insufficient numbers of fish. 
Instead, two small ponds were treated with 50 
and 150 ppb of antimycin to determine if the 
walking catfish would attempt to escape as they 
reportedly do from rotenone applications , The 
species is as resistant to antimycin as bull- 
heads, and only a few 3- to 10-lnch specimens 
were killed by 150 ppb. None of the dying fish, 
however, tried to leave the pond. 



Effect of fish control agents on blood chemistry 
and hematopoietic tissue of fish 

Antimycin is known to exert its biochemical 
effects at the subcellular level by blocking the 
electron transport chain. In these studies 
(Table 9) , fish exposed to lethal concentrations 
of antimycin die in an acidotic state. The block- 
ing of oxidative phosphorlyation causes a build- 
up of lactic acid and glucose in the plasma, 
reduces buffering capacity of the blood (as mea- 
sured by the total plasma CO2) , and drops the pH 
of the blood to lethal levels (Figure 9). 

Richard A. Schoettger 



Ralph M . Burress 



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37 




Figure 9. — Chemist Wayne A. Willford utiliz- 
ing blood gas analyzer for measurement of 
blood pH and dissolved gases. Photo by 
Bernard L. Berger. 



produces the largest change in electrolyte con- 
tent of the brain. The changes which resulted 
from exposure to quinaldine ranked second in 
intensity, and methylpentynol the smallest 
change in brain electrolytes . 

Wayne A, Willford 

Effects of fish control agents on behavior of 
fish 

Cooperative studies with the Psychology 
Department, Wisconsin State University-La 
Crosse, on the influence of quinaldine on the 
rate of conditioning in bluegills have shown no 
differences between control and quinaldine - 
exposed fish. One consistent observation was 
the wide variation in individual learning ability 
in both quinaldine -treated and control groups . 



Effect of fish control agents on the central 
nervous system 

From previous studies we have shown that 
MS -222 anesthesia disrupts, either directly or 
indirectly, the in vivo cationic equilibria in the 
brain of rainbow trout. In an attempt to deter- 
mine if these electrolyte changes are peculiar 
to MS -222, we tested two additional anesthetics, 
quinaldine and methylpentynol, using the same 
experimental design. 

Similar changes in brain electrolytes occur 
with all three anesthetics. The most significant 
of these changes are a progressive loss of K"*" 
accompanied by a progressive increase of Fe"^ 
in the brain during the initial 2 minutes of expos- 
ure to the anesthetics . Longer exposures 
result in a return of brain K and Fe"^"*" towards 
control values. Concentrations of anesthetics 
used in this study also produced the greatest 
behavioral changes within the initial 2 minutes 
and little change occurring after this period. 
Thus, the pattern of change in electrolyte con- 
tent may be associated with the knockdown time 
of the particular anesthetic . 

The degree of electrolyte change also 
appears to be associated with the anesthetic 
state of the fish. MS -222, which produces the 
deepest anesthetic condition in fish, also 



Richard A. Schoettger 

Effects of fish control on the reproductive 
system of fish 

An attempt was made to sterilize bluegills 
by exposing them to diethylstilbestrol. We used 
younger fish and a more water soluble form of 
the chemical than in our previous tests. The 6- 
month-old bluegUls averaged 1.7 inches in 
length and 1.3 grams in weight. They were ex- 
posed for 10 days to a solution of the sodium salt 
of diethylstilbestrol diphosphate containing 0.3 
ppm of diethylstilbestrol . The fish were held in 
a raceway from January to May and then in out- 
door, 0.01 -acre pools from June to November. 
Three pools contained treated fish, and three 
with untreated fish served as controls . 

There was a considerable amount of natural 
reproduction in two of the three pools containing 
treated fish. Reproductive success appears to 
have been related to the ecology of the individual 
pools rather than the treatment of the fish before 
they were placed in the pools . Any further 
experiments with diethylstilbestrol wUl be done 
with fish in their first 60 days of life, i.e., at 
an earlier stage of gonadal development . 

Philip A . GUderhus 



38 



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Figure 10. — James Hixson and Les Chew 
collecting sperm for fertilization of 
eggs used in the bluegill sex reversal 
study. Photo by photographer, Warm 
Springs, Georgia Foundation. 



Attempts at sex reversal in bluegills by 
feeding methyl testosterone were continued at 
Warm Springs (Figure 10), All fish involved in 
last year's tests were sexed. The lot which 
received medicated feed for the first 60, post- 
hatch days at the rates of 10, 30, and 50 micro- 
grams per gram of feed was the only lot that 
may contain sex -reversed males. Six males 
from this lot spawned in plastic pools, and 
progeny grew well. Next spring, when the 
fingerlings have reached a desirable size, they 
will be sexed and the results of this phase of the 
experiment evaluated. 

There were few survivors in some of last 
year's tests, and one lot of bluegills was given 
feed containing 0, 25, and 50 micrograms of 
methyl testosterone per gram of feed for the 
first 30, post-hatch days. These rates of medi- 
cation were about equal to those used last year, 
and the period of treatment spanned the life 
stage at which survival had been lowest. Sur- 
vival was good this year, and there was good 
growth before cold weather , 

No attempts had been made to treat fry be- 
fore they were old enough to feed, and this 
could be the time sex direction occurs, so 4 lots 
of eggs and the resultant fry were treated with 
1, 2.5, and 5 ppm of methyl testosterone in a 



water bath for 7 days after the eggs were 
fertilized. Some fry survived both the 1 ppm 
and 2.5 ppm treatments. They were placed in 
plastic pools where good growth was attained. 

Fry from another lot were divided into 
three tanks , and received medicated feed for the 
first 30 days at the increased rates of 100, 250, 
and 500 micrograms of methyl testosterone per 
gram of feed. Still another lot was fed at iden- 
tical rates from the thirtieth to the sixtieth days 
of life. Survival was good in all lots that 
received medicated feed this year, and good 
growth was attained by late fall. 

Leslie E . Chew 

The fate of control agents in fish 

We previously determined (1968 Annual 
Report) that MS -222 concentrated in the brains 
of rainbow trout exposed to a 100 ppm solution 
at 12 C. In recent studies on rainbow trout 
anesthetized in a solution containing a mixture of 
MS-222-quinaldine sulfate (30:5 ppm) for 15 
minutes at 7, 12, and 17 C. MS-222 indeed con- 
centrated in the brain (brain to blood ratios of 
2.1, 2.1, and 2.6, respectively) while the blood 
concentration was that of the anesthetizing solu- 
tion. MS-222 residues were rapidly cleared 
from the brain during the first hour of recovery. 

Some 320 quinaldine residue analyses have 
been performed on five salmonids anesthetized 
with quinaldine sulfate, or a mixture of MS-222 
and quinaldine sulfate. At efficacious concentra- 
tions, the quinaldine residue level in all 
species is around 0.01 ppm at the end of 8 hours 
withdrawal and after 24 hours (Figure 11) . 

Some 220 MS-222 residue analyses have 
been performed on five salmonids anesthetized 
with MS-222 or the combination anesthetic by 
colorimetric analysis. Confirmatory analysis by 
thin layer chromatography is in progress. At 
efficacious concentrations, the MS-222 residue 
level in all species after 24 hours withdrawal is 
within the background reading of the control 
fish (Figure 12). 

John L. Allen 



+ 25 P.P.M. OF QdSQ, 



O— O 5 P.P.M. OF QdSO. + 



30 RP.M. OF MS -222 




12 3 4 5 

WITHDRAWAL IN HOURS 



r/-^- 



Figure 11. — Quinaldine residue in the 
muscle of brown trout at various with- 
drawals after anesthetization in 25 ppm 
of quinaldine sulfate or a mixture of 5 
ppm of quinaldine sulfate with 30 ppm of 
MS-222. 

Effects of fish control agents on the renal system 
of fish 

Anesthetics are often used in handling 
experimental animals. MS-222 is reported to 
affect Na and H2O balance in Bufo maritius 
following anesthesia. We have detected similar 
effects in rainbow trout by urinalysis following 
MS-222 anesthesia. Nine trout were anesthe- 
tized in a 100-mg/l solution, catheter ized and 
placed into a urine collecting apparatus . These 
fish were allowed to recover for 18 to 20 hours 
before collection of a 3 -hour urine sample 
which served as a control. Then, the trout 
were re -anesthetized in the collecting apparatus 
with a 100-mg/l solution for 5 minutes. Urin- 
analysis was made on samples of accumulated 
urine collected 2, 4, 6, 8, and 12 hours post- 
anesthesia (Table 10). Urine output (ml/kg/day) 
is increased following MS-222 anesthesia. Loss 
of inorganic ions also increases and the Na 




CONTROL 



2 4 6 

WITHDRAWAL 



IN 



10 
HOURS 



24 



Figure 12. --Free MS-222 residue in brown 
trout muscle at various withdrawals 
after anesthetization in a mixture of 5 
ppm of quinaldine sulfate and 30 ppm of 
MS-222. 

concentration in the urine parallels the urine 
flow pattern. Most ion concentrations return to 
control levels within 12 to 24 hours of recovery. 

Joseph B. Hunn 

Development of methods related to fish controls 

Control of pH 

Because water quality and pH in particular 
contribute to the inactivation of chemicals and 
because many natural waters are alkaline, we 
have developed chemical buffering formulations 
to simulate problem water (Table 11). Most 
chemical buffers are toxic to fish at high concen- 
trations; the amounts suggested in the literature 
were modified to accommodate the fish. The 
buffering materials and quantities are specifical- 
ly for our standard reconstituted water of about 
44 ppm in total hardness , and they may require 
alterations in other waters . These buffers 
maintain the pH within 0.2 of a unit with minor 



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41 



Table 11. — Buffer chemicals for maintaining pH in bioassays 



pH 



Ml. of solutions for 15 1. of water 



IK NaOH 


IM 


KH2PO4 


0.5M H3BO3 


1.3 




80.0 





10.0 




30.0 





19.0 




30.0 





19.0 




20.0 





12.0 




11.5 





8.8 







30.0 


11.0 







20.0 


Ib.O 







18.0 



6.0 
6.5 
7.0 
7.5 
8.0 
8.5 
9.0 
9.5 
10.0 



daily adjustments , and we determined they are 
not toxic to fish. Bluegills survive well in 
buffered water from pH 6 to 10, whereas rain- 
bow trout require special acclimation prior to 
being placed in high or low pH water. 

Leif L. Marking 

The addition of MS -222 to soft water 
depresses the pH of the anesthetic solution, and 
fish placed in it show signs of irritation. 
Stress and irritation can be alleviated by adding 
a buffer to raise the pH. 

The efficacy of quinaldine as an anesthetic 
is greatly influenced by pH . The efficacy ap- 
pears to be directly related to the concentration 
of the lipid-soluble free base of quinaldine. 
The quinaldine ion and quinaldine free base con- 
centrations at a given pH can be calculated from 
the published pKa value of quinaldine (5 .42, 5 .8) 



John L. Allen 



DO in vinyl pools 



We have observed sharp losses of dissolved 
oxygen, from 7 .5 ppm to >1.0 ppm, in new 
1,000-gallon polyvinyl pools immediately after 
set-up. The loss may be caused by plasticizers 
in the vinyl liner. To overcome the problem, 
we made polyethylene liners and compared them 
with polyvinyl liners by filling both with well 
water and making daily O2 measurements . 
After 9 days , water in the polyethylene pools 
had 7 or more ppm of dissolved oxygen in con- 
trast with 3 .1 ppm of DO in the polyvinyl pools . 



Black polyethylene liners demonstrated an 
ability to hold cooler temperatures in the 
summer. 

Bernard L. Berger 

Automatic data processing 

We have cooperated with the Division of 
Pesticides Registration to develop a storage and 
retrieval system for toxicity data. Our data, 
principally LC^q's, are summarized on abstract- 
or cards identifying chemical structure, test 
organism, test system, and references according 
to codes previously designed. The cards are 
submitted for automatic data processing (ADP). 
The data generated by cooperating agencies are 
useful to us, to other researchers, and to chem- 
ical registration. 

Leif L. Marking 

Dispersion of chemicals in streams 

The most convenient way to predict the 
behavior of a bolt of chemical in a stream is to 
apply a tracer material such as salt or fluores- 
cent dye and measure the buildup and decline of 
concentrations at different points on the stream . 
Whereas the tracer dyes are readily available, 
there is no accurate method for conducting the 
dye study, interpreting the results, or applying 
the results to compensate for losses of concen- 
tration and time. 

Studies have now been conducted in two 
streams to determine how long a tracer dye must 



be applied to give a true picture of the 
dispersion of an extended application of toxicant. 

Several factors have become evident in our 
studies. At any point on a stream, the concen- 
tration of dye builds from zero to a peak some- 
what gradually. The time required for the build- 
up is governed by the amount of stored water in 
the stream between application point and sam- 
pling point. The more stored water there is in 
pools, the longer the buildup time. In turn, 
the longer the buildup time, the shorter the 
time that the peak concentration is maintained. 
At any given concentration, the chemical must 
be applied for long enough to saturate the 
stored water before a true peak can be reached. 

In each stream , a brief application of dye 
(rhodamine-B) gave a much lower peak than a 
longer application in the same stretch of stream. 
For example, in one stream, a 15 -minute appli- 
cation of dye at 15 ppb gave an instantaneous 
peak of 2.6 ppb at the sampling point. A 4 -hour 
application of 15 ppb gave a peak of 9 .5 ppb 
which lasted 2 hours . If the short bolt of dye 
had been used in preparation for a reclamation 
of the stream , it would have indicated a much 
greater loss of both concentration and time than 
actually the case. Thus, the amount of toxicant 
then applied to compensate for the losses would 
be several times the amount needed. 

To obtain a true estimate of the peak con- 
centration, a tracer must be applied long 
enough to give a flat peak of at least 30 minutes 
duration at the sampling point . 

Dispersion of chemicals in lakes 

The surface waters of lakes , down to 
depths of about 20 feet, are comparatively easy 
to reclaim, especially with the newer granular 
formulations which release the toxicant evenly 
as they sink. Several States , however, need to 
treat lakes to depths of 100 feet or more . The 
only method available at present is to pump a 
liquid toxicant down through a weighted hose, 
but the adequacy of the method has not been 
thoroughly assessed. We therefore cooperated 
with the State of Minnesota to measure disper- 
sion of a liquid toxicant in deep waters of a 
small lake. 



Taylor Lake has an area of 54 .8 acres and 
a maximum depth of 84 feet. The upper 15 feet 
of water were treated with sand formulation 
antimycin. The water between 15 and 35 feet of 
depth was treated with liquid formulation anti- 
mycin to which rhodamine-B dye had been added. 
The amount applied was calculated to give 1 ppb 
of antimycin and 10 ppb of the dye in the 15 to 35 
foot stratum. The liquid was pumped through a 
single hose at various depths in that stratum as 
the boat traversed a grid pattern. Water sam- 
ples were taken at selected depths in the stratum , 
and the concentration of dye was analyzed with a 
fluorometer . 

Only 30 percent of the samples taken 24 and 
48 hours after treatment contained detectable 
amounts of dye. Thus, 70 percent of the water 
in the stratum contained inadequate concentra- 
tions of toxicant. Some samples contained over 
60 ppb of dye --this indicated the formulation had 
not moved much from the paths traveled by the 
hose. 

Seven days after application, the deep 
water was sampled again. All of the samples 
between 15 and 40 feet contained detectable 
amounts of dye, but 33 percent contained less 
than 5 ppb of dye or 0.5 ppb of antimycin. 

There is, therefore, some question whether 
a toxicant will remain biologically active until 
it becomes completely circulated or dispersed 
in deep water. In this lake, however, all of the 
target fish were killed including large white 
suckers and perch- -they probably were in the 
warm , top 15 feet of water . There is a real need 
for better methods of treating deep water . 



Philip A . Gilderhus 



Water analysis 



Cooperative studies with Hatchery Biologists 
at Genoa NFH to evaluate methods of water 
analysis resulted in both stations converting 
their methods of analysis for phosphates. Some 
minor alterations were also instituted in the 
analysis for ammonia. 

Wayne A . Willford 



43 



Methods in field bioassays 



RESEARCH FISH 



Development of methods for field bioassays 
are essential to well executed chemical treat- 
ment of lakes and streams . According to labor- 
atory tests of different kinds and sizes of con- 
tainers made of 6 different materials, glass 
jars, plastic bags, and plastic waste cans are 
best for bioassays . Of them, a 75 -gallon bag 
made of clear, 3 -mil polyethylene was chosen 
for further testing as a field bioassay container 
on the basis of utility, economy, and availa- 
bility (Figure 13) , 

Initial tests of the bags in the field were 
devoted largely to comparisons of water quality 
in ponds and bags . The bags appear to be 
entirely adequate for bioassay purposes, and 
several methods for filling, suspending, and 
protecting them were developed. 



We received many requests from outside 
agencies for test fish during 1969. Among them 
were the University of Minnesota, the Hormel 
Institute at Austin, Minn., Winona State College, 
the Hydrobiology Station at Winona, Minn. , 
Hatchery Biologists at Genoa NFH, and the chem- 
istry and biology departments at Wisconsin State 
University-La Crosse. 

Our main sources of test fish for La Crosse 
were the National fish hatcheries , supplemented 
with valuable contributions from the fishery 
departments of Wisconsin, Iowa and Minnesota. 
We received late spring and early fall rainbow 
trout eggs from Troutlodge Springs . We had 
good cooperation with all agencies . 



Three ponds were treated with antunycin on 
the basis of bioassay results. Subsequent eval- 
uation of the kills afforded a good basis for 
determining concentrations required for fish 
eradication. Additional tests will have to be 
made under a variety of conditions to further 
develop the method and to find suitable techni- 
ques for choosing concentrations required for 
selective control of fish populations . 

Ralph M. Burress 



Analytical methods for residues of fish control 
agents 

A thm layer chromatographic method of 
identification of quinaldine may be applicable to 
residues in fish. A positive test for quinaldine 
in extracts containing 0.1 ppm of quinaldine was 
Indicated by gas chromatography in preliminary 
investigations. The method consists of spotting 
the extracts on an alumina TLC plate, and 
developing the plate with 1 percent ethyl acetate 
in iso -octane. The plates are examined under 
long wave ultraviolet light after spraying with 
concentrated sulfuric acid and heating. The use 
of filters transmitting light from 415-490 m^. 
decreases the background fluorescence in fish 
extracts . 

John L. Allen 




Figure 13. — Biologist Ralph Burress and 
Biological Aid Jerry Moncrief conducting 
an on-site bioassay using anchored 70-gal.ta 
plastic bags that are surrounded by a 
seine enclosure. Photo by photographer, 
Warm Springs Georgia Foundation. 



Bioassay-size fish included bowfin, coho 
salmon (both Pacific and Lake Michigan strains), 
rainbow, brown, book, and lake trout, goldfish 
carp , fathead m innow , golden shiner , white 
sucker, channel catfish, black bullhead, mad- 
tom, central mudminnow, largemouth bass , 
green sunfish, bluegill, yellow perch and wall- 
eye. Eggs from coho salmon, rainbow trout, 
lake trout, and white sucker were used. We 
spawned some rainbow trout to furnish green 
eggs for the testing programs . More than usual 
numbers of large and medium sizes of rainbow, 
brown, brook, and lake trout were used in the 
anesthetic testing program. We also acquired 
other large fish, including shortnose gar, 
northern pike, and buffalo. 



usually control the disease. Internal parasites 
and columnaris in black bullheads, fungus in- 
fections on carp and goldfish, and an internal 
bacterial disease in white suckers were also 
encountered. Several lots of different species 
were discarded when we judged they were not 
worth treating. 

Everett W . Whealdon 

The Marion and Warm Springs National Fish 
Hatcheries were most cooperative and supplied 
most of the fish that we used at Warm Springs 
this year . One lot of rainbow trout was acquired 
from the Cooperative Fishery Unit at Auburn, 
Ala. 



Commercial pellets, Oregon moist pellets, 
ground beef liver, and frozen brine shrimp are 
used as feed. We raise live daphnia for feed- 
ing small fish the year around and maintain the 
culture during winter in the large public aquar- 
ium tanks. Small minnows from bait dealers 
furnish live forage for large northern pike, bass, 
bluegills and others . 

External parasites are the most trouble- 
some disease problems. Anchor worms (Ler- 
naea) have been almost eliminated from 1969 
shipments of carp and goldfish . Most other 
external parasites can be held in check, if not 
eliminated, with formalin treatments . Ichthyo - 
phthirius continues to be a major source of 
trouble. Warm water (85-95° F.), fast flowing 
shallow water, and frequent formalin flushes, 
used separately or in combination, depending on 
the species infested or the amount of infestation, 
have all been used to eradicate ich. In general, 
prevention is better than cure. 

An interesting development was the sudden 
appearance of furunculosis in green sunfish and 
mudminnow which had arrived and been held 
here in a healthy condition for some time. Con- 
tagion was traced to brown and rainbow trout 
which appeared to be healthy but were carriers . 
Bacterial gill disease is the most often encount- 
ered trouble in small trout. Rust precipitate 
in the water , crowding , or holding the feed level 
down to prevent fast growth can all bring on an 
outbreak of B. G. D. If caught in time, Roccal 
treatments and a few days of liver feeding will 



Largemouth bass , bluegills , and channel 
catfish were the most used species of fish, and 
some were on hand the entire year. Other 
species of fish used included rainbow trout, gold- 
fish, golden shiners, black bullhead, brown 
bullhead, striped bass, warmouth, green sunfish, 
and redear sunfish. 

Prophylactic treatments of salt, acriflavin, 
or formalin were administered to all fish shortly 
after arrival and occasionally throughout the 
year to prevent outbreaks of disease and para- 
sites . One lot of channel catfish infested with 
Ichthyophthirius was cleaned up by a daily flush 
treatment of formalin (1:4000) for 4 weeks . Mor- 
tality from columnaris was arrested in one lot 
of bluegills and one lot of black bullheads by a 
72 -hour treatment with 15 ppm of Terramycin. 

Commercial pellets were fed to most of our 
fish three times a week . This was supplemented 
occasionally with fish or liver. The small blue- 
gills involved in the sex reversal experiments 
received some daphnia . Large bluegills in this 
experiment were fed some red worms and grass 
shrimp with the dry trout pellets . 

Leslie E . Chew 



45 



LIBRARY SERVICES validated and expanded to include 3 ,500 

individuals and organizations. Seventy-five 
Bibliographic services were provided on the books and nearly 700 reprints were acquired 
following topics: fish carcinomas, attractants, and catalogued for the research staff, 
repellents, catfish farming, pollution control, 

pesticides, farm ponds, rotenone, and antimycin. Rosalie A. Schnick 

A bibliography on formalin as a fisheiry tool is 
nearing completion. Special reports on the ser- 
ial holdings and the publications of the Labora- 
tory were compiled and distributed. A Library 
Service Report was submitted to the USDI 
Library. Our mailing list for publications was 



46 



FISH HUSBANDRY RESEARCH-TOMORROW OR TODAY? 



Remember the graffiti adorning the fences and public monuments a few years ago --the one that 
said, "Due to lack of interest, tomorrow has been cancelled"? Well, don't apply this to fish 
husbandry research, because we're moving ahead into the future. Rather, unfold the banner that 
says, "Because of overwhelming demand, and the success of our program, tomorrow will be held 
today." 

In the following pages are chronicled the things we have been doing in fish husbandry research 
as "today's" things. The topics look familiar to us; indeed, many of them are enduring investiga- 
tions which are just now bearing fruit as we make long strides down the research roads to disease, 
culture, and nutrition knowledge. 

Superimposed upon these pursuits of today are some we didn't expect until tomorrow. We have 
not been able to take the new efforts in stride without some interruption of ongoing research, but 
have managed to make a mix so the new and the old could both go forward. 

One of tomorrow's quests is the catfish-pesticide inquiry in the Southeast. In 1969 a new 
syndrome began to plague the catfish. Neither the fish farmer nor the fish farmer's friend (our 
scientists from the Warmwater Fish Cultural Laboratories) knew this catfish condition that had 
suddenly surfaced. Our people from Stuttgart and Marion, after much study, hypothesized that 
pesticides, in combination with cold weather, caused the syndrome. A larger program in 1970 will 
be undertaken to learn more about the new disease . 

Another of tomorrow's problems we faced was our deep involvement in educational and extension 
exercises. True, we have always distributed reprints and answered questions and looked at sick 
fish, but who would have conjectured, a few years ago, that the entrances to our laboratories would 
have lineups like that at the West Gate at Yellowstone , or that one laboratory would respond to more 
than 4 ,000 written requests for information? These things have unexpectedly been batted to us , and 
we have fielded them . 

Yes, tomorrow is upon us today.' The momentum is increasing, but we are ready, for fish 
husbandry research has not saved today's tasks for tomorrow. 



Oliver B. Cope, Chief 

Branch of Fish Husbandry Research 



47 



EASTERN FISH DISEASE LABORATORY 

Leetown, West Virginia 
S. F. Snieszko, Director 



HIGHLIGHTS 

Mr . Bullock spent nearly three months at 
the Unilever Marine Laboratories, Aberdeen, 
Scotland, working on bacterial diseases of 
cultured marine fishes . 

The reliability of methods for detection of 
furunculosis of trouts by bacteriological and 
serological examination was tested at three 
-National Fish Hatcheries . 

Two chapters for the textbook on Fish 
Diseases were submitted to the publisher. The 
chapters are "Bacterial Diseases" and 
"Identification of Fish Pathogenic Bacteria ," 

Myxosoma cerebralis , the causative agent 
of whirling disease, is being maintained in the 
laboratory for control and eradication research . 
It has been found to survive -20° C. for two 
months and in an aquarium for over 2 years . 

Dr . Wolf went to the Laboratory of 
Virology, St. Jude Children's Research Hospital, 
Memphis , Tenn . , to update his competence in 
virology. In collaboration with Dr. R. W. 
Darlington, staff electromicrocopist, he found 
the channel catfish virus to be a member of the 
Herpes virus group, and sequential changes 
during in vitro infection have been determined 
with electron microscopy. 

Channel catfish virus growth rates , 
characterization data, and sequential light 
microscopy of infected cultured cells have been 
determined. The data indicate possible control 
measures for the disease. 



Culture dish plaque assay of channel catfish 
virus has been developed for use in normal 
atmosphere; this obviates the need for CO2 
incubators and provides a sensitive, economical 
and accurate virological tool. Early trials have 
shown that salmonid viruses can be similarly 
plaqued . 

Dr. Tokuo Sano, visiting scientist, isolated 
IPN virus from glycerol -preserved trout fry 
sent here from epizootics among Japanese 
hatcheries .. 

Caudal fin erosion in Dover sole 

While in Scotland, I learned that one of the 
problems in Dover sole culture is low but 
persistent mortality from caudal fin erosion. 
Previously, I had investigated a similar condi- 
tion in hatchery -reared brook trout; therefore, 
I undertook a study of the disease in Dover sole. 
The main questions to be answered were whether 
one or more species of bacteria are involved and, 
if so, what treatment might be used. Results of 
the bacteriological examination of 15 sole with 
caudal fin erosion were remarkably like those 
obtained with the brook trout. Several species 
of aquatic bacteria were isolated from the eroded 
tan fin but none could be isolated from internal 
organs. Therefore, control of the erosion might 
be accomplished by use of external disinfectants. 
To begin with, tests were conducted to determine 
the toxicity of three quaternary ammonium 
compounds for the sole and then to determine the 
in vitro sensitivity of the isolated bacterial 
strains to the same compound. Three benzal- 
konium chlorides were used: Hyamine 3500, 
Hyamine 1622, and Hyamine 2389. The sole 



tolerated all compounds at 1 and 2 ppm for an 
hour, with no residual toxicity noted after 24 
hours . The 3 compounds were also tolerated 
at 3 and 4 ppm for 1 hour but some sole died 
within 24 hours after treatment in Hyamine 3500. 
Therefore, the Hyamines appeared to be of 
possible prophylactic or therapeutic use in 
controlling tail fin erosion. 

G. L. Bullock 

Cultural characteristics of myxobacteria 
pathogenic to fish 

Study was continued on myxobacterioses , 
especially gill disease, and including myxo- 
bacteria from Dr. Ian Anderson, Unilever 
Research Laboratory. Cultures were isolated 
from gill disease in Atlantic salmon and from a 
condition termed "eroded mouth" in rainbow 
trout raised in sea water. Earlier results 
here indicated that some characteristics of 
myxobacteria from gill disease were fairly 
homogeneous. Therefore, we were anxious to 
compare gill disease cultures from Scotland 
with our strains . Morphological and physiolog- 
ical characteristics of our old stock cultures 
were rechecked and characteristics of the new 
isolates determined. 

Myxobacteria from all sources were 
proteolytic, produced amylase, lysed intact A. 
liquefaciens cells , and grew from 5° -30° C . 
They were variable in ability to produce acid 
from glucose, reduce nitrate, and degrade tyro- 
sine. Also, there was a variety of morphologi- 
cal colony types among cultures from all 
sources . These observations showed that 
myxobacteria in gill disease are more diversi- 
fied than expected. For serological reactions, 
9 rabbit antisera were prepared against myxo- 
bacteria isolated from gill disease and eroded 
mouth in Scotland, gill disease in bluegills, and 
tail rot in our hatchery brook trout . 

G . L . Bullock and H . M . Stuckey 

Serological tests for diagnosis of bacterial fish 
diseases 

" Over the past 8 years we have concentrated 
on methods for rapid and accurate diagnosis of 



bacterial fish diseases . We have progressed 
from morphological and biochemical methods to 
the more rapid agglutinin and precipitin tests. 
One of the most rapid serological tools for 
diagnosing infectious diseases indirectly from 
infected tissue is the direct or indirect fluores- 
cent antibody technique. This has been used in 
human and veterinary medicine for some time 
and recently Klontz used it in studying serotypes 
of Aeromonas salmonicida and for demonstrating 
the presence of A. salmonicida in wild popula- 
tions of fish. 

We investigated the indirect fluorescent 
antibody technique for identification and differen- 
tiation of A . salmonicida , A . liquefaciens , and 
Pseudomonas fluorescens in infected fish tissues . 
Stock cultures of the three organisms were 
studied first to detect cross reactions among the 
three types , especially between strains of A . 
liquefaciens and A . salmonicida. We hoped the 
strains of the three bacteria would react with 
only the antiserum prepared for the particular 
species, but cross reactions occurred between 
strains of A . salmonicida and A . liquefaciens . 
No cross reactions were noted with the P . 
fluorescens strains and the two aeromonad anti- 
sera. Cross reactions were virtually elimin- 
ated between the aeromonad species by cross 
absorbing the two sera . 

Survey of trouts at three National Fish Hatcheries 
for the presence of furunculosis and kidney 
disease 

The proposed classification of the National 
Fish Hatcheries as to the presence or absence 
of furunculosis, kidney disease, whirling 
disease, infectious pancreatic necrosis (EPN), 
and viral hemorrhagic septicemia (VHS) has 
raised questions as to the best methods of 
detecting these diseases, especially in the 
latent or carrier state . Adequate methods 
already exist for IPN, but not for the other 
diseases. Since a survey for these diseases was 
to be made in the brood stock hatcheries in 
Region 5 , we decided to test different methods of 
detection of A . salmonicida, the causative agent 
of furunculosis . We also examined trout for the 
presence of antibodies against this bacterium. 



49 



We chose furunculosis rather than kidney 
disease because the kidney disease corynebac- 
terium is still very difficult to grow . 

We examined trout at Cortland and White 
Sulphur Springs, which had no known furunculo- 
sis , and from Bow den where furunculosis was 
known to be present . To avoid killing yearling 
and adult trout , blood was removed aseptically 
from the hemal canal and cultured in an 
attempt to isolate^, salmonicida . Tryptic soy 
agar (TSA) slants were inoculated with 0.5 ml 
of blood overlaid with 2 ml of nutrient broth 
containing 0.01 percent heparin. The reason for 
using a two -phase medium was to Increase the 
chance of isolating very low numbers of 
bacteria. For comparison, kidney material 
was also cultured from approximately 20 per- 
cent of all yearling and adult trout . We cul- 
tured only kidney material from fingerlings 
because we could not obtain enough blood for 
culture. A small quantity of blood was obtained 
from fingerlings . Serum and plasma samples 
were tested by means of slide agglutination test 
for the presence of antibodies against A. sal- 
monicida. Smears of kidney material from 
yearling and adult trout were stained by Gram's 
method and examined for the presence of the 
kidney disease bacterium . Cultures from all 
trout were incubated at 20° -25° C, examined 
every other day for growth, and discarded 
after 6 days if growth did not occur . Cultures 
which showed growth were streaked on TSA to 
determine the type or types of bacteria present . 
A slide agglutination test, using rabbit anti-A. 
salmonicida antiserum, was run on any isolate 
suspected of being A . salmonicida . 

Detailed results of the examinations are 
given ui Table 1. We neither isolated A. sal- 
monicida nor detected agglutinins in the sera or 
plasma of trouts at White Sulphur Springs NFH, 
so this hatchery was classified as negative for 
furunculosis . Trouts at Bowden NFH have been 
known to have furunculosis but the organism was 
isolated only from brook trout just after an 
outbreak. Adult rainbow trout at Bowden were 
probably carriers because they had agglutinins , 
but A. salmonicida was not isolated. Results 
obtained at the Cortland NFH showed that the 
yearling rainbow trout had agglutinins against 
A. salmonicida but, again, A. salmonicida was 



not isolated. This population must be 
considered as a possible carrier and all dead 
fish should be examined bacteriologically for 
the presence of A. salmonicida . Since furuncu- 
losis has not been reported at Cortland in the 
last 10 years, at least, and A. salmonicida was 
not isolated, the station can be considered as 
free from furunculosis from a practical stand- 
point. The rainbow populations should be 
closely watched. 

Kidney disease bacteria were not seen in 
any stained kidney smears from trout at the 
three hatcheries , but a latent Infection of kidney 
disease might easUy be missed with this proced- 
ure. 

The failure to isolate A. salmonicida , 
especially from the adult rainbow at Bowden 
which were probably furunculosis carriers, 
could be due to some inhibiting substance. 

WhUe our culture methods are adequate for 
detecting A. salmonicida In a population of 
salmonids that have just experienced an out- 
break of furunculosis, they are not adequate for 
reliable detection of the bacterium in carriers . 
Detection of A . salmonicida in carriers is 
apparently difficult; recently Klontz showed by 
immunofluorescence that a wild population of 
apparently healthy suckers harbored A . salmoni - 
cida in the folds of their gut wall, but the 
organism could not be cultured. Furunculosis 
developed In these fish 7 to 10 days after thermal 
or physical stress . While immunofluorescent 
technique is promising for detecting the carrier 
state of furunculosis, it is not yet practical In 
the field. Since A. salmonicida is present in 
the gut of at least some carriers , the bacterium 
may be shed In the feces . 



G. L. Bullock 
Steve Leek 
Ivan McElwain 



L. L. Pettijohn 
H . M . Stuckey 
R, E. Putz 



50 



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VIROLOGY AND CELL CULTURE 

Channel catfish virus (CCV) 

The work reported here was largely carried 
out on a training assignment at the Laboratory 
of Virology, St. Jude Children's Research 
Hospital , Memphis , Tenn . 

Auburn strain CCV obtained from 
Dr. Nikola Fijan, was cloned by plaquing with 
standard gel overlay procedures and stocks 
designated clone A were grown at the Eastern 
Fish Disease Laboratory and preserved at -80° 
C . for use in the research at Memphis . 

Two -phase (gel -liquid) procedures are used 
at St. Jude for plaque assay of polyhedral 
cytoplasmic DNA frog virus in fish and mammal- 
ian cells . These procedures were modified for 
plaquing CCV in the brown bullhead (BB) cell 
line . Excellent results were eventually 
obtained, and they showed a linear relation 
between virus dilution and plaque number (233, 
21, 3) (Figure 1). 

The BB cells did not grow at 33° C . , and 
the quantity of virus replicated at 10° C . was 
only 6 to 8 times greater than input , so 
growth curves were plotted from data obtained 
at 25° and 30° C . At 30° C , , CCV clone A had 
a lag phase of about three hours but new virus 
appeared by the fourth hour post -infection. 
Exponential growth of virus occurred for four 
hours , and growth began to level off at 10 hours. 
Maximum amounts of virus were attained by 
the 16th hour (Figure 2). 

A parallel study by electron microscopy 
was carried out in collaboration with Dr . R . W . 
Darlington, staff electronmicroscopist. The 
work showed CCV to be synthesized in the 
nucleus and that it is an encapsulated icosahe - 
dron with well defined capsomeres apparently 
having a hollow configuration. Mean virion 
diameter of unencapsulated particles is about 
125 nm, but resolution was not sufficient to 
determine the number of capsomeres . Sequen- 
tial changes of infected cells as seen by 
electron microscopy have been documented, and 
a manuscript is in preparation. 




Figure 1. — Stained dish cultures of the brown 
bullhead (BB) cell line showing plaques 
produced by the channel catfish virus. 
Top, 10~4 dilution; middle, 10~^ dilution; 
bottom, 10"^ dilution. 



52 



10» - 



\// 





HOUtS AFTEI INFECTION 

Figure 2. — Representative one-step growth 
curve of channel catfish virus in brown 
bullhead cells at 30° C. RV indicates 
released virus and CAV indicates that 
which remains cell-associated. 

A similar study of sequential changes at 
30° C. was carried out by light microscopy of 
infected BB cells . The essential changes were 
as follows: (cf, growth curve --Figure 2, 
Figure 3). 

Hour 2 Light basophilia, beginning 

margination of chromatin and 
cell fusion. 

Hour 4 Syncytia contain 3 to 5 nuclei. 

Beginning intranuclear inclusions, 

Hour 6 Inclusions well-defined. 



Hour 10 Chromatin condensed internally 
and shifted away from nuclear 
margins. Six to 15 nuclei in 
largest syncytia . Some cells 
totally pyknotic and condensed, 
sloughing begins . 

Hour 12 Syncytia increase in size to 

contain over 20 nuclei. Multiple 
intranuclear inclusions, some 
nuclei fragmenting within syncy- 
tia. 

Hour 14 Nuclear dissolution continues . 
All cells in syncytia and/or 
pyknotic . 

Hour 19 Lysis advanced and most cells 
sloughed. 




Figure 3. — Focal infection (a plaque) of 
channel catfish virus at 27 hours of 30° 
C. incubation. Terminal effects of the 
virus are evident as necrosis in the 
plaque center. Beyond the center, syncy- 
tia, so characteristic of this virus, are 
readily seen. The plaque perimeter con- 
tains pyknotic cells, the first visible 
change produced by the virus. Scale 
represents 1 mm. 



Hour 8 Increased basophilia, nuclear 
margins fading, syncytia with 
6 to 10 nuclei. 



53 



CCV Clone A was found to be totally 
inactivated by extraction with ether or with 
chloroform . The virus was not replicated in 
AKRP (frog) , primary chick embryo , BHK 
(hamster), Hela (human), H.Ep-2 (human), 
WI38 (human), primary African green monkey, 
Rhesus monkey, rabbit kidney and human embry- 
onic kidney cell cultures . All the lines tested 
support growth of one or more Herpes viruses 
from other animals . 

Nuclear replication and envelopment by 
nuclear or cytoplasmic membranes, a size of 
about 100 to 125 nm, and icosahedral morphology 
with hollow capsomeres indicate that CCV is a 
member of the Herpes virus group. Extreme 
sensitivity to lipid solvents, an unusually great 
host and host cell specificity and the induction 
of syncytium formation are all characteristics 
which support placement in the Herpes virus 
group. Determination of nucleic acid type 
remains to be done. 

Experimental infections have been 
attempted with fingerling channel catfish 
( Ictalurus punctatus) at the Fish Farming 
Experimental Station, Stuttgart, Ark., but 
the fish have succumbed to virus only after 
massive injection and when the temperature 
was 30° C . and over . Additional trials are in 
progress to learn the his topatho logy of this 
disease, to implement a search for virus in 
carriers . 

Needle biopsy of catfish kidney tissue was 
attempted in an effort to find a non -lethal way 
of virologically assaying adult tissues . The 
efforts were not successful and failure was 
attributed to the soft texture of internal organ 
tissue. Skeletal muscle could be successfully 
sampled with several different biopsy needles . 



carried in continuous cultivation for 10 years . 
The former cell line is still the culture 
requested most frequently from us --in 1969, 13 
of 18 requests which we felt could not be 
referred to commercial sources or to the 
American Type Culture Collection were for RTG- 
2 cells . The RTG-2 is also employed in the 
bioprotocol for testing lunar soil . 

Dr. Tokuo Sano, visiting scientist from the 
University of Tokyo, established primary mono- 
layer cultures from eels ( Anguilla rostrata ) in 
preparation for return to his own laboratory and 
virological work with A. japonica . The cultures 
in general grow slowly and subcultures are 
established only with prolonged incubation. The 
best nevertheless persist. 

Several tissues from spent adult lampreys 
( Petromyzon marinus) were trypsinized for 
preparation of monolayer cell cultures . Ten 
different media were tested but none proved 
better than that which we presently use for 
larval lamprey tissue . Thus far, cultures are 
maintained best at 15° C. or lower. Cells from 
adult tissues still show metabolic activity after 
9 months in vitro whereas explants of ammocoete 
heart are still beating after 17 months in 
culture . 

It is generally recognized that for detectior 
and assay of virus, plaquing is more sensitive 
and accurate than endpoint of cytopathology 
determined in cultures grown in liquid medium. 

Because of pH control and other considera- 
tions , plaquing is usually carried out in sealed 
vessels or in petri dish -type cultures in 
partial CO2 atmospheres; both methods have 
disadvantages , and a compromise would use 
dish-type cultures in normal atmosphere. 



Periodic assay of CCV preparations indi- 
cates that retention of inf ectivity at 4 ° C . is 
good if cell culture harvests are in the medium 
with 10 percent serum levels . Infectivity is not 
maintained as well in lower serum levels. 

Cold-blooded animal cell and tissue culture 

RTG-2 and RTF-1 cells, the first and oldest 
established lines of fish cells , have now been 



The brown bullhead (BE) cell line used for 
the channel catfish virus (CCV) research 
described elsewhere in this report has been 
grown in Eagle's Minimal Essential Medium 
(MEM) containing a bicarbonate buffer which 
provides pH control at equilibration with COo in 
sealed vessels or in CO2 incubators. Leibovitz' 
Medium L-15 was designed to maintain a physio- 
logical pH at normal atmosphere , but in spite 
of repeated attempts , the BB cell line could not 



be adapted to growth in Medium L-15. Thus far, 
there has been no report of fish cell culture and 
virus plaquing in dish-type cultures incubated in 
normal atmosphere. 

Several different buffer systems were 
compared for their ability to provide pH control 
in Eagle's MEM and ultimately for that medium 
to sustain BB cell growth and in turn efficiency 
of plaquing CCV. Tris (hydroxymethyl) 
aminomethane and N-2 hydroxy-ethylipiperazine 
N'-2-ethanesulfonic acid buffers both provided 
good pH control in BB cultures grown in normal 
atmosphere; moreover, results with the latter 
equaled or surpassed those obtained with control 
cultures grown in regular MEM (Table 2). 



From this work, fish cell culture techniques 
have been advanced and a more accurate and 
sensitive virological assay system has resulted. 

Ken Wolf and M . C . Quimby 

PARASITOLOGY 

Experimental transmission of Myxosoma 
cerebralis (whirling disease) and effect of 
freezing on the spores 

Before critical research can be done on 
treatment and control methods, whirling disease 
must be reliably reproduced under experimental 
conditions . Although young salmonids become 



Table 2. — Comparison of BB cell cultures grown in Eagle's 
Minimal Essential Medium with various buffer systems 



Buffer 


Relative 
culture 
growth 
rate 


pH 
control 


Relative 

efficiency of 

plaquing 


Sodium bicarbonate 
(Control) 


100% 


Excellent 


10.4 X 


lO'' pfu/ml 


Sodium-potassium 
phosphates 


35 to 55% 


Fair 


10.3 X 


10^1 pfu/ml 


Tris (hydroxymethyl) 
amino methane 


66 to 88% 


Very good 


13.6 X 


10^ pfu/ml 


N-2 hydroxyethyl 


92 to 113% 


Excellent 


12.0 X 


10^ pfu/ml 


piperazine-N -2- 
ethanesulf onic acid 











'^In suitable replicates, various stocks of channel catfish virus were plagued on cells 
grown in the several modifications of medium Representative values are given in 
plaque forming units (pfu). 



Similarly modified media were used for 
dish -type culture of RTG-2 cells, and it was 
found that the basic methodology will permit 
plaquing of Infectious Pancreatic Necrosis, 
Egtved, Infectious Hematopoietic Necrosis ai 
Chinook Salmon viruses in standard 
incubators . 



easily infected when placed in contaminated 
waters, it is very difficult to infect such fish 
at will in the laboratory. To find a reliable 
method of reproducing the disease, spores in 
infected fish tissues were introduced to 24 
aquaria, 16 of which contained 3 to 5 inches of 
mud taken from warmwater fish ponds . Some 
of the aquaria were 150-liter stainless steel 
tanks, some were 75 -liter glass aquaria, and 
some were 340-liter fiberglass tanks. Spring 
water (12° C .) flowing at about 600 ml/min was 
supplied during "aging" of the spores . After 



55 



the fish were added, the flow was increased to 
about 1800 ml/min. All aquaria had standpipe 
draiais to facilitate the retention of spores . 
Fifty to 100 rainbow trout fry, usually 3-4 
weeks old, but 10 weeks old in 2 aquaria, were 
stocked at regular intervals from to 6 months 
after the spores were added. The fish were 
observed and were autopsied and examined for 
spores 4 to 6 months after stocking. 

Fish became infected in 7 of the 24 aquaria. 
Only those aquaria containing mud and spores 
"aged" 3.5 to 6 months contained infected fish 
(Table 3). Symptoms were first noticed 2.5 to 
3 .5 months after the fry were placed in the 
aquaria . In 5 aquaria the symptoms were 
typical and spores were numerous in the fish. 
However, in 2 aquaria no symptoms were 
noticed but examination of cartilage showed 
spores in small numbers . 



of the spores . In some of the experiments 
infected trout heads were frozen at -20° C. for 
2 months , and then cut up and introduced to 
aquaria. Freezing did not kill the spores 
(Table 4). 

Experiments 67-6(3) is being maintained to 
see how long a contaminated facility remains 
so . Spores were placed in the aquarium on 
August 9 , 1967 . After fry were added on 
November 28, 1967, the mud surface was 
stirred gently several times at weekly intervals . 
Symptoms were seen February 16, 1968, and 
immature spores were present. These fish 
were removed and new fry added on February 
23; the second lot became infected and were 
removed May 21 . This procedure was repeated 
9 more times, with the fish becoming infected. 
The first 3 batches of fish were left in the 
aquarium about 3 months (long enough for spore 



Table 3. --Effect of "aging" on Myxosoma cerebralis spores 



















3-5" 


Spores 


Age of 








of mud 


"aged" in 


fry at 


Presence of 


Experiment 




added 


aquaria , 


start , 


spores in 


No. 


Facility 


or not 


months 


weeks 


fish 


66-lB 


150-liter 
steel tank 


no 


4 


3 





66-lA 


" 


yes 


4 


3 


+ 


68-14 




no 


2 


3 





67-6(1) 


340-liter 
fiberglass 


yes 


3 


10 


+ 


67-6(3) 




yes 


3.5 


3 


+ 


67-6(4) 


" 


yes 


3.5 


3 


+ 


68-11 


" 


yes 


6 


3 





68-13 


" " 


no 


. 2.5 


3 





68-14 


150-liter 
steel tank 


no 


2.5 


3 





69-5A 


75-liter 
aquarium 


no 





10 





69-6 




no 


3.5 


3 





69-7 




no 


3.5 


3 





69-8 




no 


3.5 


3 






From these experiments we assume that 
some mud is necessary to produce infection. 
The spores became infective 3 to 6 months 
after placing them in the aquaria, but we do not 
know the minimum and maximum infective ages 



production), but the last 8 were removed 
before production. Dead fish were removed 
promptly during this experiment. The results 
demonstrate that the spores remain viable for 



56 



Table 4. --Effect of freezing and "aging" on Myxosoma cerebralis spores 



























3-5" 


Spores 


Spores 


Age 


of 


Presence 






of mud 


frozen 


"aged" in 


fry 


at 


of 


Experiment 




added 


-20°C, 


aquaria , 


start , 


spores 


No. 


Facility 


or not 


days 


months 


week 


s 


in fish 


66-lbA 


150-liter 
steel tank 


yes 


270 


4.5 


4 







67-lB 




yes 


18 


4 


10 




+ 


07-0(2) 


340-liter 
fiberglass 


yes 


3 





10 







67-0(5) 








yes 


3 


3.5 


10 







67-6(6) 








yes 


00 


2.5 


10 







68-5 








yes 


DO 


6 


3 




+ 


08-0 








yes 


00 


6 


3 







68-7 








yes 


00 


6 


3 




+ 


68-8 








yes 


330 


6 


3 







08-9 








yes 


330 


6 


3 







68-10 








yes 


330 


6 


3 







69-1 








no 


480 


4.5 


3 







69-2 






no 


960 


5.5 


3 








22 months or the live infected fish shed 
infective units, or both. 

The actual mode of transmission of M. 
cerebralis has never been experimentally 
determined; therefore a filtration experiment 
was initiated to pinpoint the size range of the 
infective unit. Water and sediment from an 
infected tank, where M. cerebralis has been 
maintained since the first quarter of 1968, were 
siphoned into a 20-liter container and from this 
filtered through filters of 14 ti to 1.2 h- potasity. 
This was done each day for 5 consecutive days . 
After running the water and sediment through 
each size filter, the filters with residue were 
placed in glass aquaria with susceptible trout. 
Results are shown in Table 5 , Presence of 
spores of M . cerebralis in infected trout was 
confirmed by histopathological examination. 
This experiment is being run again with smaller 
trout and more consecutive days of filtering. 
The spores are actually 7 .5 to 9 .5 H- in diameter. 
The infective units, whether present as free 
spores or carried by larger organisms , were 
retained by the 12 y. filter. It may be that free 
spores were adsorbed to the filter pad or 
trapped in debris . 



Serodiagnosis of whirling disease 

At present whirling disease of salmonids 
cannot be detected in asymptomatic carrier fish 
without sacrificing the fish, and it is sometimes 
very difficult to find spores in adult trout . 
Therefore, an experiment was initiated to try to 
diagnose the disease using a modified indirect 
fluorescent antibody technique. Rainbow trout 
globulin (to be used as an antigen) was prepared 
by fractionating the trout serum, and was 
injected into rabbits . The system was then 
tested . 

A positive control system, using the 
indirect fluorescent antibody technique developed 
for salmonicida was run, as well as a negative 
control system using trout serum from non- 
myxosoma -infected trout. So far the experi- 
ments have not given satisfactory results because 
those not exposed to fluorescent antibody 
fluoresced as strongly as controls . Untreated 
spores of M . cerebralis fluoresced in ultraviolet 
light. 



R . E . Putz 



R. E. Putz and Ivan McElwain, trainee 



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Effects of disinfecting agents and other 
chemicals on spores of Myxosoma cerebralis 

The effects of calcium hydroxide, potassium 
hydroxide, calcium chloride, calcium hypo- 
chlorite, ammonium chloride, and sodium 
borate on Myxosoma spores are being studied by 
a local student, Lyle Hoffman. So far, a high 
concentration of calcium oxide and potassium 
hydroxide at 0.5 percent has consistently 
destroyed the spores . 

Bird transmission of Myxosoma cerebralis 

Normal Myxosoma spores are carried in 
the feces of kingfishers and herons which have 
fed on infected fish . Mr . T . Udell Myers , 
Castalia, Ohio, fed infected fish to captive 
great blue herons , collected the spore -bearing 
feces, and shipped it to Leetown. We have 
seeded experimental tanks with it, allowed the 
spores to "age," and have added swim -up 
rainbow trout fry to see if the spores are 
infective. 

Isolation and morphology of M. cerebralis 
spores 

Preliminary work has been started with 
pepsin HCl digest of infected trout heads . 
Following digest, the material was strained 
through 224-, 154 -, and 70-micron mesh screens. 
Fairly good concentrations of spores were 
recovered and sent to Dr. J. Lom for electron 
photomicrography. Spores from other species 
of salmonids will also be collected and a 
revised description of the spore prepared. 

HBTOPATHOLOGY 

An epizootic involving a fungus infection 
in the kidney and other viscera of adult rainbow 
trout was referred by Jimmy Camper, Hatchery 
Biologist, Region 4 . There were significant 
mortalities, and gross examination revealed 
swollen kidneys with dark brown spots of about 
2 mm . In severely infected fish the brown 
spots were seen elsewhere in the viscera . 
Examination of wet tissue squashes and histolog- 
ical sections of kidney showed that the fungus 
had branched mycelium and hyphae ranging 
from 1 to 2.5 ij, in diameter (Figure 4). No 



spores were observed. The Western Fish 
Disease Laboratory will further investigate 
this fungus . 

G. L. Hoffman and C. E. Dunbar (deceased) 




Figure 4. — Undescribed fungus from the 
kidney of adult rainbow trout. 



CHEMOTHERAPY 
OF FISH DISEASES 

During the latter part of the year, we 
cooperated with the Hoffman-LaRoche Company 
to evaluate sulfisoxazole, sulfadimethoxine,, and 
a combination of suLfadlmethoxine and pyrimi- 
dine for treatment of bacterial fish diseases . 

Efficacy tests were delayed because of a 
low water supply and difficulty in establishing 
infeptions which were not fulminating. 

The results of force -feeding trials indicate 
that doses of over two grams of sulfisoxazole 
per kilogram of fish weight are non -toxic to 
rainbow trout. Free -choice feeding of the drugs 
clearly indicated that the combination drug had 
a low palatibility to rainbow trout. At the high- 
est dose given, the fish refused to eat after one 
feeding. Table 6 gives the results of this experi- 
ment as measured by weight gain or loss . 

R . L . Hoffman and G • L . Bullock 



59 



Table 6. Effects of free-choice feeding of drugs 
on weight changes in rainbow trout at 12.5°C. 



Days 



Drug 



Dose 


Weight 


(gm) 


mg/kg 


Gain 


Loss 


220 


+ 140 




440 


+ 134 




880 


+ 55 




220 


+ 129 




440 


+ 46 




880 




- 54 


220 




- 124 


440 




- 51 


880 




- 30 





+ 130 







+ 122 







+ 132 




100 


Terminati 


2d— fish 




not feed 


ing 


50 


+ 191 







+ 217 





12 Sulf isoxazole 



Sulfadimethoxine 



R05-0037 



10 R05-0037 



NEOPLASTIC FISH DISEASES 

A report on Mr. C. E. Dunbar's work on 
the etiology of visceral granuloma is being 
prepared for publication. This disease is 
definitely diet -associated, and cottonseed meal 
is an important factor . When cottonseed meal 
was eliminated from a meat -meal diet known to 
produce the disease, visceral granuloma inci- 
dence was very low (4 .7 percent vs . 91.3 
percent). Cottonseed meal added to a synthetic, 
non -granuloma -producing diet caused an inci- 
dence of 21 percent. Gossypol is not the 
principal cause of this high incidence; when 
added to the synthetic diet at a rate of 333 ppm , 
it produced an incidence of only 2.6 percent. 

It is currently speculated that dietary 
mineral imbalance (e.g. , calcium, phosphorus, 
and/or magnesium) occurs, resulting in patho- 
logical deposition of calcium and osmoregulatory 
difficulties .. 

R. L. Herman 



GENERAL 

Diagnostic services 

R . L . Herman assumed the duties of 
histopathologist following the death of 
Mr . C . E . Dunbar . 

Reference tissues from Anguilla rostrata, 
Petromyzon marinus , and Acipenser sp. were 
added to the laboratory collection during the 
year. Excellent specimens of rainbow trout 
infected with infectious hematopoietic necrosis 
(IHN) became available through routine diagnostic 
examination. 

Dr. Fred Meyer, Fish Farming Experi- 
mental Station, Stuttgart, Ark., sent several 
isolates of a bacterium causing death among 
cultured catfish . The organism is not one of 
the common catfish pathogens; it appears to 
belong in the enteric group. Fingerling catfish 
injected with the organism or exposed to a heavy 
cell suspension became diseased and died two 



60 



days after injection and five days after 
exposure. External pathology with experi- 
mental infections included hemorrhage around 
the mouth, at the base of fins, and in the 
visceral mass . Microscopic examination of 
tissues of infected catfish showed only focal 
necrosis in the pancreas. 

G. L. Bullock, H. M. Stuckey 
and R. L. Herman 

More than 35 specimens of parasites were 
received for diagnosis, most notable of which 
were: unknown granulomas in goldfish 
viscera; microsporida in catfish heart and 
intestinal wall; microsporida in starry flounder 
from California; Posthodiplostomum minimum 
from the eye and ovary of Gambusia aff inis ; 
Contracaecum and Proteocephalus larvae from 
an emaciated 12 oz . largemount bass 16 inches 
long; and an Ichthyophonus -like parasite from 
frog muscle . 



A two -day workshop on general biology and 
diagnosis of whirling disease (M. cerebralis) 
was conducted at Leetown at the request of the 
U.S. Trout Farmers Association on February 
20 and 21 . This was the first project arranged 
by the Association's Disease Research Commit- 
tee, and was organized by T. Udell Meyers, 
Biologist, Castalia Farmsi, Ohio. Sixteen trout 
farmers and biologists attended. Dr. Hoffman 
participated in a similar course at the Western 
Fish Disease Laboratory, August 14 and 15. 

Florence T. Wright, Librarian, attended a 
Departmental Library Workshop held in Denver, 
Colo, on September 29, and a December 6 Board 
Meeting of the West Virginia Library Association 
as Chairman of the Special Library section. 



Noteworthy and encouraging from the point 
of international fish disease control was a 
request to examine and certify bluegUl fry to be 
free of disease before shipping to Iran by 
Eugene Surber, Virginia Commission of Game 
and Inland Fisheries . 

G . L . Hoffman and R . E . Putz 

Training and committees 

Messrs . Bullock and Putz , and former 
trainee Charles Berry, Water Pollution Board, 
State of Virginia , spent the month of July at 
the Lewis Calder Conservation Study Center, 
Armonk, N. Y. They were studying parasites, 
bacterial flora, and several blood parameters 
of lake fish as part of ecological study of a 
lake sponsored by the Biology Department at 
Fordham University. 



Dr. Glenn Hoffman serves on the council 
of the Wildlife Disease Association and its 
Awards Committee; he is also on the Inter- 
national Committee and Awards Committee of 
the American Society of Parasitologists and the 
Fish Disease Committee of the American 
Fisheries Society. 



WESTERN FISH DISEASE LABORATORY 

Seattle, Washington 
Robert R. Rucker, Director 



HIGHLIGHTS 

Furanace may prove satisfactory for 
separating the two genera Pseudomonas and 
Aeromonas . 

Adult rainbow trout are Infectious Hemato- 
poietic Necrosis "carriers," and techniques for 
identifying "carrier" fish have been developed. 

Virions of Infectious Hematopoietic 
Necrosis were observed with an electron micro- 
scope in various stages of development in fish 
tissues . 

Albino rainbow trout exhibited an anamnestic 
or memory response to the secondary inocula- 
tion of an antigen. The lag time between 
inoculation and antibody rise was considerably 
reduced when a previous stimulation had been 
given . 

Immunoelectrophoresis of the sonicated 
supernatant of Aeromonas salmonicida 
displayed some of the antigens which will 
induce antibody formation when inoculated into 
rabbits and rainbow trout. 

Cytophaga psychrophila has been found to be 
closely correlated with the occurrence of 
whirling disease of coho salmon. 

Field experiments indicate that Furanace 
(P-7I38) is effective in the control of myxo- 
bacterial infections . 

For yearling rainbow trout, benzocaine or 
neutralized MS -222 rather than MS -222 (acid) 
are the anesthetics of choice for clinical 



chemistry measurements unless anesthesia is 
limited to 3-5 minutes . 

Blood cholesterol and urea levels of 
rainbow trout fall to about half normal value in 
a few days when rainbow trout are subjected to 
crowding stress . The values slowly return to 
normal . 

The estimated normal clinical chemistry 
ranges for 7 chemical components from blood 
and interrenal tissue have been determined for 
yearling rainbow trout. 

BACTERIOLOGY 

Isolation and identifica tion of organisms 
associated with fish diseases 

Rainbow trout from several epizootics of 
unknown causes were tested for mycoplasma . 
None were isolated. 

Bacterial cultures were obtained from rain- 
bow trout at a private hatchery in Washington 
and from chinook salmon at a Washington State 
Department of Fisheries hatchery. These 
isolates were very similar to the R. M. bacter- 
ium usually associated with rainbow trout from 
Idaho . The isolates from trout differed in that 
they were non -motile in contrast to the motile 
R. M. organisms normally seen; however, they 
conformed in all other respects to R . M . 
bacterium . 

Preliminary investigations were started to 
determine the taxonomic value of extracellular 
deoxyribonuclease production from bacteria 
pathogenic to fish. Three cultures each of 



62 



Pseudomonas sp • , A . salmonicida, R . M . 
bacterium, A. liquefaciens , A, hydrophila , 
A . punctata , and Vibrio sp . were grown on a 
culture medium containing deoxyribonucleic 
acid (DNA) . A chemical test was used to 
demonstrate the occurrence of DNA degradation. 
Degradation occurred in all cultures except the 
Pseudomonas sp. and the R. M. bacterium. 
Cytophaga psychrophila and Chondrococcus 
columnari s did not grow on the test medium . 

An unidentified fungal disease of rainbow 
trout from a Tennessee hatchery is being 
studied . We are unable to infect fish after 
repeated feeding of fungal cultures ; however , 
death occurred rapidly following intraperitoneal 
injection. Tissue reaction to the fungus is 
similar to that seen in fish infected with 
Ichythosporidium . In the original material, 
cells similar to giant -cells and granulomatous 
areas were observed in abundance (Figure 1). 
A similar species has been isolated on several 
occasions from our stock coho salmon. We are 
attempting to identify the fungus (Figure 2). 




Figure 1. — Mid-kidney of fungus-infected 
rainbow trout showing cells similar to 
giant-cells (A) and granulomatous 
area (B). X320 Giemsa stain. 

Myxobacteria 

Several myxobacterial cultures have been 
frozen and held at -40 C . in order to determine 
length of survival . Hopefully this procedure 




uu^4i+ij4Ui;uuiji^ij.^c;i(iii^ilimii4Ui;ii!;iiuii44iii(W 



Figure 2. — External lesion on a coho salmon 
infected with fungus. 

can be used for maintaining a stock culture 
collection. The cultures were grown in a semi- 
solid agar medium prior to being frozen. Two 
cultures of Cytophaga psychrophila were viable 
after 10 months in the freezer and the Chondro- 
coccus columnaris culture was viable after 6 
months . 

Toxins 

It has been speculated that toxins may be 
involved in the pathogenesis of the disease 
caused by Chondrococcus columnaris . We were 
unable to demonstrate endotoxins, so diverted 
our efforts towards the isolation of exotoxins 
and proteolytic enzymes . The preparations we 
have obtained do not elicit a response when 
injected into fish. Proteolytic enzymes produced 
by some bacteria can destroy the exotoxin 
produced by the same organism . We are 
currently attempting to culture strains of jC . 
columnaris in the presence of proteolytic enzyme 
inhibitors, thus protecting the exotoxin if one is 
being produced. 

Therapeutics 

Anti-germ 50, a quaternary ammonium 
compound, was tested against Chondrococcus 
columnaris at concentrations ranging from 
1:500U through 1:100,000. Inhibition was obtained 
at the levels tested. 

Spectam, an experimental antibiotic, was 
tested against 6 strains of myxobacteria from 



63 



fish with cold-water disease in Washington and 
Oregon hatcheries , There was no inhibition at 
a drug concentration of 12.5 micrograms/ml. 
These 6 strains were also tested against 
Furanace at concentrations varying from 0.048 
micrograms/ml to 12.5 micrograms/ml. One - 
week post -inoculation growth was observed only 
in the control tubes containing no drug. 

Ten strains each of Aeromonas salmonicida, 
A. liquefaciens , Red Mouth (R. M.) bacterium, 
Pseudomonas sp. and Vibrio sp. were tested 
against Furanace at concentrations ranging from 
0,195 micrograms/ml to 12.5 micrograms/ml. 
The Pseudomonas strains were the most resist- 
ant and the strains of A. salmonicida were most 
sensitive. None of the 10 Pseudomonas cultures 
were inhibited by 12.5 micrograms/ml and only 
2 of the 10 A . salmonicida cultures were able to 
grow at a concentration of 0.78 micrograms/ml. 
Of the 10 A . liquefaciens cultures only one grew 
at a concentration of 3.125 micrograms/ml. 
Further study may show that sensitivity to 
Furanace might be of value in separating 
members of the genera Pseudomonas and 
Aeromonas . Six of the Vibrio cultures were not 
inliibited by 12.5 micrograms/ml while all of 
the R . M . bacterium strains failed to grow at a 
concentration of 6.25 micrograms/ml. 

A.J. Ross 

VIROLOGY 

Infectious Hematopoietic Necrosis (IHN) 

IHN virus was originally isolated from 
juvenile rainbow trout and sockeye salmon in 
British Columbia in 1967 . The disease recurred 
in sockeye salmon in 1968 . Between 100 and 175 
adult fish from 5 races of sockeye salmon 
were examined for IHN virus in early 1969, to 
determine geographic distribution of the virus 
in the Fraser River drainage and whether adult 
sockeye salmon were "carriers" of the disease. 
Filtered homogenates from kidney and intestinal 
material were inoculated onto FHM cells . No 
virus was isolated from any race of fish. Sub- 
sequently, the disease did not occur in the 1969 
juvenile sockeye salmon and the disease has not 
been diagnosed in Canadian rainbow trout since 
1967. 



hi 1969 we confirmed the diagnosis of IHN in 
rainbow trout from 5 new localities in 4 states . 
The mortality rates ranged from 5 to 98 percent 
and were found in fish from 3 to 5 weeks post 
hatching up to 8 months of age. In all cases to 
date epizootics occurred at water temperatures 
below 50° F. and the disease incidence appeared 
to decrease with increase in age (size) and 
water temperature . In one case the disease was 
controlled by elevating the water temperature to 
60° F . We have confirmed the temperature 
correlation experimentally. 

Methods of disease transmission and 
detection of "carrier" fish are being investi- 
gated. The disease can be transmitted by 
injection and from fish to fish, and transovarian 
transmission and exposure via feed are also 
being tested. We have demonstrated the virus 
on tissue culture from the ovarian fluid, 
pyloric caeca, and intestine of carrier adult 
fish, but not from the blood, kidney, or liver 
from the same fish. The highest titers of virus 
occurred in the pyloric caeca . We found that for 
routine sampling of brood stock, five -fish pools 
of ovarian fluid will suffice for detecting 
carriers . It was also found that fathead minnow 
(FHM) tissue cultures are more sensitive than 
rainbow trout gonad (RTG-2) cells in detecting 
carrier fish (Figure 3). 

Since increased water temperature controlled 
IHN disease in juvenile fish, adult trout prior to 
spawning were placed in 56 to 58° F . water for 
9-12 days, and then returned to 48-50° F. water 
to determine if the elevated water temperature 
would clear the fish of the virus J Fish kept at 
50° F. throughout the experiment had a minimum 
carrier incidence of 3.5 percent in a population 
of 170 fish. Immediately following the tempera- 
ture treatment, no carrier fish could be 
detected in 158 fish. However, within two weeks 
after being resubjected to 50° F . , 81 fish had 
a minimum carrier rate of 18.5 percent. 
Because eggs were poor if fish were spawned 
within one week after being removed from the 
high temperature and because the virus recurred 
within two weeks , this method is not a practical 
way of eliminating the disease. 

Attempts were made to induce an antibody 
response in rabbits, using techniques similar to 




Figure 3. — Fish specimens being processed 
for virus isolation. Betty Jefferson, 
Lummi Indian aquaculture trainee, is 
preparing bacteria-free filtrates for 
John Pietsch, Washington State Depart- 
ment of Fisheries Cooperator , to 
inoculate onto fish tissue cultures. 

those developed for "Egtved" virus. Rabbits 
were injected with purified and unpurified FHM 
tissue culture -grown IHN virus with and with- 
out the use of adjuvants , once a week for 3 
months. No IHN -neutralizing antibodies were 
detected from any preparation. In addition, 
serum from carrier trout showed no neutraliz- 
ing antibodies against IHN virus isolated from 
the same fish. We plan to repeat the experi- 
ments using concentrated virus preparation. 

A previous electron microscope study of 
IHN virus from FHM cells showed numerous 
bullet -shaped virus particles. To determine if 
similar structures could be found in diseased 
fish, fingerling sockeye salmon were infected 
with stock strain IHN-4 . After 10 days, kidney, 
liver, spleen, pyloric caeca, and liver from 
2 moribund fish were fixed with osmium 
tetroxide and examined with an electron micro- 
scope. Necrosis was seen in all tissues, 
confirming the observations previously reported 
using the light microscope, but virions of IHN 



were seen only in the kidney, spleen, and 
pyloric caeca . Virions appeared to be clustered 
aroimd certain cells in the kidney and spleen, 
but because of the extensive necrosis the cell 
type could not be identified. Compared to 
normal tissues the lymphocytes and cells of the 
early erythrocytic series were absent. Mature 
erythrocytes appeared normal . In the pancreatic 
area virions were observed only in epithelial 
layers of what appeared to be the acinar ducts . 
Various stages of development were observed 
and mature virions measured 90mn wide by 
158 my. long . This agrees favorably with the 
measurements of virus particles found in tissue 
culture . 

Donald F . Amend 

IMMUNOPATHOLOGY 

Anamnestic response 

New techniques in immunology have provided 
means for better defining the immune response 
in salmonid fishes . For example , current 
methods of electrophoresis, Immunoelectro- 
phoresis, and column chromatography have 
helped in classifying and defining the nature of 
rainbow trout antibody. 

Thirty albino rainbow trout were stimulated 
to produce specific antibody by one subcutaneous 
inoculation of Aeromonas salmonicida antigen. 
A sonicated, alum -precipitated, supernatant 
preparation of the antigen was used because it 
was previously found that this procedure enhances 
the immunogenicity. Weekly samples of one 
milliliter of blood were taken by heart puncture 
(Figure 4) and analyzed for antibody character- 
istics and titer. In this experiment a maximum 
titer was reached 5-8 weeks following the initial 
inoculation. A second stimulation was given 4 
months after the primary inoculation. 

Secondary inoculation resulted in the 
expected booster effect usually found in mammal- 
ian systems . This anamnestic or memory 
response was readily apparent one week after 
secondary inoculation. Serums from the primary 
and secondary responses were tested by 
Immunoelectrophoresis against the inoculated 
antigen. Only one precipitin line occurred in 



65 




Figure 4. — Lummi Indian aquaculture trainee, 
Clarissa Finkbonner, obtaining blood from 
albino rainbow trout by heart puncture. 
The trout are being used for furunculosis 
(A. salmonicida ) antibody formation 
studies. 

both cases. This line, however, was slightly 
skewed to the cathode. Upon further investiga- 
tion it might be found that the antibody molecule 
is not a complete homogeneous entity- -varia- 
tions may exist . The same serums were run 
through a Sephadex G-200 gel column to further 
detect differences in antibody weights and con- 
figurations (Figures 5 and 6). 

Vaccine study 

The production of effective vaccines 
depends on a thorough knowledge of the antibody 
reaction in fish and especially the identification 
of the protective antibody. Aeromonas salmoni- 
cida cells were ruptured by sonication, and 
supernatant fluids were inoculated into rabbits 
and rainbow trout on regular schedules to 
determine which bacterial antigens would elicit 
a response. Gel Immunoelectrophoresis was 
the method used for detecting the various 
antigens. 




Figure 5. --Sephadex chromatography columns 
are kept in a cold incubator. ■ Serum 
samples are separated by filtration 
through the gel column; fractions are 
collected and analyzed for specific 
antibody content. 

which was inoculated. Antiserums from rainbow 
trout precipitated only those few antigens with 
slow anodic mobility (Figure 7). 

These results do not necessarily demon- 
strate rainbow trout are less immunocompetent 
than rabbits , for it is known that different 
animals will react differently to various antigens , 
However, by these methods, we can begin to 
determine which antigens are of primary import- 
ance in giving rise to protective antibody in the 
trout . 

D. P. Anderson 



The rabbits produced humoral antibody to 
at least 14 antigens in the heterogeneous mixture 




06- 



04 



0.2 



25 




30 



4+1 4+ 4+ 2+ ± 
35 40 45 

Tube number 



50 



55 



60 



Figure 6. — The trout anti-A. salmonicida serum was fractionated by filtration through 
Sephadex G-200. The optical density (O.D.) is a measure of the amount of protein 
collected in the individual tube samples. Note that the agglutinating antibody as shown 
by dotted line occurred in tubes 32-40. Since the heaviest molecules are collected in 
the low-numbered tubes, this demonstrates that the antibody is a heavy component of the 




Figure 7. — The soluble antigens of A. salmonicida were placed in the top 
wells of both slides. After electrophoresis, the trough of the top 
slide was filled with anti-A. salmonicida trout serum and that of the 
bottom slide with anti-A. salmonicida rabbit serum. Note that the rabbit 
serum recognized many more of the antigens than the trout serum. 



67 



HBTOPATHOLOGY 



Kidney disease 

Examination of materials from a kidney 
disease histopathogenes is study was completed. 
Bacteriological and histopathological analyses 
were done on sockeye salmon fingerlings . 
Weekly samples of 5 fish were taken from each 
of three groups: A. Control --inoculated intra - 
peritoneally with saline . B. Test -inoculated -- 
inoculated intraperitoneally with kidney disease 
bacterium, Cornyebacterium sp. C. Test -fed- 
fed viable organisms which had been incorpor- 
ated into the complete test diet . 

Kidney tissue smears were made from all 
samples and gram stained to verify infection. 

Histopathological tissue changes in the B 
group were observed in the 1st week samples . 
Hematopoietic hyperactivity was evident in the 
kidney with the presence of an increased number 
of immature cells ("stem" or "blast" cells) and 
with a decreased number of lymphocytes 
(Figures 8 and 9). Minute foci of macrophages 
containing bacteria were also seen. Another 
evidence of infection was the noticeable increase 
of leukocytes in the vascular system (Figure 10). 
By the 4th week the infection in the B group had 
become systemic. Sampling was discontinued 
the 6th week since there was just one surviving 
fish. 

In the C (Test -fed) group microscopically 
observable tissue changes did not occur until 
the 5th week . Very small foci of macrophages 
in the kidney hematopoietic tissue were the 
earliest histopathological changes seen. 
Immature cells in the kidney and leukocytes 
were not as abundant as in the test -inoculated 
fish. 

Of the specimens taken at the termination 
of the experiment (12th week), 2 of the 5 showed 
clinically observable pathological changes in the 
kidney. The septicemic and systemic nature of 
the infection was quite evident histologically. 
Bacteria -engorged macrophages (Figure 11) 
were present throughout the circulatory system 
and most of the other tissues. 



V 





Figure S. --Poster ior kidney of control 
fingerling sockeye salmon showing hema- 
topoietic area (arrows) and tubules. 
X900. Giemsa stain. 




Figure 9. — Posterior kidney of 1-week test- 
inoculated fingerling sockeye salmon 
showing increasing number of immature 
"stem" cells in the hematopoietic area 
(arrows). X900. Giemsa stain. 




Figure 10. — Heart tissue of 1-week test- 
inoculated f ingerling sockeye salmon 
showing noticeable increase of leuko- 
cytes. X900. Giemsa stain. 




Figure 11 .--Macrophage with phagocytized 
bacteria in an artery of 11th week test- 
fed fingerling sockeye salmon. X2800. 
Giemsa stain. 

Whirling disease of coho salmon 

Whirling disease of coho salmon has been 
prevalent in coho hatcheries . Clinically there 
are some similarities to whirling disease of 
trout, but etiologically and histologically these 
two diseases are quite different. High mortal- 
ity has rarely been associated with the coho 
disease. In a given population only a very 



small percentage of coho become affected . 
Whirling or corkscrewing along the long axis of 
the body and scoliosis and lordosis are frequently 
observed in these fish. 

Histologically, the specimens exhibiting the 
whirling symptom frequently exhibited massive 
tissue changes in the posterior portion of the 
skull, particularly in the area adjacent to the 
medulla oblongata. The vertebral column just 
posterior to the head was also often involved. 
Invasiveness of pathological tissue suggested a 
possible neoplasm. In the earlier specimens 
received at this laboratory no organisms were 
found in the lesions . 

The specimens with spinal curvatures 
showed histopathological changes in the area of 
the curvature similar to those mentioned above. 
Here again, the invasiveness of the pathological 
tissues was quite evident . 

During the last few years we received many 
coho salmon specimens showing almost identical 
clinical manifestations and histopathological 
changes. However, there was one atypical 
aspect; a myxobacterium , Cytophaga psychro - 
phila , etiologic agent of cold water disease, was 
found in the majority of the lesions of these 
fish. This disease has been reported occasion- 
ally in Chinook and sockeye salmon, but exten- 
sive pathological changes have not been present 
when it is found in these two species . 

We are attempting to determine whether 
there is any relationship between the bacterium 
and the histopathological changes . 

Diagnostics 

Diagnostic materials (82 cases) for histo- 
pathological analyses were received from private, 
state. Federal agencies, and several foreign 
countries, including Canada, Chile, Scotland, 
and Sweden. Numerous samples this year were 
sent to us as IHN -suspect material. Several of 
these were found to be IHN -negative but had 
diffuse hepatic parenchymal cell degeneration. 
This year we have received increasing numbers 
of samples showing these hepatic cell changes . 
Although the etiological aspect of this condition 



69 



is still not clear, the histopathological picture 
suggests environmental toxicity. 

One case of hepatoma was diagnosed in a 
rainbow trout from a Federal hatchery. This 
is of interest since it was not too many years 
ago that this tumor was as common as kidney 
disease and furunculosis . 

W. T. Yasutake 

BIOCHEMISTRY 

The stress of anesthesia with MS -222 and 
benzocatne 



The calculated correlation coefficients for the 
regression of these changes on time are 0.6, 
0.6, and 0.7, respectively and are significant. 

190-1 Benzocaine r= 0.2,1=0.7 



In mammals, certain anesthetics (e.g. , 
diethyl ether) cause a marked stress reaction 
involving activation of the pituitary-adrenal 
axis, while other anesthetics, notably the barbi- 
turates , do not . 

Preliminary work reported last year 
indicated that prolonged anesthesia with MS -222 
can cause blood chemistry changes in 3 -year - 
old rainbow trout and yearling coho salmon. 
Since then, further experiments have been done 
to evaluate the stressor properties of MS -222 
anesthesia in yearling rainbows and to evaluate 
anesthesia with neutralized MS -222 (pH 7), or 
benzocaine (ethyl p-aminobenzoate), a close 
chemical relative which shows considerable 
promise as a fish anesthetic . 

Groups of 10 yearling rainbow trout held at 
10 C . in water of 20 ppm hardness (CaC03) were 
anesthetized with 80 ppm (0.03 mM) of MS -222 
or neutralized MS -222 and 50 ppm (0.03 mM) of 
benzocatne. Neutralized MS -222 (free base 
form) was as efficient an anesthetic as the sul- 
fonate form. After immobilization, fish were 
removed at about 1 -minute intervals and blood 
and anterior kidney samples taken. 

Analysis of these samples showed that with 
MS -222 anesthesia metabolic changes occur 
which are correlated with exposure time . Blood 
Urea Nitrogen (BUN) levels progressively 
increase (uremia), a tendency toward hyper- 
cholesterolemia occurs, and ACTH production, 
as measured by tnterrenal vitamin C depletion, 
takes place (Figures 12, 13 and 14). 




3456789 10 
Exposure time (min.) 



Figure 12. — Interrenal ascorbate levels in 
anesthetized rainbow trout as a function 
of exposure time; 10° C. , 0.03mM/L. 
Correlation coefficient (r) and t test 
for zero slope (T) are given; the MS-222 
regression line slope is statistically 
significant (P = 0.05, T>2.3) indicating 
vitamin C depletion with this anesthetic. 

These trends in blood chemistry reflect the 
stress of anesthesia due to the low (3 .5) pK of 
MS -222 . Anesthesia with neutralized MS -222 
(pH 7, free base) or benzocaine eliminated 
these disturbances in metabolism, implying that 
the sulfonic acid moiety of MS -222 is involved . 
The use of neutralized MS -222 or benzocaine 
also prevented the initial agitated swimming 
which occurs when fish are anesthetized with 
MS-222. In addition, benzocaine anesthesia was 
subjectively associated with less blood clotting 
and much less reflex twitching than with the 
other anesthetics . 

There were no significant changes in plasma 
Cortisol, glucose, or chloride with any of the 
three anesthetics . However , an F test of 



70 



320-1 Benzocaine r=-0.3, T=0.94 

280- 

240- 

200- 



T 1 r 



Benzocaine r= -0.02, T=0.50 
X . • . 



y 320-1 MS-222 r=0.6, T=2.2 

" 280- • 



4.0 
3.0 
2.0- 

^ I.O-U 1 ^ r 

^ 4.0-1 N, Ms-222 r = 0.2,1=0.50 
I, 3.0-):-* — • — ^x— 



-i 1 r 




Exposure time (min 



Figure 13, — Plasma cholesterol levels in 
anesthetized rainbow trout as a function 
of exposure time; 10° C. , 0.03 mM/L. 
Correlation coefficients (r) and t test 
for zero slope (T) are given. A 
moderate hypercholesterolemia, signifi- 
cant at the 93% confidence level, 
occurred with MS-222 anesthesia. 

variance ratios revealed tJiat variability in 
plasma glucose, cortisone, and cholesterol 
was greatest when MS-222 was used, while the 
variability in the chloride and BUN levels was 
independent of the anesthetic used. For inter - 
renal ascorbate, neutralized MS-222 anesthesia 
gave the least variable results. Thus, benzo- 
caine or neutralized MS-222 would be the 
anesthetics of choice for clinical chemistry 
measurements unless the exposure period was 
limited to 3-4 minutes or water of sufficient 
hardness (CaC03) to buffer the MS-222 to pH 7 
could be used. 

Crowding stress 

The effect of high loading factors on 
disease susceptibility is well known. However, 
the responsible metabolic changes have not 
been studied. To determine some of these, 
yearling rainbow trout were held at population 



4 5 6 7 8 9 10 
Exposure time (min. 

Figure 14. — BUN levels in anesthetized 
rainbow trout as a function of time 
anesthetized; 10° C. , 0.03 mM/L. Corre- 
lation coefficient (r) and t test for 
zero slope (T) are given. A statisti- 
cally significant uremia (P = 0.05, 
T = 2.3) developed when the fish were 
anesthetized with MS-222. 
o 
densities of 1, 3, or 7 lbs /ft for periods up to 

35 days . Water temperature was 50° F . , 
dissolved oxygen remained above 8 ppm, and 
free ammonia (NHo) was kept below 0.1 ppm; 
minimum inflow was 0.3 gal/min. Metabolic 
parameters measured were: plasma cholesterol, 
glucose, chloride, urea (BUN), Cortisol, and 
total protein. Pronephric vitamin C was also 
determined. 

The data indicated that limited metabolic 
changes do occur during long-term crowding. 
Of major interest was the fact that cholesterol 
and urea levels (which reflect liver function) 
fell within 3 days to about half their initial 
values and then slowly returned to "normal" over 
the 35 -day period. Vitamin C levels followed 
the same pattern but at a slower rate, presum- 
ably reflecting the initial hormonal response to 
crowding, followed by adaptation. The drop in 
BUN may have simply reflected laboratory 



diuresis but the initial decrease in cholesterol 
is unexplained. Blood glucose and chloride 
levels rose somewhat over the first three days 
and then showed little change. As expected 
from the glucose and vitamin C levels, plasma 
Cortisol was somewhat elevated during the first 
few days but gradually decreased over the 35- 
day period, again reflecting adaptation to 
crowding. Total protein levels remained fairly 
constant over the entire crowding period. 

By the end of 35 days , there were no longer 
any significant differences in blood chemistry 
among any of the crowding levels implying that 
the fish were becoming metabolically adapted 
to the high population densities . 

Blood chemistry of the rainbow trout 

The normal ranges for numerous blood 
chemistry parameters have been well estab- 
lished for many of the higher vertebrates and 
are of proven value as diagnostic tools in human 
and animal medicine . However, Information 
about the blood chemistry of fishes is fragmen- 
tary and is especially meager in the case of the 
normal ranges to be expected. Following 
clinical usage , the term "normal range" is the 
mean i two standard deviations and not merely 
the range of the data . 

Yearling rainbow trout (New Castle strain) 
averaging 100 g in weight were held at 10-13 C. 
in water of 20 ppm hardness (CaC03), main- 
tained on the Abernathy diet, and fasted over- 
night before bleeding. MS -222 or benzocaine 
anesthesia was used under conditions shown to 
have no effect on blood chemistry. Results 
were calculated from approximately 1,400 
clinical tests on more than 200 individual 
samples of blood plasma. In addition, ascorbic 
acid levels were determined on anterior kidney 
tissues from 239 fish. By graphically fitting a 
normal distribution curve to these samples, the 
mean and estimated normal ranges for a number 
of components were obtained, based on the 
assumption that these parameters are normally 
distributed in fish populations . 

The estimated normal clinical chemistry 
ranges for interrenal ascorbic acid, plasma 
chloride, cholesterol, glucose, total protein, 



Cortisol, and BUN in the yearling rainbow 
trout as derived by this statistical technique 
are shown in Table 1 . Corresponding means for 
immature brown and brook trout are included 
for comparative purposes . 

Table 1. --Estimated normal clinical 

chemistry ranges for blood and interrenal 
tissue in the yearling rainbow trout held 
under thespecified conditions. The 
normal range is the mean + two standard 
deviations. Mean values for immature 
brook and brown trout taken from Phillips. 



Chemical 


Rainbow 


Brook 


Brown 


component 


trout 


trout 


trout 


Ascorbate 


102 - 214 






tig % (kidney) 








BUN mg % 


0.9 - 4.5 


2.6 


2.6 


(plasma) 









Chloride m£q/l 84 - 132 

Cholesterol mg % 161 - 365 316 402 

Cortisol ng % 1.5-18.5 

Glucose mg % 41 - 151 70 71 



Total protein 

g % 



2.0 



2.0 



At the present time, these estimates of the 
normal clinical chemistry ranges for the rain- 
bow trout should be thought of only as a guide to 
what can reasonably be expected in a population 
of this age group held under the specified condi- 
tions. For example, total protein, BUN, or 
ascorbate levels outside the ranges given may 
reflect dietary imbalances rather than pathologi- 
cal processes while Cortisol levels can reflect 
handling stress. However, parameters such as 
blood chloride (which is involved with blood pH) 
would be less subject to environmental changes. 

Establishing normal clinical ranges for a 
wider variety of conditions and for additional 
constituents will provide new tools for deter- 
mining the optimum environmental requirements 
of fishes as well as make available disease 
diagnostic techniques now used only in human and 



72 



animal medicine. However, it must be 
emphasized that the normal range is the item of 
interest , not the mean values by themselves . 

Formalin uptake and toxicity in the rainbow 
trout 

Formalin treatments for external parasites 
have long been used in fish culture operations . 
Formalin is toxic in some situations but there 
is no information available concerning the blood 
and tissue levels of formaldehyde which build 
up during treatments, the metabolic changes 
these cause, or on clearance rates following 
treatments . 

Data showing blood formaldehyde levels 
vs , treatment levels in water of 20 ppm (CaC03) 
hardness are shown in Table 2 . There is no 
explanation for the decreased formaldehyde 
blood levels at higher temperatures; however, 
these data imply that rainbow trout of this size 
cannot survive blood levels above approximately 
40 ppm in this water supply. 

Table 2. — Blood formaldehyde levels as a 
function of formalin treatment levels 
and water temperature in yearling 
rainbow trout. 1-hour exposure. 



Treatment 


Blood 


levels 


(ppm) 


level (ppm) 


48° 


F 


56° F 


62° F 


200 


18 




15 


14 


400 


22 




18 


17 


800 


28 




25 


21 


1600 


44 




38 


29 



To learn of metabolic changes induced by 
formalin treatment , blood glucose, chloride, 
bilirubin, urea, total protein, and Cortisol 
were measured and correlated with formalde- 
hyde blood levels occurring after 200, 400, 
800, 1600 ppm 1-hour formalin treatments. 

Blood chemistry changes vs. exposure time 
are shown in Table 3. The elevated blood glu- 
cose levels may be due to formaldehyde inter- 
ference in the o-toluidine method used. The 
moderate increase in bilirubin indicates either 
accelerated hemoglobin breakdown or impaired 
liver clearance . The downward trend in blood 
chloride implies but does not prove that 



metabolic acidosis occurs. However, these 
changes are on the borderline of statistical 
significance and additional work will be required 
before definitive statements can be made. 



Table 3. — Blood chemistry changes as a 
function of time. Yearling rainbow 
trout, exposed to 200 ppm formalin, 
at 50° F. 





Expi 


osure 


time (hours) 


Constituent 





1 


3 6 


Chloride mEq/1 


124 


113 


6 
107 87 


Bi] irubin mg7i> 


0.5 


0.8 


0.8 1.8 


Glucose mg7o 


173 


452 


336 285 



Preliminary work on clearance times 
following a standard 200 ppm, 1-hour formalin 
treatment indicates that up to 3 weeks may be 
required, at 50 F., to completely eliminate 
formaldehyde from the blood . 

Gary Wedemeyer 

THERAPEUTICS 

Furanace ^P-7138) 

Following the successful experimental 
control of Chondrococcus columnaris last year, 
we set out to test the drug extensively under 
field conditions and expand our laboratory tests . 
The Dainippon Pharmaceutical Co. Ltd., Osaka, 
Japan, awarded the Abbott Laboratories the 
option for distribution of the drug in the Western 
Hemisphere. The Western Fish Disease 
Laboratory was selected to coordinate the field 
testing and approve testing procedures for the 
Japanese and American Pharmaceutical Compan- 
ies . Data were compiled for registration with 
the Food and Drug Administration. The follow- 
ing agencies cooperated in the 1969 tests: 
Washington Department of Fisheries, Game 
Commission of Oregon, Fish Commission of 
Oregon, California Department of Fish and Game, 
Oregon State University, University of 
Washington, and several Federal hatcheries. 

The myxobacterial diseases were the most 
thoroughly investigated. Bacterial cold-water 
disease, columnaris disease, and myxobacterial 
gill disease were experimentally controlled with 



73 



a single 1-hour exposure to 0.5 or 1.0 ppm 
active ingredient of Furanace or to two daily 
1-hour exposures. The recommended treat- 
ment apparently will be two daily 1-hour expos- 
ures at 1 . ppm . 

Therapeutic blood levels were obtained in 
coho salmon following a single feeding of 25 mg 
Furanace/kg body weight up to 100 mg/kg. 
However, with a hard pellet a palatability prob- 
lem developed with repeated feedings . Conse- 
quently, in vivo studies to show control of 
experimental Aeromonas salmonicida infections 
were unsuccessful because the fish refused 
feed following the first administration. Some 
control was afforded by administering the drug 
in the water for 2 to 3 consecutive days for 1 
hour at 8 ppm, but some toxicity problems were 
encountered which would contraindicate this 
method. Robert Garrison of the Game Commis- 
sion of Oregon reported successful control of 
Vibrio anquillarum in chinook salmon by feeding 
the drug at 50 and 75 mg/kg and did not observe 
any palatability problems with a soft pellet . 
Dosage at 200 mg/kg appeared toxic and 
dosages below 50 mg/kg were ineffective. 

Furanace has given poor results in control- 
ling protozoan infections . Treatment at 1.0 
ppm was ineffective against Costia infestations . 
Ellis Wyatt of the Fish Commission of Oregon 
reported that spring chinook salmon infected 
with Myxobolus insidiosis were administered 
six 1-hour treatments at 5 ppm and 10 ppm: the 
drug did not adversely affect the parasite. He 
also reported that the 10 ppm treatment was 
toxic to the fish following the fifth exposure. 

To determine some of the factors influ- 
encing the toxicity of Furanace, coho salmon 
were exposed to various concentrations of drug, 
various frequency of treatments , and different 
water temperatures . Acute toxicity was not 
observed following a single exposure up to 10 
ppm at 70° F . , but the mortality rate increased 
with repeated exposures and with higher dosage 
levels (Figure 15). In addition, the toxicity 
increased with an increase in water tempera- 
ture (Figure 16). In general, the frequency of 
treatment had influence on toxicity than did the 
other factors . Leif Marking of the Fish Control 
Laboratories, using 96 -hour standard LC^q 



bioassays , made similar tests and reported I 
similar results . In addition, he found that the i 
drug is more toxic in soft water than in hard | 
water . It was concluded that the drug is not ' 
very toxic, especially if exposure time is short, 

1 
Further studies were performed to deter- | 

mine the elimination rate of Furanace at 45° anci 
70° F. Coho salmon were given 3 daily 1-hour 
exposures to Furanace at 2.0 ppm and tissue 
residue levels determined for 96 hours. The 
drug could not be detected in the muscle, blood, 
kidney, liver, or skin 48 hours after the last 
exposure at 70° F . The drug was also not 
detectable in the muscle, blood, or skin after 
48 hours at 45° F., but traces were found in the 
kidney and liver up to 96 hours . Experiments 
are underway to determine how long the drug is 
retained in the liver and kidney at 45° F. A 
preliminary experiment was performed to 
determine its fate after absorption. Within 
minutes following treatment, high concentration; 
of drug were found in the urine and gill wash- 
ings, suggesting that Furanace crosses cell 
membranes rapidly and may not be extensively 
metabolized. 

Erythromycin (Gallimycin-5Q) 

A field test was performed at a State of 
Washington salmon hatchery by Mark DeCew, 
pathologist for the Washington Department of 
Fisheries, in cooperation with Abbott Labora- 
tories and the Western Fish Disease Laboratory 
to determine the efficacy of erythromycin therap 
for control of kidney disease in chinook salmon. 
About 40,000 fish received 100 mg/kg/ day for 
21 days and an equal number of untreated fish 
served as control. Both groups had about equal 
disease incidence before treatment . One month 
following treatment the cumulative percent loss 
in the untreated group was 2 ,4 percent and in 
the treated group, 0.5 percent. 

Donald F . Amend 



74 



100 



60 



'(0 



20 



D=J 



n 



1 PPM 



2 PPM 



H PPM 



6PPM 



PPIl 



10 PPh 



Figure 15. — Average percent mortality from duplicate lots of coho salmon after a 1-hour 
exposure to various dosage levels of Furanace at 70° F. Fish were given either 1, 2, 
3 , or 4 exposures 24 hours apart at each dosage level. 



100 _ 



3 S 



6 PPM 



10 PPM 



Figure 16. — Average percent mortality of coho salmon showing the effect of temperature on 
Furance toxicity following 3 daily 1-hour exposures at 3 dosage levels. 



75 



EASTERN FISH NUTRITION LABORATORY 

Cortland, New York 
Arthur M. Phillips, Jr., Director 



The Cortland Laboratory is operated cooperatively with New York State and Cornell University. 
Research results, published annually by the State in a numbered series, "Fisheries Research 
Bulletin," may be obtained from the laboratory or the New York Conservation Department. 



HIGHLIGHTS 

Trout fed a fat -free diet had abnormal - 
appearing livers that varied from creamy white 
to light brown. Those fed a similar diet forti- 
fied with ethyl linolenate had "normal" red- 
colored livers . 

The erythrocytes of brook, brown, and 
rainbow trout contained between 3 and 6 times 
more inorganic phosphorus, from 2 to 3 times 
more cholesterol, and between 2.9 and 3.6 
milligrams percent less lipid phosphorus than 
in human red cells . 

A combination of supplemental choline and 
niacin helped control body fat deposition in trout 
fed a fat -enriched diet. 



A -Testololactone (Teslac) increased trout 
growth when their eggs were water -hardened in 
a solution of the compound . 

Oxytocin injections into sexually mature 
brown trout did not induce spawning or spawning 
activity. 

Acid-soluble non-ionic phosphorus com- 
pounds were formed from dietary phosphate by 
both brown and rainbow trout and were used in 
the distribution of phosphorus to their tissues. 

Heavy metals significantly disabled the 
cation uptake mechanism of brown trout; alka- 
line earth cations excreted a protective action 
against toxic effects of copper, zinc, cobalt, 
and nickel . 



Massive doses of vitamin E reduced the 
hematocrit and the growth of brook trout. 

Thiamin is utilized by fish much the same 
as by higher vertebrates. A thiamin deficiency 
in trout resulted in a predictable upset of 
carbohydrate metabolism. 

The onset of functional sexual maturity of 
male brook trout was influenced by exposure to 
continuous illumination or to continuous dark- 
ness. Continuous light accelerated functional 
maturity by about 14 weeks and continuous 
darkness retarded onset by 6 weeks. 



DIET C0K4P0S1TI0N 
AND THE GROWTH, SURVIVAL, 
AND QUALITY OF HATCHERY TROUT 

The influence of essential fatty acids on brook 
trout growth and lipid metabolism 

Salmon and trout require certain polyun- 
saturated fatty acids for proper dermal pigmen- 
tation, body growth, prevention of dermal 
lesions, and survival. Our recent work showed 
a syndrome indicative of an essential fatty acid 
deficiency in fish fed hydrogenated safflower oil, 
suggesting that changes caused by hydrogenation 
had resulted in this condition. 



Duplicate groups of fingerlings, initially 
weighing an average of 4 .36 grams, were held 
for 12 weeks in troughs supplied with water at 
an average temperature of 12.4° C. and for an 
additional 12 weeks at a constant water tempera- 
ture of 8.3° C. The warm water supply became 
contaminated with freshwater Crustacea and, 
although the incoming water was filtered by 
fine -mesh screens and cloth, some of the 
smaller Crustacea were eaten by the trout . To 
overcome this difficulty a Crustacea -free 
spring -water supply at a constant temperature 
of 8.3° C. was substituted at the end of 12 
weeks . 

The fish were fed either a fat -free semi- 
purified diet in which the major source of 
energy was sucrose, or a similar diet plus 
either 1 percent of ethyl linoleate or 0.1 percent 
methyl linolenate. 

There was an apparent difference in 
terminal body weights, but the differences were 
not statistically significant. Mortality 
increased slightly in all groups during the final 
12 weeks of the study. There were no differ- 
ences in mortality among the fish fed different 
diets . 

Terminal samples of liver were frozen in 
dry ice, weighed, and held at -15° C. for liver 
fatty acid analysis. Other terminal samples 
were preserved for histochemical analyses. 

Expressed as a percent of body weight, the 
liver weights for fish fed the fat -free diet, the 
fat -free diet supplemented with ethyl linoleate, 
methyl linolenate, or ethyl linoleate plus methyl 
linolenate were 2.09, 2.33, 2.75, and 2.80, 
respectively. These are significant differences. 



Results of the histological and 
histochemical tests, conducted by Dr. Roger L. 
Herman, physiologist. Eastern Fish Disease 
Laboratory, showed that all livers except con- 
trols, were highly vacuolated. There was a 
very strong positive reaction for polysaccharide 
storage (probably glycogen) with the periodic 
acid-Schiff (PAS) stain, and Oil Red O and Sudan 
Black stains showed variable lipid storage. 
There was no indication of ceroid type pigments. 

■Fixation and storage in formalin and water 
precluded a true picture of liver glycogen 
storage. The sucrose level of the diets was 37 
percent and the livers probably would, there- 
fore, contain high glycogen levels . 



Hugh A. Poston and Donald L. Livingston 

CHEMICAL COMPOSITION 
OF TROUT BLOOD 

Because it is nucleated and can be readily 
isolated, the trout erythrocyte could serve for 
studies of cell metabolism . Although there is a 
good deal of information on the chemical 
composition of human erythrocytes and most 
domesticated mammals and fowl, there are 
little data on the chemistry of the trout erythro- 
cyte. 

This report is the second in a series of 
investigations to establish "normal" values for a 
number of chemical constituents in trout erythro- 
cytes. The initial report dealt with cation 
distribution of mature brown and brook trout . 
This report concerns the phosphorus, total 
cholesterol, and total free fatty acid distribution 
in mature brown, brook and rainbow trout. 



The livers differed in gross appearance. 
Trout fed the fat -free diet without supplements 
had terminal livers that varied from creamy 
white to a very light brown or "straw" color; 
those fed ethyl linoleate had "normal" red- 
colored livers; and those fed methyl linolenate 
had light brown livers, some similar to those 
from fish fed the control diet. Some livers 
from fish fed both linoleate were almost normal 
red but others were mottled with small white 
areas . 



Two-year-old trout were used. Five pooled 
blood samples (composed of 1.0 milliliter of 
blood from each of two trout) were taken from 
each species. The erythrocytes were isolated 
and analyzed for the constituents listed in 
Table 1. 



Table 1. — Distribution of phosphorus, total cholesterol, 
and free fatty acid in the erythrocytes of three species of trout 



Component 



Milligrams per 100 milliliters of erythrocytes!/ 
Brown trout Brook trout Rainbow trout 



Inorganic phosphorus 12.70 + 1.360 

Nucleic acid phosphorus 9.40 +" 0.045 

Pnospho-protein phosphorus 3.00 + 0.375 

Lipid phosphorus 9.00 + 1.110 

Barium fraction I 51.50 +_ 5.820 

Barium fraction II 1.50 ~ 0.180 

Total cholesterol 334.00 + 15.150 

Free fatty acid 106.30 " 5.920 



1/ All values + 1 standard deviation. 



14.70 + 


1, 


.330 


0.29 + 


0. 


.036 


2.60 + 


0. 


.412 


8.80 + 


1. 


,610 


53.40 + 


2. 


,680 


2.10 + 


0. 


.150 


279.00 + 


37. 


,820 


82.20 + 


7 . 


,640 



14, 


,10 + 


1.20C 


0. 


.37 + 


0.039 


1. 


.80 + 


0.482 


8. 


.30 + 


1.29C 


55. 


.80 + 


3.57C 


2. 


,60 + 


0.24C 


241. 


.00 + 


19.49C 


98. 


,90 + 


11.700 



Inorganic phosphorus levels were 3-6 
times higher than those reported for humans 
and total cholesterol levels were 2-3 times 
those of human red cells . The total free fatty 
acid levels were about one -half that of human 
red cells . Lipid phosphorus levels were from 
2.9 to 3.6 milligrams percent lower than in 
humans . The phosphoglycerate fraction was 
somewhat higher and the hexose mono -phos- 
phate fraction somewhat lower than those 
reported for human red cells. No comparative 
data were available for nucleic acid and 
phospho -protein phosphorus. 

The apparent differences among the three 
species may or may not be significant. The 
experiment does not lend itself to the estab- 
lishment of the significance of these differences. 

Thomas H. McCartney 

Characterization of serum protein electro - 
phoretic patterns of trout reared in continuous 
darkness or continuous illumination 



This study was designed to determine 
differences in electrophoretic patterns of 
serum proteins in brook trout reared in 
continuous light, continuous darkness, or 
continuous simulating natural seasonal photo- 
periods . Blood serum was obtained periodi- 
cally . Notes were made of the sex of each 
fish sampled, and the stage of maturity of its 
gonads. The serum was stored at -15° C. until 
electrophoresed by the Disc Polyacrylamide Gel 
method. The serum samples were being 
analyzed by the use of a microdensitometer , 



when the machine failed. Analyses will be 
completed later. 

Gross qualitative examination of the electro 
phoretic columns showed that, as the female 
brook trout of each controlled lighting environ- 
ment approached functional sexual maturity, a 
new protein fraction appeared in their serum; 
this was not present in tlic male trout serum. 
This proteni fraction has very slow mobility 
and probably is a lipoprotein. 

Seasonal seru m protein electropho retic 
properties of brook, brown, a nd rainbow trout 

A study to compare the seasonal scrum 
protein electrophoretic properties of brook, 
brown, and rainbow trout was initiated in late 
May, 1968. One hundred each of the three 
species, approximately 18 months old, were 
placed in a production x-aceway and fed a meat- 
dry meal diet daily throughout the study. 

Blood samples, obtained by severing the 
caudal peduncle, were taken at approximately 
monthly intervals until sampling was terminated 
in early November, 1969. Six fish per species 
were sampled monthly during most ol' rlie studyll 
but available numbers of fish retkicctl the 
number sampled to either four or five lish dur- 
ing the last six months. The species, sex, 
weigiit, fork length, and stage of I'unciional 
maturity and gonad condition were recorded for 
each fish sampled. 



Serum samples were held at -15° C. until 
electrophoresed. Gross inspection of the 
completed electrophoretic columns shows the 
appearance of a protein fraction with low 
mobility in the female serum of each species as 
they approached functional sexual maturity. 

Hugh A . Poston 

VITAMIN REQUIREMENT OF TROUT 

The interrelation of choline, niacin, methionine, 
and tryptophan on lipid metabolism of brown 
trout 

In our previous experiments , we have 
attempted to prevent increased body fat in 
trout fed isocaloric, fat -supplemented diets by 
using different sources of food fat, manipulat- 
ing protein sources, altering protein quality, 
and supplementing with vitamins and amino 
acids. In last year's work, supplementing fat- 
enriched diets with either choline or methio- 
nine did not prevent or reduce increased body 
fat. It may be that supplementation of more 
than one dietary ingredient before the fat- 
enriched meat-dry meal diet will produce less 
body fat . 

With this possibility in mind, we fed brown 
trout a fat -enriched diet supplemented with 
choline, niacin, methionine, and/or tryptophan. 

FingerlLngs were held at two water 
temperatures (constant 8.3° and average 12.4° 
C .) for 20 weeks . Duplicate troughs of fish 
were fed, at each water temperature, isocalor- 
ic meat -dry meal diets that varied in propor- 
tions of meat (50 or 36.5 percent) and dry meal 
(50.0 or 35 percent) and in percent of calories 
supplied as protein (67 or 46 percent) and as 
fat (25 or 46 percent). These diets either were 
supplemented with 6 percent safflower oil or 
not at all. The fat -enriched diets were forti- 
fied with varying combinations of niacin (0.05 
percent of diet) and/or choline, methionine, 
and tryptophan (each at 0.5 percent of diet), or 
not at all. 

Terminal livers were frozen in dry ice, 
weighed and held at -15° C . until analyzed for 



fatty acid composition (by gas liquid chromato- 
graphy) and total lipids . 

Body size. There were no statistically 
significant differences in average terminal body 
weights among the groups held at either water 
temperature . However , fish fed the low 
protein diet (46 percent of calories as protein; 
18.8 percent protein) containing methionine as 
the sole supplement in the colder water showed 
an apparent depression in body weight that 
approached statistical significance. 

Terminal average body weights of all fish 
in the warmer water were significantly greater 
than those in the colder water. 

Percent of body fat . Fish fed diets with 
supplemental fat had increased body fat at both 
water temperatures . Those fed the diet that 
furnished an increased proportion of calories 
as protein contained less fat than fish fed the 
other diets at the two water temperatures . 
However, those fed the high -protein diet had 
significantly higher levels of fat when held in 
the warmer water than those fed the same diet 
in the colder water. 

Trout fed the fat -enriched diet supplemented 
with methionine only, in the warmer water, had 
significantly more fat than those fed the diets 
supplemented with methionine, choline, and 
niacin or with choline and tryptophan at the same 
water temperature . 

Fish fed the fat -enriched diet supplemented 
with choline and niacin in the colder water 
contained less fat than those fed any other fat- 
enriched diet at that temperature. Their level 
of body fat was as low as that in the fish fed the 
high -protein diet in the warmer water. 

Total liver lipids . Fish held in the warmer 
water and fed the high -protein low -fat diet had 
the least lipids per gram of liver. The pattern 
of lipid deposition in fish held in the warmer 
water does not show any conclusive effects of 
the amino acid and vitamin supplementation. 



In fish held in the colder water the addition 
of the individual amino acids and vitamins, and 
choline and niacin, to the fat -enriched diet 
reduced lipid deposition. 

Liver fatty acid composition . Increasing 
the proportion of calories furnished by dietary 
fat from 25 to 46 percent, and the consequent 
reduction of calories furnished by protein from 
67 to 46 percent, caused a 182 percent increase 
in liver linoleic acid in the warmer water and a 
162 percent increase of the same fatty acid in 
the colder water. This dietary change also 
reduced oleic acid by approximately 50 percent 
at both water temperatures . Linolenic acid, 
never present in more than negligible amounts 
in livers of fish in the warmer water, doubled 
in percentage of the total fatty acids after the 
fish were fed the fat -enriched diet in the 
colder water . 

The addition of niacin, methionine, or 
tryptophan individually to the fat -enriched 
diets reduced palmitic acid at both water 
temperatures , and the supplemental mixture of 
choline, niacin, methionine, and tryptophan 
caused a similar decrease in the colder water. 

The addition of choline and niacin, or 
choline or niacin alone, to the fat -enriched 
diet increased the level of linoleic acid at both 
water temperatures , and methionine increased 
the level in the warmer water . 

Water temperature . With a few exceptions, 
the liver fatty acid composition was similar at 
the two water temperatures . Larger amounts 
of linoleic acid and some of the longer -chained, 
more highly unsaturated acids generally were 
present in fish fed a given diet in the colder 
water. Clupanodonic acid, not present in 
measurable amounts in livers from any fish 
held in the warmer water, was found when diets 
were supplemented with amino acids and 
vitamins in the colder water . 

Summary . At both water temperatures 
fat supplementation with saf flower oil increased 
the body fat without significant body weight 
increase. A mixture of supplemental choline 
and niacin reduced body fat deposition when the 
fat -enriched diet was fed in the colder water. 



but neither choline nor niacin individually 
significantly affected body fat levels . Choline 
and niacin reduced body fat in the warmer water 
when the mixture was added to the fat -enriched 
diet that also contained supplemental methio- 
nine . These results indicate a combination of 
supplemental choline and niacin is needed to 
help control body fat deposition in trout fed our 
fat -enriched diet. 

The increased liver linoleic acid, and the 
concomitant decrease in other liver fatty acids 
for fat -enriched diets at both water temperatures 
is a reflection of the high linoleic acid content 
of saff lower oil. 

The reason for the boost in liver linoleic 
acid by the Individual supplementation of 
choline, niacin, and methionine, and of choline 
and niacin is not clear, but possibly involves 
the biological donation of methyl groups . 

Hugh A. Poston and Donald L. Livingston 

Massive doses of vi tamin E in brook trout diets 

Previous work at this laboratory has shown 
that massive doses of the fat -soluble vitamins 
A and D produce physiological changes in 
brook trout . 

The study described here was designed to 
determine effects of high dietary levels of the 
fat -soluble tocopherol (vitamin E) on brook 
trout hematocrit , liver lipid content , liver fatty 
acid composition, and body growth. 

Duplicate groups of fingerlings, initially 
weighing 1.07 grams, were fed either a control 
diet (semi -purified Wolf diet) that contained 50 
milligrams of dl -alpha tocopherol per 100 grams 
of dry diet, or the control diet plus an addi- 
tional 450 milligrams of dl -alpha tocopherol per 
100 grams of dry diet. The experiments ran 20 
weeks at an average water temperature of 
12.4° C. 

Hematocrits were taken at the end of 14 
weeks and upon termination. Terminal liver 
samples were frozen in dry ice , weighed and 
held at -15° C. until analyzed for total lipids and 
fatty acid composition. 



Compared with hematocrits from the 
controls, hematocrit values for trout fed 
excess tocopherol showed a 13 percent reduc- 
tion at the end of 14 weeks, and 18 percent at 
the end of the experiment . 

Average lipid content per gram of liver 
was over 26 percent higher in fish fed excess 
tocopherol than in those fed the control diet . 

Livers from fish fed the control diet were 
heavier than those with excess tocopherol . 
The hepatosomatic index (liver weight expressed 
as a percent of body weight) was 1.73 for the 
control diet and 1.54 for the excess tocopherol. 

Liver linoleic acid, expressed as a per- 
centage of the total liver fatty acids, was 25 
percent lower with excess tocopherol. No 
other differences in fatty acids were detected. 

The average body weight of fish fed excess 
tocopherol was 6.5 percent less than that of the 
control. Neither diet caused unusual mortal- 
ity. 

Lowered hematocrit, changes in liver 
chemistry, and growth depression suggest that 
high levels of dietary alpha -tocopherol exert 
an adverse effect. Earlier work at this labora- 
tory showed that brook trout fingerlings fed 
125 milligrams of dl -alpha tocopherol per 100 
grams of dry semi-purified diet had higher 
hematocrits than those fed 20 milligrams of 
tocopherol per 100 grams of dry diet. The 
optimal level, in the semi -purified diet used in 
this study, appears to lie between 50 and 500 
milligrams of tocopherol per 100 grams of dry 
diet. 

The specific metabolic effects of high 
levels of dietary tocopherol on erythropoiesis 
and erythrocyte integrity have not yet been 
measured. 

Hugh A. Poston and Donald L. Livingston 



A thiamine deficient diet and its effects on 
serum and liver chemi stry of f ingerling brook 
trout 



Thiamine pyrophosphate is a required 
cofactor in two major biochemical transforma- 
tions during carbohydrate metabolism: (1) for 
the formation of acetyl coenzyme A from pyru- 
vate and coenzyme A, and (2) for the transketo- 
lase reaction in the operation of the pentose 
phosphate pathway for glucose oxidation. In 
higher animals the pentose phosphate cycle, 
among other tissues, is active in erythrocytes 
and liver cells and in rats the transketolase 
activity of red cells has been used as an indi- 
cator of thimine deficiency. Other studies 
have shown that the pentose phosphate pathway 
for glucose metabolism may be of more 
importance in trout liver than in that of other 
animals . 

Based upon trout growth and mortality 
rates thiamine is well established as an essen- 
tial nutrient but the biochemical changes caused 
by thiamine deficiency are not well defined. 

In this experiment, we fed f ingerling brook 
trout a thiamine -free synthetic diet for 20 
weeks. At the end of that time liver samples 
were analyzed for sedoheptulose -7 -phosphate, 
DNA, pyruvic acid, glucose, fructose, and 
organic phosphorus , and blood serum samples 
for glucose , fructose , and inorganic phosphorus , 

The liver data show the effect of the thia - 
mine deficiency on the pentose phosphate path- 
way of glucose metabolism . The amount of 
sedokeptulose -7 -phosphate (a product of the 
transketolation of xylulose -5 -phosphate and 
ribose -5 -phosphate) in the livers was only two- 
thirds that of the controls, indicating that 
absence of thiamine reduced transketolase 
activity. The liver DNA level was only one- 
half that of the controls . A significant amount 
of the ribose for nucleic acid synthesis arises 
from a reversal of the pentose phosphate path- 
way or a reversal of the transketolase reaction. 
Liver glucose and pyruvate were reduced in the 
thiamine -deficient trout, indicating a general 
suppression of glucose metabolism in the 
absence of thiamine. Liver fructose, however, 
was not affected, and no satisfactory 



81 



explanation is apparent . The inorganic 
phosphorus of the liver was not altered by 
thiamine deficiency. 

It was not possible to obtain sufficient 
serum to measure the amount of pyruvate in 
the bloodstream. An increased level of pyru- 
vate is an indication of thiamine deficiency in 
other animals . However , the increase of 
serum glucose and fructose levels show that 
there was a marked alteration in their carbo- 
hydrate metabolism . The serum inorganic 
phosphorus decreased. 

The data indicate that thiamine is utilized 
in fish in much the same fashion as in higher 
vertebrates and that the pentose phosphate 
cycle may indeed be of greater significance to 
trout metabolism than to the metabolism of 
higher vertebrates . 

Thomas H . McCartney 

PHYSICAL FACTORS AND GROWTH 
OF HATCHERY TROUT 

Effect of c o ntinuous darkness or c ontinuous 
light on sexual maturity of brook trout 

We commenced a series of experiments in 
March, 1966 to study the effect of continuous 
light and continuous darkness on brook trout 
growth and sexual maturity. 

Fingerlings, initially averaging 0.465 
grams, were stocked in each of three light - 
controlled chambers . One chamber was kept in 
total darkness except for infra-red illumination 
supplied through an 87C Wratten filter, giving 
0.32 percent transmission of 8,000 A° wave- 
length light. Infra-red illumination was used 
for observation with the aid of a mechanical 
viewer, and for biweekly or monthly weighings . 

A second chamber received light continu- 
ously from two 60 -watt and one 100 -watt incan- 
descent lamps that provided 16 foot -candles at 
the water's surface. A spectral analysis, with 
a radiospectrograph and head, showed that the 
peak wave lengths of light at nine inches 
beneath the water's surface were in the very 



deep red. A battery-powered lamp provided 
light in the case of electric power failure. 

The third chamber had light of the same 
intensity as the second chamber, but the lamps j 
were switched on and off daily by means of a 
photoelectric control as daylight and darkness 
approached . The fish in the third chamber 
were thus exposed to a daily period of artificial 
light that varied and was comparable to the 
hours of natural daylight. 

Each chamber contained one 210-gallon tank 
supplied with constant -temperature water at 
8.3° C. 

The fish, initially numbering 2,150 per 
tank, were reduced in number periodically to 
prevent overcrowding. Fish removed at the 
end of 72 weeks were fin clipped for identifi- 
cation, and held for spawning in a production 
raceway. 

The results of the first 94 weeks of the 
study were reported in the Cortland Hatchery 
Report for the Year 1967 . The following is a 
brief review of the earlier reported work. 

When the surplus fish were transferred from 
the three experimental chambers to a produc- 
tion raceway at the end of 72 weeks, male trout 
from continuous light had enlarged, milky white 
testes and copious semen with viable sperma- 
tozoa. Males from the chamber that simulated 
natural photoperiods had testes slightly larger 
than those from males in continuous darkness, 
but there was no indication of semen from fish 
in the latter two groups . Females held in 
continuous light had eggs several times larger 
than those in ovaries of females in continuous 
darkness or simulated natural light. 

We expected the fish held in continuous 
light to spawn much earlier than those held in 
either of the other two light environments . 
The trout placed in the production raceway did 
spawn at different times, as predicted on the 
basis of gonadal development. Those held in 
continuous light first spawned at about 6 weeks; 
those from simulated light first spawned at 
about 9 weeks; and those from continuous dark- 
ness about 11 weeks after transfer to the raceway. 



The time interval to first spawning in the 
trout remaining in continuous light, after 
surplus fish were transferred to natural photo - 
periods, was 12 weeks, compared with 6 weeks 
required for the fish that had been placed in 
natural light from the continuous light chamber. 
Females transferred from continuous darkness 
to natural photoperiods and light spawned 5 
weeks before those fish held in continuous dark- 
ness through spawning. 

The delay in spawning, in fish held in 
continuous light, compared with that in fish 
switched from these conditions to natural light 
and photoperiods, suggests an insufficiency of a 
release factor(s) necessary for the spawning of 
ripe eggs . 

Continuation through the second reproduc - 
tive cycle. The apparent delay in spawning 
time in fish held in continuous light, the appar- 
ent lack of effect of artificial light on the 
spawning date of fish held in light -controlled 
environments, and the reports in the literature 
suggesting that functional sexual maturity of 
trout undergoing gametogenesis for the first 
time is not affected by variation in photoperiods, 
prompted us to hold the same fish in their light - 
controlled environments until they reached 
spawning condition a second time. 

Males and females were examined 
periodically for external and internal indica- 
tions of sexual maturity. 

On April 11, 1968, several males in 
continuous light had a well -developed "kipe" of 
the lower mandible and on April 25 , 1968 , 24 
of the remaining 36 continuous light males had 
copious semen. The majority of males in this 
group continued to have semen until mid -July, 
1968. 

Males in the chamber with simulated 
natural light first showed copious semen, for 
their second season, on August 29, 1968, and 
continued to have semen through January 7 , 
1969. Eight out of 27 males in continuous dark- 
ness had reached functional maturity for their 
second season by October 10, 1968. However, 
the majority of the males in continuous dark- 
ness did not emit semen until December 5 , 1968. 



Semen could still be taken from most of these 
males on March 7, 1969, but not on April 3, 
1969. 

One female held in continuous light could be 
stripped of normal eggs on September 9, 1968. 
However, no other female in the continuous 
light group had ripe eggs until November 7, 
1968 . The majority of the females held in the 
simulated natural light environment were 
spawned from October 10 through November 7 , 

1968 . The first eggs were taken from a female 
in constant darkness on December 5, 1968, with 
the majority of eggs from this group being taken 
during January, 1969. 

The ovaries of females held in continuous 
light, and of those held in simulated natural 
light, contained a new third crop of developing 
eggs that ranged from less than one millimeter 
to over two millimeters in diameter on April 3, 

1969 . No sizeable new eggs could be detected 
in the fish held in constant darkness . 

All surviving fish were removed from the 
station on April 14 , 1969 . 

This study shows that the time of onset of 
functional sexual maturity (that is, the time at 
which copious semen can be expressed) of male 
brook trout in their second reproductive cycle 
can be influenced by exposure of the fish to 
continuous, uninterrupted illumination or by 
continuous darkness. Exposure of males to 
continuous light accelerated onset of functional 
maturity by almost 14 weeks. Exposure of 
males to continuous darkness retarded onset of 
functional maturity by 6 weeks. 

Exposure of males to uninterrupted illumin- 
ation apparently shortened the duration of func- 
tional maturity in their second reproductive 
cycle. Copious semen could be expressed from 
males exposed to continuous light for almost 12 
weeks, as compared with almost 19 weeks for 
males exposed to photoperiods simulating the 
natural environment, and 21 weeks for males in 
continuous darkness . 

Males in each of the controlled lighting 
environments became functionally mature before 



83 



the females. However, the males under 
continuous light were void of copious semen for 
16 weeks before the first eggs were taken from 
females in continuous light. Onset of functional 
maturity in the males and females exposed to 
constant darkness or to simulated natural light 
was better synchronized. 

Duration of functional sexual maturity for 
the males in their second reproductive cycle 
was more prolonged in each of the three 
experimental groups than the 6 weeks reported 
for male brook trout in the literature . 

Exposure of female trout to continuous 
light or to continuous darkness apparently 
retarded onset of functional maturity in their 
second reproductive cycle by approximately 
one month and two months, respectively, 
compared with conditions simulating natural 
light . 

The fact that eggs were not stripped from 
many of the females during their first 
reproductive cycle possibly altered their 
second reproductive cycle. Nevertheless, a 
majority of females under simulated natural 
light spawned when brook trout are usually 
spawned under natural light at Cortland . 

Hugh A. Poston and Donald L. Livingston 

TROUT ENDOCRINOLOGY 

Exposure of brook trout eggs to an androgenic - 
like prepara tion 

^ -Testololactone (Teslac) is a compound 
that is non -hormonal in routine bioassays for 
endocrine activity. It does , however, 
increase the rate of weight gain in mice and 
rats, following subcutaneous injection on the 
first day of the animal's life. It also promotes 
growth in amphibians following the incubation 
of eggs in its presence. 

Our interest was the possibility that trout 
from eggs water -hardened in a low concentra- 
tion of A -Testololactone, would grow more 
rapidly than those from non -treated eggs. 



With this possibility in mind, we water- 
hardened duplicate groups of 5 , 000 fertilized 
brook trout eggs for 30 minutes in beakers of 
distilled water containing 0.85 percent sodium ' 
chloride and 10 p. p.m. of ^^-Testololactone 
that had been dissolved in a 1:1 solution of ethyl 
alcohol and distilled water. Duplicate control 
groups of 5,000 fertilized eggs were water - 
hardened in distilled water containing 0.85 per- 
cent sodium chloride and an amount of ethyl 
alcohol comparable to the level to which the 
treated eggs were subjected. All eggs were 
incubated in flowing 8.3° C. water. 

Equal numbers of progeny from each lot of 
eggs were retained in similar troughs supplied 
with water at a temperature of 8 .3° C . The 
fish were weighed initially and at intervals 
thereafter to observe their growth. The numbers 
of fish were reduced periodically to prevent 
overcrowding. 

There was no difference in fertility, time 
of "eye -up," or percent hatch between the 
treated eggs and their controls . 

At the latest weighing, trout from the 
treated eggs weighed an average of 13 .2 percent 
more than trout from the control group, a 
significant difference. There was close agree- 
ment between replicate troughs within the treat- 
ment groups . 

The surviving fish are being held and 
observed for growth and possible effects of the 
treatment upon reproduction. 

Hugh A . Poston 

Injections of oxytocin on spawning female brown 
trout 

It has been reported that injections of 
oxytocin, a pituitary hormone that stimulates 
contraction of smooth muscles of the uterus and 
mammary glands of mammals, will initiate the 
"spawning reflex" in Fundulus heteroclitus . 
With the possibility that exogenous oxytocin will 
also induce spawning activity in trout, we 
studied the effect of injections of synthetic 



oxytocin on the activity and behavior of 
sexually mature male and female brown trout. 

Four 4 -year -old male brown trout, from 
which semen could be expressed, and four 4- 
year-old female brown trout, from which eggs 
could be stripped, were transferred from a 
production raceway to a trough supplied with 
water at a temperature of 8.3° C. 

A synthetic preparation of oxytocin, which 
contained 20 U. S. P. units of oxytocic activity 
per cubic centimeter, was injected either 
intraperitoneally or intramuscularly into the 
male and female brown trout, in dosages vary- 
ing from one and one -half to ten cubic centi- 
meters . The recipients were returned to the 
trough and observed for release of semen or 
eggs, and for unusual behavior such as the 
sigmoid-like posture displayed by Fundulus 
heteroclitus after oxytocin injections. 

No injected fish spontaneously expelled its 
eggs or semen during 6 hours of close observa- 
tion. None exhibited unusual body shapes or 
positions . 

All recipients, regardless of route of 
oxytocin administration, remained in a post- 
injection state of quiescence, during which 
they offered no resistance to handling; they had 
returned to a normal state, in which they 
resisted touch or capture, by the following day. 
This quiescent condition possibly was induced 
by the 0.5 percent chlorobutanol and/or the 
0.25 percent acetic acid contained in the 
oxytocic preparation. 

These results indicate that injections of 
oxytocin into sexually mature brown trout do 
not induce spawning or spawning activity. 

Hugh A . Poston 



MINERAL METABOLISM 

Phosphorus metabolism, comparing rainbow and 
brown trout with known metabolism of brook 



Our earlier studies with brook trout have 
shown a conversion of inorganic phosphorus 
from capsulated artificial foods into organic 
phosphorus compounds within the tissues. 
Generally, less than 10 percent of the food 
phosphate was found so converted, but analysis 
of the organic phosphorus components showed a 
significant amount of acid -soluble non -ionic 
phosphorus (probably adenosine polyphosphates) 
that could have been involved as a carrier that 
distributed the dietary phosphorus to the 
tissues. In the tissues of the brook trout diges- 
tive tract and muscle, a portion of the trans- 
ported dietary phosphorus was recovered in the 
lipid, protein, and nucleic acid phosphorus 
fractions, within one day after feeding. 

Other experiments, however, have shown 
that the great preponderance of phosphate from 
the food is recovered in the skin and skeletal 
tissues, where it remains through at least four 
days after feeding. Generally, these analytical 
results indicate an extremely efficient utiliza- 
tion of dietary phosphate. To establish the 
general existence of these efficient phosphorus 
metabolism mechanisms, yearling brown and 
rainbow trout were fed either 0.5 or 2.0 milli- 
grams of dietary phosphorus (as phosphate) that 
had been labeled with phosphorus -32. Labeled 
phosphorus in the skin and skeleton, and in the 
acid-soluble ionic, acid-soluble non-ionic, 
lipid, nucleic acid, and protein phosphorus 
fractions of homogenates of the digestive tract 
and muscle tissues were measured at one -half , 
one, two, and four days after feeding. 

Recoveries of labeled phosphorus . As with 
yearling brook trout, the utilization of dietary 
phosphate by both brown and rainbow trout was 
efficient from both dietary levels, with conver- 
sions approaching unity and with recovery of 
labeled phosphorus generally proportional to 
dietary level . At one -half day after feeding the 
food mass was essentially located in the stomach 
with considerable distribution of the absorbed 
labeled phosphorus to the other tissues of the 



tish already having occurred. One day after 
feeding the food mass had passed into the large 
intestine and the feces showed the presence of 
labeled phosphorus . The digestive tract 
contents were clear two days after feeding. 

A species difference between rainbow trout 
and brown and brook trout was evident before 
the four -day samples could be taken. The 
rainbows showed distress in the aquaria, 
probably from forced feeding of capsules, and, 
as has been observed in numerous other studies, 
the distress resulted in their deaths before the 
end of the four days . 

Except for this difference , which is only an 
artifact of the experiment, the two species 
responded like brook trout in their distribution 
and retention of the dietary phosphate , with 
significant quantities of the labeled phosphorus 
being recovered in the skin and skeleton within 
one -half day after feeding and with the skin 
again proving to be a major repository. The 
phosphorus incorporated into the structural 
tissues of the trout was essentially retained by 
the brown trout through four days after feeding 
and by the rainbow trout through the two or 
three days they survived. 

Distribution of phosphorus . As with 
brook trout, recoveries of labeled phosphorus 
in the acid soluble non-ionic fractions 
occurred as early as one -half day after feeding. 
Most of this recovery was in the homogenates 
of digestive tract tissues . Approximately the 
same amount of labeled phosphorus was 
recovered in the acid -soluble ionic fraction. 
Conversion of the ionic phosphate of the food 
to a non -ionic acid -soluble form appears to be 
a significant and efficient mechanism for 
phosphorus utilization by these three species. 
Much less labeled phosphorus was in the other 
organic fractions of the digestive tract at this 
early period after feeding. 

At this time in the muscle tissue 
homogenates, significant quantities of labeled 
ionic phosphorus were recovered, but practi- 
cally no labeled phosphorus in any organic 
form. A mechanism, therefore, for direct 
absorption of phosphate from the stomach had 
been functioning, but the presence of large 



amounts of the acid -soluble non -ionic labeled 
phosphorus indicates that probably the direct 
passage of phosphate through the membranes of 
the stomach to the blood stream is not the only 
mechanism at work. The quantity of acid- 
soluble non -ionic labeled phosphorus in the 
muscle tissues did increase with time after 
feeding, but this increase was not commensur- 
ate with the amount of inorganic, ionic labeled 
phosphorus found in the muscle tissues . The 
recovery of acid -soluble non -ionic labeled 
phosphorus in the digestive tract tissues 
continued through the two or four days of the 
experiment, again indicating some function of 
this form of phosphorus in the storage and 
transfer of phosphate from the diet to the 
tissues . 

Only small amounts of labeled phosphorus 
were recovered in the lipid, nucleic acid, and 
protein phosphorus fractions of both the diges- 
tive tract and muscle tissue homogenates . Most 
of this small quantity was found in the lipid 
fraction of the digestive tract soon after feeding. 
Only at two to four days after feeding did 
significant recovery of ^2p-iabeled material in 
the nucleic acid and protein functions occur. 

Phosphorus utilization. These recoveries 
in the organic fraction, plus the retention of 
the labeled phosphorus in skin and skeleton, 
indicate a considerable utilization of dietary 
phosphate, either by exchange to replace 
structural phosphorus in the body and thus main- 
tain the fish during food deprivation, or by 
actual accretion to form new tissue structures. 
The labile inorganic phosphorus from the 
single capsule fed each fish is rapidly trans- 
ported to the repository tissues with the con- 
comitant synthesis of acid-soluble non-ionic 
phosphorus compounds in the digestive tract 
tissues . This process apparently mediates the 
transfer of the dietary phosphorus to the tissues 
of the skin, skeleton, and muscle. From the 
long retention of labeled phosphorus in digestive 
tract tissues in both labile and depot forms , it 
appears that brown and rainbow trout also have 
efficient coupling and storage mechanisms for 
maintaining regulated and efficient phosphorus 
metabolism . 

Henry A . Podoliak and Alphonse S . Sniigielski 



Effects of divalent cations (alkaline earths and 
heavy metals) on calcium storage in skeleton 
and skin by trown trout 

In aquarium studies, brown trout have 
proved most resistant to deleterious effects of 
some abrupt and extreme water chemistry 
changes . Their resistance to these changes is 
correlated with the presence of adequate cal- 
cium hardness . 

In this experiment calcium -45 labeled, 
reconstituted water provided a means, through 
a tracer study, of establishing and measuring 
calcium uptake, exchange, and storage in the 
skeletal and skin tissues of fingerlings , and 
thus observing the effect of water chemistry 
changes on the ionic homeostasis of the brown 
trout that survive the challenging environmental 
conditions . 

Heavy metal ions were used in the 
aquarium water to provide a toxicity stress . 
Water hardness was provided by alkaline earth 
metals other than calcium to allow measure- 
ment of any protective actions (antagonisms) 
of these divalent cations against this toxicity 
stress . 

The heavy metals were used in two syner- 
gistic combinations. The first, of high 
toxicity, was a combination of 0.1 ppm of 
copper and 1.0 ppm of zinc. The second, of 
intermediate toxicity, and greater concentra- 
tion, was 1.0 ppm of nickel and 10.0 ppm of 
cobalt . 

The balanced reconstituted water 
contained 1.0 millimole per liter of both sodium 
and calcium, with either no other cations, or 
with a supplemental 1.0 millimole per liter of 
calcium, magnesium, strontium, barium, or 
potassium (an antagonistic monovalent cation), 
all as chloride salts. The fish were held for 
two days in ozonized labeled water at 10° C . , 
after which their gills, skin, skeleton, and 
remainder tissues were analyzed for radio- 
active calcium . 

No deaths occurred in the aquarium waters 
without the added heavy metals. Neither 
alkaline earth nor potassium ions appeared to 



stress the brown trout . All four of the added 
alkaline earths significantly depressed the rate 
of calcium absorption from the water to about 
two -thirds of what it had been without these 
added cations. The alkali potassium ion had no 
reducing effect on calcium absorption, but 
actually stimulated calcium absorption by about 
20 percent . The distribution of calcium to the 
different tissues was unaffected by any of these 
added ions . Most of the labeled calcium was 
recovered in the skin tissues, although the 
greatest concentration of labeled calcium, per 
gram of tissue, was in the bones, where propor- 
tionately twice the concentration of that in the 
gills and skin was measured. 

Copper and zinc . All five added ions 
effectively reduced deaths when the high toxicity 
heavy metals were present in the waters . With- 
out enrichment the trout died between 24 and 36 
hours in the toxic water. No deaths occurred in 
waters enriched with calcium, strontium, or 
barium . 

The presence of copper and zinc reduced 
the amount of labeled calcium recovered in the 
tissues to about one -fifth of that absorbed in the 
non-toxic water. Potassium again stimulated 
the absorption of labeled calcium, but now the 
supplemental alkaline earths only slightly 
reduced the calcium exchange when this 
exchange was so highly impaired by the presence 
of the toxic heavy metals . 

The ratio of labeled calcium in the skin to 
that in the skeleton was altered until, in this 
toxic water, the skin had an equal or greater 
concentration of labeled calcium. Significantly 
less of the absorbed calcium was transported to 
or exchanged with bone calcium. It appears that 
copper and zinc not only act externally to pre- 
vent normal ion absorption, but also act intern- 
ally to alter the distribution pattern of the 
absorbed ions . 

Cobalt and nickel. These intermediate - 
toxicity metals also reduced absorption of 
labeled calcium by about the same degree as the 
high-toxicity metals. Normal distribution ratios 
of labeled calcium to skin and skeleton were, 
however, retained in the presence of added 
calcium, barium, and potassium . The 



87 



aforementioned increased labeled calcium 
distribution to the skin in the water with copper 
and zinc occurred this time only in the presence 
of added magnesium and strontium . The fish in 
the aquaria with added magnesium and strontium 
also suffered the highest mortalities . 

In general, mortality was heavier in this 
greater concentration of the two intermediate - 
toxicity metals , directly because of the higher 
concentration, or because of additional competi- 
tive divalent ions provided by the cobalt, or 
simply because of a difference in the lethal 
effects of the different heavy metals . That 
their actions are different is indicated by a 
lack of increased calcium absorption in the 
presence of added potassium when the fish were 
in this intermediate -toxicity water . 

Calcium exchange . Alterations in calcium 
exchange caused by the two groups of toxic 
ions differ enough to permit speculation that 
the mechanisms of action of these heavy metals 
are significantly different. Exchange of labeled 
calcium from the waters occurs mainly through 
the permeable surfaces of the gill tissues . 
Except where double the normal amount of 
dissolved calcium was present, the normal gill- 
to-skin distribution ratio of labeled calcium 
(about 1 to 1) was maintained in the water with 
added cobalt and nickel. With added copper and 
zinc, however, this distribution ratio was 
altered to nearly 2 to 1 in favor of labeled 
calcium in gill tissues. A differing action of 
these two groups of toxic ions affected both 
fish survival and the distribution of ions in the 
body. As far as the highly toxic copper and 
zinc ions are concerned, added alkaline earth 
cations and added salinity (provided by potas- 
sium) improved survival. Least mortality 
was observed in both the high- and intermedi- 
ate toxicity solution when barium was the added 
ion. Magnesium, on the other hand, appeared 
to be somewhat antagonistic to calcium and did 
not reduce deaths in the presence of cobalt and 
nickel ions . 



regulating mechanism malfunctioned in the 
presence of heavy metal ions , but this was 
somewhat ameliorated by the supplemental 
cations, which permitted survival of the brown 
trout in stressful water chemistries. 

Henry A . Podoliak 

COOPERATIVE STUDIES 

Dr. William N. McFarland, physiologist 
at Cornell University, has participated in 
three cooperative studies at Cortland. 

Dr. McFarland has , in one study, investi- 
gated the effect of long-term exposure of brook 
trout to continuous darkness, continuous 
illumination, and conditions simulating natural 
light on the amounts and ratios of the retinal 
visual pigments, rhodopsin and porphyropsin. 

In another study he compared the levels and 
ratios of rhodopsin and porphyropsin in brook, 
brown, and rainbow trout and has analyzed for 
possible seasonal shifts in the amounts of these 
two visual pigments through monthly collections' 
of retinae from the three species of trout for 18 
months . 

In a third study he conducted a histological 
examination of fish retinae. He could find no 
evidence of degeneration of retinae in brook 
trout held for over two years in either continu- 
ous darkness (except for brief exposures to 
infra-red light), continuous light, or simulated 
natural light. 

Hugh A . Poston 



While the uptake of calcium from the 
water was profoundly affected by all of the 
added salts, ionic homeostasis appeared to be 
maintained in the presence of the supplemental 
alkaline earths. Likewise, the calcium - 



88 



WESTERN FISH NUTRITION LABORATORY 

Cook, Washington 
John E. Halver, Director 



HIGHLIGHTS 

Tiny coho salmon need 50 percent of diet 
as protein; then requirement drops with age to 
40 percent at 12 weeks in 10° C. water. 
Yearling cohos need only 35-37 percent of diet 
as protein in 10° C. fresh water. 

Fish protein concentrate is readily used as 
protein by cohos and rainbow trout. 

No tumors occurred in cohos insulted with 
aflatoxin for one year and then converted and 
reared in sea water. 

A vitamin test diet for Lahontan cutthroat 
trout was developed. 

Urea nitrogen was less than 10 percent of 
total nitrogen excreted regardless of fish load 
or time of day. 

Blood before and after gill passage shows 
that deamination occurs elsewhere than in gill 
tissue. 

Gill Na+, K"'"-ATPase drops by July and fish 
will not convert to sea water. High activity 
occurs in March, April, and May and fish can 
convert. One can condition fish to convert by 
pretreatment with high salt diets. 

Lahontan cutthroat trout need 4 percent 
salt in diet; higher protein diets are more 
efficient. Exercise seems mandatory for good 
growth and survival. 

Some plant proteins are satisfactory for 
trout and salmon diets . Maintenance 



requirements were 25 cal/g/day in 15 ° C. water; 
thus, the most rapid growth is the most effi- 
cient growth for fish. 

NUTRITION AND TOXICOLOGY 

Protein requirements of coho salmon 

Quantitative protein requirements for 
yearling coho salmon reared in 10° C . water at 
the laboratory were determined. Duplicate 
groups of cohos at initial average weight of 10 g 
were fed protein test diets containing 70 parts 
casein and 30 parts of gelatin to make 30, 35, 
40, 45, 50, 55, and 60 percent protein. 
Almquist plots of performance index showed 
inflection points after two weeks on the test 
diet at about 35 percent of protein. The results 
were reinforced after 4,6, and 8 weeks on test, 
indicating the tentative requirement of yearling 
cohos for protein to be about 35 percent of the 
ration in 10° C. water. No significant differ- 
ence in protein, lipid, or ash deposited in the 
tissues was observed between fish on different 
diet treatments (Table 1) . 

Small cohos were similarly tested in 15° C. 
water at the Hagerman Field Station. Response 
of the coho fry was similar to that of rainbow 
trout and chinook salmon fed similar diets. 
Almquist plots of weight gains after 2 and 4 weeks 
on test indicated these small salmon needed 
approximately 50 percent protein in the diet, but 
10 weeks on test indicated an inflection point at 
about 45 percent protein in the diet. 

Another study with cohos from the same 
egg source and fed the same diets in 10° C . 
water at the laboratory suggested a need for 



89 



Table 1. --Carcass proximate analysis 
Protein requirement--19D9--coho salmon 



% protein 


% protein 


% lipid 


'"i ash 






in diet 


in fish 


in fish 


in fish 


Totals 


% H20 


30 


60.02 


29.51 


8.76 


98.29 


78.90 




61.63 


29.28 


8.84 


99.75 


78.60 


35 


61.87 


30.28 


S.66 


100.81 


77.96 




61.52 


30.59 


8.49 


100.60 


77.90 


40 


63.11 


29.28 


8.57 


100.96 


78.18 




62.91 


30.80 


8.64 


102.35 


77.98 


45 


63.19 


29.29 


8.28 


100.76 


78.22 




61.59 


29.10 


8.88 


99.57 


78.63 


50 


62.96 


27.43 


8.54 


98.93 


79.27 




63.88 


27.75 


9.01 


100.64 


79.15 


55 


63.44 


28.44 


8.42 


100.30 


78.36 




63.56 


27.86 


8.71 


100.13 


78.26 


60 


66.03 


26.87 


8.97 


101.87 


79.10 




65.95 


26.20 


8.78 


100.93 


78.75 



approximately 45-50 percent of the diet as 
protein during the first 2-4 weeks of the feeding 
trial and then a subsequent drop in protein 
requirement to about 40-42 percent of the 
casein -gelatin mixture in the ration for maxi- 
mum growth as fish grew to about 3 g in size. 
Figure 1 shows average weight gain vs. protein 
content of the diet for young coho salmon fed 
these diets for 4 and 10 weeks , 

Protein sources for yearling coho salmon 

Biological utilization of protein sources for 
yearling cohos was examined at the laboratory 
with Dr. Nose, guest scientist from the 
Freshwater Fisheries Research Laboratory, 
Tokyo, Japan. Fish protein concentrate, cot- 
tonseed flour, Torula yeast, egg albumin, 
casein-gelatin, soybean meal, and opaque-2 
corn gluten were fed to 2 -year -old cohos held 
in metabolism chambers in 10° C . water . 
Results from the metabolism chambers were 
related to growth response and diet efficiency 
observed during a 6 week feeding trial with 
yearling cohos fed these protein sources as half 
the protein component of the ration. Fish 
would not readily accept soybean meal or 



cottonseed flour protein diets; therefore, the 
feeding trial was designed with half the protein 
furnished by the test protein and half furnished 
by a casein -gelatin mixture. Amino acid 
patterns were determined on 16 diets and protei 
sources for this study. Metabolizable energy 
content of the diet and partition of the protein 
components between urinary, fecal, and 
branchial excretions were measured in cohos 
at Cook, Wash. , and in large rainbow trout heh 
in metabolism chambers in 15° C. water at the 
Hagerman Field Station. 

Feeding trials were designed to test result 
of the studies described above. In addition, 
after 4 weeks on test a cytoplasmic protein 
fraction extracted from soluble components 
removed during preparation of fish protein 
concentrate was added to one group of fish on 
each diet to enhance acceptability of the dlfferci 
test diets. Then, 6 more weeks of feeding wen, 
completed. Results of the feeding trials closcl; 
resembled results from the metabolism chanibc 
analysis. Ethylene dichloride -prepared fish 
protein concentrate (Viobin) was the most rcadii 
used protein source, followed by casein -gelatin" 
egg albumin, and Torula yeast; most poorly 



90 




30 35 40 45 50 
CASEIN- GELATIN 



55 60 
MIX 



Figure 1. — Growth of coho salmon on 
different protein diets. Upper curve 
shows growth after 12 weeks on test in 
10° C. water; protein requirement about 
40% of diet (N x 6.25). Lower curve 
is plot of protein content vs. diet 
efficiency for small coho after 4 weeks 
in 15° C. water; protein requirement 
about 50% of diet (N x 6.25). All diets 
were approximately isocaloric between 
treatments . 

used were cottonseed flour, soybean meal, and 
opaque -2 corn gluten for yearling coho salmon 
in 10° C. water. Small cohos in 15° C. water 
grew best when fish protein concentrate was the 
protein in the ration. Torula yeast was well 
used, followed by the casein -gelatin mixture, 
cottonseed flour, and soybean meal; poorly used 
for growth were egg albumin and opaque -2 corn 
gluten , 

Cytoplasmic protein fraction made the 
cottonseed flour diet more acceptable but a 
negative correlation was obtained in those diets 
containing Torula yeast or soybean meal, and 
no correlation could be observed in diets 
containing opaque -2 corn gluten or the casein - 
gelatin mixture. Amino acid assay of compon- 
ents of CPF did not indicate adequate supple- 
mentary effect for the cottonseed flour protein 



diets to account for the observed increase in 
growth response. In fact, the increased growth 
could be directly correlated with the large 
amount of feed ingested and converted at the 
same efficiency as in that lot containing cotton- 
seed flour protein without added CPF . No posi- 
tive correlation between amino acid patterns 
assayed in FPC, TY, CSF, SBM, 02G or C-G 
protein component diets and the observed growth 
response could be obtained. Greatest feed 
efficiency of all protein sources tested was with 
the highly digestible casein -gelatin protein. 
Fish protein concentrate or Torula yeast will 
produce good growth in small cohos but the diet 
efficiency needs to be improved by either formu- 
lation or diet pretreatment to make the protein 
more available to these young fish. Results 
of the 6 -week test of these components, with and 
without added CPF, show in Table 2. 

Lahontan cutthroat trout test diet 

Major effort at the Hagerman and Bowman 
Bay Field Stations resulted in one vitamin test 
diet which would rear Lahontan cutthroat trout 
for at least 16 weeks without the appearance of 
any nutritional deficiency syndrome. Studies 
included varying mineral and protein content of 
the ration in troughs, conical aquaria, and a 
tank that required the fish to swim continuously. 
Feeding results indicated that the test diet 
should contain about 4 percent mineral mix and 
about 50 percent protein. Better diet efficiency 
was observed with 70 percent protein in 15° C . 
water at Hagerman. Brine shrimp nauplii for 
tiny fish and a moist commercial pellet for much 
larger fish in the 10° C . water system at 
Bowman Bay worked well . Samples of fish 
obtained after 3 weeks on test showed fish fed 
brine shrimp nauplii had intestines filled with 
undigested chitinous exoskeletons , however, and 
soon thereafter growth ceased unless these fish 
were shifted to moist pellets or casein-gelatin 
rations. 

Fish fed the laboratory complete test diet 
grew well but often had extended stomachs when 
reared in still or slowly moving water systems . 
In contrast, those fish reared in nose -cone 
aquaria or in round tanks where violent exercise 
was a continuous demand showed good growth, 
diet conversion, and diet efficiency. In tests 



91 



Table 2. — Protein sources for coho at 15°C 



Protein 



Number of 


Average 


Feed 


Diet 


fish 


weight 


used 


efficiency 


199 


2.37 


309 


0.81 


200 


2.25 


133 


1.03 


200 


2.05 


123 


1.04 


199 


1.77 


111 


0.96 


198 


2.26 


156 


0.94 


189 


1.70 


90 


0.79 


191 


1.50 


70 


0.79 


198 


0.61 


69 


0.17 


200 


0.67 


68 


0.31 


196 


1.13 


142 


0.48 


193 


1.83 


118 


1.53 



Fish Protein 
Concentrate 

Torula Yeast 

Torula Yeast 
plus CPF 

Cottonseed Flour 

Cottonseed Flour 
plus CPF 

Soybean Meal 

Soybean Meal 
plus CPF 

Opaque-2 Gluten 

Opaque-2 Gluten 
plus CPF 

Egg Albumin 

Casein-Gelatin 



in a deep square tank with rounded corners , 
water was jetted into the center to cause circu- 
lation of the water mass . Small Lahontan 
cutthroat trout reared under these conditions 
grew well, with about 85 percent survival 
through an initial 20-week feeding trial in 15° C. 
water at Hagerman. 

Chronic aflatoxicosis in coho salmon 

Cohos fed diets containing 20 ppm aflatoxin 
B^ failed to show any hepatoma after one year on 
test in fresh water . These fish were then moved 
to the Bowman Bay Field Station and adapted to 
sea water. After 18 months in sea water, all 
surviving fish were examined by necropsy, and 
liver tissue preserved for subsequent histo- 
pathology. No hepatomatous tissue was observed 
in any fish examined at necropsy, and no hyper- 
plastic or neoplastic tissue was detected in any 
of the slides examined microscopically. Coho 



are remarkably refractive to chronic insult 
with aflatoxin Bi . 

John E . Halver 

ENZYMOLOGY 

Determination of ammonia and urea in trough 
water 

The ammonia concentration in water from 
troughs holding usual loads of fish can be deter - 
mined routinely by some variation of the indo- 
phenol method, such as that of Muramatsu, 
Agr . Biol . Chem . , 31:301 (1967). Such direct 
colorimetric determination would be subject to 
interference from color produced from other 
substances , but the interference would probably 
be minimal for routine analyses . Care must be 
observed in collecting proper blank samples 
because it has been found that water flowing into 
troughs sometimes contains considerable and 
variable (with time) color -producing material. 



The concurrent determination of ammonia 
and urea under similar conditions presents 
problems that have not been completely solved . 
The required addition of urease to hydrolyze 
the usual low concentration of urea (near the 
limit of sensitivity of the method) introduces 
color -producing materials that create an intol- 
erable blank situation for revealing urea -am- 
monia by differences . Various methods used 
to concentrate the urea -ammonia seemed only 
to complicate the urease interference. Reliable 
results for relative amounts of excreted urea- 
and ammonia -nitrogen were obtained by 
treating trough intake and effluent water in 
microdiffusion dishes (modified Conway). 
Urease was even added (inactivated) to the 
dishes used for the determination of preformed 
ammonia by adding it after the alkali was added 
to release the ammonia. Alkali was added to 
the dishes for total ammonia after 30 minutes 
of urease -hydrolysis . The diffused ammonia 
was determined by the indophenol method. 

The above procedure shows that the amount 
of metabolic urea -nitrogen was always relatively 
small compared to the ammonia -nitrogen. 
Although the absolute amount of urea -nitrogen 
was not accurately determined, it was less than 
10 percent of the excreted ammonia -nitrogen 
determined under identical conditions. This 
small percentage of the total was shown to be in 
trough water regardless of the load of fingerling 
Chinook salmon (1.8 to 15.4 lbs /gal inflow /min) 
or time of day of sampling (4 hours of continu- 
ous sampling in the middle of the day or the 
night) . There was some indication of an 
expected increase in ammonia concentration 
during the day due to increased activity of the 
fish. 

GOT, GPT, GDH levels in liver, gill, and 
serum 

Spectrophotometric clinical procedures 
(Sigma 410-UV) for determining glutamic -oxala- 
cetic transaminase (GOT) and glutamic -pyruvic 
transaminase (GPT) in serum were modified 
for use with fish tissues . It soon became 
evident that light absorption at 410 my. 
decrease in a mixture of the dialyzed tissue 
homogenates, a-ketoglutarate, DPNH, and 
ammonia even when malic dehydrogenase (MDH) 



or lactic dehydrogenase (LDH) were not added 
as indicators for the GOT or GPT reactions, 
respectively. This would most logically seem 
to be due to glutamic dehydrogenase (GDH) 
activity (Figure 2). Because a combination of 



DPN 



DPNK 



NH- 



GDH 



Ketoglutarate qqj Glutamate 



Aspartate 



Oxa I acetate 

MDH 
' DPNH 



Malate <--> 

Figure 2. — Glutamic-oxalacetic transaminase 
and glutamic dehydrogenase reactions. 



GDH with GOT (GPT) activity is often postulated 
as the pathway for deamination of amino acids, 
it was decided to determine GDH along with 
GOT (aspartic acid as substrate) or GPT (ala- 
nine as substrate) by obtaining three separate 
reaction rates for each transaminase, as 
follows: 

A . All reagents present for total GDH 
and GOT (GPT). 

B. MDH (LDH) in ammonium sulfate 

solution omitted for endogenous 
material . 

C. MDH (LDH) omitted, ammonium 
sulfate added for GDH and endo- 
genous material. 

C - B = GDH activity 

A - (C - B) = GOT (GPT) acitivty 

The calculations gave two GDH values for each 
tissue --one from the GOT and one from the GPT 
determination. In most cases these two values 
were fairly similar except for serum, in which 
case the GPT -determined values seemed more 
reliable and were therefore used in calculating 
all GOT as well as GPT values . (The GOT- 
determtned GDH values of serum were often 



93 



negative, due, it is thought, to a build-up of 
glutamate from the relatively high GOT activity 
and consequent reversal of the GDH -promoted 
reaction.) 

Average GOT, GPT, and GDH values found 
for the gill, liver, and serum of rainbow trout 
and of coho salmon are shown in Table 3 . All 
of the trout were from one population, but the 
starved group had not been fed for at least 4 
weeks . The GPT values for coho gill and liver 
were significantly higher (p = 0.01) than the 
respective values for rainbow trout . Also , the 
GOT value for coho serum was significantly 
lower than for trout serum . Although there 
were considerable differences in the GPT and 
in the GDH values for sera of the two species , 
the significances were low. The differences 
may not be species differences because there 
were some uncontrolled factors. Again, big 
differences in certain values (e.g., gill GPT 
and serum GPT and GOT) for fed compared to 
starved rainbow trout were of little significance 
because of wide variations among individuals . 

The level of fish serum GOT was about 
10 -fold higher than that of normal human serum 
GOT. However, on a per -gram protein basis. 



all the fish serum activities were lower than the 
activities in the other fish tissues . 

Deamination routes 

It has been shown above that the fish tissues 
contained measurable transaminase and glutamic 
dehydrogenase activity which may function for 
the main route of in vivo deamination of amino 
acids . Analyses for ammonia concentration in 
blood removed from live fish via the bulbus 
arteriosus and the artery in the roof of the moutl 
indicated a decrease as blood passes through the 
gills . This probably precludes the gill as being 
the main tissue for deamination. When certain 
amino acids were added to dialyzed tissue homo- 
genates with other reagents shown in Table 4 , 
ammonia was produced. 

C . Bradford Croston 



Table 3. — Average transaminase and deaminase activities in fish tissues 

GOT GPT GDH 



Gill 



Rainbow trout 
Starved rainbow trout 
Coho salmon 



Rainbow trout 
Starved rainbow trout 
Coho salmon 



Blood serum 



Rainbow trout 
Starved rainbow trout 
Coho .salmon 



/pD/min/g Tissue 

7.8(10)* 0.8(10) 6.0(10) 

6.0(10) 2.0(10) 4.9(10) 

10.5(11) 3.4(11) 4.6(11) 

/po/min/g Tissue 

26.3(10) 10.4(10) 8.2(10) 

29. 1( 9) 13.3(10) 11. 9( 8) 

26.5(11) 20.1(11) 6.6(11) 

SCOT Units (Sigma) 

510. 0( 8) 22. 3( 9) 72. 0( 9) 

246. 0( 8) 43. 6( 8) 54. 6( 8) 

231. 0( 5) 30. 5( 5) 23. 7( 4) 



*Numbers in parentheses are numbers of individual fish. 



94 



Table 4. — Reaction mixture for ammonia formation from amino acids 



Volume (ml)* 
0.06 
0.12 
0.02 
0.02 
0.04 
0.02 



Reagent 



Amino acid solution (0.4'^DL-f orm or 0.2M L-form) 

Tissue homogenate (in pH 7.5 phosphate buffer) 

a-Ketoglutarate solution (0.1 M) 

DPN solution (2 mg/ml) 

Sodium arsenite solution (0.033 M) 

Pyridoxal phosphate solution (200 tig/ml) 



♦Volumes added to each modified Conway microdif fusion dish. 



MINERAL METABOLISM 

Gill ATPase activity in coho salmon 

Seasonal changes in gill ATPase activity of 
cohos indicate that a relation exists between 
the Na"*", K+-stiniulated activity and seaward 
migratory movements of juvenile fish. Constant 
monitoring of activity from February to 
October has shown that this activity in microso- 
mal particles from gill tissue of yearling coho 
maintained at a constant 10° C. (50° F.) 
increased from about 13 t^moles ATP hydro - 
lyzed/mg/protein/hr to 26 during the last two 
weeks of March. Activity remained at this 
level until the first of July, at which time it 
began to decrease, reaching a value of about 
18 ^moles by the end of the month and remain- 
ing at that level through the first of October . 
This information is given in line one of Table 5 . 
The increased Na"*", K"'"-ATPase activity appears 
at a time when these salmon normally begin 
migrating to sea and may be a biochemical 
manifestation of their readiness to accept sea 
water. This activity may also have played a 
role in results obtained by Baggerman (J_. Fish . 
Res . Bd., 17:295(1960)) in which young coho 
salmon showed a preference for fresh water at 
the beginning of March, but for salt water at 
the end of the month and during April and May. 
In July the test animals again selected fresh 
water , which may bear a direct relation to the 
puly decrease in Na"*", K"''-ATPase activity. 
Noble (Proc . N. W. Fish. Cult. Conf., pp. 48- 



51(1958)) reported that coho from rearing ponds 
in Minter Creek, Wash., in December did not 
migrate until April. Coho placed in the creek 
in July did not show an appreciable migration. 

The release of hatchery reared fish early 
enough in the spring to complete seaward migra- 
tion by July may be an important factor in 
determining the total number making transition 
into sea water. Additional support for the sug- 
gestion that a seasonal elevation in gill Na , 
K"*" -ATPase activity might be related to salt 
water selection and adaption is the observed 
elevation of this activity when coho salmon 
adjust to a salt water environment . Values for 
this activity increase 3- to 4 -fold over the fresh 
water levels (Table 5, Line 5). 

The enzyme responsible for this ATPase 
activity has a role in transporting Na across 
membranes and it would be expected that greater 
activity is required when the animal resides in 
sea water and must eliminate salt into a hyper- 
tonic environment . 

The basic Mg'^"'" -ATPase activity decreased 
from about 42 n moles Pj released/mg pr/hr in 
fresh water to 21 when the fish became fully 
adapted (Table 5, Lines 1 and 5). The reason 
for this decrease is not fully understood at this 
time but a similar decrease was detected when 
fish were fed a diet containing 12 percent (dry 
weight) added NaCl (Table 5 , Line 2) . Feeding 



95 



Table 5. --Summary of ATPase activity in gill microsomes from coho salmon 

ATPase activity (txmoles P, released/mg pr/hr) 



Conditions 



1. Complete test diet (CTD) 

2. CTD + NaCl (12%, dry wt) 

3. CTD (exercise) 

4. Hatchery raised 

5. Salt water adapted 



February to 
mid March 



42 
26 



Na , K 
13 
17 



Mid 


March to 


mi 


.d 


July 


Mg^^ 




+ + 
Na , K 


42 




26 


26 




33 


58 




26 


60 




24 


21 




93 



July to 
October 



2+ -^ + 
Mg Na , K 



NaCl also caused a moderate elevation of the 
Na+, K+ -ATPase activity. 

Cohos obtained from the Willard National 
Fish Hatchery showed higher Mg^^-ATPase 
activity (Table 5 , Line 4) than our laboratory 
fish held in troughs . We therefore took samples 
from laboratory fish in circular tanks and found 
a correspondingly elevated Mg ''"-activity 
(Table 5, Line 3). Since the only obvious differ- 
ence between the laboratory fish held in troughs 
and circular tanks was the amount of exercise 
required to maintain position we surmised that 
exercise might be a factor which influence 
observed activities . 

Table 6 shows that the seasonal changes in 
Na"*", K+-ATPase activity were relatively inde- 
pendent of the size of the fish. Activities in 
fish of 11.0 to 11.9, 12.0 to 12.9, and 14.0 to 
14.9 cm groups measures 12, 14, and 15 during 
February 12 to March 15 , while fish in the same 
size groupings had activities of 22, 25, and 28 
during March 16 to July 31. Likewise, over- 
lappings in the size groups from March 16 to 
July 31 and from August 1 to October 2 showed 
that the season and not the size was the deter- 
mining factor in Na"*", K+ -ATPase activity. 
An exception was seen in the large fish (18 .0 
to 23.9 cm), which seemed to maintain an 
elevated activity after July 31 . However , these 
fish were considerably larger than normal 
migrants . 



Data in Table 7 show how the Na"'", K"*"- 
stimulated ATPace activity increased and the 
Mg^^^-dependent activity decreased when coho 
salmon were placed in salt water (35 ppt , 
Instant Ocean salts) . Both activities reached 
maximal change after 30-35 days, suggesting that 
cohos are hot completely adapted until salt 
water residence has been established for this 
length of time . The final values in the table 
were obtained from 4 coho adapted to natural 
sea water (31 ppt) at Bowman Bay. 

We have attempted to show the minimum 
length of time in salt water required to produce 
changes in gill ATPase activities , In these 
studies we have followed the changes in individ- 
ual fish by surgically removing samples of the 
gill filaments at various salt water exposure 
times . Under anesthesia (MS -222) filaments 
from one or two arches of fresh water coho 
were removed with scissors and used for ATPase 
determinations . The fish were allowed to 
recover completely (4 hours) and were then 
placed in full strength sea water (Instant Ocean 
salts, 35 ppt) for a desired length of time. The 
fish were again anesthetized and filaments 
removed for study. Changes in ATPase activity 
were detected only after 3 to 4 days in salt 
water . 



Table 6. — Relationship between size of fish and season of the year on 
Na'*' , Kr*'-activated ATPase activity of coho salmon gill microsomes* 



Na'^ , K*-activated ATPase activity 
(timoles Pj released/mg pr/hr) 



Fork 1( 


;ngt 


:h 


(cm. 


) 




11.0 - 


11. 


,9 


12.0 - 


12. 


,9 


13.0 - 


13. 


,9 


14.0 - 


14. 


,9 


15.0 - 


15. 


,9 


16.0 - 


16. 


.9 


17.0 - 


17. 


.9 


18.0 - 


23, 


.9 



February 12 to March 16 to August 1 to 
March 15 July 31 October 2 

12 (2)** 22 (2) 

14 (6) 25 (3) 

26 (8) 

15 (2) 28 (6) 12 (1) 

23 (3) 16 (2) 

23 (1) 17 (6) 

16 (1) 

22 (5) 



*Experimental conditions listed in Table 5. 
**Number of fish in parentheses. 



Table 7. — Changes in ATPase activities upon exposture 
of coho salmon to salt water 



ATPase activity 
(jimoles Pj released/mg pr/hr) 



Days in 
salt water 



42 26 

7 42 40 

15 30 59 

22 28 70 

29 23 91 

36 22 95 

39 19 93 

46 22 102 

58 20 84 

63 20 102 

67 25 82 

77 18 90 

702 22 82 



Values given are averages of at least two fish. 

^These fish (4) were held in natural sea water at 
the Bowman Bay Field Station for 2 months. 



97 



ATPase purification 



Partial purification of the enzymes contain- 
ing ATPase activities has been achieved by 
sucrose density gradient centrlfugation. In the 
most successful preparation thus far the Mg^"*"- 
ATPase activity was increased from 20 moles 
Pi released/mg pr/hr to 69, a 3. 5 -fold purifi- 
cation. In the same fraction the Na"*", K - 
ATPase activity was increased from 56 to 258 
moles Pi mg pr/hr, a 4 .6 -fold purification. 
This magnitude of Na"*", K"*" -ATPase activity has 
been achieved in tissues of other animals only 
after extensive purification procedures . It 
might, therefore, be possible to obtain a puri- 
fied enzyme from salt water -adapted fish having 
activities exceeding those currently being studied 
in other animals . 



Waldo S . Zaugg 



PHYSIOLOGY 



to partially replace and double the holding capa- 
city of the experimental hatchery. 

High water temperatures in the experi- 
mental hatchery were corrected this past 
summer with the installation of a heat exchanger 
and preliminary tests indicate a sand filter and 
ultraviolet light system have corrected algal and 
disease problems . Vibrio in the sea water 
system necessitated the early termination of 
protein studies with yearling coho salmon in a 
sea water environment. 

Outside facilities at the station were used 
extensively by biology classes for demonstra- 
tion purposes of marine life . An undetermined 
number of individuals toured the station in 
conjunction with their visit to the adjacent park 
area which ranks second in population usage of 
the entire Washington State Park system . 



Salmon Into Sea study 



Lahontan cutthroat trout tests 



Cooperative use of the Bowman Bay Station 
by this laboratory, Bureau of Commercial 
Fisheries Biological and Technological Labora- 
tories, and the International Pacific Salmon 
Commission has been quite successful. Addi- 
tional space is being developed for new aquaria 



Tests with Lahontan cutthroat in 1968 indi- 
cated that greater efficiency and growth were 
obtained with a commercially prepared ration as 
the fish became older . The results of a 14 - 
week feeding trial with yearling Lahontan trout 
are summarized in Table 8 . 



Table 8. — Growth data: 14 week trial with yearling Lahontan cutthroat 







% 


Weight 


% 


Gain/g dry 


Hematocrit 




Diet 




gain 


Survival 


diet fed 


i S.E. 


Fresh water 


8-S* 




173 


82 


.65 


50-1 




285** 




198 


97 


.86 


48 ± 2 


5% sea water 


8-S 




240 


67 


1.04 


44 i 1 




285 




195 


85 


.92 


46 i 1 


10% sea water 


8 -A 




211 


68 


.89 


44 i 2 




285 




192 


86 


.82 


43 t 2 



*Diet 8-S contains 8% minerals. 
**Diet 285 contains 147o minerals. 



Fish were fed either the Oregon Moist 
Pellet, containing approximately 14 percent dry 
weight as salts, or a test diet with 8 percent 
dry weight as minerals . Growth in fish fed the 
OMP was nearly the same in the 3 water environ- 
ments . It surpassed the growth from Diet 8 -S - 
fed fish in fresh water but was less in a brack- 
ish water environment. 

New test diets were designed to measure 
response of coastal cutthroat and Lahontan cut- 
throat trout to various mineral levels in the 
diet. 



temperature was 13° "'^ 1° C . throughout the 24 
week experiment . Growth trends shown in 
Table 11 are raw data and have not been subjected 
to statistical analysis. Many physical require- 
ments have yet to be defined to ensure maximum 
survival, but it would appear that the present 
laboratory test diet is satisfactory for prelimin- 
are diet testing with the Lahontan trout. There 
appears to be a shift in the physiological status 
of these fish somewhere between 10 and 14 weeks 
that affects the rate of growth in a 10 percent sea 
water system. This change is affected by the 
concentration of minerals in the diet being fed. 



Initial feeding fish were challenged with 
diets containing 0, 1, 4, and 8 percent salt in 
the complete test diet . These were compared 
with others receiving Oregon Moist Pellet, 
fish meal concentrate, and cytoplasmic protein 
concentrate . Two groups from the same egg 
source were divided between (1) Hagerman 
Field Station to be held in circular glass aquaria 
or still water troughs in 15° C. hard water sys- 
tems (approximately 220 ppm total dissolved 
solids) and (2) Bowman Bay Field Station to be 
held in fresh water (170-190 ppm T.D.S .) or 
10 percent sea water systems (approximately 
3300 ppm T.D.S.). As a comparison, total 
dissolved solids of approximately 400 ppm and 
5000 ppm, respectively, are found at Summit 
Lake and Pyramid Lake , the two primary 
sources of Lahontan broodstock . 

Fish at Bowman Bay were held in "nose- 
cone" type aquaria, modified from airplane wing 
tanks. 

Growth of initial feeding coastal cutthroat 
trout at Bowman Bay was lower at the end of 6 
weeks in 10 percent sea water than in a fresh 
water environment (Table 9) . Survival was 
generally higher in fresh water -raised fish, a 
notable exception being with fish fed with no 
mineral supplement to the diet . The largest 
weight gain was found in a test diet in which 
fish meal provided the protein component 
(Diet 284). Little difference was observed in 
proximate analyses of carcasses at end of 
feeding trial (Table 10) . 

At Bowman Bay Lahontan sac -fry were 
started on test diets at swim -up. Water 



Amino acid patterns in fish tissue 

Amino acid contents of whole carcass tissue 
from yearling rainbow trout, coho salmon, and 
Chinook salmon were measured for reference 
values for future work. All animals were main- 
tained on the laboratory complete test diet for 
one year in 10° C. water before analysis of 
tissue (Table 12) . 

Clarence L. Johnson 

AVAILABILITY 
AND UTILIZATION 

Metabolizable energy of feed materials 

Availability and utilization studies this year 
were concerned with the testing of feed mater- 
ials for metabolizable energy (ME) content, the 
indirect measurement of heat production, and 
the evaluation of several materials as protein 
sources for coho salmon. 

The ME content and the digestibility of the 
following were measured using large rainbow 
trout in metabolism chambers: Torula yeast, 
egg albumin, fish protein concentrate, soybean 
meal, corn gluten, cottonseed meal, dry skim 
milk, blood meal, wheat gluten, poultry by- 
products meal, white fish meal, field pea meal, 
dried whey, and brewer's yeast. These indi- 
cated that some plant proteins are suitable for 
inclusion in fish feeds. However, these plant 
proteins failed to produce satisfactory growth in 
feeding trials because the fish refused to eat ade- 
quate amounts of diets when a substantial part of 
the protein was from plant sources . It appears 



99 



Table 9. — Growth data: Six week feeding trial of coastal 
cutthroat trout at Bowman Bay 



% Weight gain 



Survival 



Diet* Fresh water 107o Sea water Fresh water 107o Sea water 



8 


188 


8-S 


143 


289 


121 


290 


128 


291 


168 


292 


187 


284 


245 


285 


166 



175 

118 
135 
158 
158 
202 
160 



91.7 
91.0 
85.0 
87.9 
95.8 
100.0 
92.1 
85.0 



91.3 

96.3 
90.4 
90.8 
92.5 
92.1 
81.7 



*Diet Legend: 8: laboratory complete test diet (CTD) ; 8-S: CTD 
with two times standard mineral packet; 289: CTD without mineral 
packet; 290: CTD with one-four times mineral packet; 291: CTD 
with 17o cytoplasmic protein concentrate from fish meal; 292: CTD 
with 1% isopropyl alcohol washed cytoplasmic protein concentrate; 
284: CTD with commercially prepared fish meal substituted as 
protein component; 285: commercially prepared fish food. 



Table 10. — Proximate analysis of terminal samples of coastal cutthroat 
feeding at Bowman Bay 



% Lipid 



% Ash 



Total 



Fresh water 
107o Sea water 



8-S Fresh water 



74.0 
74.2 



72.3 



17.7 
17.0 



9.5 
.5 



289 


Fresh water 


71.7 


19.7 


8 


9 


100.3 


86.8 




107o Sea water 


72.2 


20.9 


8 


4 


101.5 


86.7 


290 


Fresh water 


74.9 


18.6 


8 


9 


102.4 


86.1 




10% Sea water 


73.5 


18.5 


8 


5 


100.5 


85.5 


291 


Fresh water 


74.4 


16.6 


9 


7 


100.7 


85.5 




107o Sea water 


75.4 


16.3 


9 


3 


100.0 


85.5 


292 


Fresh water 


73.8 


17.6 


9 


6 


100.0 


86.2 




10% Sea water 


75.2 


18.4 


9 


5 


103.1 


85.5 


284 


Fresh water 


75.8 


14.6 


10.4 


100.8 


84.6 




10% Sea water 


75.0 


16.5 


10.3 


101.8 


84.9 


285 


Fresh water 


74.1 


18.4 


9.0 


101.6 


85.8 




10% Sea water 


74.2 


19.9 


9.3 


103.4 


86.0 



101.2 
100.7 



100.5 



85.6 
85.7 



*See Diet Legend, Table 9. 



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101 



Table 12. — Amino acid analysis of whole carcass (minus G.I. tract) 





Rai 


nbow trout 


Chinook 


salmon 


Coho 


salmon 


Analysis 


% Dry Wt % Nitrogen 


% Dry Wt 


7o Nitrogen 


% Dry Wt 


% N 


itrogen 


Lysine 


5.06 


8.34 


5.67 


9.04 


5.65 




8.67 


Histidine 


1.86 


4.33 


1.92 


4.32 


1.99 




4.32 


Ammonia 


0.88 


6.19 


0.95 


6.51 


1.01 




6.65 


Arginine 


4.06 


11.21 


4.16 


11.13 


4.08 




10.49 


As par tic Acid 


6.55 


5.92 


6.71 


5.88 


7.01 




5.91 


Threonine 


2.57 


2.59 


3.06 


3.00 


3.18 




2.99 


Serine 


2.96 


3.40 


3.02 


3.35 


3.15 




3.36 


Glutamic Acid 


9.12 


7.46 


10.00 


7.92 


10.44 




7.95 


Proline 


2.83 


2.96 


3.16 


3.20 


3.11 




3.03 


Glycine 


5.36 


8.60 


5.10 


7.91 


5.58 




8.33 


Alanine 


4.15 


5.61 


4.24 


5.54 


4.50 




5.65 


1/2 Cystine 


0.38 


0.38 


0.42 


0.40 


0.44 




0.41 


Valine 


2.90 


2.98 


2.98 


2.97 


3.10 




2.97 


Methionine 


2.10 


1.69 


2.15 


1.68 


2.19 




1.64 


Isoleucine 


2.37 


2.17 


2.54 


2.26 


2.57 




2.20 


Leucine 


4.82 


4.42 


5.10 


4.53 


5.14 




4.40 


Tyrosine 


2.07 


1.37 


2.19 


1.41 


2.31 




1.43 


Phenylalanine 


2.49 


1.82 


2.63 


1.86 


2.70 




1.83 


Taurine 


0.14 


0.13 


0.18 


0.16 


0.21 




0.19 


Total % 


62.67 


81.59 


66.16 


83.07 


68.37 




82.43 


Dry Wt on Column 




891.8tig 




1047. Oiig 




927 


. Otig 


Nitrogen on Column 




103.8iig 




125.8iig 




115 


• Stig 


Protein Analysis 
















by Macro-Kjeldahl 




72.19 




74.26 




78 


.62 


7o Moisture 




78.0% HpO 


80 


.96% H:,0 


81 


.06% 


H.,0 



102 



that properly balanced diets containing mostly 
plant protein can be used if the diets can be 
made acceptable to the fish. 

Indirect measurement of heat production 

Groups of fish were fed diets of known ME 
content at approximately 100 percent, 80 per- 
cent, 60 percent, and 40 percent of voluntary 
food intake. The fish were weighed biweekly 
and were sacrificed at 12 weeks . The carcasses 
were analyzed for deposited protein, and calor- 
ies and efficiency of food utilization was calcu- 
lated . The energy lost as heat was calculated 
by the formula: Heat Production = ME - Stored 
Energy. 

The results indicate a maintenance require- 
ment of about 2500 cal/100 g body weight/day 
for small coho salmon in 15° C. water. Body 
maintenance required about 75 percent of the ME 
fed at the lowest level and only about 40 per- 
cent of the ME fed at the highest level . These 
data indicate that with fish, as with other 
animals , the most rapid growth is the most 
efficient growth. 

Urine flow 

Tests were conducted to measure variations 
in urine flow during confinement in metabolism 
chambers . Fish were fed two hours before 
confinement, then urine flow was collected, 
removed, and weighed at 0800 and 1630 hours 
daily. Average weight of 5 fish on test was 
about 400 g each. Samples were collected for 
10 days on test , Average urine flow was about 
15 percent of body weight /day, approximately 
evenly divided on an hourly basis, day or night. 

Robert R. Smith 

HBTOPATHOLOGY 

Cutthroat trout mortalities 

Lahontan cutthroat fry reared at the 
Hagerman Field Station began dying approxi- 
mately 3 weeks after first feeding. Moribund 
fish from each diet group were autopsied on 
site (22 days on test) but no consistent patholog- 
ical entity could be detected. Some fish 



reported to have swollen and excessively red 
gills died before samples could be preserved. 
Moribund fish examined later at necropsy and 
preserved for examination failed to show 
serious gill anomalies and no case of gill hem- 
orrhage could be verified. Microscopically, 
some gills appeared slightly hyperemic and had 
slight hyperplasia of gill epithelium, but the 
most conspicuous finding was the general occur- 
rence of short, widely-spaced gill lamellae. 
This suggests a possible hereditary anomaly 
which might have endowed a certain percentage, 
possibly one-fourth, of the population with inade- 
quate respiratory epithelium for a successful 
and independent life. Smears from skin and 
gills were negative for bacteria after Gram 
staining but a few fish had long Gram -positive 
bacilli in small clumps in the posterior intestine. 
Some moribund fish had bloated stomachs and/or 
intestines (Figure 3), particularly those in 
rectangular troughs and usually the larger fish 
of a given trough, but bloating also occurred in 
several large control fish fed only complete 
test diet (CTD): it therefore may have been due 
to engorgement. More rapidly growing fish 
reared in 5 gallon plastic cylinders in which 
water circulation kept feed agitated and thus 
encouraged feeding activity also may have 
encouraged engorgement. Fish fed brine shrimp 
larvae in the cylindrical tanks began dying on 
Day 18 . Histological examination of these mori- 
bund fish showed numerous undigested larval 
exoskeletons in the hind gut which appeared to 
cause bowel obstruction that may have resulted 
in the death of some of these fish (Figure 4). 
Cutthroat fingerlings 7 weeks on test and 
sampled when very moribund sometimes had 
skeletal muscle atrophy with inflammation and 
occasionally had petechial hemorrhages (Figure 
5). Five control fish each, from the 3 and 7 
week samples , were free from intestinal 
bacteria and had no muscle atrophy. Since 
muscular atrophy of affected fish involved myo- 
tomes both anterior and posterior to the dorsal 
fin the muscle anomalies conform to the pattern 
reported for viral hemorrhagic septicemia (VHS). 
However, evidence of hemorrhage was so mini- 
mal in the cutthroats examined as to render 
unlikely the possibility of these fish being 
infected with VHS . Several moribund fish from 
rectangular tanks were infected with water mold, 
probably Achlya or Saprolegnia . Mold hyphae 



103 



were conspicuous in both hematoxylin and 
erosin- and in Giemsa -stained sections of 
kidney, ovary, pancreas , esophagus , intestine, 
muscle, and thymus gland of moribund fish. 
When mold infected the thymus , it was some- 
times hemorrhagic (Figure 6). 

Cohos refractory to aflatoxin B] 

Coho salmon fed CTD plus 20 ppb aflatoxin 
B^ for 12 months in 15° C. spring water and then 
transferred to running sea water at 12° C . for 
18 months failed to develop a single microhepa- 
toma nodule. 

Channel catfish on lipid diets 

Sections cut at 6 microns from 150 channel 
catfish livers were stained with hematoxylin 
and eosin. Best's carmine, and with periodic 
acid Schiff (PAS) counter stained with fast 
green. Best's carmine and PAS are specific for 
tissue glycogen. Representative liver sections 
from each diet group were digested with diastase 
for 20 minutes at room temperature after which 
PAS positive materials were almost entirely 
lacking, proving the bulk of the PAS positive 
material to be glycogen. Experimental fish and 
controls all contained liver glycogen in amounts 
ranging from sparse to abundant . The kind of 
lipid fed did not appear to alter the presence or 
the amount of glycogen in the cytoplasm of 
liver parenchyma cells. Insignificant amounts 
of ceroid in portal areas and of focal necrosis 
in liver parenchyma were noted in several 
livers but were not limited to those representa- 
tive of any particular diet (Figure 7). 

Histology of mouth and pharynx 

A detailed atlas of histology of the salmonid 
mouth and pharynx is in preparation. Taste 
may be involved, along with smell, in the 
"homing" migrations of salmons, steelheads and 
other anadromous species . Taste buds are 
distributed on lips, roof and floor of mouth, 
tongue, and pharynx back as far as the begin- 
ning of the esophagus . Salmonid taste buds are 
similar to those of higher vertebrates in histo- 
logical detail . They are pale ovoid structures 
within a darker -staining stratified squamous 
epithelium and consist mainly of spindle-shaped 



supporting cells mingled with slender neuro- 
epithelial cells , each terminating in a short 
hair -like structure in the taste pore at the 
surface. 

Teeth are located not only on upper and 
lower jaws but on the roof of the mouth (on 
palatine bones, bilaterally; on the vomer bone, 
medially) and on the tongue . Additional teeth 
occur in the posterior portion of the pharynx -- 
the pharyngeal teeth (Figure 8). All salmonid 
teeth are simple conical or recurved unicuspid 
in type and are used for grasping and holding 
food when necessary. Long recurved teeth 
occur in positions corresponding to those of 
canine teeth in higher vertebrates , on either 
jaw, but similar recurved teeth may also occur 
on the tip of the tongue (Figure 9). Salmonid 
teeth appear to develop after the manner of 
placoid scales characteristic of sharks 
( Chondrichthyes) . This involves tooth buds 
consisting of inner pulp with dentine -forming 
odontoblasts derived from dermal mesenchyme 
plus an outer cup -shaped enamel organ lined 
with enamel -forming ameloblasts (Figure 10). 
Enamel organs are derived from ectoderm -- 
the stratified squamous epithelial mucous 
membrane of the mouth . The linings of mouth 
and pharynx are amply supplied with mucous - 
secreting epithelial cells whose secretions 
protect the delicate membranes and lubricate 
food materials for easy swallowing . 

Histology of 18 -year -old Bunny Lake brook trout 

A total of 104 tissue slides of 18 -year -old 
Bunny Lake brook trout and 3 - to 4 -year -old 
Cloverleaf Lake brook trout were examined 
for the Sierra Nevada Aquatic Research 
Laboratory to compare senile changes, if any, 
of the 18 -year fish. The trout were reared from 
fry planted in Bunny Lake located above the 
11,000 foot level in the Sierra Nevada of Cali- 
fornia . Cloverleaf Lake lies at an altitude of 
approximately 1000 feet and is eutrophic as 
compared with the highly oligotrophic Bunny Lake 
Very few senile changes could be found in the 18- 
year-old trout; those noted include thickened 
basement membranes in renal glomeruli, hyal- 
inization of some pancreatic arteries, slight 
skeletal muscular degeneration, and a greater 
number of atretic and degenerating ova . 











.-<y V r 



:^ .V^' 



Figure 3. --Sagittal section through cutthroat trout fry showing bloated stomach. Fish fed 
synthetic diet including 507o protein but no added minerals for seven weeks. Hematoxylin 
and eosin (H and E) . X 44. 




Figure 4. — Section of cutthroat trout fed brine shrimp nauplii for three weeks 
gut partially obstructed by undigested exoskeletal remains. H and E. X 70. 



Note liind 



105 




Figure 5. --Section of cutthroat trout skeletal muscle showing muscle atrophy and inflam- 
mation (hyperemia). Diet included 4% mineral and 707o protein. H and E. X 175. 





*/i 


f ^ 


^^,1 


^SHpQvSS^^SSRl^^^^tfMI^EIIfeiKi^H 










HlBysBR 




i 






^Jf ^^IFv^ v^i^H^^f^HIBH 


^ 








^^^^s»«Hi 



Figure 6 .--Hemorrhagic necrosis in focal fungal infection of cutthroat trout thymus gland. 
Black strands are sectioned portions of mold hyphae , most of which are surrounded by 
hemorrhaged blood. Diet was brine shrimp nauplii. 



106 




Figure 7. — Section of channel catfish liver showing heavy deposits of cytoplasmic glycogen 
in liver cells. Periodic acid Schiff counterstained with fast green. Diet included 20% 
corn oil. X 450. 




S**-^^* 



si^ 




«^'^fe- 



Figure 8. --Sagittal section through tongue of cutthroat trout showing a strong, recurved 
lingual tooth near tip of tongue. Note bony anchorextending caudal from posterior 
root of tooth. An oval-shaped unerrupted or embryonic tooth lies adjacent to the 
anterior root of the recurved tooth. Diet included 4% added mineral and 50% protein. 
.11 and E. X 110. 



107 







Figure 9. --Section through pharynx of cutthroat trout showing two pharyngeal teeth deep in 
the epidermis. Several taste buds occur at the surface above the larger tooth. Diet 
same as in the above illustration. H and E. X 450. 




Figure 10. --Section through twotaste buds in mouth of adult 12-year-old brook trout. A 
blood capillary can be seen in the dermal papilla below the bud on the right. H and E. 
X 500. 



Cloverleaf Lake fish had heavily vacuolated 
liver cell cytoplasm characteristic of well fed 
fish, while those from Burmy Lake were typical 
of poorly fed or starved fish, with almost no 
cytoplasmic vacuoles in liver cells. This 
obviously indicates a comparative absence of 
stored liver glycogen in the 18 -year -olds . Of 
interest is the fact that the 18 -year -olds average 
about the same size (10 inches) as the 3- and 4- 
year-old Cloverleaf Lake fish. The extremely 
quiescent behavior reported from the Bunny 
Lake fish suggests a long existence in a state 
of relatively suspended animation. 

Lawrence M. Ashley 

GENERAL 



water environments were received from 
Dr. Philip Snodgrass of Peter Bent Brigham 
Hospital in Boston. Physiology papers from 
Drs. Gorbman and Oshima from the University 
of Washington and Tokyo University were edited 
and submitted for publication. More data on the 
role of aflatoxin intermediates on cholesterol 
feedback control were sent to Dr. Siperstein at 
Texas Medical Center at Dallas . Drs . Maynard 
Steinberg and Harry Dupree of the Bureau of 
Commercial Fisheries and the Marion, Alabama 
Laboratory completed a fat source for a catfish 
series of experiments which will be reported in 
detail by Dr. Dupree. Many smaller projects 
using fish tissue from our experiments were 
completed by cooperating scientists, results of 
which will appear in future manuscripts , 



Research scientists from other fields 
studied at Cook to understand basic nutrition, 
biochemistry, physiology, and metabolism . 
Dr . Takeshi Nose left in March to return to 
Japan with a briefcase full of data on 3 projects 
completed in our laboratory. Papers summar- 
izing data from fish in fresh water and sea 



A cooperative program to train 6 Lummi 
Indian candidates in principles and practices of 
fish husbandry was initiated in October. At the 
end of calendar 1969, the trainees and instructor 
were transferred to the Bowman Bay Field 
Station site to complete the first phase of 
classroom and laboratory instruction. 



109 



FISH GENETICS LABORATORY 

Beulah, Wyoming 
Bruno von Limbach, Director 



HIGHLIGHTS 



BREEDING RAINBOW TROUT 



We have relinquished our limited attempt 
to breed trout for tolerance of crowding, to 
avoid further sacrifice of effort on other 
projects . 

Analysis of limited data suggests that both 
growth and formalin tolerance are strongly 
heritable and are responding to our selection 
procedures . 

Random matings again show the inherent 
diversity of available stocks and the potential 
for selective breeding. For example, similarly 
reared siblots ranged in average weight from 
14 to 333 grams, a 24 -fold difference, one year 
after fertilization. 

Performance of a few siblots of 1969 first 
generation inbred trout (progeny of full sib 
matings) can be compared with that of their 
crossbred half sibs . The inbred lots were 
generally of lower fertility and weighed less at 
150 days. Meager data suggest inbreeding 
depression comparable to that reported for 
other animals . 

Observed phenotype frequencies among 
progeny of parents of presumed genotype 
establish the postulated simple autosomal 
recessive character of albinism in rainbow 
trout. 

Inflow to our four -foot -diameter circular 
tanks, other conditions remaining standardized, 
can be reduced from 8 to 4 liters per minute 
without iniiibition of trout growth. 



At the end of the year we have 
approximately 500 experimental lots totaling 
120,000 fish. Roughly 200 lots, or 15,000 fish, 
are more than 1 year old. Some 3,200 of the 
older fish bear identification tags to permit 
individual value assessments and records of 
performance. 

Breeding for albinism 

Recent test crosses complete out matings to 
show that albinism in rainbow trout is a simple 
autosomal recessive trait. We performed 
factorial matings, including crosses, incrosses 
intercrosses, and backcrosses of the following 
phenotypes and presumed genotypes: normal 
color (AA), normal color (Aa) and albino (aa). 
Observed and expected frequencies of progeny 
phenotypes are summarized in Table 1 and 
maximum siblot deviations are footnoted. We 
also made 24 single-pair matings, 18 inter- 
crosses (Aa x Aa) and 6 backgrosses (Aa x aa) . 
Phenotypically, progeny of these intercrosses 
were 3,948 (24 .7%) albinos and 12,022 (75.3%) 
normally colored fish; the backcrosses produced 
2,402(49.8%) albinos and 2,417(50.2%) normals 

Breeding for genetic diversity 

Breeding to preserve genetic diversity 
continues. Seventeen random -bred pools of 
1965, 1966, 1967, 1968, and 1969 fiscal-year- 
class stocks are being maintained to produce 
future generations of unselected brood stocks. 
Random mating of individuals from 1968 and 
older year classes for production of 1970 stocks i 
was started in September. 



Table 1. --Albinism in rainbow trout: 
Progeny phenotypes from 1970 factorial test matings 



Matings 
Phenotype (presumed genotypes) 



Deviat ion 
Observed from 

Number Percent expected, 

Normal Albino Normal Albino percent 



4 


Normal 


(AA) X 


Normal (AA) 


1415 





100 














7 


Albino 


(aa) X 


Albino (aa) 





6034 







100 









7 


Normal 


o' (AA) 


X Albino ? (aa) 


3259 





100 














4 


Albino 


6' (aa) 


X Normal ? (AA) 


1434 





100 












,4i/ 


7 


Normal 


(Aa) X 


Normal (Aa) 


4834 


1731 


73. 


6 


26. 


4 


1. 


7 


Normal 


o" (Aa) 


X Albino $ (aa) 


1837 


1924 


48. 


8 


51. 


2 


1. 


2.^/ 


7 


Albino 


o' (aa) 


X Normal ° (Aa) 


3253 


3145 


50. 


8 


49. 


2 


0. 


si/ 


4 


Normal 


o' (Aa) 


X Normal ? (AA) 


1506 





100 














6 


Normal 


rf" (AA) 


X Normal ? (Aa) 


5003 





100 















1/ 



2/ 



3/ 



Greatest deviation from expected ratios produced by a single intercross-Albino 27.9% 
(258): normal 72.1% (668) 

Greatest deviation from expected ratios produced by a single backcross to albino 
female— Albino 54.8% (86): normal 45.2% (71) 

Greatest deviation from expected ratios produced by a single backcross to albino 
male— Albino 56.3% (291): normal 43.7% (226) 



Breeding for variant inbred lines 

We are rearing 8 siblots from 1967 and 
1968 fiscal-year matings of unrelated parents 
and 11 siblots from 1969 full sib matings (0.25 
inbreeding co -efficient) solely for use in 
future inbreeding designs, either to start new 
lines or to further inbreed existing lines. Also, 
we are utilizing or will utilize a few of the 140 
siblots from 1967, 1968, and 1969 matings, 
made primarily for other purposes, to initiate 
development of new inbred lines . Breeding of 
1967 and 1968 sib lots to produce 1970 lots is 
underway and we expect to obtain several lots 
with an inbreeding co -efficient of 0.25 and 
possibly a few 0.375 inbred lots if certain 1969 
year -class males precociously mature at an 
appropriate time. 

In a few instances we can compare the 
150 -day growth performances of 1969 0.25 
inbreds and their crossbred half sibs . An 
inadequate number of comparisons prevents us 
from making a quantitative estimate of inbreed- 
ing growth depression, but the data suggest that 
it does occur . We also have some evidence 



suggesting that we can expect a reduction in 
fertility as inbreeding progresses . 

Breeding for season of sexual maturity 

We are rearing 1968 and 1969 year -class 
lots for selection and breeding to fix or extend 
differences in seasonal maturity. Lots of both 
year classes represent parental maturity for 
each month from September through March. The 

1969 lots also include one which was produced by 
parents that matured in August. Several matings 
made for April maturity were not successful. 
Breeding for the 1970 lots was started in August . 
We have obtained lots for each month from 
August through December and hope to continue 
successful breeding beyond March, 1970. 

Breeding for age of sexual maturity 

Eighty 1967, 1968, and 1969 lots from known- 
age parents are being reared or maintained for 
selection and breeding to develop strains or 
lines differing in age of maturity. Production of 

1970 lots began in September. Generally, like- 
maturing fish, either two-year or three -year 



maturing, have been mated. However, in a few 
instances this year we paired one -year - 
maturing males with two -year -maturing females 
and three -year -maturing males with four-year- 
maturing females in initial efforts to develop 
earlier- and later -maturing lines. We still 
have only suggestive evidence that female 
maturity is correlated with the maternal pheno- 
type. 

Breeding for growth 

Growth was measured for 211 siblots from 
1969 matings reared under standard conditions 
for 150 days after fertilization. The 18 heaviest 
lots and the 12 lightest were selected for 
further evaluation. The mean of the 150 -day 
average -fish weights for the heaviest lots, 
4 .2 grams , was 4 .7 times greater than that, 
0.9 grams, for the lightest lots. 

We have previously noted that wide 
differences in the growth of siblots, under 
standardized conditions, from randomly mated 
as well as from selected parents, have been 
observed and are indicative of potential for 
selective breeding. Table 2 shows the average 
fish weight of tlie 5 extreme lots measured for 
each year of our growth selection program. 
The F . Y . 1967 spawning season data are not 
directly comparable because we got a late 
start that year and the matings exclude certain 
good growing stocks . Other differences in the 
size of the lots are probably just chance but we 
can't say that they may not reflect some minor 
influence of such environmental changes as 
modified diets and handling methods . 

Figure 1 illustrates the difference in size 
of average fish from the poorest and best 1969 
growth lots . They are shown as they appeared 
after 335 days when their average weights were 
10 and 235 grams; a year after fertilization the 
same siblots averaged 14 and 333 grams . 

Available data are insufficient for reliable 
quantitative estimates of growth heritability or 
selection response. Most of the 1969 siblots 
were from matings of unselected parents, as in 
previous years . Some lots were from parents 
selected on the basis of their attained adult 
size. Unfortunately, these spawners had been 



Table 2. --The 5 extreme growth siblots 
of 3 fiscal-year classes 





Siblot 


average 


fish 




weight in grams 




1967 


1968 


1969 


150 days after 








fertilization : 








Five lightest 


0.53 


0.59 


0.61 




0.64 


0.70 


0.73 




0.68 


0.78 


0.75 




0.68 


0.79 


0.75 




0.73 


0.80 


0.83 


Five heaviest 


2.8 


3.2 


5.1 




2.9 


3.3 


5.3 




3.0 


3.5 


5.3 




3.0 


3.5 


5.8 




3.6 


3.9 


6.3 



1 year after 
fertilization : 

Five lightest 



Five heaviest 



25 


18 


14 


28 


18 


28 


30 


20 


29 


30 


24 


30 


32 


32 


34 


107 


226 


232 


114 


235 


234 


115 


240 


252 


126 


257 


253 


176 


2d3 


333 




Figure 1. --Average fish from the poorest 
and best growing sib lots at 335 days of 
age, weighing 10 and 235 grams 
respectively. 



variously held in dissimilar environments which 
presumably had a substantial though undeter- 
mined influence on their growth. 

Among the 1969 siblots there are 15 whose 
parents both came from 1967 siblots selected on 
the basis of their 150-day growth. Of the 15 
siblots, 6 were progeny of parents from lots 
selected for good growth and the mean average - 
fish weight of these 6 progeny siblots is 2.2 
grams at 150 days. Similarly, 9 siblots were 
offspring of parents from lots selected for poor 
growth and their mean average -fish weight is 
1.1 grams. As would be expected if growth is 
heritable and responsive to selection, these two 
groups are, respectively, above and below the 
mean average -fish weight of all 1967 lots, 1.5 
grams, not only in terms of group mean aver- 
age but also with respect to their individual 
siblot averages. That is, each siblot produced 
by parents from 1967 high -growth lots has an 
average weight above the mean average of all 
1967 lots, and each siblot generated from the 
selected poor -growth lots averaged less in 
weight than the mean of those in the perform- 
ance base. 

In addition there are, among the 1969 lots, 
14 siblots whose parents were chosen on the 
basis of progeny performance, the 150-day 
average weight of their 1968 offspring which 
were of course actually sibs or, more 
commonly, half sibs of the 1969 lots. Prelimi- 
nary analysis of tiiese data again indicate a 
similar response to selection for weight, either 
high or low . 

We are breeding 1970 siblots and expect to 
produce more lots from sib and progeny tested 
parents. Hopefully they will permit reliable 
quantitative estimation of the heritability of 
growth which we suspect is relatively high. 

Breeding for crowding tolerance 

Matings of 1966 and 1967 fiscal -year -class 
fish selected on the basis of their growth under 
crowded rearing conditions for extended 
periods produced several 1968 and 1969 sib lots. 
Regrettably, most of these progeny lots could 
not be tested under crowded conditions . How- 
ever their growth was measured for 150 days 



under standard conditions and their 
performance was not unusual. Two of the 1968 
lots were evaluated in a crowded rearing situa- 
tion for about 4 months; their growth did not 
differ from that of unselected lots under the 
same conditions . We have recently abandoned 
this project because of lack of facilities and 
manpower for its effective continuation. 

Breeding for formalin tolerance 

As previously reported, siblot tolerance of 
formalin is routinely determined from the per- 
formance of sample lots exposed for 6 hours to 
high (525 microliters per liter) and to low (175 
microliters per liter) concentrations. Such 
determinations made for 179 siblots of the 1969 
fiscal-year class at about 150 days after fertili- 
zation are shown in Table 3, broken down by the 
several classes of parental selection involved. 

From these 179 lots, 18 were selected for 
retention and future program use: 12 lots, 
averaging 74% survival at the high concentration 
appear to be inherently resistant; and 6 siblots, 
averaging only 32% survival at the low exposure 
level appear relatively susceptible. 

As shown in Table 3, most of the 1969 
siblots, 144, were produced by unselected 
parents but 35 siblots were each the offspring of 
one (9 siblots) or two (28 siblots) parents that 
had been selected on the basis of their own (9 
siblots), their sibs (14 siblots--8 up and 6 down), 
or their progeny's (3 siblots) performance. The 
average performance of the 1969 progeny for 
every class of parental selection varied appro- 
priately and, except for the one -parent -only 
lots, substantially from the averages of either 
all lots or the offspring of unselected parents. 
Also, it is most appropriate to compare the 
performances shown for lots produced by 
parents selected on the basis of their sibs per- 
formance with the performance averages of the 
base population from which the parents were 
selected- -in this case the averages of all tested 
siblots of the 1967 fiscal -year class. These base 
population averages are 13% survival of the high 
test concentration and 80% survival of the low. 



Number 

of 
siblots 
tested 

144 
9 



Table 3. --Formalin tolerance of 1969 fiscal-year-class siblots 

% of sample surviving exposure 
to test concentration of 



525 til/l 



175 tJ.1/1 



Parental selection 

None (both unselected) 

None X high sib survival 

High sib survival 

Own survival (test age l| years) 

Low sib survival 

Low progeny survival 

All lots combined 



Range 



Range 



11 


0-92 


87 


16-100 


23 


0-9b 


88 


55-100 


42 


0-67 


99 


96-100 


39 


S-S7 


96 


65-100 


7 


0-20 


47 


30-50 


10 


0-24 


51 


45-53 



16-100 



These comparisons indicate that the 
tolerance of formalin is a strongly heritable 
trait. The methods of selection tried appear to 
be about equally effective at this early stage of 
the project. As expected, lots with only one 
selected parent ranged widely in performance 
and tended toward mediocrity. 

If possible, we shall intensify evaluations 
for formalin tolerance during 1970 by the addi- 
tion of test concentrations to permit estimation 
of LC50. 

Breeding for DDT tolerance 

Sample lots of 142 siblots of 1969 fiscal - 
year -class fish were tested for tolerance at 
150 days post fertilization by exposure for 12 
hours to high (40 micrograms per liter) and low 
(13,3 micrograms per liter) concentrations of 
DDT in flowing water. Survivors are counted 
after 24 hours. In general, results indicate 
some response to selection but it is disappoint- 
ingly small. Either this factor is not strongly 
heritable or our selection methods are poor. 

For all lots tested, survivals at high and 
low concentrations, respectively, are 3% and 
91%, Included are 97 siblots from unselected 
parents; these have average survivals of 1% and 
93%; no siblot was as resistant or as susceptible 
as the better performing lots among the 191 
unselected 1967 fiscal -year -class lots. The 
average performance of 11 siblots that were the 
progeny of one unselected and one selected 
parent, showed no selection response. Also 
among the 1969 siblots were 34 siblots from 
parents selected as follows: 7 siblots from 



parents surviving exposure as yearlings; 7 
siblots from parents selected for high survival 
of tlieir fingerling sibs; 3 siblots from parents 
selected for high survival of their progeny; 3 
siblots from parents selected for low survival 
of progeny; and 14 siblots from parents selected 
for low survival of their fingerling sibs. 
Combining data for these select lots: the 17 lots 
from parents chosen for resistance average sur- 
vivals of 12% and 98% at the high and low concen- 
trations; the 17 lots from parents chosen for 
susceptibility average 2% and 78% . These 
percentages , compared with one another or 
with the survivals of all lots or the unselected 
lots indicate some response to selection. 

METHODOLOGY 

Rearing capacities of circular tanks 

The feasibility of reducing the rate of inflow 
to our 4 '-diameter circular tanks was investi- 
gated. Test situations and results are 
summarized in Table 4 . Loading density levels 
were periodically restored by cropping. In no 
instance did a tested inflow rate have any signi- 
ficant effect upon fish growth. The apparent 
slight depression of growth at the loading den- 
sity of 35 grams per liter, 40% above our 
standard, has been noted in some previous 
studies . 

In consideration of these test results, we 
are adopting 4 liters per minute as our provi- 
sional standard inflow rate for 4 -foot circulars. 
This replaces the 8 1pm standard established 
last year, but we have no basis for modifying 
other provisional standards. 



Table 4. — Growth of rainbow trout in 4-foot circular tanks 



Average fish starting 

weight, loading density, 

and test duration 

g. , 25 g./l. , 28 weeks 
39 g. , 25 g./l. , 20 weeks 
39 g. , 35 g./l. , 20 weeks 



Average fish terminal weight, grams 
4 1pm inflow o 1pm inflow 8 1pm inflow 

tank 1 tank 2 tank 3 tank 4 tank 5 tank b 



172 
258 
224 



175 
270 
252 



260 
234 



274 
200 



171 
251 
238 



177 
294 
255 



Exploratory investigations 

Fish identification . Many of our 3 , 200 
individually identified older fish are wearing a 
modified Swedish dangler having a stainless 
steel tag embossed with 7 digits --4 digits for 
lot and 3 digits for individual numbers . This 
year we tried a color code, composed of 
colored glass "seed" beads threaded on the 
Carlin-type harness wire, in substitution for 
the 4 -digit lot number. A much smaller stain- 
less steel tag bears only the lot individual 
number (Figure 2). All of 111 such "tags" 
applied 8 months ago have been retained and are 
quite easily read in the course of routine 
operations such as weighing. 





Figure 2. — Colored glass seed beads code the 
siblot and a stainless steel tag numbers 
the individual in this new tag for 
identification of experimental fish. 



Figure 3. — The use of a numbered plastic 
disc, seen on fish to the right of screen, 
attached to the permanent identification 
tag reduces sorting time and handling 
during the spawning season. 

We are using another innovation to 
minimize handling during the spawning period. 
A large colored plastic disc bearing an easily- 
seen number (Figure 3) is temporarily attached 
to the permanent tag during the initial screening 
for ripeness. This permits subsequent recogni- 
tion of the individual without the necessity of 
handling it or others in the lot. The "poker 
chip" is removed when the fish is spawned. 

Benzocaine as an anesthetic . Preliminary 
investigation and limited practical use suggest 
that benzocaine (ethyl -p-aminobenzoate) is an 
effective anesthetic for sorting, fin clipping, 
tagging, and spawning rainbow trout. It can be 
obtained for about 15% of the cost of MS -222 and 
our experience indicates that it's anesthetic 
properties are satisfactory at about half the 
concentration recommended for MS -222. 



Povidone - iodine as an egg disinfectant . 
McFadden in an article appearing in the Journal 
of the Fisheries Research Board of Canad a 
(Vol. 26, No. 9, 1969) reported povidone - 
iodine (PVP-I) to be an effective and safe 
bactericidal disinfectant for rainbow trout eggs, 
whereas merthiolate or acriflavin did not 
destroy Aeromonas liquefaciens on the egg 
shell. We recently obtained a PVP-I solution 
from GSA . Inquiry has failed to produce any 
information on its content or strength. Analysis 
revealed ca . 1% free iodine, suggesting that it 
is a 10% solution of PVP-I. Preliminary trials 
of the GSA product, assuming a 10% PVP-I 
concentration, at the recommended treatment 
level (1%) and time (10 minutes) at 12 C produced 
approximately 50% mortality in eggs treated 15 
minutes or 2 hours after fertilization; there was 
little, if any, adverse effect on eggs treated 17 
days after fertilization. At an assumed PVP-I 
concentration of 2%, eggs treated during the 
early phases of water hardening were affected 
less than those treated later; 23% survived the 
treatment at 15 minutes after fertilization but 
none survived the treatment at 2 hours or 17 
days . We are presently trying to acquire a 
relatively pure PVP-I solution of known strength 
for egg toxicity tests . However, we are hoping 
that McFadden's article will stimulate search 
by qualified laboratories for a needed safe, 
effective, bactericidal disinfectant for trout 
eggs. 

Blood measurements for fish characteri- 
zation . Exploratory investigations of quantita- 
tive measurements of blood sugars, bound urea 
nitrogen, sodium -potassium ratios, and lactate 
dehydrogenase activity indicate little promise 
of potential usefulness for practical characteri- 
zation of rainbow trout stock or lines. Prelimi- 
nary studies of erythrocyte osmotic fragility 
and electrophoretic patterns of LDH isozymes 
were recently initiated. 

GENERAL 

Construction and maintenance 



usual difficulties and deficiencies. Storage 
cabinets, shelving, work benches, and miscel- 
laneous furnishings available from GSA have 
been purchased and set up. Laboratory furni- 
ture --base cabinets (but no bench tops), wall 
cases, and hoods --are almost ail delivered but 
no provision is made for their installation. 

Our more pressing need is for fish rearing 
space. To ease this shortage, an inexpensive 
pole-type shed, 30' x 72', was erected adjacent 
to the new R&D#2 laboratory (Figure 4). A 4" 
AC water main branching from the R&D#2 supply 
line has been run to the shed. Plans have been 
made for provision of electrical services, 
drain system, water distribution system, and 
addition of two new pumps and controls to the 
spring -pond pumping plant . When these are 
provided we plan to install additional stock tanks 
in the shed and to move 8' tanks from the barn 
area and from R&D#1 to new locations near 
R&D#2. 




The shell of the laboratory section of 
R&D#2, the first small step towards the long- 
planned major development of this station, was 
completed well behind schedule and with the 



Figure 4. New shed of pole-type 

construction will shelter fish rearing 
tanks . 



This development will give us a little more 
space to hold larger fish, facilitate their care by 
partial consolidation of rearing and spawning 
units, and afford a little protection against the 
elements for our staff. In addition it will free 
some space in R&D#1, where space is needed for 
fingerling rearing and to install the two stamina 
tunnels acquired this year . Hopefully they will 
provide a means of characterizing, perhaps 
even evaluating our lines and strains of trout. 



Cooperative activities 

Lectures about our program and tours of 
our facilities again were given to several 
hundred family groups who visited us, particu- 
larly during tourist season. Sometimes the 
unexpected visitors who drop in for our regu- 
larly scheduled tours include visiting scientists, 
such as Dr. Erickson, a biochemist from 
Sweden, and these we enjoy especially. In 
addition many larger groups were given special 
tours: the Wyoming Game and Fish Commis- 
sioners were here for a somewhat hurried 
visit, accompanied by some of the staff; our 
largest group, an estimated 70 persons, were 
regional members of the American Society of 
Range Management; youth organizations such as 
4 -H Clubs , Boy Scouts , and the oddly named 
Belle Fourche Birthday Boys came to see us; 
and the usual school groups such as the Sundance 
High School sophmore class, the senior girls 
from St. Martin's Convent School, and a group 
of fisheries students from Athens, Georgia, 
came with Dr. Fox, the Fishery Unit Leader. 
The Upper Missouri River Chapter of AFS held 
business sessions here and toured our station. 



Of course we also welcome visits from Bureau 
coworkers, personnel from Fish Hatcheries, 
Wildlife Refuges, the Minneapolis Regional 
Office, and the rarer representatives from the 
remote Bureau Offices in Albuquerque and 
Washington. 

Members of our staff were guest speakers 
at local service clubs, the Spearfish Fisheries 
Center, and the Black Hills State College 
Conservation Workshop. We participated in 
one session of the Great Plains Fisliery Workers 
meeting in Rapid City. 

As usual, fish that became surplus to our 
research needs were made available to the 
McNenny National Fish Hatchery for use in 
cooperative stocking programs. Often we 
released these lots or individuals with consider- 
able reluctance; our facilities just don't allow 
us to keep as many fish as long as we would 
like. In 1969 we transferred 1,250 kilograms of 
fingerlings (45,000) and 6,950 kilograms of 
catchable rainbow trout (15,000) to the local 
management activities . 



I 



SALMON-CULTURAL LABORATORY 

Longview, Washington 
Roger E . Burrows , Director 



HIGHLIGHTS 

Rolled or pressed dry pellets prepared 
from the Abernathy diet have proved equal to or 
better than the soft pellet for salmon rearing. 

A starter granule prepared from pressed 
pellets is superior to the starter mash for 
first feeding fingerlings . 

In release and recovery experiments, 
significant numbers of the smaller fish have 
disappeared from the recovery samples , 
indicating the smaller fish do not survive the 
downstream migration. 

Large fall chinook eggs , less than 99 per 
displacement ounce, produce fingerlings which 
incur abnormally high losses due to faulty yolk 
sac absorption. 

Adult returns of fall chinook salmon are 
10 to 1 in favor of large fingerlings at time of 
release. 

Unwaterhardened fall chinook eggs 
survived at approximately the same rate as 
eyed eggs in this year's incubation channel 
experiment . 

Stocking rates as high as 1,333 eggs per 
square foot of gravel are under test in the 
channel . 

Coho salmon smolts averaging 17 per 
pound were released in May after 6 months of 
rearing in the environmental control system. 



Steelhead reared in the environment control 
system at the EKvorshak National Fish Hatchery 
will easily reach migrant size after one year of 
rearing while those reared in single -pass river 
water will require two years of rearing before 
release. 

Comparative commercial pellet prices 
indicate that the production feeding of 
Abernathy pressed pellets may result in as 
much as a 70 percent reduction in the food 
costs for salmon hatcheries . 

APPLIED NUTRITION 

Feeding trials for the purpose of 
developing practical yet nutritionally adequate 
diets for salmon continued at the Salmon - 
Cultural Laboratory. This year, instead of 
continuing with the soft, moist pellet we had 
developed, we shifted emphasis to the explora- 
tion of a completely dry diet which would be 
suitable for use in salmon propagation. The 
dry diet, if successful, would be of advantage to 
salmon hatcheries in that it would eliminate the 
problems of frozen storage of moist feeds, as 
well as the difficulties encountered when trying 
to adapt moist feeds to automatic feeding 
systems . Dry feeds also should be more 
economical both in manufacturing costs and in 
conversion rates . 

Two methods of producing the Abernathy 
dry diet were tested. The first method 
employed a pelleting process developed by the 
Food Science Department of the University of 
Washington in cooperation with the Washington 



Department of Fisheries, and consisted of 
spraying a water mist on the meal and oil 
mixture of the Abernathy diet while it was being 
agitated by a rotating disc pelletizer. The 
spray mist accumulated the meal -oil mixture 
into a round, rolled pellet, which was then 
oven -dried and graded to size. 



superior diet. The granule -fed fish had a 
total gain of 146 percent while the mash-fed fish 
gained 135 percent. All indications are that the 
starter granule is the best starting diet we have 
developed so far . 

Feeding trials 



The second method of dry pellet prepara- 
tion tested was that of pressure or compaction 
pelleting, a method long in use for the pellet- 
ing of dry feeds for trout . One advantage it has 
over the rolled pellet method is that no oven 
drying is necessary since no water is added 
during pelleting. A second advantage is that 
pressure pelleting is already an established 
commercial method with a good number of 
companies capable of making this type of 
product. With more bidders available, the 
bidding should be more competitive. 

Starting diets 

The starter ration we have used in the 
past and the one we have recommended for use 
in production has consisted of a mixture of 
meals, oil, and vitamins. The meals were 
sized by running them through a 3/32-inch 
hammer mill screen and then mixing them 
with the vitamins and oil. This resulting mash 
performed well as a starting diet for first 
feeding fish, but has at times been lumpy due to 
improper mixing on the part of the 
manufacturer . 

Pressure pelleting of the Abernathy diet 
and then crushing the pellet and screening the 
crushed particles has made it possible to 
obtain a small granule that can be used as a 
starter diet. The small granules can be 
sprayed or side dressed with additional oil 
after screening . The result is a starter feed 
which has a formulation similar to our old 
starter mash but has the advantage of being an 
actual granule composed of all of the diet 
ingredients rather than a loose composite. 

A diet trial comparing the old starter 
mash with the new starter granule was run for 
4 weeks using first -feeding fall chinooks reared 
in constant 53° F. water. The results 
indicated that the starter granule was a 



Our regular feeding trials tested the 
rolled pellet with the regular Abernathy soft 
pellet and to determine optimum pellet drying 
temperatures. Other variables tested included 
the substitution of other ingredients for 
cottonseed meal in the basal mix and the use of 
soybean oil "foots" as a caloric source. The 
experiment was conducted for 16 weeks and the 
data indicated the following: 

1 . The dried rolled pellet was equal to the 
soft pellet of identical formulation when fed on 
an isoprotein basis to fall chinook salmon. No 
problems were encountered with fish accepting 
the dry pellet, but a smaller sized particle for 
a given size of fish was necessary. 

2. Pellet drying temperatures above 220° F. 
were detrimental, resulting in a reduction in 
fish growth. The condition of the fish indicated 
that the reduced growth was due to an impair- 
ment of protein quality rather than a destruc- 
tion in vitamins . 

3. Cottonseed meal could be eliminated 
from the basal mix and replaced with either 
corn meal, ground barley, hominy meal, rice 
bran, rice flour, soybean flour, or wheat 
middlings, as long as the protein content of the 
diet was maintained by varying the amount of 
fish meal. 

4 . The feeding of soybean oil "foots" as a 
caloric source resulted in less protein deposi- 
tion than a similar diet with regular soybean 
oil . The percent lipid of the flesh of fish fed 
the "foots" was the lowest of any analyzed. 

Although the rolled -pellet method of pellet 
preparation produces a satisfactory product 
which is readily accepted by the fish, it does 
have the disadvantage of requiring added water 
to pelletize and then removal of water by drying 
for sizing and storage. It is our opinion that 



119 



the drying step would add considerably to the 
cost of pelleting. This added expense would 
eliminate any cost advantage of a dry pellet 
over a moist pellet and, since pellet drying 
temperatures are critical, an exacting quality 
control would have to be maintained. 



process and the one recommended for 
production tests this coming year is shown in 
Table 1. Granule and pellet sizes are presented 
in Table 2 . 

Laurie G . Fowler 



Table 1 . --Approximate formula of Abernathy dry pellets 



Ingredient 

Fish Carcass Meal 

Dried Whey Product 

Cottonseed Meal 
Wheat Germ Meal 

Vitamin Mix -/ 
Soybean Oil 



1/ 



41.0 
23.9 



15.3 
12.8 



1.0 
6.0 



Type 

Salmon, dogfish, hake, herring or 

turbot 
Not less than 15% protein 

(Foremost or equal) 
Not less than 507o protein 
Not less than 257o protein and 

8% lipid 

Technical grade with .01% BHA and 
.01% BHT added 



1/ Fish carcass meal to have protein content not less than 70 percent , lipid less than 

12 percent, water less than 7 percent, and a TBA value below 40. 
2/ Vitamin mix as follows: 



Ingredient 



Amount (grams) 



Thiamin mononitrate 


0, 


.15 


Riboflavin 


0. 


,69 


Pyridoxine hydrochloride 


0. 


,30 


Niacin 


4. 


,77 


d Pantothenic acid 


0, 


,68 


Inositol 


13, 


.65 


Biotin 


0. 


.03 


Folic acid 


0. 


.10 


DL Alpha tocopherol acetate 






(10,500 lU) 


10, 


.50 


Ascorbic acid 


25, 


,50 


Carrier 2/ 


397, 


.23 



-/ Carrier may be wheat middlings or 

cottonseed meal sized to pass through 
a U. S. Sieve No. 20. 

To determine if this process was necessary 
feeding trials comparing the rolled and pressed 
dry pellets were conducted. After 12 weeks of 
feeding all indications were that the pressure 
type pellet was as good if not better than the 
rolled pellet when fed to fall chinook salmon . 
In addition, our vitamin analysis showed that 
the pressed pellet retained a higher level of 
vitamins after manufacturing than did a 
similar rolled pellet. The current formula for 
the Abernathy pellet made by the pressure 



Table 2. — Granule and pellet size 
specifications 



U. S. Sieve Size 



Pass 
through 



Pass 
over 



Starter granule =' 

2/64" granule i/ 

3/64" granule 

4/64" granule 

6/64" granule 

8/64" pellet 

12/64" pellet 



30 


40 


20 


30 


16 


20 


12 


16 


7 


12 


5 


7 


1/2 


5 



1/ starter granules to consist of screened 
fines from 6/64-inch crushed pellets 
and are to be side dressed with 5 per- 
cent soybean oil prior to sacking. The 
2/64-inch granule is to be side dressed 
with 2 percent soybean oil prior to 
sacking. 



120 



EVALUATION OF ENVIRONMENTAL FACTORS 
LIMITING PRODUCTION IN 
REARING PONDS 

Determination of optimum environments for 
rearing 

Five short-term experiments to determine 
the effects of different rearing temperatures on 
growth, body conformation, and physiological 
characteristics of chinook salmon fingerlings 
have been completed. In these experiments, 
groups of fingerlings ranging from 1.38 to 
8.94 grams average weight were reared at 50, 
55 , 60, or 65° F . for 4 weeks . Within this 
size range, 60° F. appeared closest to the 
optimum temperature for growth. Temperature 
apparently had no effect on body conformation 
or condition factor, and for fingerlings from 
3.05 to 17.84 grams, a linear relationship was 
found between cube of the fork length in milli- 
meters and average weight in grams. Tempera- 
ture effects on hematological characteristics 
were observed only in fish averaging four grams 
or less; increasing corpuscular counts, hema- 
tocrits, and hemoglobin levels were associated 
with increased rearing temperatures . 

An experiment is currently underway in 
which periodic increases in weight and length 
are being measured at four temperatures, 45, 
50, 55, and 60° F. Preliminary data indicate 
that linear relationships may exist between 
length increases and time at all four tempera- 
tures . If an acceptable and convenient method 
of predicting growth rates at different tempera- 
tures can be developed, close correlation of 
hatchery feeding levels to these predictable 
rates should result in improved hatchery 
production efficiency. 



Joe L. Banks 

Algacides for use in water reclamation and 
reuse systems 



An algacide is needed for use in water 
reclamation and reuse systems that will not 
harm the nitrifying bacterial culture in the 
filter beds . Four possible algacides , Karmex , 
Amine D Acetate, Simazine, and GS -13529 



were tested in model reconditioning systems 
during the summer . The models systems were 
set up outside to encourage growth of filamen- 
tous green algae. Karmex was the only 
product tested which showed any control of the 
algae at concentrations tolerated by fingerling 
chinook salmon. 

Weekly treatments with Karmex at 4 ppm 
inhibited the growth of Cladophora but did not 
eliminate the algae from the system. This 
concentration is several times higher than that 
reported to be effective against algae but it is 
probable that water temperature is a factor. 
Water temperature in the system never exceeded 
70° F . which may be lower than optimum for 
best results with Karmex or the other algacides 
tested. The results with Karmex appeared 
promising enough, however, that we intend to 
test it under production conditions during the 
1970 rearing season. 



Bobby D . Combs 

MEASUREMENT OF DIFFERENCES 

IN CHARACTERISTICS OF 

FINGERLING SALMON 

Release and recovery evaluation 

This research, begun in 1968, is designed 
to determine if measurable changes in finger- 
ling characteristics occur within a few days 
after release and to try to correlate such 
changes with adult survival. As in 1968, groups 
of fall chinook fingerlings were cold -branded for 
identification at several State and Federal 
Columbia River hatcheries . Samples of these 
fish were subjected to physical, physiological, 
pathological, and chemical tests before release. 
The same tests were performed on marked fish 
captured on their downstream migration by the 
Estuarine Investigations of the Bureau of 
Commercial Fisheries. The fish were usually 
recovered within a week after they were 
released from the hatchery. 

While fish from only four hatchery releases 
were recovered this year, several results 
appeared noteworthy. The first was that none of 
the recovery groups appeared as severely 



stressed as those in 1968, with plasma glucose 
and lactic acid levels near those of pre-release 
samples . Better condition of the fish before 
release may account for this difference. Water 
temperature in the lower Columbia River was 
lower in 1969 than in 1968 , which also would 
reduce the stress on migrating f ingerlings . 
Lipid losses were again high during migration, 
ranging up to 50 percent. One of the most 
striking results was the apparent poor survival 
of very small fish. In all groups the recovery 
fish averaged larger than those of the pre- 
release sample . In one group which averaged 
1.5 grams each at release, the migrants 
captured one week later averaged 2.7 grams or 
80 percent larger, indicating that the smaller 
fish had disappeared. 



Bobby D . Combs 

Effect of egg size on finger ling growth 

Returns of adult fish to our holding pond 
have increased to a point where we now have an 
excess of eggs each year. This desirable 
situation has made it possible to exercise some 
degree of selectivity over the eggs retained for 
rearing. The eggs of the returning adult fall 
chinooks vary considerably between fish in 
several characteristics, one being the average 
egg size. In order to determine if egg size is 



of any significance, selected females of 
similar length but with large or small eggs 
were spawned and the eggs fertilized by the 
same males. The eggs were kept separate, 
hatched, and are now being reared under identi- 
cal conditions. Physical data on the individual 
females as well as results after 6 weeks of 
rearing are shown in Table 3 . 

At present fish hatched from large eggs 
have a greater average weight than do the fish 
originating from small eggs. Unless there is 
a change from their present growth rate, the 
smaller fish will not equal the weight of the 
larger fish at time of release. An interesting 
and unexpected development has been the 
difference in mortality rates between the two 
size groups . In every instance fingerling 
mortalities have been greater in fish originat- 
ing from large eggs . There appears to be an 
egg size where these losses become excessive. 
In this experiment eggs which were larger than 
99 per displacement ounce had total mortalities 
after 6 weeks of rearing ranging from 15 to 
35 percent. Fingerling losses were caused 
primarily from faulty yolk sac absorption. It 
is apparent that egg and fry mortalities are not 
necessarily indicative of early fingerling losses 



Laurie G . Fowler 



Table 3. --Physical characteristics of adult female chinook salmon 

having large or small eggs. Their progeny average weights 

and mortality rates are for six weeks of rearing 





Adult 




Number 


Percent 


Avg. wt . 


Avg. wt . 


Percent 






female 




eggs/ 


egg and 


per fish 


per fish 


fingerling 


Total 


Adult 


length 


Total 


displacement 


fry 


at start 


at 6 wks . 


mortality 


mortalit 


female 


(cm.) 


eggs 


ounce 


mortal ity 


(g) 


(g) 


at 6 wks. 


(%) 


lAi/ 


82 


4839 


139 


5.4 


0.32 


1.34 


0.5 


5.9 


IBi/ 


87 


5036 


99 


2.4 


0.40 


1.46 


3.6 


6.0 


2A 


87 


6650 


149 


1.4 


0.30 


1.24 


0.5 


1.9 


2B 


89 


5398 


96 


5.7 


0.41 


1.51 


10.2 


15.3 


3A 


83 


6900 


136 


4.4 


0.30 


1.23 


2.0 


6.4 


3B 


88 


5192 


94 


9.6 


0.41 


1.48 


19.0 


27.3 


4A 


88 


5959 


131 


6.1 


0.33 


1.19 


0.8 


6.8 


4B 


84 


3936 


82 


10.2 


0.45 


1.94 


28.3 


35.0 


5A 


81 


4903 


141 


2.0 


0.29 


1.18 


1.0 


2.9 


5B 


85 


5026 


101 


3.3 


0.40 


1.70 


4.8 


7.9 



1/ A and B females represent pairs fertilized by the same males. 



DEFINITION OF FINGERLING 
CHARACTERISTICS NECESSARY 
FOR MAXIMUM ADULT SURVIVAL 

Environmental control systems are capable 
of producing much larger fish in the same time 
span than is possible with the colder water 
available in most single-pass systems. Larger 
fish require more rearing facilities. Experi- 
ments are underway to compare survivals of 
small creek -reared fish with fish three times 
as large reared in the environmental control 
system. While it is possible to produce fish 
three times as large as normal in the same time 
span, it is also possible to produce twice as 
many fish twice as large as normal in about 
two thirds the normal rearing time, using the 
same facilities. If such extra fish, released 
early when pond capacities are reached, 
should make a significant contribution to the 
adult run, their rearing would be justified and 
the contribution of the hatchery measurably 
increased. The 1969 adult survival experiment 
was designed to compare the survivals of 
fingerling fall chinook released March 18, 1969 
at 47 per pound with those released April 30, 
1969, averaging 21 per pound. 

Both groups were reared together in two, 
17 by 75, rectangular-circulating ponds. As 
the pond capacities were approached the fish in 
each pond were divided in half. One group of 
164,201 fish, weighing 3,494 pounds, were 
marked 1/2 anal and right maxillary and 
released on March 18 . A second comparable 
group were marked 1/2 anal and left maxillary 
and released April 30, at which time they 
numbered 138 ,450 and weighed 6 ,460 pounds . 
Both lots of fish experienced higher -than - 
normal mortalities as fingerlings due to 
coagulated yolk and an apparent inherent 
organic defect in this stock. At time of 
release there were no recognizable nutritional 
deficiencies in either group. 

Differences in the rates of adult returns 
between the two groups will be compared with 
the rates of return of adults from two previous 
experiments in which normal sized fingerlings 
and larger fingerlings were released at the 
same time . 



Two-year-olds and 3-year-olds from the 
two experiments designed to measure the 
survivals of normal and large fingerlings 
returned in 1969 . The results were most 
encouraging. 

From the 1966 brood year, 152 3-year-olds 
returned from the 33 -per -pound fingerling 
release and 14 adults from the 96 -per -pound 
fingerling release --more than 10 to 1 in favor of 
the larger fingerling at release. While this 
ratio of return may change slightly when the 4 - 
year-olds are accounted for, it is not antici- 
pated the change will materially alter the very 
significant difference in favor of the larger fish. 
A 10 -fold increase in the number of returning 
adults more than compensates for the additional 
capital outlay and operating costs of an environ- 
mental control system. Returns of such magni- 
tude also require an increase in the adult 
harvest . 

The returns of 2 -year -olds from the 1967 
brood year are even more encouraging. At 
this laboratory a large jack run has always been 
indicative of a high survival of this particular 
year class and has been correlated with 
increased adult returns. The return of 2 -year - 
olds in 1969 from the fingerlings reared in the 
environmental control system has been 
phenomenal . 

In this experiment, two groups of 200,000 
fingerlings, each, were reared in single-pass 
creek water and in the environmental control 
system at water temperatures averaging 56° F . 
Both groups were marked with a common 1/2 
dorsal clip and the removal of part of either the 
left maxillary for the 26 -per -pound fish reared 
in the environmental control system or right 
maxillary for the 80-per -pound fingerlings 
reared in creek water. Releases were made on 
May 15 , 1968 . 

In September and October of this same year 
we recovered 104 marked, sexually-mature, 
male yearlings from the adult holding pond. 
These fish were all from the 26 -per -pound 
fingerlings reared in the reuse system . At 
time of capture they weighed about one pound 
apiece. While mature yearlings are not 



123 



unusual we had never recovered them in such 
numbers before. 

In 1969 , both groups were recovered from 
the sport fishery off the Washington Coast. 
A total of 374 jacks were reported with the 1/2 
dorsal, left maxillary mark and 3 fish with 1/2 
dorsal, right maxillary mark. It is estimated 
that from 1 to 3 percent of the total chinook 
sport catch off Westport, Washington was 
composed of jacks from this single Abernathy 
release . 

The 2 -year -old return to the Abernathy 
holding pond was equally surprising. There 
were 448 fish, including 7 females with the 1/2 
dorsal, left maxillary mark, and 6 fish, all 
males, with the 1/2 dorsal, right maxillary 
mark. We have never had a marked 2-year- 
old return of this magnitude before . In fact, 
the largest previous return was in 1968 and 
amounted to 29 fish, also reared in the environ- 
mental control system . 

Needless to say we anticipate some record- 
shattering adult returns from this group of fish 
in 1970 and 1971. Unless some major ocean 
catastrophe occurs, all the evidence indicates 
that such will be the case. 

ABERNATHY INCUBATION CHANNEL 

Effect of egg development at planting on egg 
and fry survival 

The 1968-69 channel experiment involved 
eggs from 120 chinook salmon females from a 
single day's take in late September, 1968. 
Eggs from 40 females were planted in separate 
experimental areas as (1) unwaterhardened, 
green eggs, (2) waterhardened, green eggs, 
and (3) eyed eggs . Fry migration extended 
from December, 1968 until operations were 
terminated in mid-March, 1969, Migrant 
survivals from the channel were: (1) 75 .9 
percent from the unwaterhardened, green eggs, 
(2) 60.2 percent from the waterhardened, 
green eggs, and (3) 77 .6 percent from the eyed 
eggs. Earlier tests with eyed eggs had pro- 
duced survivals which varied from 68 .0 to 78 .5 
percent, similar to the present results. In the 
previous season, unwaterhardened, green eggs 



had a 50.1 percent survival and waterhardened, 
green eggs had a 37.6 percent survival. The 
present tests indicate that the planting of 
unwaterhardened, green eggs in incubation 
channels shows promise as a practical produc- 
tion procedure . 

Effect of various egg planting densities on egg 
and fry survival 

The recommended maximum egg-stocking 
densities for spawning channels vary from 139 
to 167 eggs per square foot of gravel . The 
Abernathy Incubation Channel has used stocking 
rates as high as 435 eggs per square foot of 
gravel with high fry survivals . This stocking 
rate was based upon the number of eggs planted 
in sections of the channel and included areas not 
utilized for eggs, such as drop structures. If 
based upon the actual area of gravel utilized for 
eggs --20, 000 eggs per 10 -foot trench with 
centers 36 inches apart --the density of eggs 
would be 667 eggs per square foot of gravel. 

Using the 667 egg-density as the control, 
the 1969-70 experiment seeks to determine the 
maximum stocking density per available square 
foot of gravel which will not result in reduced 
egg and fry survivals . About 600,000 eyed eggs 
of fall Chinook salmon were received from the 
Spring Creek National Fish Hatchery in early 
November 1969 . The eggs were found to have a 
fairly high incidence of "soft-shell" disease. 
To correct for this condition all lots of eggs 
were thoroughly mixed before planting. In this 
way, any resulting mortality should occur uni- 
formly throughout the channel and will not be 
interpreted as a result of planting density. 
Survivals may be lower than in previous years, 
but comparisons between eggs planted at 
various densities should still be valid. 

The eggs were divided among the three 
experimental areas and planted at densities of 
(1) 667 eggs per square foot using 36 -inch 
centers for trenches, (2) 1,000 eggs per square 
foot using 24 -inch centers, and (3) 1,333 eggs 
per square foot using 15 -inch centers. The 1,333 
egg -density appears to be the maximum stocking 
rate physically possible for the channel. Evalua- 
tions will begin in late January, 1970 when the 
first migrants begin leaving the channel. 



Mechanisms of migration 

Studies were begun to determine the 
influence of environmental factors of emergence 
and downstream movement of salmon finger - 
lings. Eight wooden troughs were constructed 
to simulate conditions found in the incubation 
channel (Figure 1) . The arrangement of water 
supplies and filters was designed to test the 
effects of water temperature, turbidity, and 
changes in water flow . The first four troughs 
were designed to test the effects of artificially- 
induced increases in water temperature, water 
flow, and turbidity. 




Figure 1 . --Simulated incubation channels for 
the study of triggering mechanisms causing 
fry migration. Sand filters in background. 
Barrel at right for introduction of silt. 
Troughs at left test effects of filtered 
and unfiltered creek water at two flows. 
Troughs at right test effects of 
increases in water temperature, flow, 
and turbidity. 

In late October, 2,000 eyed eggs from 
Abernathy Creek fall chinook salmon were 
planted in each trough at stocking rates 
comparable to the density normally used in the 
channel . Migration from the channel models is 
expected to extend from mid -January to late 
February. The effects of each variable will be 
evaluated by the pattern of the fry migration. 



Allen E . Thomas 



EVALUATION OF STRESS 
IN FINGERLING SALMON 

Exercise as a stress factor 

Two experiments were conducted to test the 
effects of water current extremes in the rearing 
environment on the physical, hematological, 
and chemical characteristics of fingerling 
Chinook salmon. In the first experiment, groups 
of fish were reared in a "fast -flow" circular 
tank and a "slow -flow" trough. Disease in both 
groups forced abandonment of the tests after 4 
weeks . The effects of disease were more prom- 
inent in the exercised group, as shown by 
higher mortalities, reduced growth, lower 
hematocrits, and reduced swimming ability. 

In the second experiment, a fish population 
was split and placed in two circular tanks, one 
with a fast water current and the other with 
essentially no current. Evaluations were made 
after 6 weeks of rearing. Individual variations 
and the small sample sizes prohibited statisti- 
cal analysis in most cases. The exercised 
group, however, developed higher stamina , 
blood counts, hemoglobins, liver glycogen, and 
lactic acid than did the non -exercised group. 
Exercised fish also were about 6 percent 
smaller, although the percent body fat and 
condition factors were the same for both groups. 
Future tests will involve larger numbers of 
fish and duplicate tanks for more valid statis- 
tical analysis and will more closely investigate 
the effect of exercise on growth . 



Allan E . Thomas 

GENERAL 

The Sixties have proved to be a most 
productive and rewarding decade for this 
laboratory, productive in that the rectangular- 
circulating pond, the environmental control 
system, and the Abernathy dry diet were 
developed and tested, and rewarding in that all 
of these developments have been applied in 
hatchery operations . One of the most frustrat- 
ing experiences for a researcher is to develop 
something which has practical application and 



125 



then not have it used. We have been most 
fortunate in being able to work with men in both 
our Bureaus and in several of the western 
states who have been most progressive and 
willing and able to apply in production opera- 
tions the results of some of our research and 
development . 

As a result, the rectangular circulating 
rearing pond is being used in new and 
remodeled Oregon Fish Commission hatcheries 
and at several National Fish Hatcheries. Small 
environmental control systems are being used 
at the Little White Salmon and Coleman 
National Fish Hatcheries with the first large 
and complete installation at the Dworshak 
National Fish Hatchery. Two other systems 
are nearing completion, one at the Fire Lake 
Hatchery of the Alaska Department of Fish and 
Game and another at the Mad River Hatchery 
of the California Department of Fish and Game . 
Several more environmental control systems 
are in the design stage. 

The Abernathy dry diet, pressure pelleted, 
is being fed on a production test basis to 25 
percent of the fall chinook fingerlings being 
reared at the Columbia River hatcheries of the 
Bureau of Sport Fisheries and Wildlife. In 
addition, the Washington Department of 
Fisheries is conducting extensive tests at six 
salmon hatcheries to compare the Abernathy 
diet as either pressed or rolled pellets . 

The year 1969, itself, has been especially 
interesting. The winter was severe with snow 
on the ground from January through most of 
March, with relatively cold weather, down to 
18° F. for some of this time. No difficulties 
were experienced from the freezing conditions 
but the snow accumulation had to be removed 
from the laboratory roof at one time to safe- 
guard against collapse . The remainder of the 
year was normal with enough precipitation in 
September and October to provide an adequate 
flow in Abernathy Creek for returning adults . 

The adult return was excellent, consider- 
ing that it coincided with the opening of the gill 
net season on the Columbia River. Despite the 
large commercial catch of fall chinook salmon, 
we took over 3,000,000 eggs, retaining 



approximately 1,500,000 and shipping the 
remainder as eyed eggs or first -feeding 
fingerlings to the Grays River hatchery of the 
Washington Department of Fisheries . 

From the previous brood year, 16,000 
pounds of fall chinook fingerlings averaging 62 
per pound and totaling 640,000 fish were 
released into Abernathy Creek. In addition, 
78 ,400 coho fingerlings weighing 4 ,730 pounds 
and averaging 17 per pound were released the 
latter part of May. The coho were from 1968 
eggs and had been brought to smolts in 6 months 
of rearing in the warm water of the environ- 
mental control system . These fish were markec 
by feeding tetracycline and removing the adipose 
fin. Adult returns will indicate whether this is 
a practical production procedure . 

The selection of eggs and fry of fall 
chinook salmon for production rearing continued 
during 1969 . The eggs from females larger 
than 80 cm. (31.5 in.) were held separately and 
culled on the basis of fecundity, viability, and 
egg size. The range of egg sizes from the 
selected fish was from 71 to 148 per displace- 
ment ounce. The range of size of the selected 
eggs was from 71 to 130 eggs per ounce . All 
lots with an egg and fry mortality greater than 
10 percent were culled and lots with less than 
3,500 eggs per female were discarded. 

We are beginning to doubt the wisdom of 
retaining abnormally large eggs for rearing. 
As indicated in the egg size experiment, 
extremely large eggs produce defective finger- 
lings with a high death rate. The disease 
appears as a type of coagulated yolk with losses 
in the early fingerling stage . Symptoms are 
similar to those of "cold water" disease but 
where the eggs of individual females are iso- 
lated the disease is confined principally to the 
large egg lots . In production, dead fish will be 
spotted, with some ponds experiencing much 
higher mortalities than others, depending on the 
distribution of the affected fingerlings . 

We have assured quality control for the 
Abernathy diet when used in production in order 
to assure a uniform product for large-scale 
tests . Proximate analyses are made of samples 
of all ingredients prior to manufacture and of 



the processed granules and pellets . Analyses 
are made to determine protein, lipid, carbo- 
hydrate, ash, and water, as well as selected 
vitamins. Specifications are so written that 
any ingredient or the formulated diet may be 
rejected if the requirements are not met. 
Usually we have encountered no difficulties but 
on one occasion the manufacturer had inadvert- 
ently omitted the entire vitamin package from 
the soft pellet. As a result, 30,000 pounds of 
soft pellets had to be reprocessed but about 
1,000,000 fall Chinook fingerlings were saved. 
Quality control is a most necessary adjunct of 
commercial pellet manufacture. 

Small tank feeders as shown in Figure 2 
have been purchased to automate the feeding of 
the fish on experiment . At a cost of $3 , 200 we 
have automated the feeding of 70 circular tanks. 
Such automation makes it possible for one man 
to handle the diet trials alone and eliminate the 
necessity for a biologist to be on Saturday and 
Sunday duty. Timers on control panels make it 
possible to control both the number of feeds and 
the amount fed per feeding. 



be a very satisfactory exhibit, 
for other showings in 1970. 



It is scheduled 




Figure 2. --Tank feeders used for dry feeds. 

A working model of the environmental 
control system, as shown in Figure 3, was 
designed and assembled at this laboratory. The 
model was constructed primarily for display 
purposes at the Boy Scout Jamboree but has 
since been used at the dedication of the 
Dworshak National Fish Hatchery and the 
Chelan County Fair. All reports indicate it to 




Figure 3. --Working model of environmental 
control system showing refrigeration unit 
and aeration chamber above, rectangular- 
circulating ponds at sides, and oyster 
shell and rock filter below. 

All production environmental control 
systems are working well. The largest and 
most complete system now in operation at 
Dworshak, is proving to be entirely practicable. 
The 1969 steclhead fingerlings in the system are 
averaging 17 per pound at present. There is no 
question but that they can produce downstream 
migrants by May. Fish reared in the river 
water, in contrast, will have to be held an addi- 
tional year before release. No major problems 
in design or operations have been encountered. 

Tests of the Abernathy diet in production 
have proved most satisfactory. Fall chinook 
fingerlings at the Quinault N.F.H. were reared 
exclusively on the Abernathy diet, pressure 
pelleted. The fish were in excellent condition 
at time of release. Coho fingerlings, also, are 
being reared at this station on the Abernathy 
pressed pellets with no problems . Steelhead at 
the Dworshak National Fish Hatchery have been 
reared for seven months to date on this diet 
with excellent results. The cost of the pressed 
pellet is 11 cents per pound by commercial 
processing, in contrast to 16.9 cents for the 
moist pellet. The dry pressed pellet is only 50 
percent the cost of the moist pellet and requires 
20 percent less feed to produce the same 



127 



poundage of fish . Feeding of the Abernathy 
pressed pellet in salmon hatcheries can result 
in as much as a 70 percent saving in food costs. 



Roger E . Burrows 



SIERRA NEVADA AQUATIC RESEARCH LABORATORY 

Bishop, California 
Norman Reimers, Director 

HIGHLIGHTS 



Immunological comparisons of bloods 
suggest a separation betweea a hatchery 
broodstock and a selected line developed from 
it by breeding survivors of stream tests . The 
third generation of the experimental line also 
continued to exhibit more wildness than its 
control, but did not survive a long-term stream 
exposure as well as the control. 

Trout were successfully cannulated for 
vascular physiological studies using a recently 
demonstrated technique, after several other 
procedures had proved unsatisfactory in tests. 
Chronic maintenance of trout with indwelling 
arterial and venous cannulae is now an avail- 
able method. 

In a program of tests designed to evaluate 
the efficacies of different soluble anesthetics, 
MS -222 significantly affected liver glycogen 
levels for critical post -anesthesia periods. 
It is therefore considered unsuitable for use as 
a stress restraint in tracer studies of carbo- 
hydrate metabolism . 

Our guinea pig colony, now bred through 
enough generations to be thoroughly altitude - 
adapted, produced several valuable immune 
sera and biologically useful blood fractions for 
use in the developing "physiology of adaptation" 
program . Rats and rabbits were added to the 
antibody factory this year. 

Partial results of a long-term experimental 
steroid stressing program, begun this year, 
suggest the possibility that measurable, stress- 



mediated leukopenia may be useful in 
evaluating adaptational success in fish. 

Preliminary experiments dealing with 
stream feeding suggest that learning plays a 
role in efficiency of natural food utilization . 

We now have evidence that night feeding by 
hatchery trout in streams accounts for a signi- 
ficant percentage of their daily food intake. 

Our stream studies suggest that winter 
conditions lead to poor feeding by reduction of 
behavioral drift of insects rather than reduction 
of feeding efficiency. 

Movement experiments indicate that 
certain aspects of trout -planting technique, 
such as time of day plants are made, the place 
and manner of planting, and nutritional state of 
fish at planting, significantly affect their 
ultimate location in a stream. 

Study of winter feeding habits of brook and 
rainbow trout in high alpine lakes indicates a 
high level of activity under heavy ice and snow 
cover. Loss of the very important midge pupae 
from the food supply soon after lakes freeze 
greatly reduces winter feeding success, com- 
pared to that in ice -free periods. 

We now have all data needed to describe a 
19-year life history of a single generation of 
stunted brook trout. This attained age is four 
to five times the normal lifespan of the 
species , 



129 



SURVIVAL AND VITALITY 
OF TROUT 

Survival selection of rainbow trout 

Long-term stream tests of initially 
matched groups of catchable -sized trout 
(Hot Creek fall-spawning broodstock, and fish 
bred from selected survivors of the same 
stock through two generations; both stocked as 
mixtures at 100 lb. /acre in two closed natural 
stream sections) began in July, 1968, and ended 
in May, 1969. We found no change from the 
previous generation in the relative performance 
of the two groups . That is , F2 experimental 
fish followed essentially the same seasonal 
course of survival as broodstock controls in 
this test as did F, experimental fish in the 
1965-1966 test. Table 1 indicates this course 
in terms of mid-term and final censuses. The 
selected groups appeared to have a slight 
advantage in the early months , but survived 
the winter and spring at lower rates than 
hatchery stock in both years . 

Table 1. — Comparative survival of selected 
(F-[_ and F2) and broodstock (B) types of 
Hot Creek rainbow trout , after summer 
stocking at 100 lb. /acre 



Trout group 






Pej 


rcent survival 






and Year 


Ai 


ug.- 


-Nov, 


Nov. -May 


Aug.- 


-May 


1965-66 
















B 




83, 


,4 


55.5 




46, 


.3 


^ 




86, 


.3 


44.0 




37, 


,7 


1968-69 
















B 




92, 


.8 


27.7 




25, 


.8 


^2 




96 


.9 


17.5 




16, 


.6 



In both experiments, the "survival -bred" 
trout were spawned from parents that had 
survived a stream test in relatively superior 
condition. Our objective was to demonstrate 
selection back toward wildness in a highly 
domesticated hatchery stock, hopefully improv- 
ing post -hatchery survival in the process. 

At this point (3rd generation) we have not 
found evidence that such selection has survival 
value in the Hot Creek stock, which supposedly 
has a very low genetic variability coefficient. 



However, we have some evidence that a 
distinguishable change of type is taking place 
within the stock as a result of the selection 
(see Physiology Section later in this report). 
We have also observed what appear to be indi- 
cations of greater tendency to wildness in the 
selected type. During a holding and feeding 
period following recovery from the stream, 
"survival -bred" trout were definitely more 
flighty and nervous, less inclined to accept 
prepared feed, and more susceptible to infesta- 
tion by pathogenic protozoans . Any methods 
for verification of selective change will be use- 
ful in further studies of type distinction and 
altered adaptive potential in hatchery trout. 

Performance and other tests of two California 
hatchery trout strains 

Stream Sections 1 and 3 were stocked in 
late September with mixtures of equal weights 
to total an initial 100 lb. /acre of catchable - 
sized Hot Creek and Mt. Whitney rainbow 
trout. Additional rainbow trout from the two 
lots, and wild brown trout of comparable size, 
were installed in indoor holding facilities for 
maintenance feeding and later comparisons with 
stream groups . 

Purposes of these exposures are (1) to 
compare survival in the stream with that of 
other marked trout from the same lots that 
were stocked in lakes by the California 
Department of Fish and Game, and (2) to 
compare stress responses in biochemical terms 
among the available situations. 

November samples of 10 fish per group 
were reserved for proximate and other analysis, 
together with initial, additional mid -term, and 
final samples . Observed mortality in the 
stream has been low to the end of the year. 

Record -age brook trout of Bunny Lake 

The original stocked generation of this 
small experimental population is now in its 20th 
(and, from all indications, final) year of life in 
a high -altitude cirque lake. Some highlights of 
previous work with these fish, whose age over 
the past several years has been unprecedented 
from our knowledge of the species, have 



been mentioned in earlier annual progress 
reports . 

Eleven of the few remaining specimens 
were removed by angling and transferred to the 
laboratory in October. One of these, shown in 
Figure 1, bore the evidence of its age in the 
stump of a pelvic fin that had been amputated 
in 1952, when about 150 of the initial 1,800 
trout were so marked. 




Figure 1. --Bunny Lake brook trout taken in 
1969. Age of 19 years verified by stump 
of fin (shown between hands) removed in 
1952. 

All possible general work on the ecology 
and ordinary histology of these aged and 
stunted fish has now been completed. Some of 
this year's findings were: 

1. A slightly higher index of abundance was 
observed for some of the invertebrate food 
forms that had disappeared following heavy food 
consumption early in the history of the trout 
group and that have reappeared in small 
numbers during the past three years. Neither 
of the two genera of larger zooplankters 
(Daphnia and Diaptomus , both rendered 
extinct by overcropping in 1953) were in evi- 
dence, however, and it is now clear that such 
small, oligotrophic lakes may suffer long- 
term and possibly permanent faunal alterations 
following continued overpopulation by trout. 

2 . Individual fish in the present remnant 
of the age -group apparently received no new 



growth advantage due to their now rapidly 
dwindling number, although increased growth 
was attributable to marked population reduc- 
tion and increased feeding at earlier ages, 
12 to 15 years. (See Figure 2, which shows two 
segments of greater growth rate and two periods 
of retardation during the long life -history . 
Length data from preserved fish, added to the 
plot, flatten the 1957-61 portion of the curve to 
a better approximation of non-growth for this 
period.) 

A laboratory-maintained individual grew 
only 1.8 cm in length and 1.3-fold in weight 
from October, 1968 to October, 1969 with 
regular brine shrimp feeding, suggesting that 
extremely advanced age by itself may be a final 
curb on the potential for growth. Another lab- 
maintenance growth test was continued for 
20 months with a 12- to 14 -year -old Bunny Lake 
specimen in 1962-64 . The results (11.3 cm 
length increase and 5 -fold weight increase) 
were much more impressive, but 1 cannot be 
certain whether an effect of lesser age or an 
advantageous individual capacity for growth was 
in control. 

3. A report on the age -indicative condition 
of representative tissues from age -group XVlll 
trout was received from Dr. L. M. Ashley, 
collaborating histopathologist at the Western 
Fish Nutrition Laboratory, in March of this 
year. This second analysis was similar to an 
earlier one made at age 13 in that no really 
definitive differences could be found between 
fish of extreme age and those grown at normal 
rates to age 3 or 4 years . 

Materials for confirmation of chronologic 
age--other than fin -clips providing known -age 
reference --a re on hand but have not yet been 
analyzed. We plan to make tests of collagen 
alteration as an indicator of aging and to 
attempt the interpretation of otoliths . 

Future work, utilizing reduced organic 
principles and other material collected this 
year, plus whatever may be left at the lake in 
the coming summer, will be more specialized 
and will be concerned with indicative histo- 
chemistry, enzyme assay, and other biochemi- 
cal evaluations to improve our knowledge of 



131 



2 50 


■ 










6 


3 


T ^ 


2 2 5 


■ 








8 


^^ 






200 
175 


- 


27^ 


37 














— 






150 


- 


^/^6 














1 2 5 


- 76^ 


^^3 3 














1 00 


- / 
















75 


f 100 
















50 


■ 
















25 


- 























1_J„ 




. J \ \ \ L 


1 







1950 



AGE - YEARS 



10 
I960 



14 IS 16 17 18 



19 20 
1970 



Figure 2. — Lifetime growth of Bunny Lake brook trout as estimated 
by available sample measurements (sample sizes shown at points). 
Broken-line section represents addition of 1960 and 1961 length 
data from preserved fish. 



age changes in freshwater salmonids and to 
explore the possible implications for alpine 
trout management . 

Norman Reimers 

PHYSIOLOGY AND BIOCHEMISTRY 

Serodiagnosis of F9 survival bred trout 

In order to test the hypothesis that the 
genetic constitution of the Hot Creek strain of 
rainbow trout could be environmentally altered 
to enhance stream survivability, the second 
generation (F2) of line-bred stream survivors 
was subjected to serodiagnosis. The data 
suggest that some serological (=genetic?) 
differentiation between the parental hatchery 
stock and the second filial generation of inbred 
stream survivors may have occurred. 

The blood of five F2 stream survivors was 
pooled and fractionated to obtain antigens for 
immunological challenge of guinea pigs . 



Three groups of five guinea pigs each were 
nnmunized against these F2 blood fractions: 

(I) Whole plasma proteins 

(II) The supernate fraction of 
osmotically lysed and 
centrifuged (15 , 000 x g) 
erythrocytes (erythrocyte 
hemolysate) . 

(Ill) The finely divided 15 ,000 x g 
pellet material . 

The respective antisera were titered by 
agar gel diffusion in the case of fractions I and 

II, and by erythrocyte agglutination for fraction 

III. This latter fraction proved antigenically 
undependable; fraction I was strongly antigenic, 
but the immunological responses of the five 
guinea pigs so challenged were too highly 
individual to be serodiagnostically reliable. 
Serial dilution of fraction II in agar gel diffu- 
sion tests against a pooled antisera, composed 
of the sera of the three most immunologically 
competent guinea pigs, selected out the most 
antigenically significant patterns . 



The cross -reactivity of the antiscra with 
blood cell fractions obtained from Hot Creek 
Hatchery rainbow trout, the Mt . Whitney 
Hatchery strain, and the brown trout was 
determined by serial dilution in agar gel. 
Figures 3 and 4 contrast the antigenic proper- 
ties of the red blood cell preparations of the 
four fish-types studied. Figure 5 is an 
Analytrol tracing of Microzone electrophero- 
grams of the whole plasmas of the F2, Hot 
Creek and Mt . Whitney rainbow trout. Further 
tests to confirm the suggested emergence of a 
variant strain as a result of line breeding of 
selected stream survivors will be possible 
when the F3 generation becomes available in 
fall, 1971. 




Figure 3. — Agar gel diffusion pattern of 
immunological responses between anti- 
sera to ?2 erythrocyte hemolysate 
(center well) and the following anti- 
gens, diluted to approximate 
"equivalent combining proportions": 

a) ¥2 rainbow erythrocyte hemolysate 
(upper left and lower right) 

b) Hot Creek rainbow erythrocyte 
hemolysate (upper right and lower left) 




Figure 4. — Agar gel diffusion pattern of 
immunological responses between anti- 
sera to Fp erythrocyte hemolysate 
(center well) and the following anti- 
gens, diluted to approximate equivalent 
combining proportions: 

a) Brown trout erythrocyte hemolysate 
(upper left) 

b) Ft rainbow erythrocyte hemolysate 
(upper right and lower right) 

c) Whitney rainbow erythrocyte 
hemolysate (lower left) 

Survey of lakes and streams for environment - 
ally -produced developmental defects in trout 

In collaboration with Dr. Bernard Baird, 
University of California at Berkeley, a terato- 
genic survey of hatchery fry and fingerlings are 
being compared with young -of -the -year wild 
trout obtained at 9,500 ft and 10,500 ft 
altitude from two representative Sierra Nevada 
drainages this year. When statistical and 
histopathologic data are correlated, physio- 
logical experiments can be designed to test the 
extent to which hypoxic stress can affect pre- 
and post-hatching developmental processes. 
It is hoped thereby to assess the role of 
natural recruitment in maintaining a healthy and 
vigorous population of fishes of various strains 
and species in marginal habitats. 



133 





Figure 5. — Analytrol scan of Microzone 
electropherogram of the plasmas of 
three test groups of rainbow trout. 

A. Whitney strain rainbow 

B. F2 survival-bred rainbow 

C. Hot Creek production rainbow 

The individual samples (pooled from 5 
animals each) were run on the same 
cellulose acetate membrane. Sample 
size 0.5 Hi; 30 minute run @ 250 v 
(2.5-4.5 mA) in pH 8.6 barbital buffer, 
M.=0.05. Arrow indicates origin. 
Polarity indicated by (+) and (-). 

Extraction and isolation of somatotropin 
from salmonid pituitary glands 

Altiiough we were unable to obtain 
several thousand salmon pituitary glands as 
planned this year, 1,154 pituitaries collected 
in the autumn of 1968 were defatted, lyophilized, 
and divided into several lots of finely powdered 
material. We have tested microanalytical 
methods and are able to identify and quant itate 
aliquots of peptide fractions eluted from 
chromatographic columns . At present we are 
working out the most efficient and least 
destructive method of extraction so that we can 
obtain other trophic peptides in addition to 
growth hormone . This can be characterized 
as a "pilot plant" approach to the extraction, 
isolation, and partial chemical characteriza- 
tion of pituitary trophic hormones, antecedent 
to the understanding of the physiological role 
of the pituitary gland in the adaptation and 



survival of hatchery-reared trout in montane 
and alpine waters . 

Immunoassay of insulin in the salmonid 
circulatory system 

The survival of hatchery-reared trout 
released into wild waters requires certain 
metabolic accommodations . Carbohydrate 
metabolism can be easily upset by the stresses 
imposed by the new environment, although the 
extent of this metabolic upset is conjectural . 
Blood insulin levels, in association with 
amounts of circulating catecholamines and 
glucocorticoids, will give valuable insights 
into the process of adaptation. To assay for 
insulin, we shall use a double antibody radio- 
immunoassay. As the first step, we have 
obtained high-titer antisera to crystalline 
bovine insulin from guinea pigs that were 
carried on an immunization program earlier 
in the year. (Fig. 6.) Guinea piganti- 
insulin, however, is a non-precipitating 
complex. At present an antibody against 
guinea pig gamma globulin is being formed in 
immunized rabbits . 

Upon receipt of our A. E.G. radioisotope- 
use license early in 1970, we shall be in a 
position to label purified insulin, prepared from 
crystalline commercial bovine insulin, with 
'^^lodine and ^"^ iodine. The facilities, equip- 
ment, and supplies to conduct large-scale 
insulin radioimmunoassays were built up this 
year and are in readiness. 

Effect of steroids on the salmonid 
hematopoietic system 

Avian physiologists have used corticoid- 
mediated leukopenia as an indicator of stress 
in birds undergoing a variety of environmental 
manipulations . If the technique were applicable 
to fish, the degree to which an animal was 
successful in adapting to a habitat could be 
gauged. 

In collaboration with Dr. Russell R. 
Burton, University of Galifornia at Davis, we 
have undertaken a study to determine the 
following: 



134 




Figure 6. — Blood is withdrawn from 
anesthetized guinea pigs to supply 
gamma globulin and other serum 
components . 



(1) Do elevated blood levels of steroids 
induce a significant leukopenia in trout? 

(2) Could a leukocyte count be used as a 
reliable diagnostic indicator of stress or 
condition? 

(3) Is the stress response, if any, 
temperature -dependent? 

Testosterone propionate is used as the 
challenge because of its low cost-per-dose 
factor as well as its demonstrated increased 
ratio, erythrocyte count /leucocyte count, in 
avian species. Dose-body weight tests have 
shown that the intraperitoneal administration 
of 10 mg testosterone propionate per 100 g 
body weight is well tolerated, even 2 to 3 
times per week. (Care must be taken, however, 
to avoid the use of connmercial preparations 
containing ethyl or benzyl alcohol since we 
have encountered significant mortality in 
experimental lots exposed to such prepara- 
tions . 



The (experimental design involved the 
maintenance of 3 groups of 30 rainbow trout 
each on 3 regimens: 

(1) Steroid -injected fish receiving a total 
of 75-100 mg testosterone propionate over a 

1 -month period prior to sacrifice; 

(2) Control fish injected with volumes of 
isotonic saline equal to the volume injected into 
the fish on the steroid regimen; 

(3) Uninjected controls . 

Upon termination of an experiment all fish 
are killed and 3 blood smear slides per animal 
are prepared. Four series of experiments 
were designed to test the influence of water 
temperature on the experimental results: 

(1) An experiment conducted in September 
when water temperature ranges between 14 and 
17°C. 

(2) An experiment in November at 6 to 8°C . 

(3) An experiment in February at 0.5 to 
3°C. 

(4) An experiment in May at 8 to 12° C. 

The first two experiments have been 
completed and are currently being analyzed. 
Analysis of variance of random samples taken 
from the September experiment, shown in 
Table 2, indicates that the leukocyte count is a 
highly individual characteristic for fish. 
There is a suggestion of steroid -mediated 
leukopenia; however, a more definite statement 
must await further analysis. 

An extension of this study is the development 
of an indirect method of total leukocyte count. 
The method appears statistically valid on 
preliminary investigation. If it proves valid, 
it will be a useful adjunct to our field program 
since it will eliminate the need for cumbersome 
equipment . 



135 



Table 2. — Leukocyte count of blood smears obtained from randomly selected rainbow 
trout injected with 75 mg testosterone propionate (STEROID) , an equivalent 
volume of isotonic saline (SALINE), or uninjected (CONTROL) during September, 1969 
(water temperature range 14. 5-16 . 3 °C. ) . Analysis of variance: F qq = 3.46. 



Animal 


Slide 


ft Leukocytes 


# Fields 


Leukocytes 




Identification 


# 


counted 


examined 


per field 


Regimen 


A 


2 


65 


30 


2.17 


STEROID 


A 


1 


53 


25 


2.12 


STEROID 


A 


3 


52 


25 


2.08 


STEROID 


H 


1 


119 


25 


4.76 


STEROID 


H 


3 


102 


25 


4.08 


STEROID 


H 


2 


114 


25 


4.56 


STEROID 


I 


1 


190 


25 


7.60 


STEROID 


I 


2 


111 


26 


4.30 


STEROID 


I 


3 


106 


25 


4.20 


STEROID 


J 


1 


54 


25 


2.20 


STEROID 


J 


2 


42 


25 


1.70 


STEROID 


J 


3 


52 


25 


2.10 


STEROID 





3 


116 


25 


4.64 


SALINE 





2 


85 


25 


3.40 


SALINE 





1 


115 


25 


4.60 


SALINE 


Q 


1 


83 


25 


3.30 


SALINE 


Q 


2 


136 • 


25 


5.40 


SALINE 


Q 


3 


139 


25 


5.60 


SALINE 


R 


1 


101 


25 


4.00 


SALINE 


R 


2 


100 


25 


4.00 


SALINE 


R 


3 


95 


25 


3.80 


SALINE 


L 


1 


339 


25 


13.60 


SALINE 


L 


2 


291 


25 


11.60 


SALINE 


L 


3 


336 


25 


13.40 


SALINE 


X 


1 


250 


25 


10.00 


CONTROL 


X 


2 


250 


25 


10.00 


CONTROL 


X 


3 


267 


25 


10.70 


CONTROL 


AA 


1 


128 


25 


5.10 


CONTROL 


AA 


2 


173 


25 


6.90 


CONTROL 


AA 


3 


122 


25 


4.90 


CONTROL 



Effects of anesthetics on carbohydrate 
metabolism 

In order to administer radioactive tracers 
to fish for in vivo studies of carbohydrate 
metabolism, a method of restraining the 
animal for injection while avoiding stress - 
induced alteration in blood and tissue carbohy- 
drate levels must be used. We are currently 
searching for a chemical agent which will 
rapidly immobilize a fish, have no significant 
effect on short term (less than 30 min) carbohy- 
drate metabolism , and work well at low water 
temperatures (0.5 - 7°C.). 



The barbituric acid derivatives, sodium 
barbital and amobarbital, were unsatisfactory 
on the basis of prolonged duration of induction 
as well as the evidence for hepatic involvement 
in metabolism of these drugs . The action of 
2 -phenoxyethanol , at 1:4500 and 1:9000, was 
unpredictable at low water temperatures , 
causing a violent contact reaction by fish, 
variable blood glucose responses and incom- 
plete blockade of pain responsiveness. Paral- 
dehyde, 1:3800, was similar in action to 
2 -phenoxyethanol . 



136 



Many workers have found MS -222 the most 
efficacious anesthetic for fish. Our investiga- 
tions indicate, however, that this popular agent 
is undesirable for use in studies of carbohy- 
drate metabolism which require repeated blood 
sampling of the sedated animal over a short 
duration following induction. Figure 7 presents 
the results of one of several experiments in 
which liver glycogen levels were significantly 
affected by maintenance of fingerling rainbow 
trout (av . wt = 30 g) in piped stream water 
made up to 1:15,000 MS -222, pH 7.0, at 2.8°C. 
Blood glucose responses, while individually too 
variable to be significant statistically, are 
suggestive of endocrine involvement. In 
progress now are studies of the effect of 
MS -222 on the circulating levels of epinephrine 
and Cortisol, soon to be expanded to include 
immunoreactive insulin and glucagon. Like- 
wise, hepatic ascorbate is being studied to 
determine to what extent MS -222 may be 
metabolized by the liver. 




DUIKTION or CXP09U*E (umi/THl 

Figure 7. — Effect of duration of exposure 
to a 1:15,000 anesthetizing solution of 
MS-222 on rainbow trout blood glucose 
and liver glycogen concentrations. 
Vertical lines indicate standard error 
of the means. N=5 fish per group. 
Time "0" indicates values obtained for 
unanesthet ized control fish. 
Glucose ; Glycogen . 



The chronic maintenance of trout possessing 
indwelling arterial and venous cannulae 

Meaningful physiological data are often 
difficult to obtain by sampling blood of fish 
under conditions of acute stress . On the other 
hand, a fish maintained chronically with 
indwelling arterial and venous cannulae can be 
expected to be "more normal" in its physio- 
logical responsiveness after passage of an 
appropriate period of accommodation. 

Several cannulation techniques were tried, 
some novel and some based on published works . 
None was satisfactory for the purposes intended. 
During a recent visit to our laboratory. 
Dr. Walter F . Garey of the Scripps Institution 
of Oceanography demonstrated a technique of 
chronic vascular cannulation which he found 
successful in respiratory and cardiovascular 
studies of nine fresh and salt water teleost 
species. This technique, now described in the 
literature (J . Appl. Physiol. 27(5):756-757 
(1969)), is eminently satisfactory for arterial 
and venous cannulation of trout since extensive 
study has indicated: 

(a) the dorsal aorta is the only feasible 
vessel for chronic maintenance of an indwelling 
arterial cannula because placement is rapid 
and effected with a minimum of trauma . 

(b) the ventral aorta is the only feasible 
vessel for chronic maintenance of an indwelling 
venous cannula because all other venous vessels 
have proven too fragile to tolerate the operation. 

Dr. Carey's technique recommends itself 
further since the simplicity of the operation 
makes possible its use in field studies. 



Gerald J . Crowley 



137 



BEHAVIOR - ECOLOGY 

Modification of feeding behavior with stream 
experience 

The time required for planted trout to 
begin utiliziag natural food as efficiently as 
wild fish can be of considerable importance to 
their subsequent success . This is particularly 
true if they are introduced at times of decreas- 
ing food abundance, or face stiff competition 
from resident fish . 

Up to now we have compared the stream 
feeding habits of hatchery rainbow trout that 
had lived in Convict Creek for 10 months with 
those of comparable individuals maintained for 
the same period in circular tanks on pelleted 
trout feed. 

Although they fed on the same types of 
food as stream -acclimated fish, the "naive" 
tank fish as groups consumed fewer of each 
kind of prey. They also appeared considerably 
less apt than stream -acclimated fish to 
utilize caddis larvae in cases and surface - 
floating items (as opposed to mid -water drift- 
ing organisms) . Apparently trout need to 
learn some new techniques before they can 
utilize these types of food efficiently. As yet 
we do not know the time necessary for such 
learniag . 

Quantitative comparison of night vs. day 
feeding in streams 

As an important step in working out 
energy budgets for trout in streams, we under- 
took with Dr. C . R. Feldmeth of UCLA a 
study of rainbow trout feeding chronologies . 
Our method involved comparing the weight of 
prey consumed by rainbow trout during differ- 
ent 5 -hour periods of the day and night . 
Similar studies were carried out in summer, 
autumn, and winter for seasonal comparisons . 

On the basis of weight consumed, 5 hour 
feeding periods in both summer and autumn 
can be ranked in importance (from greatest to 
least): mid-day (9 AM - 2 PM); late afternoon 
and early evening (3-8 PM); middle of night 



(9 PM - 2 AM); and late night and early 
morning (3 - 8 AM). 

The majority of prey taken in mid-day 
periods were terrestrial in origin, or the adult 
stages of aquatic insects . Together they 
constitute the surface -floating component of the 
organic drift. Second in importance were highl 
mobile aquatic beetles , which our drift samplin 
showed to be most active during the afternoon. 
Immature aquatic insects were rarely taken at 
mid-day, undoubtedly because most species 
enter the organic drift only during their night- 
time activity periods . 

In contrast to fish feeding at mid-day, 
night -feeding fish took numerous species of 
immature aquatic insects, and virtually no 
surface -drifting forms . The early morning 
study periods encompassed both darkness and 
daylight feeding, so trout consumed a mixture 
of surface -floating and aquatic forms . Howeve: 
feeding was light on both types of prey. The 
afternoon -evening periods also spanned both 
sunlight and nocturnal conditions , but both 
surface -floating and aquatic prey are more 
abundant at this transitional period, and 
feeding was more successful. 

By December, when the reduction of 
surface -drifting forms could have made night 
feeding of prime importance, reduction in 
abundance of all types of drifting organisms 
made day-night comparisons impossible. Even 
wild brown trout from Convict Creek fed poorly 
in the study stream . 

During mid -summer there was indication 
that light intensity on full -moon nights was 
sufficient to inhibit the activity of nocturnal 
aquatic insects, and thus reduce nighttime 
feeding success of trout. However, compari- 
sons of full and new moon drift samples in 
October and December failed to show such a 
phenomenon . 



Relationship between organic drift and trout 
feeding in high -altitude streams 

We have found wild cutthroat or brook 
trout in virtually all streams accessible to 
populations in permanent waters . Some of the 
streams we have looked at are exceedingly 
small, and often temporary, but all contain 
aquatic organisms showing behavioral drift. 
For example, in a snow -melt rivulet discharg- 
ing less than 0.08 cubic feet per second, we 
found that from 10 to 65 organisms drift past a 
given point hourly (mean 38 for 24 one-hour 
collections). Drifting organisms in the 
rivulet were most abundant in late afternoon 
and early evening, and least abundant just 
before dawn. This pattern was closely corre- 
lated with water temperature, which fluctuated 
as much as 12.5C° daily. The few resident 
brook trout appeared to be making a good 
living. 

Although we have not observed feeding 
behavior directly, comparison of stomach 
contents of trout with the composition of 
organic drift in small streams suggests that 
drifting organisms make up most of their food. 
We have as yet found no system suitable to 
evaluate occurrence of organic drift as a 
factor limiting habitation by trout. 

Post -planting movements of hatchery trout 
in a stream 

We learned previously that rainbow trout 
planted singly or in groups disperse in a 
largely predictable manner, provided that 
methods of handling and introduction are the 
same. During summer, 1969, we looked at the 
effect on dispersal tendency of certain changes 
in these methods . 

Results of a preliminary study on the 
effects of differing planting location on post- 
planting movements indicate that fish planted 
in riffle areas move predominantly upstream, 
whereas fish planted in pools tend to move 
downstream . 

We also found that direction of dispersal 
from a riffle area can be controlled further by 
orienting all fish in a particular direction with 



respect to stream flow. When so oriented, 
rainbow trout tend to move in groups in the 
direction they enter the water. 

In a study of the effects of night conditions 
on dispersal tendency, we found that dispersal 
rate at night is significantly greater than in the 
daytime. There was some evidence to suggest 
that night planting also leads to relatively fewer 
fish taking up residence in the vicinity of intro- 
duction. The time of day fish were planted did 
not seem to affect their direction of movement. 

The effect of "hunger" on post -planting 
movements was studied by comparing fish fed 
to satiation before planting with fish deprived of 
food for 88 hours. Starved fish dispersed 
significantly faster than satiated fish, and might 
have dispersed to far greater distances had the 
study stream been longer . 

Winter feeding of trout in high -altitude lakes 

Since winter conditions of ice cover, cold 
water, and near -darkness last for 8 months or 
longer in high alpine lakes , they could have 
major impact on the ecology of lake inhabitants . 
In our first study (winter 1969-70) we are inves- 
tigating feeding under the ice in two small, 
shallow brook trout lakes above 10,500 feet in 
the Rock Creek basin, and a similar lake 
containing Kamloops rainbow trout on a tribu- 
tary of the East Walker River. Our aims in 
this study are to infer from the types of food 
eaten what the fish are doing at different times 
of the winter, and to infer from the condition of 
fi^h and the quantity of food they have eaten how 
much benefit they gain from their activities. 

Our results to the end of this year indicate 
that trout are quite active in the winter and are 
still feeding on natural foods after two months 
under ice. Observations through holes suggest 
that fish in winter aggregate (and perhaps 
school) rather than remain solitary as in the 
summer. 

By the end of December, fish of both species 
were in fairly good condition, and in many 
instances still had fat stored around their 
viscera . 



139 



Variability among individuals in their 
stomach contents is great, despite their 
apparent tendency to aggregate (Table 3) . Most 
feeding involves bottom -living organisms and 
zooplankters , as opposed to the tendipedid 
pupae which predominate during the summer . 



Our results to date suggest the following 
answer: at very low densities , the more 
aggressive fish defend largely inviolate terri- 
tories , through which they move in a character- 
istic manner. Since even these individuals 
voluntarily restrict their activities to a small 



Table 3. — Stomach contents of 10 brook trout taken in 
midwinter from Chicken Foot Pothole Lake (Elev. 10,761 
feet). All were caught within 28 minutes through one 
hole in the 18-inch ice cover. 



Fish 


Numb 


ers of or 


ganisms in s 


tomachs 




No 


Diptera 


Water 


Bivalve 








larvae 


mites 


molluscs 


Copepods 


1 


32 













2 


4 













3 


11 


11 










4 


34 


2 


1 







5 


32 





2 







6 


1 










71 


7 


16 





6 







8 


2 













9 


95 


1 


1 







10 


4 





2 








Although we have made a successful start 
on this project, its completion through this 
winter and on to spring thaw is threatened by 
the inadequacy of our transportation capabilities , 
We are arranging to test larger , more powerful 
over -snow machines; the most informative test 
conditions will likely not be encountered until 
February 1970. 

Behavior of trout in experimental ponds 

To understand the role of behavior in the 
ecology of trout, we have broadened observa- 
tions to include four experimental ponds with 
natural food supplies . The ponds measure 
approximately 10 x 25 meters by 1 meter deep, 
and are equipped with screened inflow pipes and 
standpipe drains to maintain a constant water 
level . Fish food production seems to occur 
more or less uniformly over the pond bottoms . 

One of our prime questions is why 
increasing densities in some still -water 
habitats result in general stunting rather than 
the increase in size variability observed in 
some food-scarce experimental situations. 



proportion of the pond area , there is room for 
the other fish to feed in portions exploited 
only by themselves . 

As densities of fish increase, aggression 
becomes progressively less effective in separa- 
ting ranges of movement, and overlapping use 
of water increases. In fact, the average water 
volume sought by individuals appears to be 
constant over large ranges of density. By 
virtue of this "shared" use of water and its 
associated food organisms, a fish decreases 
the number of prey encountered per unit 
distance traveled both for itself and for other 
fish using the same area . 

Summer and autumn supplies of food in our 
ponds are very rich, consisting primarily of 
immature insects of the dipteran family 
Tendipedidae . Trout feed especially heavily on 
the pupae and emerging adults of this family. 
Aquatic beetles and Hemiptera bugs are also 
cropped at high rates . 

With the advent of ice cover in the winter 
we developed ice -free standpipe drains, and 



140 



plan to continue monthly stomach sampling 
through the winter. The first two under -ice 
samples indicated decreasing food consumption, 
as we might expect from the loss of midge 
pupae and emerging stages due to ice cover . 
As of the year's end, the fish were still main- 
taining their physical condition, presumably 
due to decreased maintenance costs in the cold 
water (Fig. 8). 




Figure 8. — Rainbow trout are removed from 
one of the ponds for study of under-ice 
feeding. 

As in alpine lakes , the fish in our ponds 
appear to feed in groups rather than solitarily. 
This is a striking change from summer behav- 
ior, whereby each fish has a distinctive 
pattern of movement . 

Reproductive migrations of rainbow trout 



7 March. This is a large difference in timing; 
the runs in both years coincided rather closely 
with break-up of ice cover on the lake. 

Night behavior of trout 

After several attempts , we abandoned the 
idea of pinpointing night positions of trout in 
streams by flash photography. Attenuation of 
the flashes is rapid, resulting in a dazzling cone 
of light for a short distance, and a relatively 
small strip of adequate visibility on the 
photographic plate. With luck, fish can be 
spotted by their shadows , but flashes in short 
succession indicated that the first flash, 
though only of 1/1200 second duration, drives 
them into hiding or to other stream areas . 

Evaluation of an intramuscular tag for trout 
behavior studies 

Observations of fish in our experimental 
ponds indicated that distances are too great and 
movements too frequent for identification of 
individuals with heat brands . We therefore 
tested the adequacy of a plastic intramuscular 
tag (Floy Tag Co .) which can be inserted 
rapidly with a mechanical apparatus . 

The tag is a filament of plastic with a 
"T" on one end. By means of a hollow needle, 
the T is bent parallel to the filament and 
inserted into the opposite side through dorsal 
musculature and between interneural bones . 
When the needle is withdrawn, the T opens and 
hangs up on the interneurals . 

After extensive tests in the ponds and in 
the Convict Creek controlled stream sections, 
we concluded that these tags cause no mortality 
of hatchery rainbow trout, and have no effect 
on feeding or other behavior. However, the 
flags originally provided on the protruding 
filaments had to be removed, as their presence 
resulted in significant tag loss . 



Once again we finished a calendar year 
without trapping facilities on Convict Creek, 
but were able to determine timing of the spring 
run of rainbow trout by weekly electrofishing. 
The first spawners were encountered on 4 May, 
whereas the run in 1968 began prior to 



141 



The colored tags worked well for 
identification of fish in the experimental ponds, 
and they projected enough to be visible from an 
observation tower on either side. There was no 
tendency for fish to nip at, or otherwise react 
to, tags on other fish. We consider them suit- 
able for behavioral observations requiring long- 
term retention and ready identification from a 
distance . 



Thomas M. Jenkins, Jr. 




"J^M 



«?! 



.i.*^*-'.-^ 
.v*.^"^. 



^ 



Figure 9. --Laboratory residence and surroundings in March, 1969. 



142 



WARMWATER FISH CULTURAL RESEARCH LABORATORIES 

Stuttgart, Arkansas 
Kermit E. Sneed, Director 

Laboratories 

FISH FARMING EXPERIMENTAL STATION 
Stuttgart, Arkansas 
Fred P. Meyer, Chief 

SOUTHEASTERN FISH CULTURAL LABORATORY 

Marion, Alabama 

Harry K. Dupree, Chief 

FISH FARMING DEVELOPMENT CENTER 

Rowher (Kelso), Arkansas 

John J , Guidice, Chief 



HIGHLIGHTS 

U.S. acreages devoted to warmwater fish 
farming approached 40, 000 acres . Estimated 
returns to the farmers for 1969 were $33 mil- 
lion. 

Raceway culture at Stuttgart is producing 
2,000 lbs . of fish in an area 100 ft . long, 15 ft. 
wide, and receiving a flow of 550 gpm . 

Vitamin A acetate requirement for channel 
catfish was tentatively established at 1,000 to 
2,000 units per kilogram of feed. 

Channel catfish weight gains and dietary 
lipid levels were linear; best growth was from 
diets with 15 percent fish oil. 

Weight gains of channel catfish fed purified 
diets with an insulin-sparing drug were greater 
than those of fish fed identical diets but without 
the drug. 



Raw and pasteurized fish processing wastes 
have proved suitable as feed for catfish finger - 
lings. 

Channel catfish have a significant growth 
response to increased protein percentage in 
feed and to feed amount . 



Seasonal use of "demand" feeders shows 
that catfish use much more feed during early 
summer than is presently recommended. 

Stocking density stresses can be partially 
compensated by supplying more feed. 

Pre -determined feeding schedules were 
shown to have gross errors but could be used to 
produce an average fish crop. 

Outcross hybrid catfishes failed to retain 
the high degree of vigor demonstrated by F^ 
hybrids . 

The white catfish x channel catfish hybrid 
is fertile and will reproduce. 



143 



Adult male channel catfish are more suscep- 
tible to quinaldine than adult females . 

A trapping device using feed as a lure was 
successful in removing 90 percent of the fish in 
two attempts . 

Fingerling catfish can be hauled at the rate 
of 2 lbs . per gallon in aerated well water at 
55° F. 

The S20. W value, subunit structure, amino 
acid composition, and peptide maps of the Ig M 
immunoglobulins of paddlefish and longnose gar 
have been determined, and limited primary 
sequence data from the terminal end of the poly- 
peptide chains shows a structural pattern 
similar to those of man. 

Peak periods of disease incidence during a 
5 -year period were identified and corrective 
procedures suggested. 

Aureomycin, sulfamethazine, and a combin- 
ation of the two failed to protect fish from Aero- 
monas liquefaciens when included in the diet at 
low levels . 

Branchiomyces sanguinis was identified in 
gill tissue of striped bass received from two 
locations . 



At about the same time, some states also 
began to rear channel catfish, notably Kansas, 
Oklahoma, Missouri, and Texas. By the 1930's 
production methods were fairly well defined 
and reasonably successful for the production of 
at least hundreds of thousands of fingerltngs for 
stocking public fishing waters . 

Among southern and southwestern fisher- 
men, the channel catfish was on par as sport 
and food with the trout of northern waters . 
However, catfish were abundant in the streams, 
rivers, and lakes of its natural range, which 
undoubtedly reduced the demand for stocking. 
In the 1930's and 40's, following the construction 
of large numbers of man-made lakes and ponds, 
the demand for artificial stocking suddenly 
increased for largemouth bass, bluegills, and 
channel catfish. By 1950, there was a growing 
interest also on the part of irrigation farmers 
in Arkansas, Mississippi, and Louisiana to fish- 
farm abandoned land or large irrigation reser- 
voirs . The buffalof ish or carp used for this 
purpose did not produce a profit because of low 
consumer acceptance and low selling prices 
due to seasonal competition from wild fish which 
came to market simultaneously with farm- 
reared fish . Knowledgeable farmers realized 
that the high-quality, high-priced channel cat- 
fish might succeed where the buffalo and carp 
failed. 



Dalapon 24 -hour LC5Q value was determined 
to be in excess of 4 ,000 ppm at 42° F . for 
bluegills . 

PAST, PRESENT, AND FUTURE STATUS 
OF FISH FARMING RESEARCH 

Attempts by the U.S. Fish Commission to 
produce the channel catfish for sport and food 
began before 1892, In that year 1,300 fuiger- 
lings were produced in small ponds in Washing- 
ton, D. C, from broodstock obtained from the 
Federal fish station at Neosho, Missouri. 
Considerable unrewarded effort followed this 
initial "success," but it was not until about 1915 
that the Commission's Biological Station at 
Fairport, Iowa, gained useful insight Into the 
habits and spawning requirements of this desir- 
able species . 



Two interests , potential fish farmers and 
sport fishermen, encouraged the Fish and Wild- 
life Service and a few institutions , notably 
Auburn University, to begin channel catfish 
research projects in the middle 1950's. This 
early research led not only to profitable catfish 
farming but increased production for public 
waters from both National and State fish 
hatcheries. The growth of catfish farming, 
particularly, has been so striking and captivat- 
ing, with its promise of profits and public good, 
that many institutions and agencies are now 
engaged in some type of catfish research or 
testing program . 

Research of the different agencies covers a 
broad spectrum of subjects, including basic 
nutrition, practical diets, stocking and feeding 
rates, harvesting, spawning, behavior, cage 



and raceway culture, silo culture, hybridization, 
and disease. 

The Warmwater Fish Cultural Laboratories 
pursue a broad range of research associated 
with fish culture, especially catfish and baitfish 
farming. The Bureau of Commercial Fisheries 
is engaged in harvesting research at their Gear 
Research Station, Rowher (Kelso) , Arkansas. 
They also do surveys and research concerned 
with processing and marketing farm -raised 
catfish . 

Other agencies , mostly universities, are 
also engaged in catfish research, done mostly 
by graduate students who are usually supported 
by Federal money or a combination of Federal 
and State funds. About a half -million dollars 
are being spent by the states on channel catfish 
or baitfish projects, 75 percent of which is 
furnished by Federal funds under P. L. 88-309. 
The projects cover cage culture (State College 
of Arkansas and Southern Illinois University), 
nutrition and physiology (University of Georgia), 
behavior of catfish and other species when 
confined together (Illinois Natural History Sur- 
vey), rearing in flow -through water systems 
(Skidmore Institute, Georgia) and rearing 
baitfish in the desert Southwest (Nevada South- 
ern). 

The Bureau of Sport Fisheries and Wildlife 
also conducts fish culture research through its 
Cooperative Fishery Units located at selected 
universities, particularly Auburn, Louisiana 
State , and Oklahoma State . 

Kermit E . Sneed 



NUTRITION 



Demand feeders 



Two 0.25 acre ponds were stocked at the 
rate of 1,600 per acre with blue and channel 
catfishes . In one pond the fish were fed by a 
demand feeder; in the other they were hand -fed 
3 percent of body weight daily. Results are 
shown in Table 1 . 

Blue catfish growth was not significantly 
changed, but channel catfish grew better when 
fed by the demand feeder (Figure 1). 




Figure 1. — Demand feeder similar to those 
currently used on catfish farms. 



Table l.--Data on growth and feed conversion for hand-fed and demand- 
fed blue and channel catfish. 



Hand-fed 



Demand-fed 





Blue 




Channel 


Blue 




Channel 


Stocking weight, grams 


12 






11 


12 






11 


Harvest weight, grams 


290 






320 


310 






392 


Gain, grams 


278 






309 


298 






381 


Net production, pounds 


123 






136 


131 






168 


Feed used, pounds 




387 






438 




Conversion 




1 


.50 




1. 


.47 





A demand feeder was installed for 
demonstration purposes on a 1.0 acre pond 
stocked with 5,000 small channel catfish finger- 
lings . Starting from an average weight of 5 .5 
grams, these fish reached 272 grams, using 
5 ,469 pounds of feed in 180 days . The entire 
pond produced 3,160 pounds of fish. An event 
recorder wired to a switch in the down -spout of 
this feeder showed almost constant use . Table 
2 presents data calculated from the production 
and feed consumed. The high values for "Feed 
% Fish Wt." during the early part of the grow- 
ing season indicates that the fish took more 
than one feeding each day. Conversion was 
satisfactory, but not as good as for other (hand- 
fed) ponds at the station. In August, Fintrol 
added to this pond killed an estimated 400 
pounds of sunfish and shad. Uniformity of size 
was noticeably greater than that of fish in 
an adjoining 1.0 -acre pond stocked with 2,700 
fingerlings hand -fed once daily. 



I 



and conversion. Table 3 shows data for all 
tests . 



Fish growing on feeds of different protein 
percentages and at different levels of body 
weight were analyzed statistically. A signifi- 
cant linear response was found for percent pro- 
tein and feed amount, the equation using these 
two variables being: 



136.8+12.7 (^P£2!|HL 



32.9 (% Feed - 4^ 



30 



) + 



with "y" expressed as pounds gain per 1,000 
fish during the 70-day test period. An excellent 
fit for the data was also found in the quadratic 
equation: 



Table 2. --Production in a 1-acre pond stocked with 5,000 catfish 
fingerlings using demand feeder. 



Time 


Cumulat ive 


Production 


Conversion 


F 


eed % 


days 


lbs. feed 


lbs. fish 


feed/ gain 


f 


ish wt . 








67 








35 


450 


— 


— 




— 


55 


674 


320 


2.66 




8 


85 


1,933 


800 


2.64 




5.5 


115 


2,751 


1,700 


1.68 




2.0 


157 


3,850 


2,440 


1.58 




1.7 


175 


4,870 


3,000 


1.66 




1.5 


190 


5,469 


3,160 


1.77 




1.3 



Percent protein and feed amount 

Two short-term tests used varied percent- 
ages of protein in feed . One test at Kelso in 
10' -diameter plastic pools combined the effect 
of protein percentage in feed (25 percent, 30 
percent, and 35 percent) with the amount of 
feed used daily (calculated to be 2 percent, 4 
percent, and 6 percent of fish weight). Pools 
were stocked with 50 18 -gram channel catfish 
fingerlings, and each variation in protein and 
feed amount was tested in triplicate . At the 
same time, other feeds containing fish process- 
ing waste and fish meals were tested for growth 



y = 139.4 +1.30 (Protein Wt. -48) - 0.012 
(Protein Wt. - 48)2, 

"Protein Wt." being protein fed, which is the 
calculated amount from percent protein in feed 
times the amount of feed, again on a "per 1,000 
fish" basis . 

The slope of the regression line describing 
observed data from the pools is 1.2, indicating 
that for each percent increase in protein, 1.2 
grams gain per fish will result . 



Dl 


0.88 


78 


1.23 


82 


1.73 


65 


0.76 


86 


1.09 


92.5 


1.48 


68.5 


0.74 


88 


1.05 


97 


1.37 



Table 3. — Average final weight of catfish fingerlings for 70-day test 
in pools at Kelso. 

Fish weight 
Feed treatment ( grams) Conversion 

25% Protein fed at 2% 
4% 



30% Protein fed at 2% 



35% Protein fed at 2% 

4% 
6% 

Standard formula (30% Protein) using 

menhaden meal 93 0.78 

Standard formula using catfish processing 
waste (heads, viscera, skins) dried 
into a fish meal 

Commercial fish feed, 25% Protein 

Raw catfish processing waste 

Pasteurized catfish processing waste 

Raw waste plus CMC as a binder 

Raw waste using a feed meal as a binder 



Table 4. — Biological and economic evaluation of feeds containing three 
levels of protein, fed to channel catfish in ponds during a 130-day 
period. 

Amount of Pounds gained 
WW 
Protein _o n Conversion /lOOO fish Net value 

352 $ 113.80 

389 126.20 

414 133.80 



In 0.25 -acre ponds at Stuttgart, production at the 3 percent rate, under pond conditions, 
and feed conversion for feeds containing 3 levels The slope of the regression line for this was 4 .0; 
of protein are shown in Table 4 . for each 1 percent increase in protein, fish 

responded with 4 grams more gain during the 

We found a significant linear response to 130-day period, 

increased amounts of protein in feeds provided 



84 


0.77 


78.5 


1.04 


98 


2.4 


.01 


2.4 


94 


2.4 


95 


1.3 



25% 


21.7 


181 


1.82 


30% 


21.6 


198 


1.65 


35% 


21.3 


209 


1.55 



Stocking rate vs . feed amount 

White catfish were used to test the effects 
of feed amount and stocking rate on production. 
Duplicate 0.25 acre ponds were stocked at 
three rates, 1,200, 2,000, and 4,000 per acre, 
and fed 2 percent, 4 percent, and 6 percent of 
calculated fish weight based on monthly samp- 
lings . The results are best described by a 
graph (Figure 2). At each stocking rate, 
increased amounts of feed produced more fish 
weight, except that during the last month before 
harvest, no gain occurred in the ponds stocked 
at 4 ,000 per acre and fed 6 percent of body 
weight. These ponds had received 7,440 pounds 
of feed per acre during the season, and water 
conditions were marginal for fish culture . 
Although no mortality occurred, the presence 
of fish at the surface for several mornings was 
evidence of an oxygen -related stress . 



-700 




/ '4% 


_600 




y' 
y' 


_500 




y , - - - -6% 


-«00 




// ^^ 


-300 


/. 


^ AMOUNT OF FEED 


-200 




27. 




1000 

1 


2000 1000 



STOCKING RATE PER ACRE 

Figure 3. — Fish value minus feed cost for 
three stocking rates of white catfish fed 
at 27o, 4%, and 6% of body weight. 




STOCKING RATE PER ACRE 

Figure 2. --Second-year growth response of 
white catfish stocked at three rates 
and fed at 2%, 4%, and b% of body weight. 



Economically, as shown in Figure 3, the 
4 percent level of feeding proved best. Com- 
petition for feed required that more than 2 
percent be used to assure that each fish 
received a portion. At 6 percent there was 
obviously an excess at each feeding. 



Basket culture 

In late June, three wire cages were floated 
in a 1.0-acre pond. One basket contained 
1,030 fish, another 500, and a third 200. 
These were fed a hard sinking pellet by hand 
until no feeding activity was noticed. Survival 
was excellent and growth was fair. Fish gained 
from 10 grams to 115 grams in 100 days . 
Average weights were similar in all cages. 

Waldon H . Hastings 

Dietary requirement of vitamin A acetate and 
beta carotene 

In a previous study we indirectly demon- 
strated that channel catfish require the A vita- 
min, and we suggested this species could meta- 
bolize little of the A provitamin, beta carotene, 
to the vitamin itself. Vitamin supplementation 
of rations for pond -rearing of catfish is 
increasing and, thus, we need information on 
vitamin requirements and deficiency symptoms. 

Our studies were in 32 glass aquariums 
supplied with a continuous flow of food -free 
well water . Water temperature during the 
first 18 months was a constant 70° F. and dur- 
ing the last 5 months ranged from 82 to 85° F. 



For the first 13 months , the fish were exposed 
to low-intensity light (less than 25 Weston units 
at the water surface) during working hours , 
and to outside light and darkness the remaining 
hours. For the last 10 months of the experi- 
ment, the fish were exposed continuously to 
approximately 300 Weston units emitted from 
daylight -type fluorescent lamps. Light inten- 
sity was measured by holding a Weston photo- 
graphy meter at the water surface with the 
photocell perpendicular to the light source. 

Each aquarium was stocked with 50 grams 
(approximately 20 individuals) of 4 -month -old 
channel catfish on 27 September 1967. Fish 
were offered a series of purified diets that 
contained (in parts): vitamin-free casein - 33, 
white dextrin - 20, refined cottonseed oil - 10, 
carboxymethyl cellulose - 5 , mineral mixture 

- 5, vitamin A-free vitamin mixture (in 
dextrose) - 1, and cellulose flour (dietary bulk) 

- 26. The 16 diets were supplemented with 0, 
500, 1,000, 2,000, 3,000, 5,000 and 10,000 
or 20,000 units of vitamin A as the acetate or 
as beta carotene per kilogram of dry ingredi- 
ents . One hundred parts of the dry ingredients 
were mixed with 150 parts of water using the 
carboxymethyl cellulose as a binder, and 
stored at -10° C. until fed. 

Feed allowances (dry weight basis) for all 
aquariums of fish were calculated on 2 percent 
body weight per day and provided 5 days each 
week for the first year of the experiment , and 
at the rate of approximately 1 percent for the 
remaining time. Feed allowances were revised 
quarterly based on the heaviest aquarium of 
fish. 

For diets with different levels of beta 
carotene, weight gain was generally linear with 
provitamin levels through 20,000 units. Weight 
gain with diets that contained 20,000 units did 
not equal the gain with 1,000 and 2,000 units 
of vitamin A acetate, suggesting that even 
20,000 units of beta carotene did not supply the 
needs of the fish (Figure 4) . 

Deficiency symptoms for fish fed the lower 
levels of both vitamin A acetate and beta caro- 
tene included reduced weight gain, protruding 
and opaque eyes, accumulation of clear serous 



2200- 






/ 


— \ 




2000- 




1 


/ 




\ -* 


1800- 








X- 


/' \ 
/ \ 


1600- 


/ 


1 




/ 

1 
1 




1400- 


/ 


\ 

\ 


/ 
/ 


1 

1 

1 




1200- 






/ 
/ 
/ 
\ / 












\ / 












\ / 




X X BETA CAROTENE 








X 






1000^ 




1 




' 





500 1000 2000 3000 5000 10,000 20P00 

VITAMIN LEVELS (UNITS PER KILOGRAM OF DRY FEED) 

Figure 4. — Weight gain of channel catfish 
fed purified diets containing vitamin A 
acetate and beta carotene. 

fluid in the body cavity, and death. Also 
associated with these symptoms was the pre- 
sence of an eye -pupU -sized white spot on the 
epidermis between the eyes (pinel body). 
Lethargy was observed, but we do not know 
whether it was due directly to the deficiency or 
to a failure of the fish to feed. 

The poor growth rate and relatively long 
time required to produce obvious deficiency 
symptoms needs explanation. Growth was slow 
during the first 18 months of the experiment 
due to low (70° F.) water temperatures, but 
increased to near normal rates during the last 
5 months , when water temperature was 
increased to 82 - 85° F. With mammals, and 
probably with fish, vitamin A requirement is 
linked to animal size and not to metabolic rate, 
thus slow growth retarded the development of 
symptoms . 

The fish were maintained in semi -darkness 
for the first 13 months . Since vitamin A is an 
essential component in the visual enzyme sys- 
tem (rhodopsin) and some vitamin A is destroyed 



149 



each time rhodopsin is reduced to retinene and 
vitamin A, it appears reasonable that "dark- 
ness" would spare vitamin A. 

Effect of fish oil and corn oil on growth and 
flesh quality of channel catfish 

A need for low -cost rations for channel 
catfish production, combined with the avail- 
ability of large quantities of oil from the manu- 
facturers of fish meal , brought about a coopera - 
tive experiment between the Bureau of 
Commercial Fisheries' Technological Labora- 
tory in Seattle, the Bureau of Sport Fisheries 
and Wildlife's Western Fish Nutrition Labora- 
tory at Cook, Washington, and the Southeastern 
Fish Cultural Laboratory. Most practical 
rations currently used contain approximately 
6 percent crude fat, and since many animals 
can utilize fat levels above 10 percent, we 
theorized that channel catfish could utilize more 
fat and thus spare the more expensive protein 
for growth . 

The growth phase of the experiment was 
conducted in 75 glass -fronted aquariums each 
2x2x1 foot deep and supplied with 0.2 or 0.5 
gpm of 82-85° F. heated well water; the 
greater flow was used toward the latter part of 
the experiment . Each aquarium was stocked 
with 150 grams of 8 -month -old catfish (about 20) 
and fed one of 15 purified diets that contained 
(in parts): hot -alcohol -extracted, micropul- 
verized casein (ether extractable fat -maximum 
0.01 percent) - 27.2, white dextrin - 15, 
mineral mixture - 5, vitamin mixture (in dex- 
trose) - 3, and carboxymethylcellulose (diet 
binder) - 5 . In 6 diets, 0, 5, 8, 12, 15, or 20 
parts of bleached fish oil was added; in another 
6 diets a like amount of corn oil was used; and 
the remaining 3 diets were supplemented with 
12 parts of bleached fish oil with vitamin E 
(alpha tocopherol) as an antioxidant; 12 parts of 
the same bleached fish oil, but without the anti- 
oxidant; or 12 parts of "crude" (unbleached) fish 
oil. In each diet an amount of cellulose flour 
was added, ranging from 29 .8 to 44 .8 parts 
calculated to total each ration to 100 parts . 
All rations were stored frozen until fed. 



Fish in all aquariums were fed equal 
amounts of feed daily, 6 days each week, and 
were weighed at the end of each 2 -week period. 

The influence of fish oil and corn oil on 
growth and flesh quality was based on weight j 
gain and feed conversion. Analyses included 
liver glycogen levels , proximate analysis of 
the whole fish and the fillets, gas chromato- 
graphic identification and quantitation of stored 
fatty acids, separation and quantitation of meta- 
bolically essential lipids and the non-essential 
depot lipids, liver histology, and taste panel 
evaluation. All results on proximate analyses 
and fish taste have not yet been obtained, but 
sufficient information is available to summarize 
the experimental results and conclusions. 

Weight gain increased as the level of 
bleached fish oil was elevated from to 15 per- 
cent of the dry diet, but gain decreased at 20 
percent (Figure 5). The oil used in the prepar- 
ation of these diets did not contain an antioxidant, 
but the diets were stored near 10° F . , which 
retarded increase in TBA value. 




Figure 5. — Weight gain of channel catfish 
fed rations containing 0, 5, 8, 15, and 
20 percent fish oil and corn oil. Numbers 
in parentheses represent grams of lipid 
offered during the experiment. 



An antioxidant, alpha tocopherol, added 
at the level of 0.01 percent, appeared to retard 
increase in TBA value of bleached fish oil 
stored at room temperature . Gain of fish fed 



150 



the tocopherol -protected oil was superior to the 
gain of fish fed unprotected oil, and approached 
that of the gain of fish fed freezer -stored oil 
(Figure 5). Gains of fish fed corn oil diets 
were inferior to those fed fish oil diets . The 
shape of the growth curve of the corn oil -fed 
fish, as compared with the curve for the fish 
oil -fed fish, demonstrates little benefit from 
corn oil. This may be due to a deficiency of 
essential fatty acids (C18z\3). 

The BCF Technological Laboratory reports 
the lipid, protein, ash, and moisture content of 
the fillets of fish fed the 0-15 percent fish oil 
diets were approximately the same for each 
diet oil level, although oil increased and pro- 
tein decreased slightly with higher oil-contain- 
ing diets . On the basis of protein and lipid 
content, fillets from the fish fed 20 percent 
fish oil diets were inferior to those fed to 12 
percent fish oil diets . 

Taste panel tests at Seattle describe the 
flavor of the pond -reared (control) fish and 
the corn oil -fed fish as rather "bland" and 
"delicate". All the fish oil -fed fish acquired 
the odor and flavor of fish oil, and probably 
would not be acceptable to the public . In 
subsequent taste comparison sessions in which 
the skin was removed from the fish before 
cooking, the flavor of the fish oil -fed fish was 
greatly improved and possibly would be 
acceptable . 

Researchers at the Western Fish Nutri- 
tion Laboratory report "There was no signifi- 
cant difference in liver glycogen content in any 
of the fish oil or corn oil -diet groups . Liver 
glycogen varied from 1 plus to 3 plus on a 
basis of 3 plus for maximum glycogen content. 
Ceroid appeared in small amounts at or near 
portal triads in most livers but was insignifi- 
cant in amount . Sections were stained with 
hematoxylin and eosin for routine histopatholo - 
gical survey and other sections from each 
liver were stained with Best's carmine or with 
periodic acid Schiff (PAS) for glycogen. 
Representative samples from each diet group 
were also digested with salivary diastase for 
20 minutes at room temperature , after which 
they were given the PAS reaction. These 
samples lost most of their PAS -positive 



material by diastase digestion, indicating that 
most of the PAS -positive material was indeed 
glycogen . 

"Several liver samples from 3rd genera- 
tion Donaldson rainbow trout were also stained 
with Best's carmine and with PAS, and all 
samples gave results for glycogen almost 
identical to results for catfish. An occasional 
cluster of plump, rounded liver vacuoles 
(which were probably fat vacuoles) was seen in 
catfish but their occurrence was so trivial and 
infrequent as to be considered negligible." 

Harry K . Dupree 

PHYSIOLOGY 

Quinaldine 

During catfish hybridization experiments , 
quinaldine was used to anesthetize fish during 
handling for hormone injection. Male fish 
were more susceptible than females . Responses 
observed consisted of loss of equilibrium and 
ultimate immobility. 

Attempts were made to sex 6 -inch channel 
catfish fingerlings following anesthetization 
with 10 ppm quinaldine at 66° F . , but no 
association could be found between the sex of 
fish of this size and their drug response. 

Dewey L. Tackett 

Oxygen requirements of catf ishes 

The oxygen consumption of 16 catfish was 
measured with a respirometer (Figure 6). 
Oxygen was consumed at the rate of 0.48 mg 
^2/g of body wt/hr. at 68° F. by 10-gram chan- 
nel catfish. A 523 -gram channel catfish con- 
sumed oxygen at the rate of 0.07 mg 02/g of 
body wt/hr . at the same temperature . 

Containers used in conjunction with the 
degassing system were changed from 3 -gallon 
aquaria to economical 1 -gallon pickle jars, 
but results from the 3 -gallon aquaria could not 
be reproduced with the smaller vessels . We 
believe that the reaeration capacity of the 
larger container is greater than that of the 



151 



smaller one due to a 4 -fold difference in 
surface areas . 

Dewey L . Tackett and John J . Giudice 

Salinity tolerances of catfish hybrids 

Various hybrids of channel catfish and blue 
catfish survived 96 -hour exposures to 14-15 ppt 
salinity. Channel catfish and hybrid fingerlings 
(blue catfish x blue -channel) tolerated 14 ppt 
salinity for two weeks . 

Immunology of warmwater fish 

Cooperative studies with R. T. Acton, 
P. F. Weinheimer, E. E. Evans, D. Legler, 
and J . C . Bennett of the University of Alabama 
Medical Center in Birmingham , revealed that 
the paddlefish and gar, although responding 
well to a variety of antigens , only synthesize 
one type of immunoglobulin. This can be 
"lefined as a macroglobulin having a sedimenta- 
tion coefficient of about 19S and a molecular 
weight of about 900,000. Catfish appear to 
respond somewhat more slowly but tentative 
evidence suggests synthesis of more than one 
type of immunoglobulin as far as physical and 
chemical properties are concerned. However, 
longer periods of observation will be necessary, 
using different antigens and different immuni- 
zation schedules, before this can be clarified. 
The immunoglobulins of these fish represent 
about 40 percent of the total serum proteins . 

Attention has also been directed toward the 
physical -chemical properties and subunit 
structures of the Ig M class of immunoglobulins , 
which have been isolated and characterized from 
the paddlefish and longnose gar. General 
structural relation exist among all vertebrate 
Ig M immunoglobulins observed, including those 
of man. The S20. W values, subunit structure, 
amino acid composition and peptide maps of the 
immunoglobulin have been determined and 
evaluated, and limited primary sequence data 
from the amino terminal end of the polypeptide 
chains show a structural pattern similar to 
that of man. 

The study should not only shed light on the 
genetics and biological function of immunoglo - 




Figure 6. — Respirometer used in determining 
oxygen requirements of catfish. 



bulins , which will be of value in trying to 
control the synthesis of these molecules in man, 
but also aid in the control , management , and 
development of fish which are more immunolog- 
ically competent . It is also likely that once the 
structures of immunoglobulins (sequence of 
amino acids which make up the polypeptide 
chains) are known, various genetic markers may 
be present which can be used to select for other 
characters in breeding programs . Once the 
immunoglobulins are purified from an animal, 
we can look for the exact time during the 
animal's development, from egg to adult, when 
immunological maturation occurs . This will be 
valuable information and could aid fish culturists 
in determining the time when fingerlings may be 
safely introduced to new areas where new disease 
agents might be present. By correlating biologi- 
cal properties of immunoglobulins with structure, 
much information should be gained about the 
genetics, synthesis, and control of immunoglo- 
bulins at the molecular level . 

Effect of an insulin extender and dextrin level on 
weight gain and serum glucose of channel catfish 

A study was conducted on the use of an oral 
hypoglycemic agent to increase carbohydrate 
utilization in channel catfish. The drug employed 
was Tolinase ^ (Tolazamide), whose apparent 
mode of action is stimulation of the beta cells 
causing a release of endogenous insulin. An 
increased carbohydrate utilization may have a 
protein sparing effect . 



Four levels of Tolazamide were incorporated 
in purified diets containing 4 levels of the carbo- 
hydrate, dextrin. Drug levels were selected on 
the basis of those used for diabetic control in 
humans . Forty-eight aquariums containing 100 
grams of channel catfish fingerlings were fed 
for a total of 15 weeks . The fish were weighed 
at biweekly intervals throughout the experiment . 
At the termination of the experiment, blood 
glucose levels were measured after the fish had 
fasted 48 hours and at intervals of 1, 2, 4, 8, 
18 , and 24 hours after feeding . 

Weight gains were generally higher for 
fish fed carbohydrate plus the drug. Without 
Tolazamide, there was no difference in weight 
gain between fish receiving 20 percent and 30 
percent carbohydrate diets. Those fish receiv- 
ing the 20 percent carbohydrate diet with 250 
ti g of Tolazamide per gm of dry feed exhibited 
the greatest gain. These also exhibited the 
most consistent blood glucose levels. 

Blood glucose levels began to rise within 
one hour after feeding and reached their peaks 
at approximately 8 hours . Within 24 hours blood 
glucose values had returned to or near normal. 

Blood glucose levels were consistently high 
for those fish receiving no carbohydrate as 
dextrin in the diet . This was contrary to the 
expected hypoglycemia . If comparisons can be 
made with diabetic animals , this is suggestive 
of gluconeogenesis and could account for the 
elevated blood sugar . 

Harry K . Dupree 



FBH CULTURE 

Spawning catfish hybrids 

Limited spawning attempts were made with 
hybrid catfishes at Marion. The channel catfish 
X white catfish hybrid that outperformed the par- 
ent species and other hybrid crosses when tested 
in aquariums was found to be fertile. Reproduc- 
tion was accomplished by injecting human chor- 
ionic gonadotropin at the rates and with the tech- 
niques normally used for hormone -induced 
spawning of channel catfish. It was not deter- 
mined conclusively that this hybrid will repro- 
duce naturally under normal pond conditions, but 
the genitalia of female fish suggested that they 
were "spawned -out" when examined soon after 
the normal spawning season for white and chan- 
nel catfishes . 



O. L. Green 



Hybridization 



Growth of 6 groups of hybrid catfishes was 
compared to that of channel catfish. One -hun- 
dred grams of fish from each lot were placed in 
30-gallon aquaria to which running water (75° F. 
was supplied. All aquaria received equal 
amounts of feed daily. 



Channel catfish lots were replicated 6 times, 
while the hybrid groups were replicated 3 times . 
The best performer in this study was the white 
catfish X blue -channel hybrid . Results show in 
Table 5 . 



Table 5. — Weight gains in channel catfish and six groups of hybrid catfishes fed 
equal amounts of the same diet in aquariums for 70 days. 



Hybrid 



Initial average Final weight 
weight (grams) (grams) 



Percent 



(3iannel catfish 

Blue-channel hybrid x channel catfish 
White catfish x blue-channel hybrid 
Blue-channel hybrid x blue catfish 
Blue-channel hybrid x white catfish 
Blue-channel hybrid x blue-channel hybrid 
Blue catfish x channel catfish 



3.2 


6.9 


116 


3.3 


8.7 


157 


3.2 


12.1 


241 


5.3 


16.4 


207 


11.6 


35.7 


150 


3.6 


10.1 


178 


8.3 


15.7 


69 



153 



The blue -channel hybrid x channel catfish 
grew faster than the channel catfish in this 
test, but the reverse was true in trough cul- 
ture studies in which 1,150 fish of each group 
were held in separate Indoor troughs having a 
water volume of 8 .6 cubic feet . Each trough 
received 1 gpm of water at a temperature of 
80° F. Commercial catfish pellets were 
offered to each group in equal amounts . Results 
appear in Table 6 . 



Both channel catfish and the white catfish 
outgrew the outcross hybrid even though the 
hybrid catfish was larger at the beginning of the 
test . In aquarium studies the cross outgrew the 
channel catfish. 

Inconsistencies of our evaluation of growth 
of catfishes and their hybrids suggest a need for 
improvement of evaluation techniques. Know- 
ledge of the variability of growth by different 



Table 6. — Weight gains in channel catfish and in blue-channel 
X channel catfish in troughs. 



Weight 
changes 



Channel 
catfish 



Hybrid 
catfish 



Initial average weight (grams) 

Average weight at 42 days (grams) 

Percent gain in 42 days 

Average weight at 130 days (grams) 

Percent gain at 130 days 

Average weight at 175 days (grams) 

Percent gain at 175 days 

Percent survival 



1.2 


1.5 


3.0 


3.4 


145 


132 


8.5 


9.1 


585 


543 


- 


11.4 


- 


667 


74 


77 



Although the hybrids reached a larger size 
than the channel catfish, they gained at a slower 
rate as reflected by the percent gain. The size 
of the largest hybrid exceeded that of the larg- 
est channel catfish. It is noteworthy that 881 
catfish were raised to a total weight of 10,000 
grams (2.5 lbs per cubic ft. of space) under the 
conditions described above. 



sibling lots should be a prerequisite to compari- 
sons between fishes . Growth of sibling lots of 
the channel catfish should be compared to estab- 
lish variability between lots . This variability 
between sibling lots of the same species may 
exceed the variability between sibling lots result- 
ing from other species or hybrids, so no mean- 
ingful comparisons are possible. 



Another comparison of growth was made in 
4 one -tenth -acre ponds. This study included 
equal numbers of channel catfish, white catfish, 
and the white catfish x blue -channel catfish. 
Table 7 has the results . 



John J . Giudice 



Table 7. — Growth of catfish and hybrids in ponds. 



Initial average 
weight (grams) 



Final average 
weight (grams) 



White catfish 

Channel catfish 

White catfish x blue-channel hybrid catfish 



32 

35 

72 



536 
558 
368 



154 



Feed Schedule 

A predetermined feeding schedule was 
tested on four 0.1 acre-ponds, each of which 
contained 50 channel catfish (35 grams), 50 
white catfish (32 grams), and 50 hybrid (blue- 
channel X white) catfish (72 grams). This test 
was made to study the feasibility of eliminating 
the burdensome and inaccurate task of periodic 
sampling of fish populations for the purpose of 
adjusting feeding schedules. Previous knowledge 
of the growth rates of channel catfish at given 
stocking rates provided the basis for setting the 
schedule. The schedule tested throughout one 
growing season was as follows: 



time amounted to only 2.7 percent of their 
body weight. 

This study suggests that average production 
may be achieved by using a pre -determined 
feeding schedule based on knowledge of the 
growth of fish under the existing conditions . The 
amount of marketable fish, total production, and 
feed conversion at the end of the growing season 
were similar to those which could be expected 
from feeding the amounts of feed dictated by 
periodic sampling. Discrepancies observed 
during this test, however, indicate that further 
refinements of feeding schedules could greatly 
increase efficiency. 



Dates 



Pounds per acre 



John J. Giudice and Dewey L. Tackett 



April 15 to June 15 10 

June 16 to August 31 20 

September 1 to September 30 30 

October 1 to November 1 40 

Commercial catfish pellets containing 33 
percent protein were given 5 days per week, 
weather permitting. No adverse conditions 
were observed during the study. The average 
conversion rate was 1.8 to 1.0 and the average 
production was 1,650 pounds per acre, of 
which 1,370 pounds were marketable (0.75 
pounds or above) . All channel and white catfish 
were saleable, whereas 90 percent of the 
hybrids were subsaleable. The fish were har- 
vested on October 8 at the end of a 181-day grow- 
ing season. 

At the beginning of the test (April 10) , all 
lots received feed considered equal to 6 percent 
of their body weight. Prior to the first 
scheduled increase in feed amount, a sampling 
of the fish indicated they had been given only 2 
percent. The scheduled increase in the amount 
of feed resulted in their being given 4 percent. 
During this feeding period the rate dropped to 
1 percent before the next scheduled increase 
(September 1). Sampling revealed that during 
September, 30 lbs /A feed was equivalent to 
approximately 2 percent of the body weight. 
On October 1, the feed amount was increased to 
40 lbs /A as scheduled. The fish were harvested 
8- days later and the actual feed given at that 



Hauling 

An experimental hauling unit was constructed 
with inside dimensions of 2 x 2 x 2 feet. Air 
was supplied through copper tubing placed at the 
bottom of the unit . This tubing was formed into 
a square 18 inches on a side and had 1/32 -inch 
holes drilled 2 inches apart around its periphery. 

The unit was filled to a depth of 6 inches 
with well water having a total alkalinity of 450 
ppm and a pH of 7 .4 . This contained 2 cubic 
feet or 15 gallons with a surface area of 4 square 
feet. Air entered at the rate of 0.5 CFM. 
Dissolved oxygen was monitored continuously 
with a membrane -type electrode. The tempera- 
ture remained at 63° F. throughout the study. 
Thirty-two 1-pound catfish were placed in the 
unit and after 30 hours were found to be in 
excellent condition. The dissolved oxygen level 
dropped to 40 percent of saturation 1 hour after 
the introduction of the fish. Thereafter there 
was a gradual decrease in the level of dissolved 
oxygen to 25 percent of saturation at 30 hours. 
The pH remained constant, suggesting there was 
no accumulation of ammonia or carbon dioxide. 

These data suggest that with sufficient 
aeration Ln waters of high alkalinity, channel 
catfish can be transported at the rate of 2 
pounds per gallon of water . 



155 



In response to a request from the State of 
California , tests were run to learn the number 
of catfish fingerlings which could be trans - 
ported in a gallon of water . Lots of channel 
catfish were prepared which yielded loadings 
of 1.25, 1.5, 1.75, and 2.0 lbs. per gallon of 
well water. Compressed air was used for 
aeration. Temperature during the test was 
72° F . + 2° . Survival in all lots was good 
during the first 16 hours . However, it was 
noted that at the 2 lbs /gal. level, most of the 
fingerlings exhibited convulsions and died when 
removed from the container. Approximately 
10 percent of those in the 1.75 lbs/gal. loading 
exhibited similar behavior. It was concluded 
that 1.5 lbs /gal. would represent a safe level 
at which to transport fingerlings at 72° using 
compressed air for aeration. 

A shipment of blue catfish fingerlings was 
sent to California in December in milkcans 
filled with well water and aerated with chilled 
compressed air. Temperature during hauling 
was approximately 55° F. Nineteen cans were 
stocked at 1.5 lbs /gal., and one can was 
stocked at 2.0 lbs /gal. All lots had excellent 
survival during and following a 14 -hour journey 
indicating that at 55° ,2.0 lbs /gal, may be a 
safe loading density. 



Dewey L. Tackett 



Fish transfers 



During 1969 , stocks of fish produced as an 
adjunct to research activities were transferred 
to State and Federal organizations . The 
Southeastern Fish Cultural Laboratory provided 
180,378 catfish weighing 2,814 lbs. and the 
Fish Farming Experimental Station transferred 
11,850 lbs. (26,300 fish). 

Kermit E . Sneed 

Combination stocking of channel, white, and 
blue catfishes 

Researchers , fish farmers , and sports - 
men have long discussed the possible desir- 
ability of stocking a combination of catfishes 
for sport and food. At Auburn University, 
researchers conducted tests with white catfish 



stocked alone and in combination with channel 
catfish in fish -out ponds . Little work has been 
conducted on combination stocking of fish for 
commercial food production and no controlled 
studies, to our knowledge, using blue catfish. 

During the period of April 7-16, fish were 
individually weighed, measured, and stocked 
into triplicated 0.1-acre earthen ponds. Stock- 
ing rates are presented in Table 8 . All ponds 
were fed equal amounts of feed each day, based 
on 3 percent of the calculated weight of the fish. 
Manufacturers' analysis of the ration is shown 
in Table 8 . 

The ponds were drained on Day 199 of the 
test, and the fish were individually weighed 
and measured . Survival of the channel catfish 
at all stocking rates ranged from 94 to 96 per- 
cent, exceeded somewhat the survival of the 
blue catfish (82-93 percent), and greatly 
exceeded the survival of the white catfish (10- 
80 percent). The data from Prather's work in 
which white catfish were stocked alone and in 
combination with channel catfish support these 
observations . 

No statistical difference was measured 
between the total productions of any two stock- 
ing combinations . Average production ranged 
from 1,930 to 2,147 pounds per acre, a differ- 
ence of only 11 percent , which is well within 
experiment variations observed in earthen 
ponds . Some differences in production did 
occur in the various stocking combinations , 
but inspection of the data in Table 8 suggests 
that the greatest production occurred in those 
ponds in which the greatest survival occurred. 

The data in Table 8 also show that at all 
stocking ratios the weight contribution of 
channel catfish exceeded their stocked percent- 
age . For example , channel catfish comprised 
90, 80, and 50 percent of the stocked number, 
but their weight contribution to the total produc- 
tion averaged 95, 90, and 66 percent, respect- 
ively. Thus, it appears that best survival and 
best production was obtained in those ponds 
stocked with channel catfish alone or with a 
large percentage of channel catfish . 



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Individual weight and length measurements 
were made of the fish at the start and end of 
the experiment. Non -statistical graphic plots 
of most of the data show that the variation in 
weight of the harvested channel catfish exceeds 
by 100 percent the variation in weight of the 
stocked fish. However, a similar comparison 
for stocked and harvested blue catfish suggested 
a fairly uniform population growth rate. Low 
survival levels of the white catfish precluded 
any conclusion. Thus, we believe the data show 
that variation in the size of the harvested fish 
is due to differences in the sizes of the stocked 
fish and to differences in the growth rate poten- 
tial or aggressiveness of individual fish. Sex 
differences were considered, but after sexing 
a reasonable sample of fish, we could not attri- 
bute all the variation to that factor. 



O. L. Green 



FISH BEHAVIOR 



Trap sampler 

Additional tests were run to evaluate the 
effectiveness of a trap for sampling channel 
catfish. Groups of 100 fingerlings were tested 
in a 60 -gallon aquarium . The fish were allowed 
to move freely about the aquarium, but were fed 
inside a 1 -foot -square trap. The trap was 
constructed of hardware cloth with one open 
side which could be closed by dropping a plexi- 
glas gate . The fish were fed in the trap 65 
times over a period of 1 month. Once every 5 
days, after food was offered, fish in the device 
were trapped and removed from the aquarium . 
The device was most effective when placed dir- 
ectly on the aquarium bottom, trapping 99 per- 
cent of the fish in 2 trials, compared to 87 per- 
cent in 7 trials when placed 6 inches above the 
bottom. As a comparison, the trap was also 
tested with white catfish fingerlings . One 
hundred percent of the fish were removed from 
the aquarium in 1 trial after they had been fed 
in the device 30 times during a 10-day period. 

A larger trap (4 feet by 6 feet) for tests 
with 8- to 16 -inch channel catfish was installed 
on the bottom in a 1/40 -acre pond. The fish 
were first trained to feed on floating pellets, 
and then food was offered inside the trap. After 



they had been fed in the device 38 times during 
a 13 -day period, 90 percent of the fish were 
removed from the pond in two trials (Table 9). 
Trapped fish were not returned to the pond 
between tests . During this period surface water 
temperatures taken at midday ranged from 69 
to 78° F. 

Sonic attractant 

Mechanical sounds associated with surface 
feeding activity of channel catfish were recorded 
with a Panasonic battery-powered recorder 
(Model RQ-102 S) . Fifty 16 -month -old fish were 
held in a 34 -gallon aquarium. To avoid back- 
ground noise in the recordings due to the opera- 
tion of an aquarium aerator and pump, the fish 
were conditioned to associate the cessation of 
this noise with food, thus avoiding fright responsi 
which normally follows the sudden interruption 
of a continuous sound. Playing back feeding 
sounds to the fish that had produced them evoked 
a generalized exploratory response such as 
might result from any unrelated sound of a 
similar frequency and volume. However, these 
fish were easily trained to exhibit a conditioned 
response to their recorded feeding sounds by 
following these sounds with food . After 20 
rewarded trials the fish showed active surface 
feeding behavior prior to the introduction of 
food. 

Learning capacity 

Tests were run to study learning in channel 
catfish. Twenty 17 -month -old fish were held in a 
60 -gallon aquarium which could be partitioned 
into 2 equal sections by dropping a transparent 
plexiglas divider, thus allowing the fish in each 
section to be counted. For 34 days the fish were 
fed by introducing equal amounts of food simul- 
taneously in both ends of the aquarium; they soon 
fed actively at both sites . They were then 
trained to associate the dropping of the plexiglas 
divider with the introduction of food. This was 
done by offering 4 food pellets in each feeding 
area simultaneously. After 15 seconds the 
divider was dropped, and 15 seconds later the 
regular amount of food was introduced in each 
area. Fish in each half of the aquarium were 
then counted, and after 2 minutes the divider 
was raised. At first, dropping the divider 



Table 9. — Effectiveness of a trap in harvesting lo-month-old channel catfish 
in a 1/40-acre pond. 



No. of 

fish 
in pond 



Percent trapped Percent left 
No. of (of fish in in pond 
fish pond at time (of original 
trapped of test) no. of fish) 



318 
SO 



238 
47 



25 
10 



caused a fright response, and the fish did not 
feed until after it was raised. However, after 
12 reinforced trials some fish began feeding 
when the food was first offered, and the initial 
fright response gradually diminished. Soon 
they fed actively when the food was introduced. 

After 100 conditioning presentations over a 
32 -day period, a new procedure was initiated 
in which the fish in only one half of the aquarium 
(section B) were rewarded. Results of these 
tests are shown in Table 10. Even prior to 
conditioning, section A of the aquarium was 
used as a sanctuary when the fish were distri- 
buted. This preference was evident once con- 
ditioning was begun, with an average of 67 per- 
cent of the fish choosing section A during the 
first 25 trials . As conditioning progressed the 



percentage of fish in section A decreased. 
After 100 reinforced trials, the fish in only 
section A decreased. Then, after 100 reinforced 
trials, the fish in only section B were rewarded, 
but the effect of this change was not apparent . 
In 50 additional trials the percentage of fish in 
section B was not significantly greater than in 
earlier trials . 

Robert Tarrant 



Table 10. — Distribution of 20 channel catfish in a 60-gallon 
aquarium in which they were trained to associate the dropping 
of an aquarium divider-*- with the introduction of food in both ends 
of the aquarium. After 100 reinforced trials, the fish in only 
one half of the aquarium (section B) were rewarded. 



Trial 


no. 




1 - 


25 


26 - 


50 


51 - 


75 


76 - 


100 


101 - 


125 


12b - 


150 



Mean 










Mean 


percentage' 


of 






percentage of 


fish in sec' 


tion 


A 


f 


ish 


in section 


67.0 










33.0 


63.8 










36.2 


59.8 










40.2 


55.2 










44.8 


52.2 










47.8 


49.8 










50.2 



Preceded by four food pellets in each end of the aquarium. 



159 



DISEASES AND PARASITES 

Henneguya infections 

A species of Henneguya which develops in 
the interlamellar spaces of channel catfish gills 
has been observed for a number of years . It 
was known from hatcheries at Marion, Alabama, 
and Tishomingo , Oklahoma , as well as from 
certain natural environments . Recently this 
parasite has appeared on an increasing number 
of private fish farms, perhaps due to interfarm 
shipments or to the use of wild fish as brood - 
stock. 

While most species of Henneguya do not 
cause problems of epizootic proportions , the 
species developing in the interlamellar spaces 
causes catastrophic losses . This form appears 
similar to Henneguya ex ills but differs in two 
respects . The ends of polar filaments of the 
interlamellar form are coiled as in a corkscrew 
but are straight in H. ex ills . Henneguya ex ills 
develops within the blood capillaries of lamellae 
whereas the new form develops in basal cells 
between lamellae. (See Figures 7-10.) 

Over 90 percent of the interlamellar space 
on fingerling channel catfish has been observed 
filled with cysts . Heavily infected fish show 
syinptoms of anoxia, even in waters containing 
8 ppm dissolved oxygen. Fingerling producers 
have reported losses of over 95 percent in 
fingerlings less than 2 weeks old. Post-larval 
fingerlings have been observed with every inter- 
lamellar space filled with a cyst . 

Although farmers have been urged to 
destroy infected fish, this has not been done, 
and the spread from infected farms to new areas 
through sales has been documented. 

Lernaea control studies 

Dursban and Naled were compared with 
Dylox under pond conditions to evaluate their 
potential use in the control of the anchor para- 
site, Lernaea cyprinacea . Dursban at rates of 
0.02 and 0.03 ppm proved overly toxic to the 
fish even though it did control the parasites; at 
0.03 ppm it was lethal to the fish in both 




Figure 7. --Early development of interlamellar 
form of Henneguya sp. in gill tissue of 
channel catfish. Note Costia also on 
lamellae. (K. E. Sneed Photo) 



iil^i^ -■•^ 



m 






f* 



Figure 8. --Later development of interlamellar 
form of Henneguya sp. in gill tissue of 
channel catfish showing complete filling of 
space between lamellae. Costia is also 
present. (K. E. Sneed Photo) 




Figure 9. — Mature cyst of interlamellar 
form of Henneguya sp. showing spores of 
parasite . 

replicates. Some mortality occurred at 0.02 
ppm and all fish surviving this level developed 
scoliosis and lordosis, 

Naled is a compound widely used in Israel 
for the control of the anchor parasite. How- 
ever, for the second successive year, it has 
failed to give control, even at levels 4 times 
that used in Israel. An exchange of chemical 
with Dr. Sarig has been achieved and the 
Israeli formulation will be tested at Stuttgart 
this year. 

Branchiomyces sanguinis 

Branchiomyces sanguinis was positively 
identified in the gills of striped bass, Morone 
saxatilis , received from two locations. This 
fungus is responsible for a disease known as 
"gill rot" in Europe, where it is considered to 
be a serious threat to commercial fish culture. 
Dr. Pietro Ghittino of Italy confirmed the diag- 
nosis during his visit to the laboratory this fall. 
Histological sections are in preparation and a 
manuscript will be prepared when the studies 
are completed. 



Figure 10. --A developing cyst of Henneguya 
exilis in channel catfish gill tissue. 
The cyst is within the lamellae rather 
than between, as in Figures 1-3. (K. E. 
Sneed Photo) 



Prophylactic use of drugs 

Aureomycin and Sulfamethazine were used 
continuously at low dosages in the daily ration 
of channel catfish confined in 10 -foot -diameter 
plastic swimming pools to determine if these 
compounds had a preventive effect on the develop- 
ment of bacterial infections or a growth-stimu- 
lating effect on the fish . The fish experienced 
severe low -oxygen stresses on several occa- 
sions, but few fish were lost. Ten to 14 days 
after these stresses, however, Aeromonas 
liquefaciens infections appeared in treated and 
untreated lots , and all groups suffered nearly 
complete mortalities . (See Table 11.) Only 81 
fish of the original 1,200 used in the experiment 
survived, and no benefits were noted in the pre- 
vention of bacterial disease. Although some 
increase in growth was apparent in the treated 
fish, it was not significant. 

Fish disease symposium 

Dr. Meyer assisted Dr. Snicszko by serving 
as a section chairman in the preparation of a 



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162 



fish disease symposium for the American 
Fisheries Society. 



exposed to C -tagged herbicide in a controlled 
environment. 



Diagnostic service 

During 1969, 475 cases were handled by the 
diagnostic laboratory at Stuttgart, and 125 by the 
Marion, Alabama, laboratory. The majority of 
these cases occurred from March 1 through 
October 31, Unseasonably hot, dry weather 
aggravated the fish by adding environmental 
stresses to bacterial or parasitic diseases. 
Oxygen depletions were common. 

A distribution of incidence of types of 
etiological agents diagnoses is shown in Table 
12. Pesticide -related problems were more 
numerous than during any previous year . Liver 
abnormalities believed to be related to inade- 
quate nutrition also were apparent for the first 
time. 



Fred P. Meyer 



PESTICIDES 

Dalapon toxicity 

Toxicity tests, using new facilities, were 
conducted during the latter part of the year . 
Results with the herbicide Dalapon indicated 24 - 
hour LC50 values in excess of 4 ,000 ppm at 
72° for bluegills. Twenty-four-hour LC50 
values at 93° with channel catfish were consist- 
ently near 3,000 ppm. No pronounced reduction 
in toxicity was noted at lower temperatures . 
Simultaneous testing under dark and light con- 
ditions indicated Dalapon to have a higher toxi- 
city in total darkness. Light may, therefore, 
partially degrade Dalapon. 

Toxicity also appears to be lower under 
alkaline conditions. 



Ray L. Argyle 

EXTENSION 

Fish farming statistics 

Fish farming statistics were revised and 
updated periodically during the year, using a 
cross-reference system of data cataloging. 
Current lists of fish farmers by States, species 
of fish reared, fish processing plants, haulers 
of live fish, dealers in fishery supplies, fish 
feed manufacturers, catfish franchise restau- 
rants, and consulting personnel in fisheries 
are among the data maintained. We also tabu- 
late acreages of fish farms in each State, by 
county, with records of growth of the industry 
in recent years (Table 13). 

Over 4 ,800 requests for information were 
received at the Fish Farming Experimental 
Station in 1969, and in excess of 250 requests at 
the Southeastern Fish Cultural Laboratory. 

Visitors at the Fish Farming Experimental 
Station in 1969 numbered over 1,400. One hun- 
dred eight were foreign visitors representing 
28 countries . Ten students and researchers 
from 5 countries abroad spent a total of 68 days 
at the Stuttgart station to observe and study 
American fish farming. 

Don S . Godwin 



Varying results were obtained in attempts 
to raise cattails under artificial light in the 
laboratory. The results were generally satis- 
factory, and this technique may be used in 
tests in which cattails, water, soil, and blue- 
gills, channel catfish, and other fish are 



Table 12. — Numbers of various etiological agents encountered 
in disease cases handled by the diagnostic laboratory at 
the Fish Farming Experimental Station during 1969. (More 
than one organism was encountered in a number of cases.) 



PROTOZOANS 



Ichthyophthirius multif iliis 28 

Trichodina sp. 172 

Scyphidia sp. 129 

Trichophrya ictaluri 26 

Chilodonella sp. 12 

Plistophora ovariae 27 

Cos tia sp. 26 

Myxosporidia (all species) 55 



MONOGENETIC TREMATODES : 



Gyrodactylus elegans 28 

Dactylogyrus sp. (all species) 21 

Cleidodiscus sp. (all species) 101 



DIGENETIC TREMATODES : 

Clinostomum marginatum 
ENVIRONMENTAL PROBLEMS: 



Oxygen depletions 25 

Pesticide-related problems 26 



BACTERIAL DISEASES: 



Aeromonas liquefaciens 49 

Pseudomonas sp. 12 

Myxobacteria 48 



Table 13. — Estimated gross income, by States, from intensive culture of warmwater fishes in 

1967, 1968, and 1969 





Species 




1967 




1968 




L969 


State 


Surface 


Estimated 


Surface 


Estimated 


Surface 


Estimated 






acres 


income 


acres 


income 


acres 


income 




Minnows 


$ 620 


$ 190,960 


$ 620 


$ 190,960 


$ 528 


$ 187,440 


Ala. 


Catfish 


100 


47.000 


496 


233.120 


y 933 


438.510 




TOTAL 


720 


237,960 


1,116 


424,080 


1,461 


625,950 




Minnows 


14,500 


5,147,500 


15,000 


5,325,000 


20,150 


7,153,250 


Ark. 


Catfish 


4.750 


2.997.250 


7.632 


4.815.792 


11.736 


7.405.416 




TOTAL 


19,250 


8,144,750 


22,632 


10,140,792 


31,886 


14,558,666 




Minnows 


. 


s 


. 


. 


160 


56,800 


Calif. 


Catfish 
TOTAL 


. 


. 


. 


. 


587 
725 


275.890 




- 


- 


- 


- 


332,690 




Minnows 


« 


. 


. 


. 


80 


28,400 


Fla. 


Catfish 


200 


94.000 


224 


105.280 


224 


105.280 




TOTAL 


200 


94,000 


224 


105,280 


304 


133,680 




Minnows 


. 


_ 


. 


. 


. 


. 


Ga. 


Catfish 


200 


94.000 


699 


328.530 


2/ 699 


328.530 




TOTAL 


200 


94,000 


699 


328,530 


699 


328,530 




Minnows 


200 


61,600 


200 


61,600 


. 


. 


Kan, 


Catfish 


800 


376.000 


406 


190.820 


483 


227.010 




TOTAL 


1,000 


437,600 


606 


252,420 


483 


227,010 




Ml nnows 


1,500 


462,000 


2,300 


703,400 


1,971 


705,705 


La. 


Catfish 


1,500 


705,000 


2,693 


1,265,710 


3,222 


1,514,340 




TOTAL 


3,000 


1,167,000 


4,993 


1,974,110 


5,193 


2,220,045 




Minnows 


1,500 


462,000 


1,500 


462,000 


3,768 


1,337,640 


Miss. 


Catfish 


4,500 


2,839,500 


8,966 


5,657.546 


17,972 


11.340,332 




TOTAL 


6,000 


3,301,500 


10,466 


6,119,546 


21,740 


12,677,972 




Minnows 


3,500 


1,242,500 


3,500 


1,242,500 


1,254 


445,170 


Mo. 


Catfish 


1,200 


564.000 


692 


325.240 


794 


373.180 




TOTAL 


4,700 


1,806,500 


4,192 


1,567,740 


2,048 


818,350 




Minnows 


200 


61,600 


200 


61,600 


106 


37,630 


Okla. 


Catfish 


200 


94.000 


198 


93.060 


415 


195.050 




TOTAL 


400 


155,600 


398 


154,660 


521 


232,680 




Minnows 


_ 


_ 


, 


. 


90 


31,950 


Tenn. 


Catfish 
TOTAL 


. 


_ 


. 


. 


261 
351 


122.670 




- 


- 


- 


- 


154,620 




Minnows 


650 


200,200 


650 


200,200 


480 


170,400 


Tex. 


Catfish 


2.000 


940.000 


2.490 


1.170.300 


2.595 


1.219.650 




TOTAL 
Minnows 


2,650 


1,140,200 


3,140 


1,370,500 


3,075 


1,390,050 


ALL 


22,670 


■■ 7,828,360 


23,970 


8,252,260 


28,587 


10,154,385 


STATES 


Catfish 


15.450 


8.750.750 


24.496 


14.185.398 


39.921 


.23,545,855 




TOTAL 


38,120 


16,579,110 


48,466 


22,437,658 


68,508 


33,700,243 



- Lanier Green, Southeastern Fish Cultural Laboratory, Marion, Ala., states that there are 
more than 3,000 acres of catfish in Alabama. 

—^ Paul Schumacher, Soil Conservation Service, lists 2,992 acres of catfish in Georgia. 

165 



THE NEW ENVIRONMENTAL AWARENESS 



A number of years ago marine and reservoir fishery research were placed in a Branch of Fish 
Ecosystem Research. The change in title made no difference in the way the concerned scientists 
approached their work; it was merely a more precise and logical definition of the field. In short, 
the new title was more responsive. It was therefore somewhat surprising to find the change caused 
distress among a few people iaside as well as outside the fishery research field. It was this 
attitude which prompted our attempt several annual reports ago to discuss the ecosystem approach 
to fishery research. The gist of these remarks was that planning is in terms of communities 
rather than individuals , and the preferred method is to go to the environment rather than to bring 
the environment into the laboratory. We went on to point out that the laboratory approach was not 
by any means scorned and that the behavior, physiology, disease, and biometric aspects all 
involve extensive bench research activities. Even here, however, the approach is essentially 
ecological. 

If the change in branch title were to be made today, it would hardly cause a ripple in the new 
atmosphere of environmental awareness where words like ecology, ecosystem, and environment are 
becoming so commonplace that they are in danger of becoming downright platitudinous'. 

We are pleased with this new awareness. Some of the scientists in fishery research have spent 
as much as 40 years of their life working in ecology, and the promise of recognition is sweet. 
These men know a lot about aquatic environments and some of them bear the scars of numerous 
conseirvation battles . 

A disturbing note frequently creeps into public exhortatives for support of the new awareness . 
Too often statements include remarks such as "virtually nothing is known," "little work has been 
done," or "the problem has received little attention." In reality, a great deal is often known, years 
of work have been devoted to the subject, and whole institutions have been created to address the 
problem. In Progress in Sport Fishery Research- -1967, the Director of the North Central 
Reservoir Investigations, after outlining the progress made in defining the relations between reser- 
voir ecology and fish populations, made the remark that, "System ecology is becoming a part of 
water management in reservoirs." He also pointed out a number of ways in which this knowledge is 
actually being applied by the U.S. Army Corps of Engineers in the upper Missouri River impound- 
ments . Yet we still hear people who should know better stating categorically that we know nothing 
or can do nothing about reservoir fishery management . The same general statement can be made 
about virtually any field of fishery management . 

We believe fishery ecologists have a tremendous opportunity to contribute to the well being of 
the environment in which our society exists. They have the research -based ecological knowledge, 
the political community recognizes the need for ecological consideration, and there is clear-cut 
support from an alerted public . 



The ecological approach to solving environmental conflicts has never been an easy one. We 
are hopeful that when the need to apply what may be drastic measures to maintain quality and 
productivity, the new awareness will be strong enough to square off with the traditional and easily 
rationalized economic commitments . Will the need to protect a watershed, a swamp, or an estuary 
for not easily rationalized esthetic, productivity or recreational purposes prevail over the conven- 
ience of their uncontrolled use as sources or disposal areas for coolant from a power plant which 
will permit all the air conditioners in a city to operate? We hope so'. 



J. Bruce Kimsey, Chief 

Branch of Fish Ecosystem Research 



167 



ATLANTIC MARINE GAME FISH RESEARCH PROGRAM 

Lionel A. Walford, Director 



SANDY HOOK MARINE LABORATORY 
Highlands , New Jersey 



HIGHLIGHTS 

In our efforts to explore the biology of 
game fish, we have been confronted this year 
more than any previous year with the tremen- 
dous influence that man has on the marine 
environment. At this time many of our studies 
and observations relate to rapidly changing 
environmental conditions . 

The estuarine zone is one of the most 
productive, fragile, and yet exploited areas 
along the Atlantic coast. Estuaries are neces- 
sary for survival of the juvenile forms of such 
coastal migratory game species as striped bass, 
mackerel, drums, sea bass, flatfishes, and 
bluefish. Since 1966 we have been systemati- 
cally collecting and identifying the eggs and 
larvae of coastal fishes over the continental 
shelf from Martha's Vineyard, Massachusetts, 
to Florida. We have determined the times and 
places of spawning of the economically-import- 
ant species . That they migrate to the estuarine 
zone as they develop is shown by the fact that 
the larvae are progressively larger as we 
collect closer inshore. We are engaged in 
detailed studies of estuarine -dependent factors 
which we began this year with out analysis of 
juvenile bluefish feeding habits . As the 
juveniles leave ocean waters to enter estuaries 
they switch from a diet of plankton to one of 
small fishes and herrings . 

The New York Harbor area, now highly 
polluted, has become a virtual death trap, at 
least during the summer months, especially 



for young fishes of several species. Last 
summer and early fall the fin rot disease 
reached epizootic proportions. On the basis of 
test cultures made from tissues of diseased 
fish, we have presumptive evidence that marine 
bacteria are the cause of the infection. 

The coastal waters may be destroyed by 
pollution before we can determine their value. 
Data collected in the past year as part of a 
study we are conducting for the U.S. Army 
Corps of Engineers to determine the effects on 
marine resources of waste disposal practices 
in the New York Bight show clearly that 40 years 
of dumping have done great damage to benthic 
life. We can now confirm that 10-12 square 
miles of bottom at the sewage sludge dumping 
grounds are devoid of life. Part of this condi- 
tion is due to the low dissolved oxygen content 
of the water, especially during part of the 
Slimmer, when the DO is less than 1 ppm, too 
low to support normal benthic life. A coopera- 
tor found that population growth of phytoplankton 
is inhibited in water from the sewage sludge 
disposal area. We found up to 250 ppm of lead 
in bottom deposits and many other toxic agents . 
The dumping grounds are located in a dynamic 
current system with bottom water moving over 
the sludge area towards New York and New 
Jersey shorelines . 

The story out of Puerto Rico , one year after 
the sinking of the oil tanker. Ocean Eagle , is a 
happier one . We observed no traces of oil on 
the lower intertidal zone and Invertebrates and 



fishes there appeared to be again abundant and 
healthy. 

During the year the Coast Guard assumed 
responsibility for collecting the monthly 
Atlantic Shelf survey temperature data and we 
began concentrating our efforts on surveying 
estuarine areas threatened with thermal load- 
ing. We are attempting to obtain baseline 
temperatures of the areas soon to be exposed 
to heat loading. 

Environmental conditions such as those 
caused by pollution and physical change often 
have dramatic effects on the activities of 
marine animals . But natural factors such as 
water temperature, length of day, and avail- 
able food are what determine an organism's 
daily and seasonal patterns of behavior. We 
began laboratory studies on summer flounder 
(fluke), commonly thought to be a relatively 
inactive benthic species, and found that during 
the day, except for a period in late summer, 
the fish swam continually and were active pred- 
ators . The most surprising discovery was the 
manner in which fluke would swim vertically 
towards the surface, then glide gradually 
towards the bottom , covering long distances 
with a minimum expenditure of energy. 

Most of the economically important sport 
fishes are migratory species, which move up 
and down the Atlantic coast in response to 
seasonal changes in food supply and water 
temperature. So that knowledgeable manage- 
ment policies can be made, we are making 
detailed life history studies of several of these 
species. We have defined populations, migra- 
tory routes , growth patterns , and spawning 
places of bluefish and have just completed our 
first year of a similar study on the drum family, 
including croaker, weakfish, and spot. 

Awareness of patterns of migration, daily 
activity habits , definitions of populations , and 
the effects of environmental conditions has led 
naturally to attempts at population conservation 
and enlargement through habitat improvement . 
Artificial reefs of scrap material have been 
successful in concentrating game fish all along 
the coast in areas which were once flat and 
barren, hence unproductive. In the past year 



we installed 35,000 tires on two reef sites. We 
now have 8 experimental reef sites between 
Florida and Long Island, N. Y. One way we 
are determining the success of the artificial 
reefs is by examining the success of the anglers 
who fish over them. Another way is first-hand 
observation of the reef community. Dives 
made over the South Carolina reef site revealed 
a well-balanced community; sea bass, sheeps- 
head, pinfish, and some invertebrates are 
dependent on the reef fauna and were observed 
in active competition for food. Observations 
made on the wreck Delaware during August 
revealed conditions of such high turbidity 
(possibly caused by disposal of solid wastes and 
dredge spoils) that the ambient light at mid -day 
was zero . Reef fishes which normally feed 
during the daytime were wedged in crevices and 
were so lethargic that they could be touched. 

HYDROGRAPHY OF COASTS 
AND ESTUARIES 

Since 1962 an aerial survey team at Sandy 
Hook recorded biological sightings and collected 
infrared surface temperatures over Atlantic 
shelf waters. More than 10,000 observations of 
fishes, turtles, and marine mammals, in addi- 
tion to thousands of transect miles of surface 
temperature, were recorded. These data were 
subjected to preliminary analyses and sent to 
any interested individual or institution immedi- 
ately after each monthly survey. 

During the first 6 months of the year we 
continued monthly aerial surveys to map surface 
temperatures and marine animal distribution. 
Since the Coast Guard assumed responsibility 
in July for routine field aspects of the shelf 
program, time is now available for complete 
analysis and publication of these data. Initially 
we will concentrate our efforts on animal 
distributions and their relation to surface tem- 
peratures . 

Biological observations through the October 
flights were incorporated into our ADP section 
for correlation analyses of these observations 
and ambient water temperature . 

The use of helicopters for our radiometer 
surveys proved feasible. Although a helicopter 



is limited in its range when compared with 
fixed -wing aircraft, its ability to maneuver and 
hover offsets this disadvantage (Figure 1). The 
low altitude maneuverability allows greater 
precision in navigation and hence better quality 
of data collected from relatively confined 
bodies of water , while the ability to hover per - 
mits lowering of a thermistor for temperature 
checks of the remote sensor and for obtaining 
inflight water samples . 



We conducted radiometer surveys of the 
Connecticut River, Barnegat Bay, and Long 
Island Sound, all areas either now exposed to 
thermal additions or expected to be so in the 
near future. The objective of such surveys is 
to obtain baseline temperatures before any 
thermal additions . These will be followed up 
by surveys to depict variations in the plume of 
heated water, specifically designed to document 
the extent and increment of such heating. 




Figure 1. — A jet-powered helicopter used 
for inshore temperature surveys. 



We continued a cooperative study of Block 
Island Sound with the Naval Underwater Sound 
Laboratory. A report of the surface heat 
configuration is nearly completed. 



A sample of our results on the Connecticut 
River is shown in Figure 2 as an example of a 
fluvial survey, having several dams and 
industrial zones . We prepared a report of a 
series of surveys for the Technical Committee 
for Fishery Management of the Connecticut 
River Basin. 

Thomas Azarovitz, 
Malcolm Silverman, and 
Charles Morrison 

ENVIRONMENTAL ANALYSIS 

We completed a world distribution map of 
bluefish. The plot shows a scattered array, 
with major populations in waters off our eastern 
seaboard, southern Brazil, Venezuela, South 
Africa , Australia , and ui the Mediterranean and 




RIVER MILES 

Figure 2. --Surface water temperature of the Connecticut River recorded by radiometer 
technique on two surveys. 



170 



Black Seas; all in temperate zones near the 
annual range of the 20° C. isotherm. Tempera- 
ture differences appear to effectively isolate 
groups of bluef ish . One example is the absence 
of bluef ish on the SW coast of South America. 
This area is apparently isolated from other 
locations where blucfish live by constant cold 
water to the south and tropical waters to the 
north. 

We also continued our studies of groundfish 
distribution in the New York Bight. From sam- 
ples taken at 24 stations, we gathered basic 
data on species composition, lengths, and 
weights for correlation with temperature, 
salinity, depth, and distance from shore at time 
of capture . 

L. A. Walford, 
Robert Wicklund, and 
DeWitt Myatt 

ESTUARINE DEPENDENCE 
OF COASTAL FISHES 

As the year ended we brought to completion 
the sorting of the southern series of R/V 
Dolphin collections . With the processing 
completed we are now concentrating on analysis 
and publication of oceanographic and ichthyo- 
plankton data . By the end of 1970 we shall be 
able to report with assurance on the spawning 
places and seasons for most economically 
important estuarine -dependent species that 
spawn on the continental shelf. 

We are now commencing the planning of 
field work for several subsequent phases of the 
study. One is a survey within the estuaries of 
the distribution and ecology of estuarine -depend- 
ent juvenile fishes . This would be a large-scale 
effort requiring a sampling period of 1-1/2 to 2 
years . The second is a survey of the Gulf 
Stream front to discover the mechanism of 
transport of larvae and juveniles of such 
species as bluefish from southern spawning 
places to northern nursery areas . A third 
phase involves detailed studies of estuarine - 
dependent factors, as exemplified by the study 
of bluefish feeding phases reported in the 
following pages. 

John Clark 



Plankton sorting 

We removed the fish eggs and larvae from 
plankton collected on southern cruises of the 
R/V Dolphin and separated the larvae into 26 
groups to facilitate final identification. We 
determined the volume of plankton in the south- 
ern samples and prepared these data for pre- 
sentation in a technical paper. A total of 1,400 
samples of plankton collected on our 12 survey 
cruises from Massachusetts to Florida were 
sorted. In a check for thoroughness of sort we 
found an average of 99 percent of the eggs and 
96 percent of the larvae had been retrieved. 
Much of the hydrographic data as well as the 
distribution and size data for all fish larvae 
investigated to date are keypunched for computer 
analysis. 



Arthur Kendall 



Croakers and mackerels 



We examined all Atlantic croaker, spot, 
and banded drum taken from the survey area 
between Martha's Vineyard, Massachusetts, 
and Florida (Table 1). Atlantic croaker larvae 
occurred from August to April . Spawning time, 
as indicated by presence of smaller larvae, 
occurred between August and December . Spot 
spawned later in the season and appeared in 
catches during November to May with smaller 
specimens taken during November and December. 
Banded drum larvae occurred north of Cape 
Lookout, N. C. from April to October with a 
peak in catch during August and on each of the 
four cruises south of Cape Lookout. A prelim- 
inary review of the data indicates a strong 
positive correlation between distance off-shore 
and the length of spot larvae; the largest larvae 
being found nearest to shore. 

Eggs and larvae of Atlantic mackerel. 
Scomber scombrus , from the R/V Dolphin 's 
ichthyoplankton survey were sufficiently 
numerous to justify preparation of a manuscript 
describing the egg and yolk-sac larval stages 
and the distribution of young stages collected 
during 1966. We completed a first draft 
summary. 



171 



Table 1. — Mean standard lengths of three sciaenids taken in Gulf V plankton net tows by 
R/V Dolphin, on twelve cruises. 





















Atlantic 


croaker 
Mean 




Spo 


t 


Bande 


;d drum 






Mean 


Mean 






length 






length 




length 


Cruise date 


Number 


(mm) 




Number 


(mm) 


Number 


(mm) 


Martha 


s Vineyard 


Mass. - 
4.2 


Cape 


Lookout , 
2094 


N. C. 

4.4 






Dec. 3 - 15, 1965 


602 




Jan. 25 - Feb. 9, 1966 


33 


7.5 




399 


9.2 






Apr. 6 - 22, 1966 


2 


6.4 




24 


7.4 


1 


5.2 


May 12 - 24, 1966 








3 


11.6 


7 


3.9 


June 17 - 29, 1966 












3 


3.8 


Aug. 5 - 26, 1966 


263 


3.6 








90 


3.2 


Sept. 28 - Oct. 20, 1966 


420 


3.7 








21 


3.9 


Nov. 9 - Dec. 4, 1966 


1039 


5.2 




54 


3.9 







Cape Lookout , N. C. - West Palm Beach, Fla. 



May 7-15, 1967 
July 22 - Aug. 1, 1967 
Oct. 19 - 26, 1967 
Jan. 27 - Feb. 4, 1968 



446 
110 



3.6 
6.2 



2203 



6.3 



64 

21 

19 

1 



3.1 
2.6 
6.5 
5.0 



Total number 
Weighted mean 



3.5 



Several specimens of the genus Scomber 
taken south of Cape Lookout appeared morpho - 
logically distinct from Atlantic mackerel and 
were tentatively identified as chub mackerel 
(S . japonicus) . Several criteria including 
vertebral counts, body proportions, and pig- 
mentation were used in separating the tv^o types . 
Figure 3 depicts one separating feature, the 
relatively shorter preanal length of Atlantic 
mackerel . We continued to compile reference 
material as an aid to separating and identifying 
other scombroids in the collections . 



Peter Berrien 



Cods 



We completed sorting all larval gadids 
collected during the northern series of cruises 
(1966) which include larvae of Atlantic cod, 
pollock, haddock, cusk, fourbeard rockling, 
sUver hake, and hakes of the genus Urophycis . 









I 


°' 









= 


°^ 


"oo° 






o oo o ° o t, 


oo 


°°o 


OS* * 




- 






oo 








o ooo 


o 


oo 


• • 


a 




orr o 


• 


• . 


• 






e o o . . 

o J.. . < 


- 




. • 1- ' 




- •• 


o«t ~ 




. 






» 


•• • t» 

!• • • 

^ • . • • • 


• 


• 








; • 














o CMua MACKEREL 












• ATLANTIC MACKEREL 










4 6 




8 




10 I? Id 





Figure 3. — Data point array showing body 
proportion differences between Atlantic 
and chub mackerel. 



We placed initial emphasis on the silver 
hake, Merluccius bilincaris , collecting a 
total of 11,316 larvae tliroughout the year. We 
isolated, counted, and measured all silver hake 
larvae and plotted their geographic relative 
abundance. We are preparing these data for 
publication. Collections within the 1966 samp- 
ling area (Figure 4) indicate a prolonged spawn- 
ing season, extending from May into December 
with a peak from August to October. Geo- 
graphic distribution of larvae was similar during 
all months the species was taken. We made the 
largest catches on transects off Martha's Vine- 
yard, Massa., and Montauk Pt., N. Y. We 
found larvae increasingly restricted to the 
offshore ends of more southerly transects . 
Generally, we captured smaller larvae north, 
inshore and near the surface and larger larvae 
south, offshore and deeper (Table 2). 

We began examining a series of Merluccius 
larvae, presumed to be M. albidus . The post- 
larva of this species is at present undescribed. 

Michael P. Fahay 

Sea Bass 

Black sea bass larvae, recognized from our 
plankton samples north of Cape Lookout, have 
not been described in the literature. Our series 
includes 135 larvae ranging from 2.1 to 11.8 mm 
long. These larvae occurred from June through 
October over the middle of the continental shelf 
from New Jersey to North Carolina (Figure 4). 
We identified the larvae by meristic characters 
and a characteristic series of ventral pigment 
spots (Figure 5). The absence of larger speci- 
mens in plankton and midwater trawl samples 
and their reported occurrence inshore as juven- 
iles indicate an estuarine dependence for the 
species . 

Arthur Kendall 

Flatfishes 

Our efforts centered on species identifica- 
tion, analysis of findings and preparation of 
manuscripts from data collected during the two- 
part coastal ichthyoplankton survey of 1965-66 
and 1967-68. Figure 6 depicts the density 




Figure 4. --Capture locations of black sea 
bass larvae from R. V. Dolphin survey 
cruises. Regular sampling stations indi- 
cated by the array of smaller dots. 



Table 2. --Mean lengths of silver hake larvae collected during an August cruise 

(R/V Dolphin, D-bO-lO). 





Depth 


State 




Distance 


offshore (.nautical miles) 




Weighted 

mean 

length 






5 


10 15 


25 35 50 b5 


80 




Transect 




mm 


(Notochord length) 




N 



Weighted mean length 



2, 


.8 


4.0 


3. 


.1 


5.0 


4.0 


3.0 


ns 


3.8 


598 






5.8 


5, 


.1 


5.3 


5.8 


4.2 


ns 


5.6 


658 


3. 


,8 


2.0 


3, 


,9 


4.1 


5.4 


6.0 


ns 


5.4 


4.3 


3. 


.6 


3.3 


5, 


.5 


6.2 


6.8 


8.5 


ns 


7.8 


1037 






3.2 


3, 


,0 




3.2 




4.9 


3.5 


54 








4, 


.7 


3.5 




5.3 


5.4 


5.3 


98 












3.8 


5.8 


6.0 


3.6 


5.6 


33 












3.2 


5.3 
6.0 

6.0 
7.0 


12.2 

3.3 
5.5 

7.5 


10.2 

ns 
ns 


10.3 

4.0 
5.7 

7.3 
7.0 


71 

3 
8 

8 
2 












3.6 






ns 
ns 


3.6 


1 












14.8 






ns 


14. S 


1 












14.5 




15.1 


ns 


15.0 


3 



3.0 3.2 4.2 3.6 5.1 5.6 

18 67 82 357 472 853 



15.1 


ns 


5.7 


ns 




ns 


7.9 


7.4 


987 


153 



Shallow net (S ) samples 0-15 m; deep net (D) , 18-33 m. ns , not sampled. 




Figure 5. — Black sea bass larva, 7 . 9 mm 
long, from R. V. Dolphin ichthyoplankton 
survey cruises. 



patterns of summer flounder eggs and larvae 
collected during 1965-66. Eggs were present 
during three cruises . We collected summer 
slounder larvae regularly during October, 
November, and December, and occasionally dur- 
January, March, and April, 1966. Larval con- 
centrations centered off New York, New Jersey, 
and Delaware in October, 1966, and off New 
Jersey in December, 1965 and 1966, With few 
exceptions larvae occurred only between Cape 
Hatteras and Cape Lookout during the January, 
March, and April cruises. 

We made three unsuccessful attempts to find 
postlarval and juvenile summer flounder in areas 
other than the North Carolina estuaries , where 





Figure d .--Distribution and relative abundance of summer flounder eggs (left) and larvae 
(right), from R. V. Dolphin ichthyoplankton survey cruises, 19C5-66. 



they occur regularly. During February and 
May we sampled with a 3/4 -scale Yankee trawl 
in depths varying from 13 to 91 m at 60 stations 
along the continental shelf between Cape 
Hatteras, N. C, and Sandy Hook, N. J., and 
in June, seined at 32 shore stations in estuaries 
of eastern Virginia, Maryland, and Delaware. 
We followed up several reports of small 
summer flounder taken in local estuaries but in 
every instance caught only juvenile winter 
flounder . 

W. G. Smith 

Estuarine occurrence of juveniles 

We continued to receive and prepare contri- 
butions to a review of data on the eggs, larvae, 
and juveniles of estuarine fish of the Atlantic 
coast. The publication is a product of coopera- 
tive effort between the Atlantic States Marine 
Fisheries Commission and both Bureaus of the 
service, who jointly sponsored a workshop 
meeting in 1968 . We corrected and revised one 
particular section which summarizes geographi- 
cally, by species, the known literature on dis- 
tribution of juveniles . 

A. L. Pacheco 

Bluefish origins 

In June, we sampled for occurrence of 
juveniles between Cape Cod, Mass., and 
Barnegat, N. J., as far as 280 miles offshore 
into the Gulf Stream and took bluefish only near 
shore. The capture of some juveniles of 
mullet and goatfish- -typically shallow -water 
forms --in and near the Gulf Stream, indicated 
a transport mechanism from southern waters . 
Apparently a body of juvenile bluefish had moved 
shoreward before our cruise, probably because 
of an early warming of coastal water. We also 
sampled for juvenile bluefish around Sandy Hook 
from April through October to determine their 
seasonal occurrence and habitat preference . 
Of particular interest was the occurrence of 
several 50 mm bluefish in October night -lighting 
collections, suggesting an earlier mid-summer 
spawning . 



Food habits of juvenile bluefish 

We carried out a preliminary study of the 
feeding habits of juvenile bluefish to relate the 
movement of juveniles into estuaries with 
changes in feeding habits . The result demon- 
strates a shift in feeding from plankton to 
small fish and shrimp when juveniles reach a 
length of about 75 mm (3 in) . 

We examined stomach contents of nearly 
300 juvenile bluefish, taken from the ocean, bay, 
and river habitats surrounding Sandy Hook, 
N.J. Food occurred in 66 percent of the 
stomachs; 26 percent were empty, and 8 percent 
contained slurry, sand, or plant debris. Of the 
fish which had eaten, 48 percent contained fish 
and 55 percent contained invertebrates . Of the 
major food items, silvers ides ranked first in 
frequency of occurrence (33 percent), and 
accounted for 75 percent of the aggregate food 
volume . Copepods ranked high in frequency of 
occurrence (28 percent), but made up only 1 
percent of the total food volume . One copepod 
species occurred in 18 percent of the stomachs 
containing food. Shrimp, especially the estua- 
rine species Crangon septemspinosa , ranked 
next in total food volume (12 percent). 

Fish under 70 mm contained mainly cope- 
pods , fish eggs and crab larvae , while those 
over 70 mm contained mainly shrimp and fish. 
This change in diet with size (Figure 7) also 
coincides with a change from ocean to estuarine 
habitat . 

Susan Smith and Ann Gall 



Arthur Kendall 



-OCEAN 
99% plankton 
l%shfinip(nA«fite) 



BAY-OCEAN 


BEACH 


75%lish 




15% plankton 




K)%shnmp 






RAY MARSH A RIVFRS 




Sr%liSh 




12% shrimp 



TOTAL LENGTH (mm) 

Figure 7. — Variations in young bluefish 
stomach content in relation to fish sizes 
and habitat. 





Figure 8. — Healthy (upper) and fin rot 
infected (lower) bluefish. 



SPECIAL MICROBIOLOGICAL PROBLEMS 
IN ESTUARINE AND COASTAL AREAS 

Study of two important and recurrent local 
problems, a fin rot disease and red tide, 
continued during the year. Work consisted 
largely of monitoring the occurrences. Study 
of both problems will be expanded in 1970 to 
include tests to determine their causative 
mechanisms . 

Fish disease study 

The fin rot disease (Figure 8) again reached 
epizootic proportions in fishes in the Raritan 
Bay, Lower Bay, and Sandy Hook Bay area . 
Table 3 provides the incidences of the disease 
throughout most of the year in the four princi- 
pal species affected. 

In November, following an inshore move- 
ment of white hake, we observed the disease in 
this species for the first time. We had not 
observed the disease in smaller white hake, 
summer residents in the Bay area. Subsequently, 
trawling in Raritan Bay, Lower Bay, and Sandy 
Hook Bay yielded catches of white hake with 
incidences to 60 percent whereas catches made 
at several ocean stations in a line starting 12 
miles east of Sandy Hook to a point 5 miles 



south were almost free of diseased fish. Of 
over 700 white hake collected in ocean stations, 
we obtained only a few diseased specimens in 
the vicinity of ambrose Light. South of Ambrose 
none showed the disease . 

We completed generic characterization of 
100 bacteria cultures isolated from the necrotic 
fins and internal tissues of diseased fish sam- 
pled during the 1968 epizootic. Most of these 
(83) belonged to three closely related genera: 
Aeromonas, Vibrio, and Pseudomonas . 
We have presumptive evidence that the bacteria 
are marine. Tests of the effects of NaCl on 
growth of these cultures revealed that 98 either 
did not grow at all in the absence of salt or had 
greatly increased growth when salt was added. 
We initiated a year-round program of blood 
testing, including hematocrit, hemoglobin, red 
blood cell counts, and serum protein determina- 
tions on fresh -caught winter flounder to mea- 
sure the relation of blood quality with disease 
incidence. 

Red tide 

Red tide was not a serious problem in the 
Sandy Hook area in 1969 . On July 8 , a bloom 
developed in a square mile area of the 



1 



Table 3. --Incidence of fin rot disease in principal species affected 
during 19b9 in the Raritan Bay, Lower Bay, Sandy Hook Bay area. 



Winter flounder 

Summer flounder 

Bluef ish 

Weakf ish > 20 cm standard length 

Weakfish > 10-20 cm standard length 



March 




July 


Se 


jptember 


to 




and 




too 


May 


June 


August 


November 




Percent 


diseased 




1 
_1/ 


5 
25 


20 
28 




^- 1 


- 


2 


13 




6 


- 


- 


16 




10 


- 


- 


66 




100 



1/ 



Dash symbol signifies fish either not in the area (migratory species) 
or absent from collections. 



Shrewsbury River, consisting mostly of Proro- 
centrum micans (9,000 cells per ml) and 
Massartla rotundata (80,000 cells per ml). 
The next day, in another part of the river, an 
Olisthodiscus luteus bloom reached 25 , 000 cells 
per ml. We observed the first and only major 
dinoflagellate outbreak in the ocean from July 
10 to 13 . The bloom extended 15 km southward 
from the tip of Sandy Hook to Sea Bright , N . J . , 
along the shore and out to 100 m. We examined 
samples of bloom water and found four species 
of phytoflagellates present in about equal 
numbers. These included the species mentioned 
above and Euglena sp. Total cell counts 
reached 60,000 cells per ml. For comparison 
the more severe blooms of 1968 contained 
600,000 to 800,000 cells per ml. We believe 
the combined effects of heavy rainfall, colder 
water, and prevailing southerly and westerly 
winds prevented dinoflagellate blooms develop- 
ing as much as in the previous summer. From 
August through November the dominant phyto- 
plankton in the area was a diatom , Skeletonema 
costatum . 

John Mahoney 

OFFSHORE WASTE DISPOSAL 

Dredge spoils and sewage sludge have been 
dumped at designated disposal areas in the New 
York Bight for 40 years . Our research in the 
past two years has revealed that these activities 
have had a major effect on the ecology of 
marine organisms which habituate the disposal 



areas and surrounding environments . In the 
final phase of the study we plan to determine: 
1) the rates of accumulation of wastes and 
spread of impoverished bottom areas , 2) uptake 
of toxic pollutants in marine food chains, 
3) possible effects of spoil and sludge wastes on 
coastal waters and beaches along Long Island 
and New Jersey, 4) effects of pollutants on a 
variety of organisms held under controlled 
laboratory conditions , and 5) relationship of 
zooplankton, phytoplankton, and pelagic organ- 
isms to the waste disposal areas . We also plan 
to survey and census additional bottom areas 
which might serve as more appropriate tempor- 
ary dumping sites as well as conduct experi- 
mental dumping to determine the immediate and 
long-term effects of dumping in a previously 
uncontaminated environment. The project ends 
in Fall 1970 unless further funding is provided 
by the support agency, the Army Corps of 
Engineers . 

Effects of offshore waste disposal practices on 
marine resources of New York Bight 

Our analyses of quantitative bottom grab 
samples and physical data from 221 benthic 
stations confirmed our initial estimates that 10- 
12 square miles of bottom at the sewage sludge 
dumping grounds are devoid of life. An area of 
about 5-7 square miles in and around the dredge 
spoil disposal grounds proved to be even more 
heavily damaged. 



178 



The bottom sediments at the sewage sludge 
and dredge spoil disposal areas are character- 
ized by their high content of organic matter and 
heavy metals (Figure 9). The distribution of 
these materials confirms the patterns of water 
movement indicated in the hydrographic study. 
We also found sediments collected from the 
dredge spoil disposal area to contain over 1 
percent petrochemicals . Many of the dredge 
spoils originate in harbors polluted with petro- 
leum products . 




Figure 9. — Distribution of organic matter 
and lead in sediments of the northwest 
section of the New York Bight. High 
levels are associated with the disposal 
areas for sewage sludge (A) and dredge 
spoil (B). (cf. also Figure 11.) 



We started a series of experiments to 
determine whether the heavy metals are taken 
up by benthic organisms and, if so, how they 
are moved through the food chain. 



DO may account for the mass mortality of 
several fish and invertebrate species in 
September, 1968, off the New Jersey coast. 

Our analysis of benthic macrofauna indi- 
cates that the distribution of benthic inverte- 
brates is affected by the presence of sewage 
sludge or dredge spoils . Benthic communities 
surrounding the areas devoid of life are of low 
diversity (few species), generally dominated by 
a burrowing sea anemone, Cerianthus , and a 
rubber worm, Cerebratulus . We analyzed the 
distribution of 23 species of amphipods collected 
with soft sediments and found only one species 
( Unciola irrorata ) in the disposal areas. Our 
observations of the meiofauna (forms ranging in 
size from 0.25-1.00 mm) indicate that nema- 
todes, one of the few groups generally regarded 
as resistant to organic pollution, are not found 
in the fludge and dredge spoil disposal areas . 

Laboratory experiments to determine lethal 
and sublethal effects of sewage sludge and dredge 
spoils on benthic organisms showed exposure to 
sludge resulted in severe pathological anomalies 
and death in crabs and lobsters . In preference 
and avoidance experiments we found most organ- 
isms avoided contact with sludge if a more 
suitable substratum was available. 

Richard Barber , Woods Hole Oceanographic 
Institution, cooperating with us in studying the 
effects of sewage sludge on phytoplankton popu- 
lations , found that water collected from the 
sludge disposal area inhibits cell division and, 
thus, population growth. He did not isolate a 
causative factor. Water from other stations in 
the Bight did not inhibit growth. 



We observed that water overlying the 
bottom sediments at the dredge spoil and sewage 
sludge dump areas contains much less dissolved 
oxygen (DO) than water overlying unpolluted 
sediments at similar depths. Dissolved oxygen 
in water over the sludge grounds falls below 
1 ppm for several weeks during summer months, 
far less than that required to support normal 
benthic life. The low DO undoubtedly results 
from the high biological and chemical oxygen 
demands associated with various organic wastes 
dumped at the two disposal sites. The move- 
ment of this extensive body of water with low 



Personnel of the PHS -FDA Laboratory at 
DavisvUle, R.I. found sediments from the 
sludge disposal area contaminated with coliform 
bacteria. Their counts in the sludge area were 
higher (160,000 MPN) than in uncontaminated 
sediments 5-6 miles from the center of the 
disposal area. 

We studied effects of waste disposal on the 
biology and distribution of the surf clam, 
Spisula solidissima, and the rock crab. Cancer 
irroratus. The former is an important commer- 
cial species found in the vacinity of both the 



179 




STATION 76- 



Figure 10. — Percent composition of zooplankton groups in surface waters at one sampling 
station from January to June. 



dredge spoil and sludge disposal areas . We 
are following the development of a particularly 
heavy set of clams which occurred in 1968 . The 
rock crab, a dominant food species utilized by 
finfishes of the New York Bight, is also a poten- 
tial market item . 

Zooplankton samples are used to determine 
the distribution and abundance of organisms 
(Figure 10) in relation to sewage sludge and 
industrial acid wastes . 

Chemical analyses of sea water showed the 
water overlying the sewage sludge disposal 
area to have a high organic and inorganic phos- 
phorous content in comparison with the sur- 
rounding waters . 

Preliminary data from trawling surveys 
indicate bottom -dwelling fishes are present in 
the disposal area during late spring and early 
summer . We did not find fishes in the late 
summer when DO levels were less than 1 ppm , 
Analyses of stomach content indicated fishes 
collected in the disposal area were feeding 



on pelagic and planktonic organisms . 

Jack B. Pearce, Charles Gibson, and 
Andrew Draxler 

Temperature and current study 

Our hydrographic study of the New York 
Bight area shows the present sludge dumping 
ground to be within an apparent dynamic cur- 
rent system. Inshore and longshore movements 
of bottom water are its most obvious and persist- 
ent features . 

Our source of information comes from an 
array of 26 sampling stations . At each station 
we measured water temperature and salinity 
at 4 m depth intervals , the amount of dissolved 
oxygen at the bottom and at selected sites, and 
we released bottom and surface drifters . At 
four stations we located instruments to measure 
continuously the current velocity, direction, and 
temperature at a depth of 15 m and at the 
bottom . 



Preliminary examination of the hydrographic 
data and the recovery locations of 1,200 drifters 
gave us an indication of the seasonal variations 
in current which will be useful in predicting 
movements of sewage sludge from the dumping 
site. 

We also found indications of a movement of 
bottom water northward up the Hudson Channel , 
trending to the northeast at its head (Figure 11). 
From an analysis of water column sections this 
showed up as a relatively warm, high -salinity 
dome of water over the channel during winter 
and a tongue of relatively cool water in summer. 




Figure 11. — Distribution of bottom water 
temperature in the disposal study area of 
the New York Bight . 

We have evidence, from distribution of 
bottom temperature data, of a southerly flow- 
ing countercurrent further offshore during the 
summer . 

The returns of current drifters support the 
conclusions from station data. The recovery 
pattern of bottom drifters showed a northerly 
and inshore pattern, whereas the surface 
drifters, entrained in the longshore current, 
were returned from southerly points . 

Robert Wicklund and David Hansen 



BLUEFISH BIOLOGY 

During 1969 we continued analyses of data 
collected since 1963 to define various aspects 
of the life history and population structure of 
the bluefish. From studies on age and growth, 
larval occurrence, morphology, and migrations, 
we have now defined two major populations of 
bluefish along the Atlantic coast. We are 
continuing to correlate data from the various 
studies and plan completion of our bluefish 
studies by the end of 1970 . 

Natural history 

We continued to study differences in body 
proportions to test our hypothesis of coastal 
contingents . We measured and photographed 
samples of bluefish from Pamlico Sound, N. C. 
and Sandy Hook Bay, N.J. A discriminant 
function analysis of 13 ratio measurements 
indicated 91 percent of the individuals could 
have originated in the sampling locality. We 
have collected additional data for use in 
improving the analysis (Figure 12). 




Figure 12. — From a series of systematic 
measurements, biologists are learning of 
fish population differences. 



We continued to receive tag returns from 
the 1,106 tagged bluefish released during the 
summer and early fall of 1967 . These tags 
bore a request for return of a scale sample with 
other recapture information. Of 64 tags 
returned 62 percent included scale samples . 



181 



All scales returned this year had two additional 
annuli, further confirming our interpretation 
of scale characters as indicators of age . One 
fish, at liberty for 755 days, grew nearly 40 cm, 
a rate in agreement with our growth estimate. 

We collected more bluefish in the 8 to 15 lb 
(4 to 8 -year-old) category to supplement the 
length -weight and age-weight data we have on 
hand. 

Between May 13 and 23 , we made a R/V 
Dolphin cruise to fish water over the Hudson and 
Wilmington Canyons by trolling and gill netting 
for evidence of bluefish migrating toward the 
coast from offshore wintering grounds , but 
caught no fish. At most stations water tempera- 
ture was below 17 to 22 C . 

L. A. Walford, 
S.J. Wilk, and 
M.J. Silverman 

Migrations 

We are still reviewing returns from the 
15 , 699 bluefish tagged from 1963 through 1967 . 
Nine tag returns came in during the year from 
fish caught in New York -New Jersey waters . 
Four of the fish had been at liberty since 1965, 
the longest tune out to date of tagged bluefish . 

We have had tags returned from 98 bluefish 
which had been at large for one year or more . 
Of these, 80 fish were caught after one year, 
10 after two , 4 after three , and 4 after four 
years out. Most of these longer-term recap- 
tures came from either the area of release or 
an adjacent area (Table 4). 

Using ADP techniques, we completed 
summaries of all fish released and recaptured, 
grouped by data and area, fish size, tag type, 
and fishing gear of capture and recapture . We 
began processing these data to detect differences 
in movements, rate of movement, and to esti- 
mate apparent mortality indices . 

David G . Deuel 



BEHAVIOR OF GAME FISHES 

Behavior of summer flounder 

After studying patterns of behavior for 
more than four years in the bluefish, a pelagic 
species, we began studies on a semi-benthic 
species , summer flounder (fluke) . Our aim 
was to observe daily and seasonal patterns of 
activity, feeding behavior, and response to 
temperature . We added a sand bottom to the 
aquarium and lowered daytime light intensity to 
simulate the type of habitat in which the fish 
normally reside. 

In May we introduced six fluke ranging 
from 50-70 cm into the aquarium. Our pre- 
liminary observations showed that there were 
several basic patterns of behavior. At times 
the fluke would lie flat on the sand surface, 
eyes retracted, apparently unresponsive to 
movements of prey or other fluke . At other 
times, when lying on the sand, their eyestalks 
were extended, and they were seemingly more 
responsive to movement around them. Fre- 
quently the fish partially raised themselves off 
the bottom , supported by their dorsal and anal 
fins, with their heads up and each eye moving 
independently. In this posture they showed a 
high degree of responsiveness. Fish, partially 
or fully buried, were characteristically 
unresponsive. To bury, the fluke would vigor- 
ously beat both head and tail against the 
bottom, throwing sand up with their fins until 
partially or completely covered. 

The fish swam at every level in the tank 
from bottom to surface. One of our most inter- 
esting observations regarding swimming was the 
ability of the fish to glide considerable 
distances with a minimal expenditure of energy. 
A fluke would swim vertically toward the sur- 
face, position its body horizontally and then, 
by changing his head position, glide to the 
bottom . The fish would use its body position to 
control its forward speed and descent, in con- 
junction with caudal and median fins . Gliding 
is apparently an important example of an 
adaption for a migratory fish which expends 
high levels of energy for swimming. 



Table 4. — Summary data of bluefish tagging, 1963-1967. 



Release area 



Recapture 
area 





Conn. 






Del. 














Mass. 


and 






and 












Fla. 


R. I. 


N. Y. 


N. 


J. 


Md. 


Va. 


N. 


C. 


s. 


c. 


(East) 



Numbers recaptured between 1-4 years at liberty 



Mass. , R. I. 

Conn, and N. Y. 

N. J. 

Del. and Md. 

Va. 

N. C. 

S. C. 

Fla. (East) 

Fla. (West) 

Total at large 

longer than 1 yr. 

Total at large 

longer than 2 yrs. 



1 
43 
19 

1 



1 

8 

12 



22 



2 
52 
33 

1 
1 
2 

6 
1 



98 



Numbers of fish 



Total returned 


2 


151 


322 





76 


79 


Total tagged 


30 


3,318 


5,694 


20 


968 


1,110 



5 470 1,105* 

79 4,480 15,699 



*Does not include 9 illegible tag returns. 



Seasonal patterns of behavior were reflected 
in changes in daily activity. In June the fish 
swam continually night and day, taking only 
occasional rests of 2 to 4 minutes, lying on the 
sand. After 5 weeks the fish almost completely 
ceased swimming at night. Then from early to 
late fall, the fluke remained motionless on the 
sand for long periods, finally resuming their 
day-active pattern which continued through the 
winter. This change may be related to their 
activity during their normal migratory period. 

We began studies of feeding habits and fed 
the fluke grass shrimp once a month. We 
found three basic methods of feeding: 

(1) fluke, lying on the bottom, would 
visually fix on a shrimp 12-25 cm away, and 
while raised on its dorsal and anal fins, inch 
forward slowly stalking the prey and then, 
arching its back, strike and ingest the shrimp. 
Occasionally while stalking, a fluke would trap 



a shrimp in a sand depression, then proceed to 
strike and ingest. After feeding, the fluke 
settled on the sand or swam slowly around the 
tank bottom before resuming feeding. 

(2) fluke would swim vertically towards 
the surface usually within several inches of the 
perpendicular side of the tank, sight a shrimp, 
grasp it directly off the tank wall, then turn 
and glide or swim around the tank until sighting 
another shrimp. 

(3) fluke, while swimming at intermediate 
levels in the water column would visually fix on 
a shrimp, swim towards it, pause for 1-2 
seconds, and with an intense caudal downbeat, 
lunge forward and ingest the prey. 

Bori 011a, Anne Studholme, 
Dale Martin, Carol Samet, and 
Kenneth Hirsch 



Schooling behavior 

We began preliminary observations on the 
schooling behavior of mullet as part of our 
continuing studies to define normal patterns of 
behavior in marine fishes. Since there is a 
great deal of evidence that visual cues act as 
primary stimuli for drawing schooling fish 
together, it was our intention to examine whether 
mullet were attracted to each other by visual 
cues alone. 

We separated two adjacent tanks by an 
opaque partition and placed a single fish in one 
tank and a group of two to three fish in the 
other. By removing the partition we were able 
to examine the responsiveness of the isolate to 
its species -mates. We found that when the 
isolate saw the group it responded positively by 
swimming immediately to the exposed wall 
where it continued to bump vigorously for the 
duration of the 15 minute test. This indicated 
to us that the isolate was highly motivated to 
join its species -mates, and that its behavior was 
stimulated solely by visual cues . Each of the 
isolated mullets maintained a maximum response 
to the group fish for eight 15 -minute exposures 
over a 2 -day period. After this time we found 
that the response of the isolate to the group 
diminished significantly. 



To examine the influence of internal 
factors on these changes , we held flounder 
under constant dark conditions for 72 hours . 
For the first 24 hours we found the cones 
changed positions at the time corresponding to 
real sun time. The pigment epithelium, in 
contrast to what we observed under natural 
conditions, remained stationary. For the next 
48 hours, there was no change in either the 
position of the cones or pigment epithelium. 
The influence of an internal mechanism was 
slight . 

Bori OUa and Dale Martin 

Underwater observations on fish behavior 

We made SCUBA dives to observe the 
endemic fish population near Fire Island, N. Y. 
particularly noting fish response to current. 
Species included tautog, cunner, young weak- 
fish, puffers, sea robins, andkingfish. We 
consistently found the young of most species 
avoided strong tidal currents and maintained 
position by seeking shelter behind various bot- 
tom obstructions . The strong currents also 
inhibited feeding and spawning activity of 
several adult species . During slack water 
periods, feeding, spawning, and juvenile activ- 
ities increased. 



To define the specific visual cues to which 
the mullet respond, we are currently exposing 
isolated fish to stationary and moving models of 
different shapes, and models with eyespots in 
different locations. By using these techniques 
we also plan to study the animals' responses to 
the more subtle effects of such stresses as 
temperature changes which are not necessarily 
detected by other experimental methods . 

Bori 011a, Kenneth Hirsch, and 
Carol Samet 



Bori OUa, Robert Wicklund, and 
David Hansen 

NATURAL HISTORY OF DRUMS 

We began our study of the sciaenid species 
in late 1968, to determine distribution, migra- 
tory patterns, age and growth, and ascertain 
through morphometries racial composition of 
present stocks. In the forthcoming year we 
plan to extend our present sampling area (Cape 
Cod to South Carolina) south to Florida . 



Retinal changes in winter flounder 

Preliminary studies on the winter flounder 
eye indicated that it adapts to light and dark by 
a series of positional changes in retinal ele- 
ments . Changes in the position of the cones and 
pigment epithelium correspond to the diurnal 
activity of the animal in the field. 



During cruises from Charleston, S. C, to 
Shinnecock Inlet, N. Y., we tagged and 
released 3,357 Atlantic croaker and 507 weak- 
fish. We received only two tag returns; one 
from a weakf ish tagged and recaptured near 
Cape May, N. J. > and one from a croaker 
tagged near Morehead City, N. C . , and recap - 
tured near Myrtle Beach , S . C . Our catch data 



indicated the following occurrences: concen- 
trations of yound-of-the-year weakfish from 
Ocean City, Md, , to Sandy Hook Bay, N. J. , 
with large weakfish regularly occurring in the 
New York Bight area; large aggregations of spot 
between South Carolina and southern New Jersey 
showing greatest abundance in the Capt Lookout, 
N. C. and Ocean City, Md., areas; young -of- 
the-year and yearling croaker from South 
Carolina to Chesapeake Bay but concentrated in 
the Cape Lookout area . We encountered no 
concentrations of older croaker in any of our 
sampling areas . 

We began an analysis of sciaenid scales to 
determine age composition and growth character- 
istics of the six species under study. From a 
food habit analysis of 125 weakfish sampled from 
Sandy Hook Bay, N, J., we learned that grass 
shrimp was the dominant food. 

Stuart Wilk and Myron Silverman 

INVENTORY AND ATLAS 
OF SPORT FISHING FACILITIES 

"Anglers Atlas of the United States Atlantic 
Coast" is the title of our forthcoming, four -color 
guide book . We completed the 35 maps which 
detail over 75,000 square miles of inshore 
waters and 28,000 miles of coastal land. We 
have included the most recent available infor- 
mation on location of fishing reefs , fishing 
access points, and boat and angler facilities 
from Passamaquoddy Bay, Me., to Plantation 
Key, Fla. 

We rechecked all cartographic details, 
typeset, and completed the 115 illustrations of 
game fish . We readied the typeset tabular and 
text material to accompany the illustrations and 
completed draft of the glossary text. The pro- 
ject will be completed with submission of the 
manuscript to the printer this spring. 

Bruce Freeman 



ARTIF1CL\L REEF DEVELOPMENT 
AND MANAGEMENT 

During the first four years of our artificial 
reef program we found answers for many of 
the questions we posed at the inception of this 
study. Some of the information we can now 
provide includes: 1) the cost and methods of 
building reefs with several different materials, 
2) life expectancy of car body reefs, 3) tech- 
niques to use in building effective tire reefs, 

4) which substrate appears to be most effective 
for colonization by epibenthic organisms , and 

5) feeding habits of various fish on artificial 
habitats . 

There are still many questions we are 
trying to answer . One of the problems that has 
confronted us throughout our study is highly 
restricted visibility on our artificial reefs in 
the New York Bight because of turbid water 
conditions. We had hoped to obtain quantitative 
data on fishes and study their behavior on 
artificial habitats through thfe use of SCUBA . 
With poor visibility, however, this has proved 
impractical. 

^yith the addition of two reefs, one off 
Sea Girt, N. J. , and the other off the coast of 
southern Georgia (Figure 13), we now have 8 
experimental reefs under study. We gave 
technical assistance to groups creating 8 more 
reefs along the east coast , two off the coast of 
New York, one in Chesapeake Bay, three off 
the coast of South Carolina, and one each in 
Georgia and Florida. We completed a precon- 
struction survey and site selection off 
Chincoteague , Va., in a cooperative experi- 
mental reef effort between the Chincoteague 
National Wildlife Refuge and the Sandy Hook 
Marine Laboratory. 

Our cooperative study with the Environ- 
mental Control Administration's Bureau of 
Solid Waste Management invtestigating the use of 
scrap tires as artificial reefs was highlighted 
by the installation of 35,000 tires on two reef 
sites in the New Jersey -New York area. We 
tested different techniques of incorporating 
scrap tires as reef -building material in con- 
figurations that provided necessary relief, 
ease of handling, and low cost. These are 



185 




necessary criteria if the material is to be 
practical for use by sport fishing groups and 
conservation agencies. After selecting a com- 
bination of rod units (Figure 14) and single tire 
units (Figure 15), we deposited 30,000 tires 
between June and October on the Atlantic Beach 
artificial reef off southern Long Island. We 
then deposited 5 , 000 tires in November on our 
new experimental reef site off Sea Grit, N.J. 




Figure 14. --Barge loading 7-tire units. 
The units have concrete ballast and are 
held together with tie-rods. 




Figure 15. — Individual weighted tires added 
to an artificial reef increase its 
functional profile. 



Figure 13 .--Location of experimental reef 
sites under study. 



Our inspection dives on the Jacksonville 
and Palm Beach, Fla., reefs revealed numerous 
game fishes of many species and a thick growth 
of encrusting organisms on the materials at 
both reefs (Figure 16). The car bodies on the 
two -year -old Jacksonville reef showed appreci- 
able deterioration. The car frames remained 
intact and supported a considerable growth of 
invertebrates but the thin metal of the roof and 
sides of many cars had disappeared. 

To compare the biomass of encrusting 
organisms on artificial reefs with populations on 
natural bottom around the reef, we resumed and 
refined the tabulation of data collected on a 
benthic survey off southeastern Long Island from 
February 1966 to January 1967 . Two polychaetes 
were tentatively identified as new to this area. 
We found three types of invertebrate distribu- 
tion present in this area, two specific and one 
ubiquitous . 

Richard Stone and Chester Buchanan 

Creel survey technique 

We developed and tested several creel 
survey methods for estimating fishing pressure, 
catch per angler hour, and anglers' total har- 
vest around artificial reefs. We defined the 
angling population in our study area as all sport 
fishermen fishing beyond the surf zone between 
Manasquan Inlet, N. J., and Jones Inlet, N. Y. 
To sample this population, we divided the 
anglers into two groups: 1) party and charter 
boat anglers and 2) private boat anglers . 

In our first attempts to gather information 
from party boat anglers, we distributed a 
limited number of log books to the captains and 
attempted to interview the anglers when they 
returned to the docks. The dockside interviews 
proved impractical. However, we are getting 
encouraging results from the log book returns . 




Figure 16. — Diver biologist examining 
development of attached growth on an 
artificial reef. 

boat owners. We received completed question- 
naires from over 80 percent of the boat owners 
sampled. Errors introduced from non- 
response were minimal --a follow-up survey 
differed by only 0.07 fish per hour in the 
estimate of fish per angler hour and 4 percent 
in the number of unsuccessful anglers . We are 
using aerial surveys to estimate total angling 
pressure in the test area . 

Chester Buchanan and Richard Stone 

Ecology of fish populations of artificial reefs 

We supplemented SCUBA observations with 
longlining (Figure 17) on the Atlantic Beach, 
N. Y., reef and the adjacent flat sand bottom 
in our quantitative comparison of artificial 
reef with natural habitat . We caught numbers 
of migrant cod (Figure 18) on clam-baited hooks 
along with taut og, longhorn sculpin, little 
skate, spiny dogfish, and goosef ish . Stomach 
contents of the cod indicated that they inhabit 
the reefs as well as the adjacent flat bottom . 



We designed a mail survey which proved 
to be the best sampling method for private boat 
anglers. We identified the owner of a particular 
boat by recording his registration number as he 
passed an observation point and then checking 
with the State Marine Police to see who owned the 
boat. Then we mailed questionnaires to 196 



By studying feeding habits , we learned 
more about the dependency of black sea bass on 
our South Carolina reef. They feed mostly 
during the day on free-living and attached organ- 
isms associated with the reef (amphipods and 
barnacles). To a lesser degree, they foraged 
on burrowing and demersal organisms of the 



187 




summer was associated with the change in 
reef fish populations. 



Figure IT. --Setting a baited longline on an 
artificial reef to gather quantitative 
information on reef productivity. 

adjacent sand bottom . Feeding habits differed 
with size; smaller fish fed on amphipods and 
razor clams and larger fish on barnacles and 
crabs . Competition was high among sea bass , 
sheepshead, pinfish, and invertebrate predators 
for attached food organisms on the reef. In 
New Jersey, adults occupied new reefs immedi- 
ately, even before an overlying forage popula- 
tion developed, suggesting an attraction to 
reefs based on shelter and touch -sense. We 
experienced highly turbid water during most 
diving operations in the New York Bight. The 
persistent disposal of solid wastes and dredge 
spoils, suspended in wind -generated wave 
surges , may produce this . We recorded low 
dissolved oxygen levels during summer, but did 
not witness any evidence of fish or shellfish 
mortalities, as in the autumn of 1968. These 
adverse water conditions may account for the 
paucity of demersal fishes on reefs during part 
of the summer, followed by repopulation from 
local movement when conditions improved later 
in the summer , A variation in oxygen concen - 
tration from 1.5 to 7 ppm from mid to late 






Low light , resulting from high turbidity, 
may reduce feeding activity of tautog and 
cunner, fishes which normally browse during 
daytime on attached organisms . We found a 
heavy, relatively undisturbed, population of 
mussels on the upper surfaces of the Atlantic 
Beach reef in August with fewer tautog and 
cunner (Figure 19) than the dense mussel growth 
could support. We witnessed direct effects of 
low light on fishes when we made a dive on the 
wreck Delaware. Ambient light at mid-day was 
zero and under artificial lighting we found 
cunner wedged in crevices of the wreck where 
they could be touched. Their behavior was the 
same as that of cunner observed at night --the 
normal diurnal activity had been modified by 
turbidity -induced darkness . 

At the Fire Island, N. Y., reef we made 
night observations to become familiar with 
nocturnal behavior of common reef species . 




Figure 18 . --Wintertime reef fishing produces 
cod. 




Figure 19. --The dense growth of mussels on 
our New York reef affords good forage. 

We found aggregations of tautog and cunner 
wedged in spaces of sheet piling and oriented in 
various positions, so lethargic that sea stars 
were able to crawl over them (Figure 20). 
Although we did not witness predation of fishes 
by sea stars , the seasonal drop in temperature 
may reduce cunner activity sufficiently to allow 
such predation by an invertebrate organism . 

In May and July we resurveyed the wreck 
Delaware to note long-term effects on this reef 
habitat from the mass mortality of 1968 . The 
wreck fauna had re-established itself. All 
sizes of cunner and medium to large tautog were 
common and were feeding on mussels attached 
to upper surfaces; some large areas had been 
grazed bare . We found many ocean pout occupy- 
ing spaces around bottom wreckage, squirrel 
hake nearly as numerous, but only two black sea 
bass along the 140-ft. long ship. Large sea 
anemones, especially numerous on under sur- 
faces and inner spaces, probably survived from 
last year. Lobsters and rock crabs had repopu- 
lated lower portions of the wreck to nearly pre- 
mortality levels . 

Larry Ogren and Jeffrey O'Neill 



Distribution and ecology of attached marine 
organisms 

We established two new research sites for 
comparative investigations of epibenthic 
communities. In mid-October we placed a 
multiple disc sampling apparatus (MDSA) near 
the New York State artificial reef (8 m deep) in 
Great South Bay, 700 yards at a bearing of 35° 
30'T from the Fire Island radio mast. In 
cooperation with the Marine Science Research 
Center, State University of New York at Stony 
Brook, we investigated the colonization of hard 
surfaces (MDSA) in the intake and discharge 
canals of a steam -electric generating station 
located on Long Island Sound at Northport, 
New York. 

Samples of epibenthic communities taken 
at the Shrewsbury Rocks, N. J . , site over a 
30-month period, provided data which allows 
us to predict the periods of larval settlement 
and colonization by species important to the 




Figure 20. — At night, wrasses lie in bottom 
debris or wedge against solid objects. 
The effect of starfish is not known. 



life history and success of a variety of reef- 
dwelling finf ishes . 

We are investigating the predation of the 
starfish, Aster ias forbesi, on finfish and 
attached invertebrates . Our field observations 
and literature reviews indicate this species 
competes with and preys upon a variety of fin- 
fishes . We started a series of experiments to 
determine if sea stars are attracted to finfish 
by using olfactory receptors as they do with 
invertebrate prey. 



Jack B. Pearce 



Virgin Island Reef studies 



This study began in February, 1968, when 
we conducted a SCUBA investigation of finf ishes 
and invertebrates at Cow and Calf Reef, Jersey 
Bay, St. Thomas, V. I. and at Lameshur Bay, 
St. John, V. 1. We placed a Multiple Disc 
Sampling Apparatus (MDSA) at Cow and Calf 
Reef to study larval settling, colonization, and 
succession of epibenthic organisms . From then 
to March, 1969, we collected discs monthly 
from the MDSA. We continued the SCUBA obser- 
vations in March at the Cow and Calf Reef site 
and adjacent mangrove habitats in Jersey Bay. 

Our analysis of disc samples indicated that 
tropical epibenthic communities develop much 
more slowly than those in temperate waters . 
We found only one species of garamarid amphi - 
pod, one snail, a juvenile spiny lobster, and a 
small unidentified crab with the discs . In 
contrast, discs collected after one year expos- 
ure in temperate waters of Massachusetts and 
New Jersey often have over 100 different species 
of unattached organisms associated with them. 

Colonization occurred only on lower disc 
surfaces . Intensive grazing on the tops of the 
discs by reef -dwelling finfishes which apparently 
do not feed on the under surfaces of objects 
accounts for the paucity of attached or erect 
reef forms . The first significant settlement 
occurred after a 3 -month period of submergence 
by several tube -dwelling worms on concrete and 
rubber discs . The oyster, Ostrea equestris , 
set the next month and became the dominant 



organism on the discs . After 12 months 
submergence at least six species of hard corals 
had colonized the discs . 

We observed 68 species , representing 31 
families or reef -type fishes, on the Cow and 
Calf Reef and adjacent area. More intensive 
surveys of this fringing reef could double this 
number. Non-piscivorous carnivores and 
herbivores (grunts, butterf lyf ish , angelfish, 
damselfish, parrotfish, wrasses, fUefish, 
triggerfish, squirrelfish) dominated the fish 
fauna. Most piscivorous fish were non-game 
species , such as the trumpetf ish . 

The most notable feature of the Cow and 
Calf Reef was scarcity of predatory game fish, 
especially groupers and snappers . These fish, 
usually active at dusk or during the night, may 
have been missed because most of our diving 
occurred during the day. The reef had many 
caves , ledges , and pinnacles , which could 
function as diurnal retreats for any groupers 
and snappers in the area. The pelagic, wide- 
ranging jacks and mackerels are more diffi- 
cult to observe and are seen infrequently. 

In the shallow mangrove zone of Jersey 
Bay, St. Thomas, we recorded 20 species of 
fishes of 16 families . Most were juveniles of 
large fish found on reefs or sub -adult and adult 
forms of smaller fish. The shallow depths of 
the lagoon may preclude the larger fish from 
occupying this habitat . Juvenile spiny lobsters 
were common under the mangrove roots and 
rocks bordering the lagoon. The mangrove 
embayment affords a large protected area for 
the growth and development of many reef- 
dwelling fishes and economically important 
crustaceans . 

Overfishing and physical alteration of 
stable reefs are a threat to this fragile environ- 
ment. Slow to recruit new faunas, reef com- 
munities of the Virgin Islands will not survive 
effects of unregulated economic growth. 
Because the native fishing population is reef 
oriented, they should respond favorably to 
management recommendations to preserve and 
improve their catch, both for recreation and 
food. 

Jack Pearce and Larry Ogren 



190 



COOPERATIVE PROGRAMS 

Oil pollution 

Pearce and Ogren returned to San Juan, 
P. R. , in March and re -visited the intertidal and 
sublittoral environments. They had surveyed one 
year earlier immediately after the sinking of the 
tanker. Ocean Eagle. There was no trace of oil 
on the lower intertidal zone. Except for some 
areas recently or chronically polluted by fresh 
oils the sandy beaches and mangrove swamps 
were oil -free. Invertebrates and fishes appeared 
to be healthy and in abundance. 

Underwater activities 

Wicklund participated in a diving expedition 
to British Honduras with Edwin Link and 
Seward Johnson . There he gained experience in 
using a special chamber for decompression 
diving and experimented on rapid pressure 
changes on reef fishes , 

Oceanic fish investigations 

To facilitate investigation of bluefin tuna 
populations, Edmunds agreed to exchange blood 
and tissue samples from the western Atlantic 
for some from the Mediterranean collected by 
P. Pichot, Institut des Peches Maritimes, 
Laboratoire de SETE, France. 

Cooperation with U. S . S . R. 

Wilk was a member of the scientific party 
on the R/V Ecliptaka , a Russian research vessel 
taking part in joint U. S. A.-U. S. S. R, study 
of Atlantic shelf groundfish resources . 

Cooperation with Japan 

Edmunds was a member of the scientific 
party aboard Shoyo Maru , a research vessel of 
the Japan Fisheries Agency. He collected blood 
and tissue samples from billfish longlined from 
the central Caribbean in December. 

North Carolina industrial fish 



■ During cruises and field trips to sample 
sciaenids from North Carolina waters, we have 



been assisted by biologists from the States' 
Division of Commercial and Sports Fisheries . 

Red Tide information panel 

Mahoney and Pacheco served as contacts in 
an information alert on red tide outbreaks . 
They maintained liaison among biologists of 
the FWPCA, FDA, and N. J. State Health 
Department . 

MEETINGS AND TRAINING 

Walford participated in a symposium series 
on water pollution at Monmouth College, which 
was moderated by Clark. An effective citizen 
action group was organized as a result of the 
sessions. 

Clark testified as expert witness in connec- 
tion with effects of a proposed Hudson River 
Expressway in New York and to the Subcommit- 
tee on Fisheries and Wildlife Conservation of 
the Home Committee on Merchant Marine and 
Fisheries . He also accompanied Congressman 
Howard (N. J ,) to the Waterways Experiment 
Station, Vicksburg, Mississippi, to view model 
operations of a proposed coastal inlet . 

Azarovitz and Clark participated as 
members of the Marine Resources and Ocean- 
ography Working Group of the Interior's EROS 
(Earth Resources from Orbiting Satellites) 
program. This group gave partial funding sup- 
port for Barnegat Bay radiometer studies . 
Azarovitz also attended the Sixth International 
Symposium for Remote Sensing of Environment 
at the University of Michigan and a workshop on 
Spacecraft Oceanography conducted by the Naval 
Oceanographic Office at the Naval Research 
Laboratory facilities in Washington, D. C. 

Olla was an invited attendee to the 11th 
Annual Ethological Conference held in Rennes, 
France, and participated in the discussions on 
schooling behavior and feeding motivation. 
Later in the year he participated in the BSFW 
physiology workshop in LaCrosse, Wis. 

Wicklund served on the Department's Man - 
in-the-Sea Committee. 



191 



In September, Kendall began a 10 -month 
training session in LaJoUa, Calif. He attends 
graduate courses at Scripps and study under 
Dr. Elbert H. Ahlstrom, a senior scientist of 
BCF . His work centers on identification of 
ichthyoplankton collected during the R/V Dolphin 
surveys . 



Mahoney completed attendance at the ^ 

Advanced Course in Fish Diseases at the BSFW 
Eastern Fish Disease Laboratory, Leetown, 
W. Va. 



NARRAGANSETT MARINE GAME FISH LABORATORY 
Narragansett, Rhode Island 



HIGHLIGHTS 

Our studies of spawning behavior and 
juvenile fish at Narragansett are yielding encour- 
aging results, partially due to the fact that we 
have high quality water available for our sea - 
water flow system. Six species of marine game 
fishes spawned in the laboratory aquaria . Two 
species, scup and tautog, were induced to spawn 
twice within the year by controlling temperature 
and light. 

The life history studies of larger , offshore 
game species such as sharks and billfishes have 
revealed the extensive seasonal north -south 
migrations undertaken by many of these fishes . 
We have found that part of the blue shark popu- 
lation migrates at least 2,000 miles between 
New England and Surinam, off South America . 
One of the highlights of the year was our first 
swordfish tag return. This fish was at liberty 
four years and was the first tagged broadbill 
recovered in the U.S. Atlantic waters. 

We have also made progress in finding a 
means for differentiating marlin racial stocks . 
We examined about 350 white marlin and found 
that they exhibit three genetic polymorphisms, 
each of which may be a racially significant 
character . 

ECOLOGY OF OCEAN 
GAME FISH 

Our studies of life histories and migrations 
have yielded new information on large game 
species. In 1969, we tagged 1,775 sharks (18 
species) and recovered 39 tags (Table 1). Since 
the program started in 1963, sportsmen have 



assisted us by tagging nearly 8,000 sharks 
(Figure 1) of which 217 (2,7 percent) have been 
recovered. 

We have completed most phases of our 
field work and in the coming year plan to 
analyze all past data and prepare it for publi- 
cation. 

Blue shark . Five blue sharks recovered in 
1969 migrated south from New England to tropi- 
cal waters . The fastest rate of travel was 27 
miles per day for a shark tagged near Block 
Canyon in September and recaptured off 
Venezuela in December (1,720 miles in 64 days). 

Recaptures from the Caribbean area 
strengthened our hypothesis that this species 
makes extensive seasonal north-south migrations 
(Figure 2) similar to those proposed for white 
marlin and possibly for swordfish, mako, and 
other pelagic species. 

We can show several migratory patterns 
for different segments of the blue shark popu- 
lation: 1) a movement of 300-400 miles by adult 
males and juveniles of both sexes between 
wintering grounds near the Gulf Stream, and 
summer grounds along the continental shelf 
north of 40° lat. , an inshore passage probably 
related to feeding; 2) an offshore migration of 
over 700 miles by juvenile females from the 
coastal zone to beyond the Gulf Stream; and 3) 
a north-south offshore migration by part of the 
male population that extends at least 2,000 
miles between New England and Surinam, 
South America . 



192 



Table 1. — Summary of shark tagging and recapture data, 1969 









Maximum 


Maximum 




Number 


Number 


days at 


distance 


Species 


tagged 


recovered 


liberty 


traveled 


Sandbar 


142 


3 


lb05 


155 


Blue 


1402 


31 


1010 


2000 


Mako 


20 


1 


56 


320 


Black Tip 


17 


2 


161 


800 


Sharpnose 


7 


1 


1 





Smooth Dogfish 


5 


1 


549 


217 


Other 


172 











Total 


17b5 


39 








Figure 1. — A blue shark released bearing 
dart tag. 

Sandbar shark. We had tags recovered 
from sandbar sharks after 3 and 4 -1/2 years at 
liberty. An average annual growth increment 
of 4 cm shown by tagged juvenile sandbar sharks 
is in close agreement with estimates from our 
analysis of vertebral marks . 

Our evidence from vertebral rings shows 
the species grows only a few inches per year and 
matures in 10 to 15 years. In June we succeeded 
in capturing small (60-80 cm) sandbar sharks 
in gill nets on their Virginia nursery grounds . 
With this additional material we completed the 
examination of vertebral sections from over 500 
individuals . 



Figure 2. — Migrations of the blue shark 
intimated from long-range recaptures. 
Probable return routes are indicated by 
dotted pathways. 



Blacktip shark. A blacktip shark tagged 40 
miles south of Pensacola, Fla., in August, 
1968 was recaptured 80 miles ESE of Vera 
Cruz , Mexico , 161 days later . This is the first 
evidence of a trans -Gulf migration by any 
species of shark. 

Swordfish. On July 4 , 1969, a 500 lb. 
swordfish tagged 200 miles south of Montauk, 
N. Y., in August, 1965 was recaptured 48 miles 
ESE of the tagging area after nearly 4 years at 
liberty. This is one of five swordfish we tagged 



and is the first recovery of a tagged broadbill 
in U . S . Atlantic waters . 

Dolphin. We kept three juvenile (38-45 cm) 
dolphin for 10, 22, and 52 days from August to 
October to study feeding and growth . Individuals 
ate up to 138 food items per day, amounting to 
17 percent of their body weight, and grew at a 
rate of about 3 inches per month . The fish held 
longest ate a total of 6.8 lbs of food, converted 
approximately 26 percent of this to body weight 
and grew from about 1 lb to over 2 lbs during the 
period. These data supports evidence of a rapid 
growth rate for dolphin which reportedly can 
reach 40 lbs in 7 months under natural condi- 
tions . 

John Casey and Charles Stillwell 

CULTURE OF SALT WATER FISH 

With the completion of work ensuring a 
seawater flow system with high quality water we 
were able to concentrate on observations and 
special studies of water characteristics and 
associated biota necessary to the well-being of 
marine game fish. In the coming year we plan 
to emphasize experimental work on behavior, 
physiology, and feeding of larval fishes. 

Juvenile fish studies . We measured varia- 
tions in growth of tautog and started a special 
series of experiments to learn effects of lighting 
and sheltered habitats . In another set of tanks 
we fed juvenile tautog, weakfish, and scup known 
amounts of fish and shrimp daily. Average 
weight gains over a 2-3 month period amounted 
to 2.5, 22.0 and 2.0 g. Expressed as percent 
increase of fish weight at the beginning of the 
study these gains were 31.9, 113.7, and 11.2, 
respectively. 

Spawning behavior . A pair of tautog, kept 
in our large tank, spawned for two weeks in 
April providing us with viable eggs . In early 
June we added four males and seven females to 
compare group behavior with that of the pair. 
The newly added fish began spawning in three 
days continually for a month. The original 
pair of tautog resumed spawning in early 
September and continued until mid -November . 



We collected cod from lower Narragansett 
Bay during November and December and held 
them in our large tank in water the same tem- 
perature as that of the Bay. At the time of 
collection, specimens were nearly ripe (Figure 
3), and we stripped some of the cod for develop- 
ment studies of fertilized eggs . Cod began 
spawning in our tanks on December 15 and we 
collected and maintained fertilized eggs in lab 
aquaria (Figure 4). In cooperation with 
Dr. Howard Winn (U. R. I.), we installed a 
hydrophone to monitor any sounds cod make 
during spawning. 




Figure 3 . --Biologists regularly examined cod 
ovaries to determine the maturation of 
eggs. 




Figure 4. --Development of larval cod is 
followed by sampling specimens held under 
controlled conditions in an experimental 
trough. 



Six scup began spawning in our tanks in late 
March and continued for 40 days . In September 
we added six more scup and in November time- 
phased the lighting and lowered the temperature 
to 15 C . for two weeks . We then lenghtened the 
lighted time and increased water temperature. 
Fish activity increased at 17 C. and in late 
December the scup spawned a second time with- 
in the year when temperature was 17 .5 C . 

Larval fish . Our second attempt to raise 
larval tautog beyond 10 days after hatching failed. 
In the trials we tested various prepared foods 
and investigated variations related to tank popu- 
lation density, water flow rate, temperature, 
and lighting. Seven days after hatching, larvae 
responded to objects in the tank, regardless of 
the object size or shape. 

Preliminary results of a study to determine 
response to different light frequencies by 16 -day- 
old cod larvae indicated a high degree to yellow, 
low degree to green and red, and none to blue. 

We have had success in maintaining larval 
cod on dry prepared food and natural plankton. 
Preliminary observations indicated no larval 
response to objects placed in the aquarium. 

We began monitoring development of winter 
flounder gonads and in the sampling found sever- 
al barren adults . Some spawning occurred in 
our holding tanks and produced fertile eggs. We 
resumed rearing studies on eggs and larvae and 
have noted a differential development rate of the 
natural egg clumps with slowest rates occurring 
in the innermost eggs . 

Connie R. Arnold and Carolyn Rogers 

Effects of DDT and dieldrin on reproductive 
success of winter flounder 

We undertook a cooperative study with the 
University of Massachusetts, to develop methods 
for sublethally dosing adult flounder with DDT, 
spawning, and raising the offspring of such dosed 
flounder. We tried the following methods of 
dosing: 1) incoming water, 2) food, 3) direct 
injection into the gonad tissue. 



Water dosing proved most effective. We 
encountered mixed success in spawning and 
raised the flounder. Though spawning and egg 
development proceeded satisfactorily, less 
than 1 percent of the larvae survived to 26 days 
after hatching. We noted small but inconclu- 
sive differences in larval mortality between 
dosed and control groups . Improved techniques 
and materials will hopefully afford greater suc- 
cess in the 1970 spawning season when both 
DDT and dieldrin will be used. 

Rod Smith and C. R. Arnold 

RACIAL STUDIES 

We continued to study similarities and 
differences of fishes on the basis of genetically- 
controlled protein characteristics. From this 
effort we are learning about the population 
structure of selected game fish species, such 
as whether particular stocks consist of a num- 
ber of subpopulations. We hope to complete 
all present phases of work this year and analyze 
and publish results as appropriate. 

We collected blood and tissue samples 
from: 452 bluefish taken along the U.S. Atlan- 
tic and Gulf coasts; 119 white marlin taken off 
U.S. Atlantic and Gulf coasts and from the 
Caribbean off Venezuela; 125 bluefin tuna along 
the U. S. and Canadian Atlantic coast; and 21 
bluefin from Mediterranean waters. We con- 
centrated on electrophoretic analyses of 14 
blood and tissue proteins, 12 of which were 
enzymes (Table 2), and identified three addi- 
tional genetically polymorphic characters --an 
oxidase in bluefin tuna and 6-PGD in both bluefin 
and white marlin. The oxidase system com- 
prises two allelic genes and three electrophore- 
tic patterns and was easily identified in fresh 
red blood cell (RBC) and frozen tissue. The 6- 
PGD enzymes, relatively unstable, show good 
patterns from fresh RBC, but are virtually un- 
detectable in homogenates of frozen muscle, 
heart, and liver tissue. Because RBC's quickly 
deteriorate, 6-PGD analyses must be completed 
within a few days of collection. 

We identified some racial differences 
between Rhode Island bluefish and those from 
North Carolina Sounds . Slight dissimilarities 



Table 2. --Summary of electrophor etic separations and results, 1969 







Tissue source i/ 
and activity ^^ 




Numbers of fish examined 
White Bluefin 


Protein 


M 


H L G RBC 


P 


Bluefish marlin tuna 



Enzyme : 

Lactic Dehydrogenase (LDH) X X X X 

X 

Malic Dehydrogenase (MDH) X X X X 

X 

Glucose-6-Phosphate 0X0 

Dehydrogenase (G-6-PD) 

Isocitric Dehydrogenase (IDH) 0X0 



6-Phosphogluconate 

Dehydrogenase (6-PGD) X 

Succinic Dehydrogenase (SDH) 

Malic XXX 

Carbonic Anhydrase (CA) 

Alpha-Ketoglutarate - 6 - 

Decarboxylase ( -KG) 

Alkaline Phosphatase (AP) - 2 2 

_ 6 - 

Oxidase X - - 120 

Esterase X X X X 



120 


168 


48 


6 


98 


12 


120 


144 


48 


6 


6 


6 


2 


_ 


3 


- 


6 


6 


1 


1 


1 


394 


118 


96 


- 


2 


2 


2 


2 


2 


_ 


6 


2 



- 


168 


- 


393 


134 


113 


382 


134 


49 



Non-enzyme : 

Homoglobin (Hb) X 227 214 

Transferrin (Tf) X - 135 

k/ M, muscle; H, heart, L, liver; G, gonad; RBC, red blood cells; P, plasma. 

2/ 

— X - enzyme activity; - little or no enzyme activity. 



are evident when these groups are compared on 
the basis of the newly discovered 6-PGD system 
or the plasma esterase system we identified in 
1967 , Neither system alone provided proof of 
racial separation but the combined information 
is suggestive. Additional samples should give 
us more conclusive evidence of this difference. 

Having examined only about 350 white mar- 
lin and less than 200 bluef in tuna , we must also 
accumulate more data on these species before 
conclusions about their population structures are 
justified. The difficulty in getting large numbers 
of white marlin samples from widely separated 
geographical areas such as the Caribbean Sea 
and South Atlantic Ocean is especially unfortun- 
ate and frustrating. The species exhibits at 
least three genetic polymorphisms: plasma 
esterase, plasma transferrin, and 6-PGD from 
RBC. Each of them may be a racially signifi- 
cant character and the systems are independent 
of each other . Collectively they represent a 
powerful means for differentiating marlin racial 
stocks . 



variations are rare (e.g., 2 of 168 marlin with 
an unusual pattern of MDH from heart tissue) 
or absent entirely (e.g. , identical patterns of 
tissue LDH from 129 bluefish) . Some enzymes 
(SDH, IDH, CA, KG, AP) lost activity too 
quickly to be detected by our procedures or may 
have been absent from those tissues that we 
examined. 

Philip H. Edmunds 

TECHNICAL TRANSLATIONS 

During 1969, 47 assorted documents in 
Russian, German, Spanish, and French, total- 
ing approximately 166,000 words, were trans- 
lated into English and all scientific reports ab- 
stracted for inclusion in Sport Fishery Abstracts, 
Preparation is underway to transfer publication 
of The Division's Sport Fishery Abstracts to the 
Narragansett Laboratory. 

Robert M. How land 



We analyzed many fish for some proteins 
which exhibit genetic polymorphism in other 
animal species, but failed to identify such poly- 
morphism . Some individual differences are 
common (e.g. , 6-PGD from liver tissue of blue- 
fish and tuna) but too complex for us to interpret 
with confidence. In other systems individual 



TIBURON MARINE LABORATORY 

Tiburon, California 
Gerald B. Talbot, Director 



HIGHLIGHTS 

Responsibility for conduct of the airborne 
sea surface temperature program is being 
assumed by the U.S. Coast Guard. 

A prototype magnetic tape digitizer for the 
airborne sea surface temperature program was 
completed and tested . 

A study was begun to determine the catch 
temperature for important marine game fishes . 

Foreign fishing on the stocks of billfish in 
the eastern Pacific has resulted in fewer catches 
by marine game fish anglers . 

Interest in the cooperative billfish tagging 
program has increased; however, fewer bill- 
fish were caught and fewer tagged by sportsmen 
during the past year . 

Food studies on striped marlin show that a 
major portion of their diet when off southern 
California is anchovies . 

Life history studies are continuing on the 
white seaperch and redtaU surfperch, import- 
ant marine game species occurring along the 
Oregon coast . 

A study of the ecology and behavior of 
Hawaiian reef fishes was begun , 

Observations along the Kona coast of the 
Island of Hawaii show that the much discussed 
coral reef destroyer, the crown -of -thorns sea 
star, contrary to reports, has not increased in 
abundance in this area. 



Field sampling was completed in San Pablo 
Bay as part of a study to determine the effects 
of turbidity on Bay species . 

Laboratory tests measuring the response of 
fish to varying levels of turbidity indicated that 
higher turbidity results in increased mortality. 

ENVIRONMENTAL STUDIES 

Recent Federal legislation has directed the 
U.S. Coast Guard to conduct increasing researcl 
in the field of coastal oceanography. This has 
resulted in the development of plans by the 
Coast Guard in cooperation with the Bureau of 
Sport Fisheries and Wildlife, to assume full 
responsibility for the temperature surveys in the 
near future. In late 1969, Coast Guard marine 
science technician personnel were trained in the 
techniques of operation of infrared equipment 
and in the conduct of airborne surveys, and by 
the year's end the Coast Guard assumed partial 
responsibility for this project. 

The change from the fixed -wing Grumman 
Albatross amphibian to twin turbine helicopters 
at the San Diego Air Station required changes in 
the survey flight track and modification of the 
methods of mounting the infrared instrument. 
The limited range of the new helicopters , when 
compared to the fixed -wing aircraft, caused 
substantial reduction in the length of the survey 
flight track off southern California . 

The development work on an automatic 
digitizer for the airborne radiation thermometer 
was completed by the U.S. Navy Fleet Numeri- 
cal Weather Central, Monterey, California. 
The prototype unit has been flight -tested and is 



now in regular service on the central area 
suirey. 

The digitizer unit records sea surface 
temperature on magnetic tape at one -second 
intervals . Upon return from the survey flight , 
the magnetic tape data are forwarded via direct 
line to the Fleet Weather Central in Monterey. 
The data are used in computation of Navy 
coastal sea surface temperature charts, and 
the computers at Fleet Weather Central can be 
programmed to draw isotherm charts for each 
of the three coastal survey areas . This 
method will provide a method of obtaining 
electronically -computed and drawn isotherm 
charts of the coastal area within a short period 
after landing. 

Sea surface temperature data obtained 
from August 1963 (5 years) have been analyzed 
and mean temperature charts drawn for each 
calendar month. From these charts the season- 
al change in temperature gradients and iso- 
therm patterns can be followed. A manuscript 
describing results of the cooperative airborne 
sea surface temperature program is in final 
draft . 

Sea Surface Current study 

Drift cards ballasted and sealed in plastic 
envelopes were dropped monthly from March 
1964 through February 1966 at predetermined 
stations in the three airborne sea surface 
temperature survey areas . The results of 
drift card recoveries in the northern survey 
area (Cape Flattery, Wash, to Cape Lookout, 
Ore.) have been analyzed and results have been 
submitted for publication. Progress is being 
made on the analysis of the results of drift card 
recoveries for the central area (Point Arena to 
Point Sur, Calif.) and the southern area (Point 
Conception, Calif, to Point Salsipuedes, 
Mexico). Meteorological data on winds at 
selected locations in the two areas have been 
plotted and illustrations have been completed. 

James L. Squire, Jr. 



Itelagic fish monitoring 

In 1969, six aerial fish spotters were under 
contract to furnish on charts a record of their 
flight track during fish -spotting operations with 
estimates of tonnage of the various species 
observed. These data are used in studies of the 
distribution and apparent abundance in near sur- 
face schooling species. This program was 
started in September 1962 and has provided data 
on the occurrences and estimates of tonnage 
observed for important sport and commercial 
species, such as yellowtail (Seriola dorsalis) . 
Pacific barracuda ( Sphyraena argentea), Pacific 
bonito ( Sarda chiliensis) . Pacific mackerel 
( Scomber japonicus ), jack mackerel ( Trachurus 
symmetricus) , northern anchovy (Engraulis 
mordax) , and Pacific sardine ( Sardinops sagax) . 
An index of relative apparent abundance for each 
species has been calculated from data collected 
from September 1962 through December 1966. 
The data have also been analyzed for diurnal 
variation in sightings, average size of school, 
and for statistics describing the magnitude of 
the fish spotting effort and amount of effort 
expended for both day and night survey flights . 

A manuscript on the results of the first 
three years of the survey is in final draft. 

Catch -temperatures of important marine game 
species 

Using the airborne infrared radiation thermo- 
meter, we have obtained sea surface tempera- 
tures for each 10 -minute longitude by latitude 
area having extensive sport fish catches off the 
southern California and central California coast. 
The California Department of Fish and Game 
records the monthly catch of each sport species 
caught for these same areas and these data have 
been furnished to us . Species under study 
include salmon in the central California area and 
Pacific bonito. Pacific barracuda, yellowtail, 
white seabass ( Cynoscion nobilis ), California 
halibut ( Paralichthys californicus) , kelp bass 
( Paralabrax clathratus) and sand bass (Parala- 
brax nebulifer), jack mackerel and Pacific 
mackerel in southern California . For each of 
these species we are determining the mean 
catch -temperatures and the seasonal range in 
catch -temperature, both for each large 



199 



geographical area (such as central California 
or southern California) and for the important 
local fishing areas along the southern California 
and central California coast. These data are 
now in the process of being analyzed by comput- 
er. 

James L. Squire, Jr. 

COOPERATIVE TAGGING PROGRAM 

The Tiburon Marine Laboratory coordinates 
this program as part of a cooperative effort 
with Woods Hole Oceanographic Institution, the 
International Game Fish Association, and the 
Mexican Department of Fisheries. Sport fisher- 
men who enjoy catching billfishes and other 
large game fishes initiated the tag -and -release 
concept as a conservation measure and to learn 
about their migratory habits (Figure 1). This 
program began in 1963 at about the time the 
Japanese longline fleet moved into the Mexican 
sport fishing area . Tremendous catches of 
billfish made by the Japanese longline fishery 
have resulted in a 50 percent decline in catch 
per boat -day by the Mexican sport fishery fleet 
during the past five years . The number of 



charter boats operating in this area has 
increased about 14 percent during this time, but 
total catch has declined about 40 percent. 
Interest in the billfish tagging program is at an 
all-time high, but the number of billfish tagged 
has decreased during the past two years simply 
because fewer fish are caught . 

During 1969, the following billfish were 
tagged: striped marlin ( Makaira audax ) 747; 
blue marlin (Makaira nigricans ) 31; black marlin 
( Makaira indica) 40; sailfish ( Istiophorus greyi) 
319. In addition, 82 roosterfish (Nematistius 
pectoralis) , 10 yellowfin tuna ( Thunnus albacares) 
16 yellowtail (Seriola dorsalis), 3 bonito (Sarda 
chiliensis) , 7 dolphin (fish) ( Coryphaena hippur - 
us), and 1 each of thresher shark (Alopias 
vulpinus ) and sheephead ( Pimelometopon pul- 
chrum) , and 14 unidentified species were tagged 
for a total of 1,271. The three species of 
marlin tagged totaled 818 as compared to 1,119 
in 1968 and 1,279 in 1967 . The number of sail- 
fish tagged (319) shows a decline from 432 in 
1968 and 491 in 1967. 

Nine tags were returned during the year. 
Five were from striped marlin, and one each 





Figure 1. — Sailfish t-.m^ t.i-,:'-' i" -^i K.xiu :i... I.Uk na Viola, Baja California Mjr , Mcxilo. 

Fish is played to side of boat, plastic tag is affixed using a tagging pole, and fish is 
released by removing hook or cutting leader. 



200 



from a black marlin, ycllowfin tuna, rooster- 
fish, and shark. The longest time between 
tagging and recapture was for a striped marlin 
tagged near Cabo San Lucas and recovered 157 
days later 72 nautical miles northeast in the 
Gulf of California . The longest migration was 
285 nautical miles from Cabo San Lucas to near 
the Rcvilla Gigedo Islands. 

Merest in the tagging program increased 
in scope during the year. In Cairns, 
Australia, 39 black marlin were tagged com- 
pared to 13 the previous year. A charter boat 
operator in Guayaquil, Ecuador, who operates 
a fleet of sportfishing boats out of the port of 
Salinas, has begun tagging in that area. 

Gerald B. Talbot 

LIFE HISTORY OF FISHES 

Life history of billfishes 

Field investigations were primarily aimed 
at determining spawning time (by collection of 
ovarian tissue samples and examination of ovum 
diameters); gathering dorsal and anal fin 
spines for aging; and obtaining morphometric 
and meristic data for racial studies. Samples 
and data were gathered from 750 striped marlin 
( Makaira audax ), 550 saiLfish (Istiophorus greyi), 
and 40 blue marlin ( Makaira nigricans ) landed 
by the sport fisheries at Mazatlan, Sinaloa, and 
Rancho Buena Vista in Baja California Sur, 
Mexico (Figure 2). The sampling was conducted 
from late February through July and for one 
week in November . 

The problem of aging oceanic species such 
as marlin is a complex one . Marlins tend to 
remain in waters of a relatively restricted 
temperature range and may grow at about the 
same rate the entire year; therefore, the 
resulting marks on the scales and the bony parts 
are most difficult to interpret for age. Initially, 
otoliths were considered as a possible method of 
obtaining age . However, otoliths in striped 
marlin are extremely small (1-2 mm) and are 
very difficult to locate within the bony skull . 
Scales are also very small and irregularly 
shaped. In search of better aging methods, 
anal and dorsal fin spines were obtained from 



an array of fish sizes . These fin sections 
show check marks, but as the fish grows, a 
cavity forms in the center of the spine that may 
erode away annular marks . The effect of this 
erosion or enlargement on the check marks is 
now being studied. Thin sections of the fin 
spines have been prepared in the laboratory for 
250 billfish and are being examined (Figure 3) 
for evidence that some of the rings on the 
sections are annual marks and to determine if 
a method of distinguishing these from false 
annual rings can be found so that the age of 
these fish can be determined. 

The location of striped marlin and Pacific 
sailfish spawning in the eastern Pacific has not 
been well documented although ripe marlin have 
been noted in Japanese catches of striped marlin 
near the Revilla Gigedo Islands . Our data from 
samples of striped marlin taken at the tip of 
Baja California indicate that as summer 
approaches, the gonad size increases markedly. 
However, no ripe females have been observed 
in the catches landed at either the tip of Baja 
California or at Mazatlan on the west coast of 
Mexico. Gonads from marlin landed at San 
Diego in late summer and early fall show that 
they are either post-spawners or in a resting 
stage . 

Food studies were conducted by sampling 
stomach contents over several fishing seasons 
off southern California, the tip of Baja California, 
and the west coast of Mexico . A paper is near 
completion which describes in detail the food 
habits of 924 striped marlin caught off San Diego, 
Mazatlan, and Buena Vista and 197 sailfish from 
off Mazatlan and Buena Vista . Qualitative food 
data obtained in 1969 added six new fish to the 
list of fish species eaten by billfish in the two 
Mexican study areas . 

While many species were consumed by 
billfishes, it appears from our data that they 
prefer certain species. In each locality one or 
two comprised the major pwrtion of their diet. 
Off southern California, anchovies (Eugraulis 
mordax) were the dominant species eaten by 
striped marlin, with jack mackerel ( Trachurus 
symmetric us) the second most abundant by 
volume. Off Mazatlan and Buena Vista, squid 
was the most important food item, with California 



201 




Figure 2. — Measuring the pelvic fin of a sailfish at a sport fishing dock in Mazatlan, 
Mexico. Morphometr ic data such as these are used in identifying racial stocks. 




Figure 3. — Thin cross sections of spines from the dorsal and anal fins of billfish show 
concentric rings v\Siich may provide a means of determining age. Here, a projection of 
an anal spine section of 72-pound striped marlin is being examined which shows two rings 
and a cavity in the center of the spine which may obscure other rings. 



round herring ( Etrumeus acuminatus) compris- 
ing 30 percent by volume from marlin caught at 
Buena Vista. Squid was also a dominant food 
item of sailfish caught in Mexican waters . 
Other important species were threadfin ( Poly- 
dactylus opercularis ), California round herring, 
and cornetfish ( Fistularia sp.). 

Arrangements were made with the Depart- 
ment of Tourism for the Territory of Baja 
California Sur, Mexico, to obtain annual data on 
sport fishing effort and catches of billfishes in 
Baja California. Supplementing this, we have 
developed estimates on the amount of striped 
marlin and Pacific sailfish landed about the tip 



of Baja California and along the west coastal 
mainland of Mexico. These data, combined, 
with the records of the Japanese longline fishery, 
give an estimate of the total catch of striped 
marlin and Pacific sailfish in the northeastern 
Pacific . 

Paul G. Wares 



203 



BEHAVIOR AND ECOLOGY 
OF INSHORE FISHES 

Ecological relations of Hawaiian 
shore fishes 

Our study of ecological relations of 
Hawaiian shore fishes began June 15 . We are 
located on the Kona Coast of the Island of Hawaii, 
which offers the most favorable conditions for 
this type of work to be found in the Islands . In 
this area the bottom slopes away gradually from 
shore for 50 to 600 yards to where the water is 
60 to 70 feet deep. Here the sea floor drops 
abruptly and precipitously to great depths. 
Thus the study area is actually a very narrow 
shelf on the side of a mountain, the top of which 
is the Island of Hawaii. 

In addition to expanding our knowledge of 
Hawaiian shore fishes, the data obtained fur- 
ther broadens and refines generalizations that 
developed from earlier work in the tropical and 
warm temperate eastern Pacific. As these 
generalizations become better defined, many 
factors that influence shore fishes in all seas 
appear in sharper focus . 

During the period June 16 to December 15 , 
165 separate underwater observation periods 
were logged--112 in daylight, 53 after dark-- 
involving a total of over 310 hours of diving. 
The study is based on direct observations of 
activity, supplemented by examination of 
stomach contents. To establish differential day- 
night feeding activity where it occurs, collec- 
tions, all by spear, have been concentrated 
during two periods of daylight and darkness: 
I) the three hours immediately preceding sun- 
set, and 2) the two hours immediately before 
first light in the morning. To further elucidate 
the habits of certain species, additional speci- 
mens have also been collected at other times of 
day and night. Thus, crepuscular fishes are 
also sampled immediately after morning and 
evening twilight, and species whose prey 
rapidly become unrecognizable because of 
digestion are also taken shortly after their 
feeding period begins. As of December 15, 475 
specimens of 76 species had been collected for 
analysis of stomach contents. 



Twilight activity 

The transition period between day and night 
--morning and evening twilight --is under 
special study. As of December 15, observations 
had been made through morning twilight on 18 
occasions and through evening twilight on 17 
occasions . In addition to noting changes in the 
activity of the various fishes relative to sunrise 
and sunset, we have simultaneously recorded 
the changing levels of incident light (in foot- 
candles). Our photometer is not sensitive to the 
lower light levels (below .05 ft-c) at which many 
of the significant events occur. Nevertheless, 
we have obtained measurements when many 
species, for example certain wrasses, parrot- 
f ishes , and damselfishes, emerge from cover 
in the morning and take shelter in the evening . 

Observations are still in progress, and at 
this time data are not ready for analysis. 

Plankton -feeding fishes 

The plankton -feeding fishes are a major 
component of the inshore fauna. None of diese 
fishes feed on plankton during both daylight and 
darkness --all are either diurnal or nocturnal. 
Diurnal species include Chromis ovalis , C. 
veratcr, C_. vanderbilti, C . Icucurus , Abudefduf 
abdominalis , and Dascyllus albisella , all 
members of the damselfish family Pomacentri- 
dae; Hcmitaurichthys zoster and H . thompsoni 
and Naso hexacanthus , both of the surgeonf ish 
family Acanthuridae. Nocturnal species include 
Myripristis bernti, M. argyromus , and M_. mul- 
tiradiatus, all of the squirrelfish family Holo- 
centridae; Apogon menesemus and A . snyderi 
both of the cardinalfish family Apogonidae; and 
Priacanthus cruentatus, of the bigeye family 
Priacanthidae. 

Casual observations have indicated that the 
composition of the plankton, hence prey avail- 
able to the plankton feeders , differs between day 
and night. We are investigating this possibility 
by taking samples of the plankton with a diver - 
towed net at different times of day and night at a 
constant depth over two particular reefs where 
both diurnal and nocturnal plankton feeders are 
active. Forty-four collections had been made 



204 



by December 15 . Cursory examination of the 
samples confirms that the composition of the 
plankton does indeed vary at different hours , 
but a complete analysis of the collections is yet 
to be made. 

Fishes that excavate their prey 

A contrast to the plankton feeders are those 
fishes that seek prey which are buried in the 
sand. In Hawaii, the most evident of these are 
species of the goatfish family Mullidae, which 
locate hidden prey with sensory barbels carried 
under their chin. Although one might not expect 
to find a day-night distinction in feeding behav- 
ior of such fishes, those studied so far have all 
been primarily either diurnal or nocturnal. 
Those feeding mostly by day include Parupencus 
bifasciatus , P. multifasciatus , P. chryscydros , 
and P. pleurostigma . Primarily nocturnal 
species include Mulloidichthys samoensis , M. 
auriflammu, and Parupeneus porphyreus . 
However, the distinction is not so clear-cut as 
in the plankton feeders, with the diurnal species 
feeding to a variable, though lesser extent at 
night, and the nocturnal feeding to a variable, 
though lesser extent in daylight. 

Nocturnal bottom -feeders 

Bottom -feeding fishes active on the reef at 
night prey mostly on the many small benthic 
crustaceans that are themselves active in 
exposed locations after dark. Fishes with these 
nocturnal habits include Flameo sammara , 
Adioryx lacteoguttatus , A . tiere , A . diadema , 
A . xantherythrus , and Holotrachys lima , all 
members of the squirrelfish family Holocentri- 
dae. These fishes are all similar in appear- 
ance, a fact probably reflecting their generally 
similar diets. Some of the nocturnal plankton- 
feeders, especially Apogon menesemus and A. 
snyderi also feed to a lesser extent on benthic 
prey at night . 

Diurnal bottom -feeders 



Small, active crustaceans, the principal 
prey of nocturnal bottom -feeders , are far less 
important as prey to diurnal species . Where 
they are taken, as by many species of the 
wrasse family Labridae, they generally occupy 
a secondary position in a far more heterogeneous 
diet than regularly occurs in nocturnal species. 

The many sessile organisms occurring on the 
reef, for example the corals, bryzoans, sponges, 
etc . , are not generally exploited by nocturnal 
fishes. However, many diurnal fishes, most of 
them highly specialized, prey heavily on these 
organisms. These fishes include members of 
the butterflyfish family Chactodontidae, the 
triggerfish family Balistidae, the pufferfish fam- 
ily Tetraodontidae, the filefish family Monacan- 
thidae, and the trunkfish family Ostraciontidae. 

Also included among the diurnal bottom - 
feeders are all of the herbivorous fishes (with 
the exception of a few diurnally active species 
that habitually take fragments of drifting vegeta- 
tion from midwater). These include many 
species of the surgconfish family Acanthuridae, 
the parrotfish family Scaridae, the damselfish 
family Pomacentridae, the rudderfish family 
Kyphosidae, and the blenny family Blenniidae. 
The damselfishes and the blcnnies, especially, 
show a gradation of species from carnivores to 
omnivores to herbivores. Consideration of the 
habits of these fishes provides insight into the 
evolution of the herbivorous diet, which is a 
highly evolved trait in marine fishes . 

Diurnal -nocturnal coloration 

Coloration of many fishes differs between 
day and night. We are compiling data on these 
color variations (Figure 4), hoping to recognize 
trends that suggest the significance of these 
variations in at least some cases . A difficulty 
often encountered lies in the color patterns that 
express stress in many species when they are 
held in the beam of a diving light (Figure 5). 
These are often difficult to distinguish from 
normal nocturnal patterns. 



In contrast to the morphological similarity 
among so many of the nocturnal bottom -feeders, 
those finding food in these same areas in day- 
light are extremely varied in morphology and 
diet. 



205 




Figure 4 . --Priacanthus cruentatus displaying; 
its solid red coloration. When active in 
midwater at night this fish usually fades 
to a pale silver hue. 




Figure 5. --This stress coloration of 
Priacanthus cruentatus usually appears 
when the fish is held under a diving 
light at night. This phenomenon, which 
occurs in many species and is usually 
expressed as some sort of a blotched 
pattern, complicates the task of recog- 
nizing true nocturnal coloration. 



Observations on the 
Crown-of -Thorns Sea Star, 
Acanthaster planci , in Hawaii 

During recent years the coral -eating crown- 
of -thorns sea star, Acanthaster planci, has 
become unusually numerous in certain regions 
of the western Pacific Ocean. Some of the 
ocean -oriented public, alerted by the news 
media to extensive damage by A. planci to the 
reefs of Guam and other areas , have begun 



looking for, and finding, concentrations of these 
predators on Hawaiian reefs. One major report, 
generating headlines in a Honolulu daily news- 
paper, described a vast concentration on the 
Kona Coast. A. planci was reported to occur 
"every ten feet" over the five miles between 
Kealakekua Bay and Homaunau. We know this 
report to be grossly exaggerated because the 
stretch of water in question is our Kona study 
area . If typical , it casts doubt on the many 
other similar reports that surged into popular 
print following press coverage of the Guam 
situation. I have not found A_. planci significant- 
ly more abundant on Hawaiian reefs today than 
10 years ago . Yet these reports have spawned 
widespread cries for control measures -- 
generally for plans to exterminate A. planci 
wherever it can be found . 

In the absence of good evidence that a 
threat to Hawaiian reefs actually exists, pre- 
mature action of this sort could have undesirable 
results . There is no reason to believe that A . 
planci , a natural component of Pacific coral 
reef communities , has not been preying on 
coral for millions of years. Quite likely this sea 
star has contributed to the situation existing on 
Hawaiian reefs as we know them. Indeed a 
healthy situation may well require a certain 
number of active individuals to be present. 
Consider, for example, that dead coral is 
quickly overgrown with algae, and at this time 
becomes a major source of food for many herbi- 
vorous fishes, prominent on coral reefs, includ- 
ing some of the acanthurids , scarids and others . 
Wherever dead coral occurs on the reef, tooth 
marks of these grazing fishes are usually clearly 
visible where the algal covering has been scraped 
away (Figure 6). Thus, in providing a feeding 
substrate, at least some coral mortality is 
probably necessary for the existence of certain 
coral reef fishes . Other similar examples 
could be offered to underscore the point that 
measures to eradicate the sea stars should be 
considered with great care. At the very least, 
an objective study should first determine whether 
or not A. planci has indeed become a threat to 
Hawaiian reefs. A long-term solution to the 
problem throughout the Pacific awaits a broad 
study of the biology of this animal . 



^^ 




R!'^ 


O 






^^ 


^ 






^^ 


1 






es 


|Bj^2 


^^^ .j|^^H 


itjijL ''i/'i'v^VyMI 


IRtl 


■ 



Figure o. — Tooth marks of feeding herbi- 
vorous fishes, probably parrotf ishes , 
which have scraped algaL" from tlie surface 
of dead coral. Note tliat the adjacent 
living coral is untouched. 



Acanthaster plane i in Kona 

Incidental to our work with the fishes of 
the Kona region , we have gathered data on the 
occurrence and habits of A . plane i . During 
surveys of fish populations we simultaneously 
recorded the incidence of this sea star, noting 
also the activity of each individual, as well as 
the species of coral that was being attacked by 
those that were feeding. All feeding sea stars 
were preying on madreporarian corals. 

The observations are grouped according to 
tlirec subjectively defined habitats: 1) Rocky - 
Reef Face, 2) Boulders , and 3) Coral - Rich 
Bottom . 



carry the same ct)rals as the rocky-reef face. 

Coral - Rich Bottom . - -Wlicre there is 
shelter from the waves of occasional storms at 
a water depths of 10 to 70 feet the bottom is 
heavily overgrown with corals that completely 
carpet the sea floor in many areas. Li water 
depths between 10 and 35 feet, most of this coral 
growth consists of massive tower -like forma- 
tions of Poritcs . In water depths between 35 and 
70 feet the coral is predominantly a form of 
Porites that grows as finger -like branches an 
inch or so in diameter. Scattered in these 
expanses of Porites are the corals listed for 
the other two habitats, but in lesser abundance 
here. 

Table 1 shows the number of surveys made 
during day and night in the different habitats, 
the average number of A . planci observed/hr . , 
and the percent that were feeding. Table 2 
shows the relative frequency with which the 
various forms of coral were observed among 
prey of A . planci . 

In the rocky - reef habitat, where sea stars 
occur in greatest numbers (Table 1), corals 
grow mostly as isolated encrustations and in 
small heads less than 12" in diameter. These 
are the corals most often preyed on by A. planci 
in Kona (Table 2), even in the coral - rich 
habitat, where other corals are far more abund- 
ant. These smaller sized coral-colonies can be 
completely engulfed by the everted stomach of 
the feeding sea star, and this fact may contri- 
bute to what seems their preferred status . 



Rocky - Reef Face . --The Kona shoreline 
is mostly rough lava -rock, and in many regions 
precipitous reefs of bare rock drop abruptly 
from the surface, or near surface, to water 
depths of 15 to 45 feet . Coral occurs on these 
reefs as small isolated heads of Pocillopora , or 
small isolated encrustations of Porites , Monti - 
pora, Pavona , Cyphastrea , or Leptastrea . 
This category includes the bottom at the base of 
these reefs, which usually are broken lava rock 
dotten by the same corals as the reef itself. 

Boulders . --In many regions that are 
^periodically exposed to strong surge, the sea 
floor is mostly bare lava boulders, which 



Massive growths of Porites , which were 
prey of only 3 percent of the feedmg sea stars 
(Table 2), and the branching finger -like colonies 
of Porites , which were never seen being 
attacked by A. planci, are by far the most abund- 
ant corals in the whole study area. 

A. planci has been reported as a nocturnal 
animal which emerges to feed at night after being 
inactive under cover during the day. This is not 
true in the Kona region (Table 1). Most of those 
observed by day were feeding, and there was no 
evidence of increased activity at night. We noted 
no significant day-night difference in this animal's 
behavior. The relatively fewer individuals seen 



Table 1. --Number of surveys made during day and night 

in different habitats, average number of A. planci 
observed per hour, and the percent that were ft-eding. 











Avg. no. 


% of total 










sea stars 


that were 


Habitat 


No. 


surveys 


Total time 


observed/hr 


feeding 



Rocky-Reef 














Face 














Uay 


21 


lb. 45 


hrs 




9.96/hr 


76% 


Night 


4 


3.75 


hrs 




4.27/hr 


50% 


Boulders 














Day 


15 


10.31 


hrs 




2.33/hr 


79% 


Night 


3 


1.63 


hrs 




1.23/hr 


100% (2 of 2) 


Coral-Rich 














Bot toni 














Day 


25 


20.03 


hrs 




1.04/hr 


76% 


Night 


17 


14.27 


hrs 




.07/hr 


100% (1 of 1) 


All Habitats 














Day 


61 


46.80 


hrs 




4.47/hr 


76% 


Night 


24 


19.65 


hrs 




.97/hr 


58% 




auencv of v£ 


ir ious 


San 


Pablo 


Bay study 





Table 

forms of coral observed among prey 
of A. planci . 



Coral 



% occurrence amon^ 
prey of A. planci 



Pocillopora 
Encrusting Porites 
Encrusting Leptastrea 
Encrusting Pavona 
Encrusting Montipora 
Encrusting Cyphastrea 
Massive Porites 



30% 
30% 
19% 
7% 
7% 
4% 
3% 



at night probably reflect the reduced visibility 
after dark, which is only partially offset by our 
diving lights . Despite reduced effectiveness of 
observations at night, we would have recognized 
any sharp increase in activity of A. planci if it 
occurred. Our observations on A. planci are 
continuing. 



Edmund S . Hobs on 



The U. S. Army Corps of Engineers' 
John F . Baldwin Navigation Project calls for the 
deepening of the ship channel from San Francisco 
Bay to Stockton from the present 35 -foot depth to 
a 45 -foot depth. This would entail dredging 
seven channel segments totaling 68 .8 miles . 
The initial bottom spoil material would total 84 .5 
million cubic yards . Approximately 8 .7 million 
cubic yards would be disposed at sea and 20.9 
million cubic yards in San Francisco and San 
PablQ Bays . Between Martinez and Stockton, 
about 54 .9 million cubic yards would be disposed 
on 26 land and shallow water sites varying from 
15 to 1,150 acres. 

The Bureau of Sport Fisheries and Wildlife's 
report on the project, dated November 1963, 
recommended that a study be accomplished prior 
to project construction to determine the impact 
this project might have on fish and wildlife. Part 
of this study has been completed by this labora- 
tory in cooperation with the Division of River 
Basin Studies for the U.S. Army Corps of 
Engineers . 



The purpose of the study is to determine 
the relative abundance of marine organisms 
at selected sites within San Pablo Bay, the rate 
of natural rehabilitation of bottom fauna in areas 
recently disturbed by dredging and spoiling 
operations, and the gross effects of turbidity on 
fish life. 

Sampling began in September 1967 at 12 
stations in San Pablo Bay from the Richmond- 
San Rafael Bridge to Mare Island (Figure 7) . 
These sites were selected so that dredged chan- 
nel areas, spoil areas, and unspoiled areas 
would be sampled. In May and July 1968, three 
additional sampling sites were established to 
monitor dredging in Point San Pablo harbor and 
associated spoiling operations near Marin 
Island. Sampling methods included trawling for 
demersal fish, dredging for benthic organisms, 
and collecting water samples for oxygen, salin- 
ity, temperature, pH, and turbidity determina- 
tions (Figures 8 and 9). Field sampling was 
terminated August 1969 . Normal seasonal 
fluctuations were evident in all physical para- 
meters of Bay water measured. The highest 
levels of dissolved oxygen, pH, and turbidity 
occurred during winter and spring. Chlorosity 
and temperature levels were highest during 
summer and fall . Water samples taken after 
the spoil material had been dumped from a 
barge at the Marin Island spoil sites (stations 
6A, 6B) during July 1968 were analyzed for 
hydrogen sulfide, dissolved oxygen, and turbid- 
ity. Hydrogen sulfide was not detected in any 
of the water samples and dissolved oxygen 
levels remained stable during the spoiling opera- 
tion. The highest turbidity level measured 
immediately after the spoil material was 
released was 375 Jackson Turbidity Units (JTU). 

The same procedure was again followed in 
December 1968 when a corps of Engineers' 
hopper dredge was maintenance dredging in the 
Pinole Shoal Channel. This time, the water 
samples were taken during the release of the 
spoil material. The highest turbidity level 
recorded at the associated spoil site (station 
3A) was 2,000 JTU, taken from a bottom water 
sample, which also had a dissolved oxygen 
content of O.I ppm. Additional samples taken 
a few moments later Indicated that the oxygen 
level was quickly restored. This same 



phenomenon has been demonstrated in the 
laboratory. The highest surface turbidity 
measured at the spoil site was 875 JTU which 
was collected at the same time as the 2,000 JTU 
bottom sample. No hydrogen sulfide was 
detected from any of these water samples . 

The collection of Bay organisms with an 
otter trawl and anchor dredge in San Pablo Bay 
over the two-year sampling period has shown 
seasonal fluctuations for fish and shrimp, with 
the highest abundance occurring during the 
summer and the lowest during the winter. No 
seasonal fluctuations were apparent for benthic 
organisms although a reduction in numbers was 
observed in 1969 which lasted until the end of 
field sampling in August 1969 . This reduction 
may have been caused by the prolonged winter 
and heavy spring run -off of 1968-69, although 
the numbers of fish and shrimp were not affected. 
The central and south end of San Pablo Bay had a 
higher abundance of benthic organisms and fish 
which decreased in numbers towards the north- 
east end of the Bay. Shallow water areas had 
higher numbers of fish and shrimp than deep 
water areas , and except for dredged channel 
areas , the deeper water areas were higher in 
numbers of benthic organisms than shallow 
water areas. The dredged channel had signifi- 
cantly lower numbers of benthic organisms , 
demersal fish, and shrimp. 

The collection of biological data before and 
after spoiling operations near Marin Island in 
July 1968 indicated that the abundance of fish and 
shrimp were significantly reduced, with evidence 
of increasing abundance after four months. 
However, the benthic organisms (numerical 
abundance, numbers of species, and species 
diversity index indicative of the wealth or com- 
plexity of the community) were not significantly 
reduced by this same spoiling operation. One 
reason for this could be that spoil areas are 
being replenished with the benthic organisms 
found in the spoil material . 

The spoil site located near Mare Island 
(station 5C), which is spoiled biannually with 
1,250,000 cubic yards of spoil material from the 
Mare Island Strait and the Pinole Shoal Channel, 
had, on the average, higher numbers of benthic 
organisms and demersal fish than at the 




Figure 7. — Map of San Pablo Bay showing West Richmond and San Pablo Channels which the 
Corps of Engineers propose to dredge to a mean depth of 45 feet, and sampling stations 
used during the study. 



210 




.V. 




vmi 



1 



Figure 8. — Biologist removing thermograph trace from continuously recording thermograph 
which makes week-long records of San Francisco Bay temperature at the Tiburon Marine 
Laboratory dock. 



unspoiled area (station 5B) which was of 
comparable depth and chlorosity. Shrimp 
numbers were, however, slightly less than at 
the unspoiled area. 

Low numbers of benthic organisms, shrimp, 
and demersal fish within the dredged channel 
areas of the Pinole Shoal Channel after dredging 
operations in November and December 1968 were 
not attributed to the dredging activities because 
this same occurrence was typical for the entire 
San Pablo Bay during this time of year. 

Laboratory experiments were begun in 
February 1968 to test the gross effect of various 
turbidity levels on shiner perch (Cymatogaster 



aggregata) , rubberlip seaperch (Rhacochilus 
toxotes ), white seaperch ( Phanerodon furcatus ) 
striped bass ( Morone saxatilus) , brown rockfish 
(Sebastodes auriculatus) , and Pacific tomcod 
( Microgadus proximus) . 

The effects of turbidity on fishes in 
general (measured in terms of fish-days-- 
defined as one fish living in the test aquarium for 
one day, thus, ten fish living in an aquarium for 
one day would be equal to ten fish -days) was found 
to be nonsignificant between the control and 500 
JTU, but to be significantly different between 
control, 1,500, and 2,500 JTU levels. There 
was a trend toward a gradual reduction in the 
number of fish -days and an increase in body 



211 




Figure 9 . --Technician using a hydrometer to measure salinity of a sample of San Francisco 
Bay water. 



weight loss from the control to the 2,500 JTU 
level. On the average, the fish in the control 
tank incurred the lowest percent body weight 
loss. All other test fish lost considerably more 
body weight, with the highest percent loss 
occurring in the highest turbidity levels . This 
indicates that the increased turbidity levels were 
either preventing the test fish from visually 
finding their food; caused the fish to burn more 
body energy from stress; or affected the fishes' 
well-being so that they preferred not to eat. In 
either case, the effect would be eventual starva- 
tion or a lowering of the fishes' body resistance 
to other factors which might cause death. 

Brown rockfish and striped bass had a 
higher tolerance to high turbidity levels than 



shiner perch, white seaperch, and tomcod. 
Rubberlip seaperch, shiner perch, and tomcod 
were considered to have an intermediate toler- 
ance to high turbidity levels , while the white 
seaperch were the most sensitive to turbidity of 
all the species tested. 



Floyd A . Nudi 



Biology of the white seaperch 



There is considerable interest in such bay 
fishes as the surfperches for sport and commer- 
cial catch. This interest is increasing at a time 
when industrial demands are being made on our 
estuaries which might be detrimental to these 
fish. The white seaperch (Phanerodon furcatus) 



is a principal component of the sport and 
commercial catch of bay fishes in Oregon and 
California. There is a paucity of information 
about factors regulating its distribution and 
abundance . 

A study of the relation of first year growth 
rates and abundance of white perch to abundance 
of principal food items is being emphasized in 
this investigation. The influence of first year 
growth rates to subsequent reproduction is also 
being considered. Work in the current year has 
consisted chiefly of sampling young perch and 
benthos. Four stations have been designated 
in Yaquina Bay, Oregon, which should represent 
the diversity of the Bay as an environment. 

Sampling at two -week intervals commenced 
in late June this year . Those samples have 
consisted of trawling with a shrimp try-net at 
each station for a minimum of 100 fish per sta- 
tion when possible. Also included in biweekly 
samples are triplicate bottom dredges from 
each station. Samples of older perch have been 
taken monthly since September by using experi- 
mental gill nets . 

The data on catch per unit effort for 
October and November of this year (Table 3) 
indicate that as young -of -the -year fish the white 
seaperch were numerically second only to the 
shiner perch ( Cymatogaster aggregata) . Com - 
parisons of catch -per -unit effort data among 
stations is less reliable than comparisons of 
relative seasonal abundance within a station 
because of the physical properties of the 
stations. 

A decline in catch per unit effort was 
observed between October 8 and December 3 at 
station 2 , where all samples were taken at low 
tide. The number of fish caught per hour on 
October 8, October 20, November 17, and 
December 3 was 31.0, 20.6, and 0, respectively. 
This decline may reflect a real seasonal change 
in numerical strength of white seaperch during 
this time . Catches of other perch species 
decreased somewhat earlier in the season. 

Growth rates of young -of -the -year perch 
have been calculated from changes in mean 
weight and from changes in weight frequency 



modes. Changes in weight frequency modes 
appear to give more reliable estimates of 
growth. 

Monthly percentage growth rates (Table 4) 
were calculated by the formula; 



R = 



W2 - Wl 
^( W2 - Wl ) 



X 100 



in which 

R = percentage monthly growth rate 

Wl = weight -frequency mode at beginning 
of period 

W2 = weight -frequency mode at end of 
period 

T = time expressed as (££11) 
30 

After an initial lag in growth rate in July, there 
were highs in August through September followed 
by decreasing rates in later months. If the 
reduction in catch per unit effort is a reflection 
of movement of young perch from the Bay, then 
the decreased potential for growth by young perch 
may provide an explanation for such movement 
to other areas where the available food supply 
might sustain a higher growth rate. This inter- 
pretation is speculative at present and must 
await further analyses of food relations for 
verification. 

To date, the food from 46 of the 225 stomachs 
of young perch has been examined. Five species 
predominated in the stomachs of fish from 
station 1. Three of these species are amphipods; 
two from the genus Corophium and one gammarid . 
The other two principal species are small bivalve 
moUusks . Although it is not yet possible to make 
an interpretation of the influence of food abundance 
on stomach contents of fish, principal stomach 
components appear to be benthic components . 
Benthos estimatics at station 1 are 1,330 per 
square meter for amphipods, and 450 and 145 per 
square meter for the two species of mollusks. 
Oligochaete worms were more abundant in the 
benthos than one of the species of mollusks but 
the worms were not found in stomachs . Fish 



213 



Table 3. — Catch per unit of effort by shrimp try net for all 
stations in Yaquina Bay, October 7 to November 19, 1969. 





Number 


Number 


Percent 


Pe 


rch only 


Species 


of fish 


per hour 


total 


Percent perch 


Starry flounder 


390 


37.7 


35.4 






White seaperch 


68 


0.6 


6.2 




2S.6 


Pile perch 


10 


1.0 


0.90 




4.2 


Striped seaperch 


14 


1.4 


1.3 




5.9 


Shiner perch 


146 


14.1 


13.2 




61.3 


Sand sole 


217 


21.0 


19.7 






Staghorn sculpin 


170 


16.4 


15.4 






Buffalo sculpin 


2 


0.2 


0.2 






Kelp greenling 


4 


0.4 


0.4 






Anchovy 


2 


0.2 


0.2 






Pipef isn 


10 


1.0 


0.9 






Dungeness crab 


53 


5.1 


4.S 






Bay shrimp 


17 


1.6 


1.5 







Table 4. — Percentage monthly growth rates 

for young-of-the-year white seaperch 

in Yaquina Bay for July through 

November, 1969 





Mean 


Percentage 


Inclusive 


weighti' 


monthly 


dates 


(g) 


growth rate 


7/1 - 8/8 


4.3 


25.6 


8/8 - 8/25 


5.7 


43.3 


8/25 - 9/8 


7.0 


39.6 


9/8 - 9/22 


8.5 


43.1 


9/22 -10/7 


10.2 


37.1 


10/7 -10/21 


11.8 


23.6 


10/21-11/19 


12.8 


5.9 



1/ 



Mean of modal weights at beginning and 
ending of period. 



examined from station 2 contained principally 
a single species of the amphipod genus Coro- 
phium . The estimate of benthos from station 2 
indicates levels of amphipods at 2100 per 
square meter and levels of bivalves at 30 and 
90 per square meter. 

Condition coefficients were calculated for 
the young-of-the-year perch in hope that they 
might corroborate observed growth rates . 
That was not the case; rather the data weakly 
support a generalization that condition factor 
increases with size. The condition factors 



observed were comparable with those reported 
for young white perch from Humboldt Bay, 
California , 

Since the only pregnant female perch was 
captured in late June, I believe the spawning 
season ended in June. This female contained 
35 near-term embryos enclosed within individ- 
ual membranes within the ovisac, a condition 
reported for other members of the family 
Embiotocidae. The embryos had a mean 
standard length, mean total length and mean 
weight of 53.8, 66.9 (mm), and 3.2(g), respect- 
ively. The scales were fully developed and the 
hypural plate and lateral line were evident. 

A second year of the study will include 
samples of food and young perch from Waldport 
Bay, Oregon, for comparative purposes. 

James R. Vanderhorst 

Biology of the redtail surfperch 

The redtail surfperch, Amphistichus rhodo- 
terus (Agassiz), is perhaps the species offering 
the greatest recreational potential along the 
extensive sandy beaches of tlie Oregon coast. 
This species is also found in northern California 
and Washington. Published literature on the 
biology of this species is limited. 



My major objectives were to investigate age 
and growth by sex, length-weight relations, 
relation between age and size to sexual maturity, 
reproductive biology, food habits, and parasites. 
This biological information will be useful in 
assessing the sport potential of this species and 
management needs of the species. 

Gillnets, an otter trawl, and hook and line 
sampling between June 1967 and January 1969 
indicated the redtail is available to the angler 
throughout the entire year in the surf and during 
the months of May through September in some 
estuaries . Rough surf conditions in winter 
limit angling to the most ardent of fishermen. 

The catch per unit of effort in the surf 
fishery varied from 0.0 to 10.8 fish per angler 
hour with an average of 2.5 fish per angler 
hour. The best catch per unit of effort occurred 
during an incoming tide and when the surf was 
moderately calm. Success in an estuary 
(Alsea Bay) varied from. 0.0 to 8 .3 fish per 
angler hour with an average of 1.0 per angler 
hour. General observations of the sport fishery 
and gill -netting indicate redtails enter the 
estuary with an incoming tide. The majority of 
the fish leave the estuary just after the tide 
changes from high slack to outgoing. The fish 
move through the estuary in tight schools as 
indicated by the flurries of activity in the sport 
fishery, and by gill -net sets made at 15 -minute 
intervals . The best fishing success in the 
estuary was found to be within an hour before 
and an hour after high slack tide. 

The percentage of regenerated scales from 
a sample of 17 fish varied between 26.6 and 85 .0 
with a mean of 57.7. Twelve scale samples 
from 785 fish contained regenerated scales only 
and could not be aged. The age composition 
determined from the first scale reading of 773 
surf perch is shown in Table 5 . Age determina- 
tions from 108 otolith samples agreed 97 per- 
cent with readings from scales . 

The body-scale relation for 773 fish was 
S = 0.44 L - 12.42 where S = antero -lateral 
scale radius magnified 27 times and L equals 
total length. The correlation coefficient (r) for 
this regression was 0,95. Females grow faster 
than males . The longest fish was a female with 



Table 5. --Age composition of 773 redtail 

surfperch as revealed by examination 

of scales. 



A 


»e 


Number 


ess than 1 yr 


3 


1 


yr 


96 


2 


yr 


130 


3 


yr 


197 


4 


yr 


157 


5 


yr 


101 


6 


yr 


57 


7 


yr 


26 


8 


yr 


6 


9 


yr 


5 



a total length of 375 mm (14 .8 inches) and the 
heaviest fish was also a female with a weight of 
1,125 grams (2.47 lbs.); whereas the heaviest 
male weighed 695 grams (1.53 lbs.). All three 
fish were 9 years old. Equations for conversion 
of total lengths (TL) to standard length (SL) and 
fork length (FL) calculated from means of one- 
centimeter groupings of total length are SL = 
0.81 TL - 5.29; and FL = 0.95 TL-5.09, 
respectively. 

A maturity index for males based on rela- 
tive size of gonads reached a peak in September; 
however, sperm was readily emitted during late 
November and early December. Based on this 
index all males three years of age or older and 
20 percent of the two -year -old males were 
sexually mature while all younger males were 
immature. Females matured later than males 
with none mature under three years of age. 
Eight percent three years old, 56 percent four 
years old, and all five years old or older were 
found to be mature , The numbers of embryos 
increased with the size of the parent female and 
varied from 1 to 39 with an average of 13 per 
female. The young redtails are born between 
August and October, Newly born redtail surf- 
perch from four females held in the laboratory 
had a mean standard length (SL) of 75 ,78 mm 
and a mean weight of 5 ,57 grams , Because the 
embryos were preserved in 10 percent formalin, 
a shrinkage correction factor (SL fresh = SL 
preserved x 1.08) was calculated to eliminate 
shrinkage of specimens as a source of error in 
the study of embryonic development . This factor 
was determined from 12 lots of fresh embryos 



215 



with mean standard lengths between 13 and 35 
mm . 

Food habits will be determined by frequency 
of occurrence and percent of total volume from 
preserved stomachs . These data will be further 
analyzed to learn differences by size of fish and 
differences in food habits in the surf and an 
estuary. Two hundred -twenty -two of 285 
stomachs that have been examined to date 
contained a variety of food items that are being 
identified and categorized, while 63 stomachs 
were empty or contained only bait. 

A sample of 357 redtail surfperch of both 
sexes and all ages were examined for parasites 
shortly after they were killed. External body 
parasites included the copepods Clavella sp., 



from fins and gills and Caligus sp . , Argulus 
catostomi, and an unidentified species from the 
skin. Of particular interest was a large unde- 
scribed monogenetic trematode found on the 
gills . Dr . Ivan Pratt of the Zoology Department 
of Oregon State University is currently writing 
a description of this new species. This mono- 
genetic trematode has also been found in silver 
and walleye surfperches. The digenetic trema- 
tode Genitocotyle acirrus was found in the 
intestine of every redtail examined. Nine 
unidentified nematodes were found in the intes - 
tine or body cavity. There was no indication 
that the health of the fish was affected by the 
parasites, but damage did occur to gill filaments 
and fins from the copepod infestations . 

Donald E . Bennett 



NATIONAL RESERVOIR RESEARCH PROGRAM 

Fayetteville, Arkansas 
Robert M. Jenkins, Director 



HIGHLIGHTS 

A nationwide compilation of reservoirs 
( > 500 acres) showed there were 1,320 as of 
December 31, 1969, totaling 8,844,000 acres at 
mean annual pool. During the past decade, 
about 314 were added, totaling 2,394,000 acres 
(3-1/2 percent increase in area per annum). 

Partial correlation analyses involving 
standing crops of 32 species and species groups 
and 9 environmental factors provided clues of 
value to sport fishery management . For 
example: with increase in reservoir mean 
depth, an increase occurs in sunfish and a 
decrease in channel catfish, largemouth bass 
and white crappie crops; with increase in outlet 
depth, an increase in total sport fish crop; with 
increase in water level fluctuation, an increase 
in flathead catfish, black bass and white crappie 
and a decrease in pike and sunfish crops; with 
increase in storage ratio, increases in bullhead, 
channel catfish, largemouth bass , smallmouth 
bass and white crappie and decreases in flat- 
head catfish, bluegill and longear sunfish crops. 

The first segment of sport fish harvest 
analysis, involving sample characteristics, 
partial correlation and multivariable regression, 
was completed. Mean values of annual angler 
effort, success rate and harvest in 107 reser- 
voirs were: angler -hours /acre = 71.8; angler- 
days/acre = 16.5; fish/hour = 0.9; pounds /hour 
= 0.5; pounds /acre = 24 .4 . The estimated mean 
annual harvest in all U. S. reservoirs in 1960 
was 19.2 pounds per acre. 



Partial correlation indicated that reservoir 
area , growing season and age have the most 
significant influence on angling. Area is nega- 
tively related to angler -hours/acre and fish 
caught/acre, but positively related to number of 
fish and pounds caught per hour. Growing sea- 
son is positively related, and age of reservoir 
negatively related, to all angler effort and 
success rate parameters . 

Effects of different environmental variables 
on both standing crop and harvest of black basses, 
sunfishes and catfishes were similar, but there 
was little agreement between total sport fish 
crop and total harvest. 

Application of calculated curvilinear harvest 
regressions to the 1,320 U. S. reservoirs indi- 
cated: 1) 50 percent of the estimated total 
sport fish harvest (weight) occurred in 160 reser- 
voirs over 12,000 acres in size; 2) although one- 
half of the total U.S. reservoir area is contained 
in 75 reservoirs over 24,710 acres (10,000 
hectares), only 30 percent of the sport fish were 
harvested from them; 3) one -half of the U.S. 
reservoirs are from 500 to 2,000 acres in area, 
but accounted for only 15 percent of the total 
harvest; 4) 35 percent of the harvest came from 
462 reservoirs 2,000 to 12,000 acres in size. 

NATIONAL RESERVOIR 
DATA COLLECTION 

A nationwide compilation of reservoirs was 
completed with the aid of State fishery chiefs 
and River Basins Studies supervisors. For our 
purposes, a "reservoir" is defined as an 
impoundment with a mean annual minimum pool 
of 500 acres wherein the environment is markedly 



217 



influenced by engineering design and operation. 
Where a dam is placed at a natural lake outlet , 
the resulting impoundnnent is not considered a 
"reservoir" unless the area or volume is 
doubled. Most run-of-the-river (storage ratio 
< 0.01) lock and dam impoundments are 
excluded. Surface area is listed at mean annual 
pool where data are available; otherwise conser- 
vation, summer, operating or power pool area 
is listed. 

There were about 1,320 reservoirs, totaling 
8 , 844 , 000 acres , in the U . S . on December 31 , 
1969. Revision of the inventory data presented 
in ORRRC Study Report 7 ("Sport Fishmg Today 
and Tomorrow") to provide reclassification of 
reservoirs to natural lakes in conformity with 
our definition yielded a 1960 estimate of 1,006 
reservoirs, totaling 6,450,000 acres. 

During the decade, about 314 new reservoirs 
encompassing 2,394,000 acres have been added 
--an annual rate of area increase of 3-1/2 per- 
cent. Major additions in area during the 1960s 
occurred in Texas, South Dakota, Utah, Arkan- 
sas, Oklahoma, Louisiana, Kansas, North 
Dakota, California and Oregon --accounting for 
80 percent of the total increase. 

At a continued annual increase in area of 
3-1/2 percent, there will be almost 11.5 
million acres at the end of 1976. This would 
represent an increase of 5 million acres over 
1960, as predicted in ORRRC Study Report 7. 
However, there is some evidence that the cur- 
rent rate of increase will not be sustained in 
the 1970s . Numbers of new reservoirs will 
probably be added at the current rate (3 percent/ 
year), but average area per new reservoir will 
decrease. 

Some characteristics of U. S. reservoirs: 

1) 52 percent are 500 to 2,000 acres in size, 
but make up only 15 percent of the total area; 

2) 75 reservoirs over 24,710 acres (10,000 
hectares) comprise 50 percent of the total area; 

3) one -fourth of the total area is accounted for 
in 16 reservoirs; 4) there are 304 reservoirs 
2,000 to 5,000 acres in size, 130 between 
5,000 and 10,000 acres, and 115 between 10,000 
and 24,710 acres; 5) mean area equals 6,730 
acres . 



ENVIRONMENTAL EFFECTS 
ON FISH STANDING CROP 

Partial correlation analyses involving 
standing crop of 32 species or species groups 
and 9 environmental variables in 7 subsamples 
of the 140 reservoir total sample were completed. 
Partial correlation eliminates the effect of those 
environmental variables which bias the true 
correlation due to their common relation with 
the other variables . As many of the variables 
used are highly correlated, partial correlation 
is essential to proper interpretation of the data. 

Total standing crop in hydropower main- 
stream (storage ratio < 0.165) reservoirs is 
positively influenced by shore development, total 
dissolved solids (TDS) and growing season, and 
negatively by mean depth (0.05 confidence inter- 
val). These more river -like waters have rela- 
tively small differences in water level fluctua- 
tion and storage ratio, and standing crop is 
apparently little influenced by outlet depth and 
age due to high water exchange rate . 

The most significant positive factor in 
hydropower storage reservoirs is TDS. In these 
more lake-like waters, storage ratio has a posi- 
tive and outlet depth a negative influence (0.20 
confidence interval) on standing crop . Only one 
of the storage reservoirs in the sample had an 
outlet above the top of the thermocline, preclud- 
ing more definitive statements on high level 
vs . low level outlet effects . 

The positive effect of outlet depth on crop 
appeared in the nonhydropower subsample . Age 
of reservoir also appeared as a positive influ- 
ence, suggesting that flood control reservoirs are 
subject to more rapid eutrophication than hydro - 
power reservoirs . 

Correlation of environmental variables with » 
the sport fish portion of the standing crop in the 
total sample indicated that outlet depth was the 
most significant influence (Table 1) . Dissolved 
solids did not appear as a factor at the 0.20 
confidence level. Surface area, fluctuation, and 
age of reservoir were not significant in any of 
the subsamples. However, some sharp differ- 
ences between reservoir types are apparent. 
Mean depth appeared as a negative influence and 



Table 1. — Logarithmic partial correlation of nine environmental variables with 
standing crop of sport fishes (trout, mooneyes, pike, pickerel, catfishes, 
bullheads, white and yellow bass, sunfishes, black basses, crappies and 
percids) in 140 reservoirs, and in 44 hydropower mainstream, 37 hydropower 
storage and 59 nonhydropower reservoirs. One symbol denotes positive or 
negative correlation at the 0.20 confidence level; two symbols indicate 
correlation at the 0.05 level; three symbols at 0.01 level. 





Sport fish standing crop 




Total 
sample 


Hydropower 




Environmental 
variables 


Main- 
stream 


Storage 


Non- 
hydropower 



Surface area 

Mean depth 

Outlet depth 

Water level fluctuation 

Storage ratio 

Shore development 

Dissolved solids 

Growing season 

Age of reservoir 



Storage ratio as a positive influence on sport 
fish crops only in the storage reservoirs, and 
outlet depth as a positive factor only in the non- 
hydropower reservoirs. Dissolved solids was 
a positive factor in hydropower storage and a 
negative factor in the nonhydropower reservoir 
subsample. Most of the storage reservoirs had 
low TDS content , whereas many of flood control 
reservoirs had mean TDS values exceeding 350 
ppm, with sulfate -chloride predominating over 
carbonate -bicarbonate chemical types. 

The hydropower subsample was redivided 
on the basis of presence or absence of a stable 
thermocline. In 55 reservoirs with a stable 
thermocline, partial correlation revealed signi- 
ficant (0.05 level) positive effects of storage 
ratio and TDS on total standing crop. Increase 
in thermocline depth has a negative effect on 
total crop. However, reservoirs with a thermo- 
cline typically have higher total standing crops 
that those without . 



The analysis was expanded through partial 
correlation of the 9 environmental variables 
with 32 important species or species groups of 
fishes in the total sample. As all of the species 
did not appear in each reservoir, sample size 
varied from 23 to 139 . Some generalizations on 
sport fish production influence (0.20 confidence 
interval) include: with increase in reservoir 
area , an increase in pike crop and decrease in 
bullheads, sunfishes and black basses; with 
increase in mean depth, an increase in sunfishes 
and decrease in channel catfish, largemouth bass 
and white crappie; with Increase in outlet depth, 
an increase in combined sport fish crop; with 
increased water level fluctuation, an increase in 
flathead catfish, black bass and white crappie 
and a decrease in pike and sunfish crops; with 
increase in storage ratio (i.e. , lower water 
exchange rate), increase in bullhead, channel 
catfish, largemouth and smallmouth bass and 
white crappie crops and decreases in flathead 
catfish, bluegill and longear sunfish; with 



21 c 



mcreased shore development, increase in 
channel catfish, white bass and bluegill and 
decrease in redear sunfish and black crappie; 
with increase in TDS, increase in catfishes, 
white bass, green sunfish, largemouth bass and 
white crappie and a decrease in pike, bluegill, 
warmouth, and black crappie crops. 

Forage fish (gizzard and threadfin shad) 
crops are positively influenced by increase in 
TDS . Gizzard shad production also responds 
positively to increased outlet depth, but nega- 
tively to water level fluctuation. Threadfin shad 
are positively influenced by growing season 
length, and negatively by storage ratio. 

Clues to rough fish control through environ- 
mental manipulation include: mean depth is 
negatively related to longnose gar, carp, 
buffalofishes and drum crops; outlet depth is 
positively related to carp, carpsuckers and 
buffalofishes; water level fluctuation is nega- 
tively related to carpsuckers; storage ratio is 
negatively related to spotted sucker and red- 
horses; shore development is positively related 
to buffalofishes and carp; TDS is positively 
related to longnose gar, carp and carpsuckers; 
and age of reservoir is positively related to 
buffalofishes and drum and negatively to carp. 

Hypothetically, largemouth bass production 
would be greatest in smaller, shallower 
reservoirs with a deep outlet, considerable 
annual water level fluctuation, low water 
exchange rate, high TDS and a long growing 
season. Northern pike production, in contrast, 
would be greatest in large reservoirs with 
minimum water level fluctuation, low TDS and 
a shorter growing season. The responses of 
these two species to the variables considered 
indicate that large crops of both could not be 
produced in one reservoir. 

White crappie production response parallels 
that of the largemouth bass . White crappie 
crops are positively linked with outlet depth, 
fluctuation, storage ratio and TDS and negative- 
ly with mean depth. In contrast, the closely 
related black crappie responds positively to 
growing season and negatively to increased 
shore development and TDS . A decision on 
which of the two crappies to introduce in a new 



reservoir could be guided by these differences. 

Correlations involving various species in 
all reservoirs with a stable thermocline were 
also computed. Some examples of apparent 
changes due to thermocline presence follow; 
largemouth bass --the negative effect of mean 
depth increased in significance, fluctuation 
appeared as a positive (0.05 level) influence, 
storage ratio increased and TDS decreased in 
positive significance. White crappie - -only 
dissolved solids and fluctuation remained as 
significant positive variables; catfishes and 
buffalofishes --outlet depth did not appear as a 
positive influence; sunfishes- -only growing sea- 
son remained as a significant factor. Depth of 
thermocline had a negative effect on largemouth 
bass and catfish crops , and no significant effect 
on the other species cited. 

Largemouth bass crop in reservoirs with a 
thermocline is positively (0.05 level) correlated 
with water level fluctuation, storage ratio, TDS 
and growing season, and negatively with both 
mean and thermocline depths . Knowledge of 
these relationships is of value in the design, 
operation and fishery management of impound- 
ments , large or small . 

SPORT FISH HARVEST 

Harvest data were accumulated from 183 
reservoirs , collated and prepared for computer 
analysis by staff biologist David Morais. Par- 
tial correlation and multiple regression programs 
were developed by Dr. James Dunn, University 
of Arkansas. Estimated sport harvest, by 
species, was available from 119 reservoirs, 
including 286 annual summaries. Where esti- 
mates for two or more years were available 
from one reservoir, a mean value was used in 
this analysis. Of the 119 reservoirs, 107 had 
data on angler effort in hours per acre and 103 
in days per acre. 

Mean age of the 119 reservoirs in the sample 
at the time of estimate was 17 .4 years . Mean 
year when the estimates were made was 1960; 
ranging from 1941 through 1968. Twenty-two 
estimates were made before 1950; 108 from 1950 
through 1959 , and 156 from I960 through 1968 . 
Mean surface area of the reservoirs in the 



Table 2. — Mean values of angler harvest, success rate and effort in 119 
reservoirs (286 annual estimates). Mean reservoir area in sample 

equals 13,830 acres. 



Pounds/acre 

Fish/acre 

Fish/hour 

Pounds/hour 

Pounds/day 

Pounds/fish 

Angler-hours/acre 

Angler-days/acre 

Angler -hours/day 



Number of 




Area-weighted 


reservoirs 


Mean 


mean 


119 


24.4 


14.7 


110 


53.7 


25.7 


107 


0.8 


0.85 


107 


0.4 


0.6 


103 


1.5 


2.5 


107 


0.5 


0.7 


107 


71.8 


29.4 


103 


16.5 


6.4 


98 


4.4 


4.6 



sample was 13,830 acres, compared to the 
U.S. mean of 6,730 acres , 

The mean spoit harvest of the sample was 
24 .4 pounds per acre; weighted by area it was 
14 .7 pounds per acre (Table 2). Using the 
regression equation derived from untransformed 
data (Figure 1) of pounds/acre/year on area, it 
is estimated that the mean harvest from all 
U.S. reservoirs in 1960 was 19.2 pounds/acre 
(17.1 kilograms/hectare). Estimated harvest 
from all reservoirs in 1969 totaled 170 million 
pounds . 

Other regressions yielded the following 
estimates of total National reservoir harvest 
and effort in 1969 (based on 1960 means): 
Anglers expended 460 million man-hours, or 
105 million man -days and caught fish at a rate 
of 0.37 pounds per hour, or 1.6 pounds per day. 
Average effort and catch rates per acre were: 
52 man-hours, 11.9 man-days, 19.2 pounds, and 
50 fish. 

The authors of ORRRC Study Report 7 
estimated mean harvest in 1960 at 17.5 pounds/ 
acre and predicted a yield of 23 pounds/acre in 
1976. Our calculations indicate a slightly higher 
rate of harvest in 1960, which may be attribut- 
able to our elimination of some very large 
waters from the "reservoir" category included 
in their computations. There was no significant 
correlation between harvest and year of census 
in our sample, precluding projections of future 
■yields . 



(Q 30 



^ 

















■ 


--<«* 


\ 












^^ 








.^^^HS^ol^Mffl 










^ 




^ 




\ 












l\ 


I, 










X 


V 



Reservoir area in acres 

Figure 1. — Quadratic regressions of sport 
fish harvest on area in 119 reservoirs. 
For the untransformed data regression, 
the probability of obtaining a larger F 
by chance if the hypothesis of no corre- 
lation is true = 0.17. For the log 
transformation, the probability of a 
larger F = 0.01. Equations: 1) Un- 
transformed data, pounds/acre = 
0.000000001105 area^ - 0.00035525 area 
+ 30.61; 2) log transformation, log 
(pounds/acre) = -0. 2648(log[area] )^ + 
1.8154 log(area) - 1.8848. 



221 



as reservoir size increases, effort and harvest 
tend to decrease, but pounds/hour increases 
(Figure 2). When harvest exceeds 20 pounds/ 
acre, catch per hour typically increases. 
Apparently, if catch falls below 1.5 pounds /man- 
day, effort drops after about 50 man-hours/ 
acre of fishing pressure. Similarly, below a 
catch rate of 0.5 pounds /hour there is a tendency 
for effort to decrease beyond 70 man-hours/ 
acre. 

Mean harvest by species reveals highest 
yields of rainbow trout, crappies , sunfishes and 
black basses (Table 3). High trout harvests 
were tallied in some intensively managed reser- 
voirs, and a substantial portion of the yield is 
attributable to hatchery production. The 
standing crop estimates (derived from summer 
rotenone sampling) listed are not directly com- 
parable, as only 46 reservoirs in the two 
samples had both crop and harvest data . How - 
ever, it suggests hypothetical mean harvests of 
60 percent of the summer black bass standing 
crop, 25 percent of the sunfish crop, 20 percent 
of the catfishes and carp, and 35 percent of the 
crop of all sport fishes . Inadequate sampling of 




20 40 60 80 100 

Sport harvest in pounds per acre 

Figure 2. — Logarithmic regression of sport 
harvest on angler-hours in 107 reservoirs. 
The coefficient of determination = 0.67; 
i.e., two-thirds of the variability in 
sport harvest is explained by hours of 
angler effort. Commonly cited rates of 
harvest are plotted for comparison. Equa- 
tion: log(hours/acre) = -0.275 (log/pounds 
[acre])2 + 1.230 log(pounds/acre) + 0.589. 



Table 3. — Mean angler harvest compared with mean standing crop in 
reservoirs, by species or species groups in pounds per acre. 
Only 46 reservoirs in the sample supplied both crop and harvest 
estimates . 







Sport 


harvest 


Standing crop 




Number 


of 


Pounds 


Pounds 




reservoirs 


per acre 


per acre 


Black basses 


92 




5.3 


9.0 


Crappies 


84 




8.5 


6.2 


Sunfishes 


86 




6.1 


24.8 


Catfishes 


69 




2.2 


10.5 


Bullheads 


55 




2.7 


2.2 


White bass 


33 




2.8 


3.2 


Rainbow trout 


36 




13.7 


- 


Brown trout 


8 




1.8 


_ 


Walleye 


18 




2,0 


1.2 


Sauger 


7 




1.2 


- 


Pike 


6 




0.1 


1.3 


Pickerel 


5 




1.4 


1.3 


Carp 


43 




2.5 


19.3 


All sport species 


119 




24.4 


67.0 



Table 4. — Simple correlation matrix of reservoir environmental variables 
and angler effort, success rate and total harvest. One symbol denotes 
positive or negative correlation at 0.20 confidence level; two symbols, 
the 0.05 level; and three symbols, the 0.01 level. 



Hours/ 
acre 



Fish/ Pounds/ Fish/ Pounds/ 
acre acre acre acre 



Area 

Outlet depth 

Fluctuation 

Storage ratio 

Growing season 

Age 

Hours/acre 

Fish/hour 

Pounds/hour 

Fish/acre 



crappies, white bass and walleye with rotenone 
precludes comparison of these species . 

ENVIRONMENTAL EFFECTS 
ON HARVEST 

Simple and partial correlation analyses 
involving harvest and 9 environmental factors 
revealed that only reservoir area, outlet depth, 
water level fluctuation, storage ratio, growing 
season and age were significantly related 
(0.20 confidence interval) to total angling effort 
or yield. Simple correlation indicated that 
area, outlet depth, growing season and age are 
the greatest influence on angling (Table 4) . 
Area is negatively related (0.01 confidence inter- 
val) to angler hours/acre and fish and pounds/ 
acre harvested, but positively linked to pounds 
caught/hour. Length of growing season has a 
higlily positive effect on effort and harvest. The 
correlation matrix indicated positive links 
between all effort and yield parameters , except 
hours/acre vs . pounds /hour. 

Partial correlation, which eliminates the 
bias introduced by independent variable 



intercorrelations, showed that area, growing 
season and age are the most significant factors 
(Table 5) . As area increases , angling effort 
per acre decreases but success rate increases. 
Outlet depth, fluctuation and storage ratio are 
negatively related to fish and/or pounds caught 
per hour. As length of growing season increases 
yield and rate of catch increase . As age of 
reservoir increases, rates of harvest decrease, 
but there is no significant relation with angling 
effort. Somewhat surprisingly, no correlations 
were evident between shore development (rela- 
tive shoreline length) or dissolved solids and 
angling harvest or effort. 

Comparison of partial correlation results 
from harvest and standing crop studies showed 
little agreement between total harvest and crop, 
but close agreement between black bass, sunfish 
and catfish crops and environmental responses 
(Table 6). Both black bass and sunfish harvests 
and crops are negatively affected by area; black 
bass harvest and crop is positively influenced 
by growing season; sunfish harvest and crop are 
both negatively related to reservoir age. The 
crop and harvest of catfishes are both positively 



223 



Table 5. — Partial correlation of six reservoir environmental variables 
with angler effort and success rates in 107 reservoirs. One symbol 
denotes positive or negative correlation at the 0.20 confidence 
level; two symbols, the 0.05 level; three symbols, the 0.01 level. 





Hours/ 


Fish/ 


Fish/ 


Pounds/ 




acre 


acre 


hour 


hour 


Reservoir area 





— 


+ + 


+ + + 


Outlet depth 






~ 




Fluctuation 








- 


Storage ratio 






— 


- 


Growing season 


+++ 


+ + + 


+ + 


+ 



Age 



Table 6. — Partial correlation of seven reservoir environmental variables vs. total 
standing crop and harvest of sport fishes and crop and harvest of black basses, sun- 
fishes and catfishes. One symbol denotes positive or negative correlation at the 0.20 
confidence level; two symbols, the 0.05 level; three symbols, the 0.01 level. 

Sport fishes Black basses Sunf ishes Catfishes 
Crop Harvest Crop Harvest Crop Harvest Crop Harvest 

No. of reservoirs 139 107 135 87 136 77 124 60 

Reservoir area -- - - - 

Outlet depth +++ +++ + 

Fluctuation + 

Storage ratio + 

Dissolved solids + + ■•■ *** 

Growing season +++ +++ +++ 

Age of reservoir - — 



influenced by outlet depth and dissolved solids. fishing weather. Growing season is positively 

No significant correlations appeared between related to angler -hours /acre (Table 4). 
the environmental variables and harvest of 

crappies . Correlation and multiple regression analy- 

ses now underway involve 7 environmental 

The negative relation between total sport factors and sport fish harvest in 4 use -type 

fish harvest and area is due, in part, to reduced subsamples: 1) hydropower, 2) irrigation, 

access per acre and location of most huge 3) flood control, and 4) water supply and 

reservoirs away from large population centers. recreation reservoirs. Results should clarify 

Increased harvest resulting from longer growing some of the findings derived from total sample 

seasons may be attributed to extended favorable analysis. 



NORTH CENTRAL RESERVOIR INVESTIGATIONS 

Yankton, South Dakota 
Norman G. Benson, Chief 



HIGHLIGHTS 

Because of the high water volume in the 
Missouri River main stem system, the U. S. 
Corps of Engineers increased the discharge 
after 1 July from Gavins Point from around 
33,000 cfs in former years to over 50,000. 
Some effects of this increased discharge have 
already been identified and others will become 
apparent with further data analysis. In Lewis 
and Clark Lake, an estimated 11 million larval 
fish passed through the powerhouse in one 24- 
hour period. Temperatures were lower in all 
reservoirs and temperature stratification was 
reduced in Lakes Sharpe and Oahe . Plankton 
production was lower in Lakes Oahe and Sharpe. 
Sections of the system virtually reverted to 
river environment. This abrupt change in 
reservoir ecology further elucidates the domin- 
ating influence of water management on reser- 
voir biological production. 

With the rise of Oahe water level from 1964 
to 1969 , there has been a shift in distribution 
of the young of many fish species . Abundance 
has decreased in the middle and lower sections 
of the main reservoir and in the larger arms, 
and increased in the reservoir headwaters and 
arms. The virtual disappearance of both littoral 
zone and spawning habitats accounts for these 
changes . 

Analysis of northern pike reproduction and 
survival in Lakes Oahe and Sharpe over the 
past 6 years suggests artificial propagation may 
be required to maintain a fishable pike popula- 
tion. Suitable spawning habitat appears unlikely 
under present water management . 



We are determining the causes of differences 
in phytoplankton abundance by Carbon 14 produc- 
tion experiments . In situ fertilization experi- 
ments are used in Lake Francis Case, Chemical 
budgets of nitrogen and phosphorous as related to 
phytoplankton are being computed for Lewis and 
Clark Lake. These findings will enable us to 
relate water management to production at all 
trophic levels and to interpret water chemistry 
measurements made in the other reservoirs of 
the system by other agencies. 

Many fish species in the Lewis and Clark 
Lake tailwaters grow faster than those in the 
reservoir proper, because of more abundant 
food. With our knowledge of the discharge of 
zooplankton, fish and benthos, feeding habits of 
fish, and the relations between different dis- 
charge rates and the associated biota, we should 
be able to predict the effects of various dis - 
changes on different fish species both in the 
tailwaters and in the reservoir. 

The effects of various temperatures on the 
development of northern pike embryos were 
determined under controlled laboratory conditions . 
The results agreed closely with both field experi- 
ments and data on natural fish stocks . 

FISH LIFE HISTORY 

Spawning- -Lakes Oahe and Sharpe 

We continued to study spawning of common 
fishes in both impoundments to measure time 
variations in relation to changes in reservoir 
environment and to determine spawning success 
by species . 



We found the spawning period of almost 
every species investigated has shortened during 
the past 6 years . During 1964 -65 , when Lake 
Oahe was rapidly filling and Lake Sharpe was 
attaining operational level, spawning of most 
species lasted from 6 weeks to over 3 months .. 
By 1968, when Lake Oahe's maximum pool ele- 
vation had been reached, the spawning period 
of many species was noticeably shortened, and 
in 1969 it was even more so . This trend was 
evident at least a year earlier in Lake Sharpe . 
Yellow perch spawning, for example, occurred 
during a 2-month period in 1964 and 1965, while 
in 1968 it lasted 4 weeks in both impoundments 
and in 1969 , 3 weeks . This finding suggests the 
reproductive potential was enhanced during the 
years the environment was expanding. 



variations in fecundity and incidence of atresia 
within the spawning stock. 

We found differences in the size at which 
pike reach sexual maturity in the two impound- 
ments . The shortest mature female in Lake 
Oahe measured 41.8 cm, and relatively few 
females under 50 cm were mature. The small- 
est mature male was 31.5 cm, but few males 
under 40 cm were mature. Mature males gener- 
ally averaged about 10 cm shorter than mature 
females at all ages. The shortest mature fe- 
male in Lake Sharpe was 32.2 cm, and numerous 
females under 50 cm were mature. Although 
males in Lake Sharpe reached maturity at about 
the same length as the females , males averaged 
nearly 15 cm shorter at all ages • 



Some species that spawned successfully 
during earlier years of impoundment either 
have had limited spawning success or failed to 
spawn in recent years, with much of the egg 
production being resorbed. Included in this 
group are the pallid and shovelnose sturgeons , 
river carpsucker, blue sucker, northern red- 
horse, and channel catfish. Resorbtion of eggs 
appears to have resulted from lack of suitable 
river -type spawning habitats. 

We began summarizing information 
collected during the past 6 years relating to 
spawning and survival of northern pike to make 
recommendations for management of this 
species in Lakes Oahe and Sharpe. The spawn- 
ing stocks and measures of relative year -class 
abundance differ in these adjacent impoundments. 
One feature common to both populations is that 
spawning and survival were highly successful 
in the first year following impoundment. Rela- 
tively large year classes of pike were produced 
in Lake Oahe in 1959 , the first year following 
impoundment , 1962 , 1965 , and 1969 . The 1964 
year class was nil, and remaining year classes 
were small. A relatively large year class was 
produced in Lake Sharpe in 1964, the first year 
following impoundment, but subsequent year 
classes were virtually absent. Relatively large 
year classes in Lake Oahe were produced only 
in those years when there was a rise in water 
level over vegetation during spawning and the 
•level maintained for a time after spawning. 
Variations in year class size also reflected 



We also learned that smaller, younger pike 
were first to occupy newly-inundated spawning 
grounds. Moreover, females less than 50 cm 
tended to spawn early in the season, while the 
largest females generally spawned about mid- 
season. The tendency for larger, more fecund, 
females to spawn later might enhance survival, 
since environmental conditions usually are more 
favorable later in the season. 

We concluded that future success of 
natural reproduction of northern pike in Lake 
Oahe will be largely dependent upon water-level 
management. However, because provision of 
suitable sf)awning habitat appears unlikely under 
present water -management, artificial propaga- 
tion may eventually be required to maintain a 
fishable population. Prospects for a viable pike 
population in Lake Sharpe appear to be poor. 
Lack of suitable spawning and nursery habitats , 
along with high population levels of walleye (all 
ages), are the major limiting factors. 



Fred June 



Northern pike experiments 



We installed portions of the aquarium sys- 
tem in our new laboratory and initiated controllcil 
temperature experiments with embryos , 

We artificially fertilized eggs and incubated 
them in constant temperature chambers (Figure 
1) at temperatures ranging from 3 to 21 C . 




Table 1. — Time (in days) required for hatch- 
ing of northern pike embryos held 
at various water temperatures. 



Figure 1. — Part of the experimental layout 
for the study of the effects of tempera- 
ture on northern pike embryos and yolk- 
sac larvae. 

graduated at 3 C. intervals. Survival to hatch- 
ing at 6 to 21 C . was 90 percent or above and at 
3 C . about 10 percent . Time to hatching and 
duration of hatching were dependent upon the in- 
cubation temperature (Table 1) . Hatching began 
in 4 days at 21 C . and in 30 days at 3 C , We 
transferred some of the embryos that had been 
incubated for 6 days at 3 C. to 12, 15, 19, and 
21 C . water and found that survival to hatching 
among these lots ranged from 20 percent in 21 
C . water to 70 percent in 12 C . water . Hatch- 
ing occurred in 3 days in 21 C . water and in 5 
days in 12 and 15 C. water. Embryos that had 
been incubated for 15 days at 3 C . did not sur- 
vive transfer to 15 C. water. 

Survival of unfed yolk-sac larvae ranged 
from less than 1 percent at 3 C . to 90 percent 
at 21 C. at the end of 7 days . Yolk-sac larvae 
hatched and developed at temperatures of 6 to 
21 C. appeared to be healthy, while those incu- 
bated and hatched at 3 C . were fragile and 
nearly all died when disturbed or transferred to 
higher temperatures . We also found that sur- 
vival of yolk-sac larvae that had hatched in 18 
and 21 C . water before transfer to 3 , 6 , 9 , and 
12 C. water was relatively high, ranging from 
75 percent at 12 C . at the end of 7 days to 90 
percent at 3 and 6 C . At the end of 9 days sur- 
vival was 60 percent at 3 and 6 C . 



Tempe rature 
(C) 



Hatching time (days) 
Began Completed 



9 
12 
15 
18 
21 



30 

16 

12 

8 

6 

5 



42 

25 

20 

9 

7 



Our earlier field studies indicated that 
prolonged exposure of pike embryos to water 
temperature of near 5 C. during early develop- 
mental stages approached the lower temperature - 
tolerance limit for this species in Lakes Oahe 
and Sharpe . Our laboratory studies corroborated 
this finding and furthermore established that 3 
C. was near lethal, whereas 6 C. was within the 
tolerance range of both embryos and yolk-sac 
larvae . 

Thomas Hassler 

White bass --Lewis and Clark Lake 

We began studies on the reproduction poten- 
tial of white bass . Pre -spawning females were 
captured on 15 May and the post -spawning fe - 
males on 24 -28 June . Ovaries were removed 
from fish and ovary volumes (cc) before and 
after spawning were measured and regressions 
calculated (Figure 2), Pre -spawning ovary 
volumes were termed potential fecundity. Post- 
spawning volumes were termed residual fecundity 
or the volume of .eggs retained in the ovary after 
spawning. The difference between potential and 
residual fecundity is the volume of eggs spawned 
and is termed effective fecundity. There was an 
average of 3,904 eggs, 600 microns and larger 
per cc, in the pre -spawning ovaries. Eggs less 
than 600 y. in diameter were immature . 

We made mature ova counts on 9 fish rang- 
ing from 325 to 421 mm. The number of mature 
ova ranged from 280,100 to 567,200. Number of 
ova per female was more related to fish length 
and weight than age . 



100- 






90- 




^^^^"'^'^ 


80- 




^,.^^'^ POTENTIAL 




FISH CAPTURED 


• — FECUNDITY 


70- 


MAY 15 ^^^^^1 




y 60- 


^^-^ 


EFFECTIVE 


IbU. 


^^.-■''''^ 


FECUNDITY 


S u>- 


^-^^^ 




> 

% JO- 
°?0- 


\r RESIDUAL 
FISH CAPTURED JUNE 21.-28 ccniunnv 


10- 







JIG J20 JJO iiO J50 J60 570 J80 

Figure 2. — Effective fecundity (number of 
ova spawned) by length (mm) in white bass, 
Lewis and Clark Lake, 1969. 1 cc of ovary 
contain an average of 3,904 ova. 



Estimated mortality was calculated for age 
white bass between 20 and 84 mm collected 
from 1964 to 1969 by trawl in the lower two- 
thirds of Lewis and Clark Lake (Figure 3). The 
relative height of each year's regression at 20 
mm is an estimate of survival of young fish to 
a length of 20 mm. Initial survival was highest 
in 1969 and lowest in 1964 , Relative height of 
the regression at 84 mm is an estimate of year- 
class strength by 1 September . In general , year 
classes abundant at 20 mm remain abundant 
throughout the first summer of life and year 
classes in which few fish are taken at 20 mm 
remain poor . 

Richard Ruelle 

Channel catfish 

We determined the diet of 141 age channel 
catfish collected from Lewis and Clark Lake. 
We conducted this study in cooperation with the 
FWPCA Laboratory in Duluth. Catfish begin 
feeding when approximately 15 mm long. Fish 
15-20 mm long prefer zooplankton while larger 
fish eat both zooplankton and bottom fauna . 
Rotifers and algae were absent from stomachs . 
Diaptomus , Daphnia, and Cyclops were pre- 
ferred zooplankton . Chironomids, particularly 
Ablabesmyia and Procladius , were preferred 
bottom fauna. Food electivity indices for fish 
15-20 mm long showed that Diaptomus forbesi, 
D . ashlandi , and Daphnia pulex were highly 



selected. Cyclops bicuspidatus was selected by 
15 mm fish but rejected by larger individuals . 

Studies on the movement of catfish between 
Lewis and Clark Lake and the 44 mile section of 
the Missouri River between Fort Randall Dam 
and the reservoir headwaters were continued. 
Five hundred and thirty fish were tagged with 
nylon stream tags and released in the Missouri 
River. Nine fish were recaptured and most 
recoveries were upstream from location of tag- 
ging. 

Charles Walburg 

Walleye --Lake Francis Case 

We studied spawning in May and June . Eggs 
were collected 5-9 May with a suction pump from 
near shore spawning areas at the rate of 0.64 
embryos per minute of sampling. The following 
week only 0.06 embryos per minute were col- 
lected from the same areas . A cold wave with 
minimum air temperatures of 3-4 C. on three 
nights with accompanying strong winds occurred 
during the intervening weekend. No walleye 
larvae were taken in 212 tows with a Miller 
sampler during May and June . Poor hatching 
success for walleye in 1969 appears related to 
unfavorable weather conditions during the incu- 
bation period. 




Figure 3. --Est imated mortality rates for 
white bass 20 to 84 nun long captured by 
trawl, Lewis and Clark Lake, 1964-69. 



-Food habits of age I and older walleye in percent occurrence 

and percent of total volume (in parentheses), Lake Francis 

Case, 1969. Walleye were taken with a bottom trawl in July 

and August, and with gill nets from September through November, 
t = trace 



Organisms 



July-Aug. 



Sept . 



Zooplankton 

Fish 

Yellow perch 
Gizzard shad 
Freshwater drum 

White bass 
Unidentified 

Total fish examined 

Percent empty stomachs 



0( 


0) 


64(100) 


13( 


9) 


0( 


0) 


3( 


12) 


7( 


18) 


55{ 


61) 


67 




36 





0( 0) 


2( 


t) 


2( 0) 


41(100) 


61(100) 


87(100) 


7( 14) 


3( 


2) 


0( 0) 


2( 15) 


8( 


42) 


63( 84) 


9( 15) 


13( 


15) 


7( 2) 


2( 30) 


3( 


11) 


0( 0) 


27( 25) 


44( 


32) 


42( 10) 


195 


158 




102 


59 


37 




13 



The water management of Lake Francis 
Case includes a 35 -foot water level drawdown 
each year between 1 September and December . 
We collected 552 age I and older walleye be- 
tween July and November 1969 to determine 
change in fish diet in relation to drawdown. 
Yellow perch, gizzard shad, freshwater drum, 
and white bass were the major diet items 
(Table 2) . Drum was a diet item in all months , 
perch and white bass decreased in diet between 
July and November, and shad, while not found 
in stomachs in July -August, became the pre- 
dominant food in November. The diet of 5 wall- 
eye and 35 sauger collected in November from 
Lewis and Clark Lake, where water levels 
remain relatively stable, was similar to that in 
Lake Francis Case. 

Charles Gasaway 

POPULATION DYNAMICS 

Lewis and Clark Luke 

Main stem Missouri River reservoirs 
might be termed confused environments because 
of the changes they undergo over the years . 



This reservoir was considerably different in 
1969 from any year since impoundment. Reser- 
voir releases were increased from 30,000 - 
33,000 cfs to 53,000. Water exchange rates 
(flushing rates) were thereby increased from 7 - 
8 days to 4 -6 days . Currents created by the 
high water exchange affected survival of young 
fish in the reservoir and had an unknown influ- 
ence on the vulnerability of young and adult fish 
to our gears during summer and fall population 
monitoring periods . 

Losses of larval and juvenile fishes from 
Lewis and Clark Lake through discharge were 
examined on 30 days between 4 June and 13 Aug- 
ust (Figure 4) . Three metered nets were set 
above the powerhouse intakes to sample fishes 
at the surface, mid-depth, and bottom. Fishes 
of 15 species 5-20 cm long were taken on all but 
two sampling days. Species most commonly lost, 
in order of abundance, were freshwater drum, 
emerald shiner, sauger, and channel catfish 
(Table 3) . 

Estimated peak loss of drum was 10 million 
on 16 and 3 July, and 4 million on 14-15 July. 
Peak loss of 800,000 emerald shiner occurred on 



230 




tigure 4. --Gear used to collect fish above 
the discharge intakes of Gavins Point 
Powerhouse. 

24 July. About 700,000 sauger were lost on 10 
June, and 170,000 catfish on 28 July. Most carp, 
carpsucker, and white bass were lost during 
the third and fourth weeks of July. Except for 
white bass, fish loss in the discharge generally 
reflected species abundance in the reservoir. 

Reservoir flushing rates on the 30 sample 
days ranged from 4 .0 to 9.8, the number of 
days necessary to empty the reservoir at a 
given volume and discharge. Most fish were 
lost at flushing rates between 5.0 and 6.9 . 
Lower rates were in August when most remain- 
ing fish were large enough to avoid downstream 
currents . 



shiner. Species showing the greatest decrease 
in year -class abundance were all lost in large 
numbers in reservoir discharges (Table 3). 

Adult fishes were systematically sampled 
for the fourth consecutive year. Catches of 
both gill and trap nets were about 20 percent less 
than in 1968 (Table 5). This decrease may be 
the result of increased reservoir currents dur- 
ing the fall of 1969 . If we assume increased 
discharge had no effect on catch, comparison of 
annual catch can indicate trends in species abun- 
dance. Abundance of all species except carp- 
sucker has decreased over the past 4 years 
(Table 5). Carp, carpsucker, and the buffalo - 
fishes have poor reproduction in the reservoir, 
and their numbers are expected to decrease. 
The remaining species reproduce each year but 
spawning success or survival of young has been 
only moderate . 

Adult fish collected in 1966 , 1967 , and 1968 
have been aged. Lengths and weights for most 
ages of fish decreased between 1966 and 1968 . 
Greatest weight loss was experienced by carp, 
carpsucker, white crappie, and sauger. These 
species are all dependent on benthos and forage 
fish for food. Abundance of Hexagenia , gizzard 
shad and emerald shiner declined between 1966 
and 1968 . We believe that the decrease in food 
abundance caused fish growth to decline. 



Charles Walburg 



Gavins Point tailwater 



Regular collection of young-of -the -year 
was continued for the fifth consecutive year. 
Fish were sampled weekly with trawl and seine 
between the first week in June and second week 
in September. Nine species were common in 
collections (Table 4). Sauger and walleye are 
grouped together because most were less than 
25 mm and hybridization makes separation of 
species difficult. 

Strengths of the 1969 year class were 
estimated from comparison of annual catches 
(Table 4). Only white bass had a strong 1969 
year class . We found increases over 1968 for 
yellow perch and gizzard shad . Decreases are 
indicated for catfish, drum, and emerald 



Sampling to determine abundance and sea- 
sonal occurrence of fishes in Gavins Point Dam 
tailwater was concluded in April. Information 
on gonad development, diet, and available food 
was also obtained. We will relate the tailwater 
fish population data with that in Lewis and Clark 
Lake and determine the probable reasons for 
concentration of fish in the tailwaters . 

We collected 29 fish species from the tail- 
waters with gill nets, but only 20 from the 
reservoir (Table 6). Catch -per -effort was 90 
fish in the tailwaters and 27 in the reservoir. 
This difference in catch illustrates that fish do 
concentrate in the tailwaters . Blue sucker and 
shortnose gar are abundant in the tailwaters but 



231 



-Estimated number (thousands) of fishes commonly lost in discharge from Lewis and 
Clark Lake on 30 days between 4 June and 13 August, 1969. Reservoir flushing 
rates are given for each sample day. 



River White 
Carp carpsucker bass 



Channel 
catfish 



Sauger 



Freshwater Emerald Flushing 
drum shiner rate (days) 



4 

5 

10 


June 


- 


- 


- 


- 




_ 


_ 


_ 


_ 


16 




- 


- 


- 


- 


17 




- 


- 


- 


- 


18 




- 


- 


- 


- 


23 




- 


- 


- 


- 


24 




- 


- 


- 


- 


25 




- 


- 


- 


- 


30 




- 


- 


- 


- 


1 
2 
7 


July 


- 


- 


- 


- 




17 


- 


- 


- 


8 







- 


- 


- 


9 







- 


- 


- 


14 




9 


- 


18 


- 


15 




9 


32 


9 


- 


16 




65 


54 


22 


11 


22 




56 


14 


19 


23 


23 




4 








98 


24 




16 


6 


22 


99 


28 




30 


95 


5 


170 


29 




16 


5 





22 


30 









11 


22 


4 


Aug. 


10 





_ 


15 


5 




- 


10 


- 


26 


6 




- 


- 


- 


23 


11 




- 


- 


- 


5 


12 




- 


- 


- 


4 


13 




- 


- 


- 


7 


Length 










range 










(mm) 


10-26 


12-28 


11-35 


12-35 



47 

145 

698 

73 

30 

14 



9 







- 


- 


5.6 


- 


16 


5.8 


- 


5 


5.5 


- 


27 


6.0 


- 


23 


6.1 


- 


136 


6.0 


- 





6.9 


- 


9 


6.6 





5 


7.3 


- 


24 


6.9 


_ 


13 


8.6 


- 





9.8 


101 


169 


7.0 


558 


177 


7.1 


675 


89 


6.8 


4,889 


299 


6.7 


3,490 


482 


6.5 


,0,222 


318 


6.4 


301 


207 


5.8 


335 


165 


5.4 


8dO 


794 


5.5 


6d8 


135 


5.8 


97 


22 


5.6 


117 


44 


5.4 


50 


10 


4.5 


47 


10 


4.6 


IS 


56 


4.6 


78 


16 


4.4 


14 





4.3 


289 


35 


4.3 



uncommon in the reservoir. Freshwater drum 
are abundant in the reservoir but uncommon in 
tailwaters . A number of the remaining species 
appear about equally abundant in both tail- 
waters and reservoir. These latter fishes will 
be examined in detail to ascertain if this por- 
tion of the tailwater population originated from 
the reservoir. 

Preliminary findings indicate that fish 
concentrate in the tailwaters for spawning and/ 



or feeding. Growth of most species collected in 
the tailwaters is superior to that found in Lewis 
and Clark Lake . 



Charles Walburg 



Lake Francis Case 



Sampling of young -of -the -year fish to 
estimate relative abundance and mortality rates 
was continued in the lower third of the reservoir 



-Catch-effort of age fish per standard haul, 
June-September, Lewis and Clark Lake, 1965- 
1969. Emerald shiner and gizzard shad 
taken by seine, all others by trawl. 



Species 


1965 


1966 


1967 


1968 


1969 


Channel catfish 


48 


50 


14 


17 


2 


White bass 


37 


21 


73 


42 


79 


White crappie 


23 


20 


10 


9 


8 


Yellow perch 


1 


1 





16 


19 


Sauger-walleye 


9 


13 


3 


Q 


10 


Freshwater drum 


234 


138 


70 


133 


28 


Emerald shiner 


55 


83 


49 


58 


32 


Gizzard shad 


72 


67 


47 


14 


26 



-Number of each species of fish commonly collected in September and October by gill 
and trap nets, Lewis and Clark Lake, 1966-1969. (Fishing effort similar among 
years. ) 







Gill 


net 






Trap 


net 






Species 


1966 


1967 


1968 


1969 


1^"166 


1967 


1908 




1969 


Carp 


222 


153 


168 


141 


241 


205 


165 




172 


River carpsucker 


241 


244 


340 


200 


1,052 


2,011 


2,357 


2 


,138 


Smallmouth buffalo 


12 


19 


31 


21 


505 


565 


558 




255 


Bigmouth buffalo 


9 


34 


43 


30 


2,133 


1,307 


1,149 




952 


Channel catfish 


273 


194 


203 


l6S 


82 


07 


63 




45 


White bass 


115 


45 


31 


25 


1,010 


1,378 


570 




642 


White crappie 


134 


53 


34 


8 


1,189 


1,680 


629 




490 


Sauger 


415 


265 


303 


260 


142 


222 


144 




103 


Freshwater drum 


377 


381 


368 


297 


1,143 


2,155 


l,o20 


1 


,233 



Total (all species) 2,364 



1,846 



9,352 



10,698 



8,208 



6,357 



for the fourth consecutive year. Most river 
carpsucker, bigmouth buffalo, emerald shiner, 
and walleye were taken by 100-foot seine; most 
gizzard shad, white bass, white crappie, and 
yellow perch were taken by 27 -foot bottom 
trawl; and most black crappie and freshwater 
drum by 8 -foot midwater trawl. May and June 
levels were slightly above normal with some 
flooding of shore vegetation, but reproduction 
for most species was poor (Table 7). Only 
white bass reproduction was more successful 
than in previous years. Summer abundance of 
age-0 white bass has been increasing each year, 
but fall abundance appears similar. Few adult 
white bass have been captured in gill nets or in 
'the sport fishery. 



Echo sounding and midwater trawling in the 
limnetic zone in both 1968 and 1969 indicates 
there are few fish in this area. One dense fish 
concentration was found in this zone during the 
summer, and the majority of these were age-0 
drum. 

Charles Gasaway 

Young fish stocks in Lakes Oahe and Sharpe 

We measured the distribution and relative 
abundance of young -of -the -year fishes for the 
sixth consecutive year in Lake Oahe and for the 
third consecutive year in Lake Sharpe with the 
objectives of(l) assessing annual spawning 



233 



. — Common fishes collected with experimental gill 
nets in tailwaters of Gavins Point Dam, 
February 1968 to April 1909, and Lewis and 
Clark Lake, September and October 1968. 



Species 



Tailwaters 


Lake 


20.0 


2/ 


19.0 


IS. 5 


14.8 


2/ 


14.1 


16.4 


6.7 


9.1 


6.5 


11.0 


6.0 


6.6 


2.0 


2/ 


2.0 


2.3 


1.9 


1.6 


l.S 


2.3 


2/ 


19.6 


2/ 


5.0 


2/ 


2.4 


2/ 


l.S 


2/ 


1.6 


2.2 


2/ 


5,4Sd 


1,843 


61 


68 


90 


27 



Blue sucker 

River carpsucker 

Shortnose gar 

Sauger 

Carp 

Channel catfish 

Walleye 

Shovelnose sturgeon 

Northern redhorse 

White bass 

Goldeye 

Freshwater drum 

Gizzard shadii/ 

Bigmouth buffalo 

Smallmouth buffalo 

White crappie 

All other species 

Total catch 
Total effort 
Catch-effort 



Total species 



20 



1/ 



Age 



2/ 



Less than one percent 



success of common species, (2) following 
changes in the spatial distribution of early life 
stages in relation to water level fluctuations, 
and (3) estimating mortality rates at different 
developmental stages. The work consisted of 
biweekly sampling of selected spawning and 
nursery areas in both impoundments with a 
standardized haul seine from June to September 
and additional sampling with an otter trawl in 
Lake Sharpe . 



Yellow perch dominated our catches in 
Lake Oahe for the fifth consecutive year, and 
white bass replaced emerald shiner as the 
second most abundant fish. Emerald shiner 
decreased noticeably in 1969, while bigmouth 
and smallmouth buffalos , northern pike , and 
carp increased. We found that years of high and 
low abundance of the latter four species corres- 
pond, which suggests similarities in their spawn 
ing habitat requirements . 



We caught 30 species of fishes in Lake Oahe 
and 31 in Lake Sharpe. The average catch per- 
unit -effort was higher for most species in Lake 
Oahe than in Lake Sharpe. Relative abundance 
indices, however, for common species in both 
impoundments were generally lower than in 
1968 (Table 8). 



Gizzard shad, yellow perch, emerald 
shiner , and walleye were the most common 
fishes in our catches in Lake Sharpe . Catch per 
unit -effort of black and white crappies and sau- 
ger suggested downward trends in 1969 while 
white bass apparently increased. We caught onl^ 
two young -of -the -year northern pike and one 
black bullhead. 



-Catch per seine haul of age-0 fish during August , Lake 
Francis Case, lObb-lQC-^. 19oo and l^^oT catches are 
adjusted for station changes made in later years. 



Species 



Gizzard shad 




0.2 


12.4 


25.2 


6.5 


Bigmouth buffalo 




0.2 


0.6 








River carpsuckc^r 










0.4 





Carp 







0.4 








Emerald shiner (adu 


It) 


155.5 


217.4 


130.7 


6.1 


Emerald shiner (age 


-0) 


15.2 


132.3 


27.6 


11.2 


White bass 




3.0 


9.1 


11.6 


38.8 


White crappie 




21.0 


lb. 3 





0.1 


Black crappie 




15.7 


2.7 








Walleye 




0.2 


0.3 


0.3 


0.1 


Yellow perch 




4.5 


9.2 


1.6 


1.3 


Freshwater drum 




3.7 


4.4 


2.7 


3.0 



Table c. — Average nujuuers of coniiuon young fishes— caught pei 
standardized seine haul in Lakes Oahe and Sharpe, 
South Dakota, 1968-1969, 



Species 



Lake 


Oahe 


Lake 
19dS 


Sharpe 


196 8 


19d9 


190 9 


614.3 


310.4 


151.3 


76.0 


62.0 


20.7 


26.5 


21.4 








188. 3 


175.6 


4.2 


2.6 


1.3 


0.3 


4.2 


35.4 


0.2 


0.7 


15.6 


3.6 


1.8 


0.1 


0.1 


0.6 


7.6 


5.5 


Trace 


Trace 


1.3 


0.3 


22.9 


1.4 


2.2 


0.1 



Yvllow perch 
Emerald shiner 
Gizzard shad±/ 
Silvery minnow 
White bass 
Black crappie 
Walleye 
Sauger 
White crappie 

Number of hauls 



204 



1/ 

All age groups of minnows included; remainder are young-of- 

the-year only. 

2/ 

~ Absent in Lake Oahe. 



With the rise in water level of Lake Oahe 
over the past several years there has been an 
upstream shift in the distribution and areas of 
heaviest concentration of the young of many 
species. In the Cheyenne River embayment, 
for example, the relative abundance of common 
fishes was significantly higher in the upper 
third than in the lower and middle reaches in 
1969 (Table 9), and similar trends were shown 



in Lake Oahe proper. Yellow perch provides an 
example of the changes in distribution and rela- 
tive abundance that characterized a number of 
species in Lake Oahe (Figure 5). The relative 
abundance of young -of -the -year yellow perch in- 
creased from 1965 to 1967 and decreased in 1968 
and 1969 . Identical trends were shown in this 
species in the Cheyenne River embayment. 
Relative abundance in the lower third of Lake 



Table 9. — Average numbers of common young fishes 

caught per standardized seine haul in the 
upper, middle, and lower thirds of the 
Cheyenne River embayment of Lake Oahe, 1969 







Loc at ion 






Upper 


Middle 


Lower 


Species 


third 


third 


third 


White bass 


244.9 


7.5 


2.0 


Bigmouth buffalo 


14.7 


0.1 


0.1 


Smallmouth buffalo 


6.1 








Carp 


14.4 


0.1 


0.7 


White crappie 


2.1 


0.5 


1.5 


Freshwater drum 


1.6 


1.1 


0.1 


River carpsucker 


1.1 








Silvery minnow 


0.8 








Sauger 


0.2 








Number of hauls 


30 


30 


30 




Figure 5. — Average numbers of yellow perch 
caught per standardized seine haul (C/f) 
in the lower, middle, and upper thirds of 
Lake Oahe, South Dakota, 1965-1969. 

Oahe similarly increased each year through 
1967, dropped slightly in 1968, then dropped 
sharply in 1969 . Relative abundance in the 
middle third of the impoundment was notably 
low in 1965 and 1966, but it increased sharply in 
1967 when extensive gently sloping areas in mid- 
reservoir became inundated. Relative abun- 
dance in the upper third of the impoundment was 
also low in 1965 and 1966 but increased in 1968 



and 1969 when a rapid rise in water level flooded 
the upper reach. We conclude that the shift in 
distribution of young fishes simply reflects the 
virtual disappearance of a shallow littoral zone 
in much of the lower reservoir coupled with an 
upstream shift in the available spawning habitat 
for many species. 

Lance Beckman 

Adult fish stock in Lake Sharpe 

Our studies of the adult fish stock in Lake 
Sharpe were continued for the fifth consecutive 
year with the objectives of (1) assessing changes 
in composition (species, age, length, and sex) 
in relation to the age of impoundment, (2) pre- 
dicting trends in abundance of important game 
fish populations, and (3) elucidating the vital 
statistics of selected species populations . We 
collected biweekly samples of the adult stock 
with a standardized gill net at six reservoir 
locations from June to September and in the tail- 
water area from March to December . 

Of 22 species taken in our nets, walleye was 
the most common game fish , although its rela - 
tive abundance was the lowest since 1966 (Figure 
6). Five post impoundment year classes of wall- 
eye were represented, and the 1964 year class 
dominated for the fifth consecutive year. Inci- 
dental catches of age-1 walleye suggested that 




Figure 6. — Catch of some common game fishes 
per standard gill net (C/f) at six loca- 
tions in Lake Sharpe , South Dakota, June 
to September, 1965-1969. 

the 1968 year class was the strongest to appear 
since 1964 . Yellow perch abundance continued 
to decline in 1969 and reached its lowest level 
since impoundment. For the third consecutive 
year about 85 percent of the perch catch con- 
sisted of age-II and age-Ill fish. Survival from 
age-U to age- III declined from 67 percent for the 
1965 year class to 16 percent for the 1966 year 
class. The decline in relative abundance of 
age-II and age -III perch was probably due to in- 
creased predation by walleye on perch of all 
ages . The relative abundance of sauger re - 
mained at about the same level as in previous 
years, but incidental catches of age-I fish indi- 
cated that the 1968 year class probably was the 
smallest produced since impoundment. Our 
catches of northern pike have declined by about 
50 percent per year since 1965 and, along with 
those of black bullhead, reached their lowest 
level in 1969 . 

Of rough fishes represented in our catches , 
six warrant comment. Relative abundance of 
freshwater drum continued low in 1969 (Figure 
7), but the age composition gradually shifted 
from 21 percent postimpoundment fish in 1965 
to 71 percent in 1969. The 1964 year class of 
carp accounted for over 80 percent of the catch 
each year through 1968 , but very small year 
classes have been produced since. Thus the 
apparent increase in carp abundance was an 
artifact of changing vulnerability of the fish to 



our gill nets . The relative abundance of river 
carpsucker and goldeye have shown similar 
trends. Goldeye had good year classes in 1965 
and in 1967, with lesser abundant year classes 
produced in other years , but recruitment has not 
kept pace with mortality of older fish. In 1968, 
46 percent of the goldeye catch consisted of pre- 
impoundment fish; in contrast, over 98 percent 
of the carpsucker catch consisted of preimpound- 
ment fish. Bigmouth and smallmouth buffalos 
have remained at relatively low levels since 
1965 with little evidence of recruitment from 
postimpoundment year classes. 



Joseph Elrod 



LIMNOLOGY 

Lewis and Clark Lake 

Winter- -1969 

The objective of this program is to deter- 
mine the relations between events and conditions 
under the ice to subsequent conditions found dur- 
ing the spring and summer. Once these rela- 
tions are better understood, it may be possible 
to predict such occurrences as the nature of 
spring "blooms." 

We collected data on water chemistry, 
zooplankton, and phytoplankton under the ice 
from 1 January to 15 April. We developed suit- 
able equipment and techniques for most phases 
of the work and collected samples biweekly from 




1965 1966 1967 1968 1969 

Figure 7. — Catch of other common fishes per 
standard gill net (C/f) at six locations 
in Lake Sharpe, South Dakota, June to 
September, 1965-1969. 



237 



one station near the dam . Total phosphorous 
(P) during this period averaged 0.029 mg/liter 
(range, 0.017-0.047), This was not significant- 
ly different from values obtained at the same 
station during the ice -free period of 1969 (Table 
10). Soluble P averaged 0,015 mg/liter (range, 
0,012-0.020). This was about twice the concen- 
trations encountered in the lake during the 
following spring and summer . Nitrate (NO3) was 
twice as high (average, 0.203 mg/liter; range, 
0.166-0.262) under the ice than in the ice -free 
period. 

Chlorophyll remained uniformly low (aver- 
age 1.43 mg/m^; range, 1.02-1.67) throughout 
the period. Because of the low chlorophyll con- 
tent of the water and the reduced light conditions 
due to heavy snow cover, the potential for pri- 
mary productivity was extremely low. Attempts 
to measure photosynthetic rates using changes 
of dissolved oxygen in light and dark bottles 
were unsuccessful. The more sensitive ^'^C 
method would probably measure C uptake , but 
it was not used because of difficulties encount- 
ered in in situ incubation of samples . We 
recently developed methods to permit the use of 
14 r- 



Aster ionella formosa was the most abun- 
dant phytoplankton found under the ice . Popula - 
tions in early January were low (20/ml), they 
increased to a high of 850/ml on 20 February, 
and declined until ice left the reservoir on 14 
April. Concentrations of about 100/ml were pre- 
sent at the end of the ice cover period. Rhodo - 
monas , the next most numerically abundant 
phytoplankton taxon, were highest in January 
with about 500/ml present. 

Cyclops bicuspidatus was the most abundant 
crustacean zooplankton species during the ice 
cover period. Individuals of the third and 
fourth copepodite stage were much more abun- 
dant than adults or other immature stages . 
Diaptomus was the only other important taxon, 
but densities were low. 

Spring and summer- -1969 

In 1968, samples were taken at six stations, 
located equidistant along the main axis of the 
reservoir, to determine physical, chemical. 



and biological changes that occur in water as it 
moves down the reservoir. This sampling de- 
scribed the reservoir at a given time and pro- 
vided information on such dynamic processes as 
net increase (or decrease) in plankton biomass 
or removal of a critical inorganic nutrient , 
Objectives were the same, but analyses of 1968 
data resulted in a design modification for 1969 . 
Samples in 1969 were taken: (1) in the Missouri 
River directly above Lewis and Clark Lake 
(incoming water, and termed "Headwater"); 
(2) from the surface (0-3 meter composite) of 
the reservoir at a point 3 miles from the dam 
over the old river channel (surface water condi- 
tions in the lower end of the reservoir and 
termed "Lake Surface"); (3) from a depth of 1 
meter off the bottom at the same location as the 
lake surface sample (termed "Lake Bottom"); 
and (4) from the Missouri River directly down- 
stream from the Gavins Point Dam outlet 
(termed "Tailwaters"). 

Some of the average chemical and biologi- 
cal conditions at the four locations for the 
spring and summer are shown in Table 10. A 
net loss of nitrate, total phosphorous and soluble 
phosphorous is shown as the difference in con- 
centrations present in the Headwaters and Tall- 
waters samples . This means that the reservoir 
is retaining phosphorous at a rate which can be 
quantified. The nature of the retained fraction 
cannot be specified, but it must include incor- 
poration into the food web and higher trophic 
levels . The fate of nitrate nitrogen (NO3) is not 
known at this time , Changes in the form of 
nitrogen may occur which do not include the 
direct synthesis of organic matter. It is reason- 
able to assume, however, that uptake of NOo by 
auto trophic organisms plays a major role in 
this net loss of NOo, Measurements in 1970 will 
include NH4-N and NOj-N. Experiments to deter- 
mine rates of uptake of all forms of nitrogen by 
phytoplankton will be carried out. We will cal- 
culate a detailed phosphorous and nitrogen budget 
for Gavins Point Reservoir. The nutrient budget 
can then be related to primary production and 
water management practices . 

Phytoplankton standing crop increases 
significantly between the headwaters and the dam. 
This is shown by the chlorophyll concentrations 
at the four locations (Table 10) . Accompanying 



Table 10. — Some chemical and biological characteristics of four sampling locations in Lewis 
and Clark Lake. Values are averages of all samples taken during the spring and 
summer of 1969. 















Total 












productivity 
mg C/m^/hr 


zooplankton 


Sampling 
station 


NO3-N 
mg/1 


Total P 
mg/1 


Soluble P 
mg/1 


Chlorophyll 
mg/m^ 


1/ 
No/m^ 



Headwaters 


0.120 


0.059 


0.009 


7.38 


7.3 


170.1 


Lake surface 


0.106 


0.030 


0.008 


12.68 


13.2 


403.6 


Lake bottom 


0.115 


0.032 


0.008 


7.49 


5.6 


- 


Tailwaters 


0.109 


0.034 


0.006 


11.47 


11.3 


283.1 



1/ 



Represents total number in 1 square meter from surface to bottom. 




Figure 8. --Culturing Cyclops bicuspidatus 
under controlled temperatures. 

these changes in chlorophyll is an increase in 
the primary productivity potential of the phyto- 
plankton community as shown by the average 
^■^C productivity of water from each station. 
These figures tell an important story with re- 
spect to water management in the reservoir. 
Phytoplankton biomass and "potential productiv- 
ity" flushed from the reservoir is lost in terms 
of utilization by higher trophic levels in the 
lake . Minor decreases in flushing rates would 
result in proportional increases in organic 
carbon synthesis within the reservoir. 



Zooplankton exported from the reservoir 
also exceeds that imported. This means that 
production must be in excess of that used by pre- 
dators present in the lake . 



Another interesting feature is that the water 
discharged from the reservoir is more closely 
related to surface water than to bottom water. 
This is especially true of the phytoplankton 
characteristics of chlorophyll and ^^C uptake 
(Table 10). In this respect Lewis and Clark 
more closely resembles a natural lake than a 
typical "deep discharge" reservoir. 



Dan Martin 



Cyclops bicuspidatus 



Laboratory studies of Cyclops bicuspidatus 
thomasi from November 1968 through April 1969 
revealed instar duration, length of life cycle, 
behavioral characteristics, and developmental 
changes at 23 C. and 4 .4 C. (Figure 8). Mating 
was observed several times and usually resulted 
in the production of viable eggs within 1-3 days . 
Most eggs were successfully hatched, and the 
young were reared. Females continued to form 
viable egg sacs for 3-4 times after initial fertili- 
zation. Egg sacs formed thereafter, without 
contact with males , degenerated. Unfertilized 
egg sacs were produced for as many as four 
more times, but with progressively fewer eggs. 

Nauplii hatched directly from the egg sacs 
of the females after spending the entire pre- 
hatch period attached to the adult . This period 
lasted for 1-3 days at 23 C. and 7-10 days at 4 .4 
C. An adult female, if allowed to remain in the 
rearing chamber with a newly hatched group of 
nauplii , would eventually consume the lot . Thus 
the females were separated from the nauplii 
soon after hatching. 



239 



Naupliar duration, the period in which 
Cyclops are most subject to heavy mortality, 
was 6-10 days at 23 C . , and 17-47 days at 4 .4 C. 
There are six molts before the first copepodite 
stage . 

Rearing from egg to adult at 23 C . required 
an average of 29 .7 days . Only two specimens 
were kept alive long enough, however, to com- 
plete the cycle at 4 .4 C . They attained the adult 
stage in 110 and 120 days, respectively. These 
findings will be used to interpret field measure- 
ments . 

Some specimens, both adult and immature, 
became heavily laden with an epizooic alga 
(keyed to Chlorella ) at both temperatures . This 
algal covering commonly lead to eventual immo- 
bility and death . The alga was noted only on 
those individuals that lived in one instar for an 
extended period of time. However, some Cy- 
clops continued to molt, even though covered 
with algae. They discarded the algae covered 
with carapace and appeared to be normal. 

During January -March, samples were 
taken through the ice near Gavins Point Dam . 
Samples were also collected during the open- 
water season in the headwaters, lower reser- 
voir, and tailwaters. The tailwater sampling 
will continue during the fall and winter. The 
sampling will show numbers per liter for nau- 
plii, the five copepodite stages, and adult 
males and females , and will explain annual pop- 
ulation trends and fecundity rates . 

Jerry Novotny 

Zooplankton discharge --1964-69 

Crustacean zooplankton collected from the 
discharge by the automatic plankton sampler 
was compared to the five previous years 
(Figure 9). Daphnia, Cyclops , and Diaptomus 
declined in density from 1968 to 1969 . Diapto- 
mus showed the most drastic reduction from a 
6 year high in 1968 . In 1969 the second highest 
densities were recorded for Daphnia and Diapto- 
mus . These genera had typically low densities 
in Lewis and Clark Lake for the 6 year period 
ranging from ,65 to 2.63 per liter for Diaptomus 
and .63 to 1.17 per liter for Daphnia. 




Figure 9. — Mean annual densities in number 
per liter of Daphnia, Diaptomus , Cyclops , 
and total crustacean zooplankton from 
Lewis and Clark Lake, 1964-1969. Samples 
collected every 6 hours by automatic 
plankton sampler. 

Cyclopoids, on the other hand, continued a 
decline initiated in 1968 and reached the second 
lowest recorded yearly mean. Since Cyclops 
represent an average 76 percent of the zooplank- 
ton population, any fluctuation in total zooplank- 
ton numbers is directly associated with Cyclops 
densities . 



Jerry Novotny 



Benthos abundance --1963-69 



We summarized standing crop data and pro- 
duction rates of Hexagenia in Lewis and Clark 
Lake from 1963 to 1969, Hexagenia was the 
dominant benthic invertebrate in 1963 and reached 
peak abundance of 6.7 g/m^ (wet weight) in 1966. 
The population then declined and leveled out at 
around lOO/m^ and a biomass of 4 g/m"^. The 
average May biomass levels from the eastern 



section of the reservoir from 1963 to 1969 was 
5 .0 g/m^ while the October estimate from 1964 
to 1968 was 4 .1 g/m"^. Maximum biomass 
occurred in May 1966 at 7.4 g/m^. Highest 
biomass levels by area were 18.8 g/m^ Ln the 
shore area during October 1965; the lowest was 
0.5 g/m^ in the channel during September 1965. 
Production rates of Hexagenia follow the stand- 
ing crop levels with the maximum annual rate of 
20g/m2/yr, occurring in 1966. The annual 
turnover ratio (annual production rate /mean 
density) was estimated to be 3.0. 

Patrick Hudson 

Benthos in the limnetic zone and discharge 

We studied the occurrences of benthos in 
the limnetic zone and the discharge in 1968 to 
delineate the relations among discharge rates, 
benthos loss through the discharge, and the 
biology of the benthic organisms . Miller 
sampler tows taken immediately ui front of the 
discharge tunnels contained mainly chironomid 
larvae and pupae, Hexagenia nymphs, larval 
fish, ceratopogonids and water mites . Night 
chironomid larvae densities ranged from 8.0/ 
m"^ in May to 0.1/m^ in September and pupae 
ranged from 1.0/m^ in August to 0.2/m2 in 
July. Maximum nocturnal densities of Hexa - 
genia reached O.S/m^ in May. Larval fish 
densities ranged from 0.3/m^ in June to 0.1/m^ 
in July. 

We also studied the relations between the 
abundance of these migrating organisms in the 
water column to the biomass on the reservoir 
bottom and the crustacean zooplankton. Only 
about 4 percent of the chironomid larvae and 
Hexagenia nymphs on the bottom migrated into 
the water column at night . Length frequency 
distributions of migrating Hexagenia nymphs 
approximated those on the bottom . Although 
these insects were never as abundant as zoo- 
plankton, they comprised a significant portion 
of the plankton when zooplankton abundance was 
low . On 16 April 1969 , along the south shore of 
the reservoir, a horizontal tow at mid-depth 
yielded 1 .5 mg/m^ (dry weight) of Hexagenia 
and chironomid larvae with zooplankton amount- 
ing to 7.0 mg/m^. 

Patrick Hudson 



Tailwater sampling 

We used Miller nets in the tailwater only to 
relate the collections to those taken above the 
dam; most sampling was done with a D-Net. 
This was placed 900 meters below the Gavins 
Point Powerhouse, and fished 24 hours biweekly. 
In addition to species found in the reservoir, 
many species endemic to the tailwaters were 
collected. At least 70 species of aquatic inverte- 
brates were collected; these included 27 species 
of chironomids, 11 Ephemeroptera , 11 Trichop- 
tera, 5 Corixidae, 4 Odonata, and 3 Plecoptera. 
Seasonal differences in drift rates were large, 
with the catches highest during spring and sum- 
mer . Hexagenia nymphs reached the highest 
abundance in April and May; this is a behavioral 
response to population pressure in the reservoir. 
Trichoptera adults and pupae and chironomid 
pupae dominated catches from June through 
September as a result of normal nocturnal pre- 
emergence activity. Several species showed 
distinct seasonal and nocturnal drift patterns not 
related to emergence activities. Other species 
appeared in the drift because of physical distur- 
bances (e.g., spillway releases) or maintained 
a constant low level of drift . Analyses indicate 
that this drift is the primary food of many tail- 
water fish. 

Patrick Hudson 

Systems ecology 

We are going to analyze the Lewis and Clark 
Lake data by a compartment systems analysis 
program developed at the Oak Ridge National 
Laboratory (COMSYS). The model has been 
used primarily in terrestrial ecology. This 
stochastic program was selected because it is 
flexible, adapted to the type of data collected, 
and will work with few assumptions . The com- 
ponents that will be used initially will include 
fish (species, age, growth, and mortality rates), 
zooplankton, phytoplankton , and benthos . Five 
years of data will be used. Environmental vari- 
ables such as temperature, turbidity, water 
level, discharge rate, and wind will be related 
to the flow of energy or material between com- 
partments . Facilities at the University of South 



Dakota will be used, with Dr. George Hoffman 
collaborating. 

Norman G . Benson 



Incubating with ^^C of aliquots from each 
enriched sample was done immediately upon 
addition of the nutrient (day-0) and at subsequent 
intervals of 1, 2, and 4 days (Table 11) . 



Lake Francis Case 

Fertilization studies 

Previous work on phytoplankton standing 
crops, and primary productivity in this reser- 
voir revealed extremely low biomass and auto- 
trophic carbon assimilation during the summer 
months. The cause is unknown, but it is 
assumed that either the chemical environment 
limits phytoplankton growth or that the algae 
are being heavily grazed. Possibly both factors 
operate . 

Experiments to determine possible factors 
limiting phytoplankton productivity were begun 
in 1969. The effects of phosphorous, nitrogen, 
and potassium enrichment were studied during 
May, June, July, and August on natural popula- 
tions maintained in situ . Uptake of "C was 
used to measure the response of phytoplankton 
to various levels of inorganic enrichment . 



Addition of potassium (K) resulted in a slight 
inhibition of primary production during May. 
This effect appeared to increase with duration of 
the incubation until by day -4 C uptake was about 
one -half of that encountered in the controls. A 
progressive increase in C assimilation due to K 
enrichment was noted during June, and a final 
increase of 5 .6 times that in the control was 
obtained by day-4 . After an initial inhibition in 
July, a slight enhancement by K was obtained. 
In August, inhibition occurred. An initial in- 
crease of about 2 -fold was obtained but response 
then declined to 0.8 for the duration of the 
experiment. 

Addition of nitrate (NO^) resulted in inhibition 
during May. Nitrogen in the form of KNOo was 
added to the treatments and the results look simi- 
lar to that obtained with K alone . The strong 
possibility thus exists that, during the May 
experiment, the effect of K inhibition was being 
measured in the N treatments rather than any 



-Response of phytoplankton to enrichment by smallest 
additions of potassium (K) , nitrate (NOj) , and phosphate 
(PO^) in Lake Francis Case, 1969. Represented as: 

average disintegrations per minute of treatment 
average disintegrations per minute of control 







Day 



4 



May 



K 

NO 3 

K 

NO3 



0.8 
0.9 
0.8 

1.0 
1.1 
1.0 



0.7 
0.8 



0.5 
0.6 
1.3 

5.6 
1.7 
7.5 



July 



Aug. 



K 

NO3 
^4 



PO. 



K 

NO3 



1.1 

1.6 

11.6 

0.8 
0.9 
4.9 



1.5 

2.6 

36.6 

0.8 
0.7 
6.6 



eJEfect of N per se . N treatment in June resulted 
in less enhancement than that found in K alone . 
Therefore, it is not possible to conclude that N 
alone had any enhancement effect during this 
month. In July, a slight increase in N effects is 
shown. C uptake in the N treatmentb exceeded 
that found in either the control or the K treat- 
ments by the end of the experiment . Response 
of K and N treatment in August was similar, 
again leading to the possibility that N effect may 
be obscured by the simultaneous addition of K. 

Phsophorous had the greatest enhancement 
effect of any nutrients studied. In May, the 
increase in production was slight. Enhancement 
increased progressively to a high in July and 
continued through August . The effects of P 
enrichment appear to be rather easy to interpret. 
The P limitation is slight in spring when natural 
concentrations of inorganic P are highest. As 
natural P decreases the addition of P increased 
primary production. The rate of response to P 
additions can be followed by noting enhancement 
from day 0-4, and appears to increase logarith- 
mically. 

Little evidence of a NOo deficiency was 
found during the experiments . Only in July, 
when natural NOo concentrations were lowest, 
did NO3 addition cause increased C uptake. 
Results of K enrichment were rather compli- 
cated. In some cases enhancement was noted, 
while in others inhibition seemed to take place. 
This complexity made NOo results difficult to 
interpret. Several problems encountered dur- 
ing 1969 have been solved. 

Dan Martin 

Benthos --St. Phillips Bay (Lake Francis Case) 

This study, begun in 1968, was to relate 
benthos abundance to other chemical and bio- 
logical data , Collections were made at two 
stations in the lower end of the reservoir. 
Analysis of biweekly bottom samples taken at 
the deep (32 m) station from May to October 
showed that oligochaetes dominated (95 percent), 
averaging 3,017/m2 (range, 42-8,538/m^) over 
11 sampling dates . Major peaks occurred in 
May and August -September, with minor peaks 
in June -July and October . Chironomid larva 



averaged Yll/m^ and the rest included nematodes, 
mites, and ceratopogonids . 

Chironomid larvae dominated the shallow 
(9 m) station with average density of 789/m2 
(range, 419-2,550/m2). After an initial recovery 
due to reflooding in May the density of chirono- 
mids decreased in June and remained fairly con- 
stant into October when receding waters or 
recently hatched individuals caused a significant 
increase. The pattern of benthos development 
did not follow that found in Platte Creek in 1966 
where chironomids increased continually over 
the summer after initial reflooding and did not 
decrease until October, 

Samples were not analyzed to species, but 
adult chironomids collected from emergence 
traps in the area have been processed. Six 
forms were keyed to species, and 13 genera 
were identified. Harnischia darbyi comprised 
67 percent of the summer catch with Procladius 
sp. 16 percent. Other forms which were rela- 
tively abundant were species of the subfamily 
Orthocladiinae and the species Paracladopelma 
sp., Cryptochironomus fulvus , Parachironomus 
sp . , and Coelotanypus scapularis . 

Patrick Hudson 

Benthos monitoring Platte Bay (Lake Francis 
Case ) 

We made the fourth annual fall population 
estimate in Platte Bay in September . We sample 
4 transects at 5 foot depth intervals from 5 to 
20 feet; this amounts to about 23 samples. 
Mean chironomid densities (No/m^) from 1966 
through 1969 were: 2,360, 1.842, 2,649, 2,544, 
respectively. Because of the large number of 
species present and single sampling date it is 
difficult to assess changes without critical 
analysis of size distribution and species compos- 
ition. 

Patrick Hudson 

Colonization of flooded vegetation 

We are studying the colonization of peri- 
phyton and invertebrates on newly flooded 
terrestrial vegetation in the drawdown zone. 



It is important to understand how rapidly these 
nursery areas for young fish develop fish food. 
We planted sorghum -sudan hybrid in the draw- 
down zone in the fall of 1968 , but inadequate 
moisture and a late drawdown resulted in poor 
growth. However, natural vegetation developed 
abundantly. The terrestrial vegetation was 
flooded by rising water around 13 April 1969 
and was sampled for benthos and periphyton 
weekly from 22 April to 20 June in St. Phillips 
Bay. The dominant species of vegetation pre- 
sent at flooding were the common sunflower 
( Helianthus annuus) , horseweed ( Conyza cana - 
densis ), sedge ( Carex) , and wild lettuce (Lac- 
tuca virosa). 

It took about 25 days after initial flooding 
for stems to become completely covered with a 
layer of periphyton. The stems were initially 
colonized by the sessile green filamentous 
algae Gongrosira which remained the base layer 
throughout the study period. This layer was 
subsequently colonized mainly by diatoms with 
Navicula , Diatoma . and Fragilaria succeeding 
each other in that order from 29 April to 29 
May (Table 12) . By 6 June the lowering of the 
water level exposed most of the plants with 
periphyton. 

Aquatic Insect development did not become 
significant until 40 days after flooding and was 
still increasing when the study was terminated. 
Grab samples of vegetation on the furst two 
sampling dates contained no aquatic Insects but 
contained semiaquatic Oligochaetes and larval 
forms of terrestrial Lepidoptera and Coleoptera . 
Collections in the following weeks showed a few 
chironomid larvae and egg masses . On 22 May 
early Instars of Chlronomus attenuatus became 
extremely abundant (Table 12) . They were the 
most abundant Invertebrate until the final sam- 
pling date when the mayfly Calllbaetis and dam- 
selflies became numerous . Quantitative samples 
were taken in the vegetation and in a control 
area. The processed results will describe the 
development of fauna and flora on flooded vege - 
tat ion. 



turbidity limited periphyton development. This 
turbidity and wuidrowed vegetation resulted in 
temperatures 13 C . greater along the shore and 
in small keys than in the main body of the reser- 
voir on 22 May due to low water exchange rate. 
Carp spawning activity in the areas during May 
also caused high ttirbidity levels . Many carp 
eggs were found on vegetation on 22 and 29 May, 

Patrick Hudson 

Lakes Oahe and Sharpe 

We completed seven llmnological cruises 
on Lakes Oahe and Sharpe during which we 
measured water temperature , turbidity , conduc - 
tivity, transparency, oxygen content, phytoplank- 
ton, and zooplankton at established stations for 
purposes of determining seasonal and annual 
variations in the reservoir environment and 
assessing their effect on the fish stocks. Sum- 
maries of physical and chemical data are com- 
plete: processing the plankton samples remains 
to be done. 

Pool elevation in Lake Oahe increased from 
a low of 1,604 ft msl In mid -January to a maxi- 
mum of 1,616 ft msl In early May and remained 
fairly constant through the remainder of the 
month . Discharges through Oahe Dam into Lake 
Sharpe Increased during June and early July but 
reached record volumes during August, when 
there was a loss of 1.32 x 10^ acre ft of water 
from Lake Oahe. The impact of this high dis- 
charge was most obvious in 85 -mile long Lake 
Sharpe, where in order to maintain a relatively 
constant pool elevation, the rate of flow through 
Big Bend Dam (lower end of Lake Sharpe) equaled 
the inflow from Oahe Dam. Some of the immedi- 
ate effects Included (1) a marked decrease In zoo- 
plankton abundance, (2) a lower mean annual 
cycle of water temperature, and (3) a virtual 
absence of thermal stratification. The impor- 
tance of these and other changes to the biology 
of the fish stocks in Lake Sharpe is being inves- 
tigated but analysis of the data are too incomplete 
to permit an assessment at this time. 



Wave action on exposed vegetation quickly 
knocked down and eroded away most plant mater- 
ial and piled it along the shoreline and in small 
bays . This physical action and wave induced 



Mr. Ron Rada, a graduate student at the 
University of South Dakota, completed the sort- 
ing and counting of organisms In phytoplankton 
and zooplankton samples collected in Lake Oahe 



244 



Table 12. — Dominant invertebrates and periphytic algae found on flooded 
terrestrial vegetation in St. Phillips Bay, Lake Francis Case 
during the spring of 1969. Flooding occurred on 13 April. 









Maximum 






Invertebrates 


temperature 


Date 


Periphyton 


(*very abundant) 


(C) 



22 April 
29 April 

7 May 



Gongrosira 



Navicula 
Gongrosira 



Gomphonema 
Gongrosira 



Terrestrial forms 



Terrestrial forms 



Chironomid egg masses 
Micropsectra nigripila 
Cricotopus sp. 
Trissocladius nivoriundus 



10 



14 May 



22 May 



29 May 



Diatoma 
Synedra 
Gongrosira 
Fragilar ia 

Fragilar ia 

Synedra 

Gongrosira 

Fragilaria 

Synedra 

Gongrosira 



Cricotopus sp. 20 



Chironomus attenuatus * 

Cricotopus 

Trissocladius nivoriundus 



Chironomus attenuatus * 22 
Glyptotendipes barbipes 
Chironomid egg masses 
Aquatic beetles 



Periphyton exposed 
by drawdown 



Chironomus attenuatus * 
Glyptotendipes barbipes 
Corixidae 



20 June 



Periphyton exposed 
by drawdowi 



Chironomus attenuatus ^ 
Callibaetis * 
Damself lies* 
Tanypodinae 



from 1966 to 1968 . Some of the more important 
features shown by the phytoplankton data were 

(1) relatively low overall densities, combined 
with a general decline during the 3 -year period, 

(2) higher densities and a greater diversity of 
organisms at the mid -reservoir stations, and 

(3) low densities and few kinds of organisms at 
the downstream stations , Of 54 genera of phy- 
toplankers found in the samples , only three 
( Asterionella , Rhodomonas , and Cryptomonas ) 
were consistently represented at most stations, 
and seven were considered to be of major 
importance . Completion of the phytoplankton 
analysis will permit us to subject all of the 



physical and biological data collected during 
the 3-year period to computer analysis. 

We held two workshops in Pierre for pur- 
poses of reviewing our limnological studies in 
Lakes Oahe and Sharpe, discussing long-term 
research goals and needs , and coordinating 
our studies with those of other State and Federal 
agencies. One of the immediate results of the 
workshops was an exchange of data collected by 
the various agencies. We distributed summar- 
ies of our chemical and physical station data 
and wUl soon disseminate the plankton data. 

Fred June 



245 



SOUTH CENTRAL RESERVOIR INVESTIGATIONS 

Fayetteville, Arkansas 
Thomas O. Duncan, Chief 



HIGHLIGHTS 

Gizzard shad larvae show progressive 
seasonal changes in vertical distribution, with 
concentration near the surface in late April, 
shifting to 5 meters in late May. Threadfin shad 
larvae appeared in greatest numbers along 
shorelines in May, but peak densities alternated 
between shoreline , open water surface and 5 
meter samples thereafter . Both species moved 
to deeper water following prolonged strong 
winds in June . 

SCUBA was used in placing and retrieving 
benthic fauna samplers in the littoral region of 
Beaver and Bull Shoals reservoirs. Fish exclud- 
ers of different mesh sizes were placed around 
some of the samplers . Although ceramic pot 
samplers are not the final answer, they are well 
suited for comparative studies by offering a 
uniform dimension and functioning over a wide 
range of substrates . 

Avoidance of bluff habitat by spawning 
spotted bass appears to be positively correlated 
with high water levels . The number of spawning 
spotted bass in Bull Shoals reservoir along an 
800 yard bluff was much smaller in 1968 and 
1969 when water levels were about 20 feet higher 
than in 1965 , 1966 , and 1967 . Nests of spotted 
bass in coves were of expected densities suggest- 
ing more attractive spawning habitat due to inun- 
dation of dense vegetation. A positive correla- 
tion between nest depth and water transparency 
has been confirmed. 

Gill net sampling indicates white bass have 
sharply increased in Beaver and Bull Shoals 
reservoirs. Increases are attributed to a 



strong 1968 year class in both reservoirs --a 
year of high runoff and water levels . Walleyes 
also showed an increase in Bull Shoals reservoir 
with catches up from 0.22 fish/net day in 1968 
to 0.91 fish/net day in 1969. 

Midwater trawl sampling of shad populations 
in Beaver reservoir provided new information on 
growth and population size and revealed a strong 
positive correlation between shad abundance and 
white bass growth. Production of threadfin and 
gizzard shad in Beaver has exhibited great varia- 
tion from year to year. 

Coverotenone sampling in Bull Shoals showed 
a decrease in total standing crop, due to a large 
decrease in adult gizzard shad. There was an 
increase in the intermediate and adult largemouth 
bass standing crop. Rotenone samples in Beaver 
indicated lower growth -rate and production of 
young -of -year largemouth bass in 1969, accom- 
panied by a decrease in standing crop of inter- 
mediate and adult largemouth bass . 

White bass eggs were hatched in jars and 
reared in aquaria to over 40 millimeters total 
length. Slight drops in temperature from incu- 
bation until feeding begins (10th day) are posi- 
tively related to mortality. 

Recaptures in Beaver of white bass from 
spawning ground tagging indicate a more complete 
distribution over the reservoir than in 1967-68. 
Slightly more than one -half of the tags recaptured 
by fishermen were voluntarily returned to us . 



INTRODUCTION 



Shad population estimation 



A wet spring and a dry summer and fail 
occurred in 1969. Power generation outflows 
and evaporation lowered the Beaver Reservoir 
pool level 21 .7 feet between February and 
December . The water level in Bull Shoals 
Reservoir dropped 23.9 feet in the same period. 



Sampling shad populations with midwater 
trawls in both reservoirs continued. Population 
estimates were calculated for July through 
October in Beaver and July through September 
in Bull Shoals . Populations in both reservoirs 
were smaller than those of 1968 . 



POPULATION DYNAMICS 

Gill net sampling 

The annual January, 1969 gill net sample 
from Bull Shoals suggested a sharp increase in 
abundance of white bass . Catch per net day 
increased from 4 .33 in 1968 to 9 .51. This in- 
crease is attributed to a strong 1968 year class . 
The abundance of walleye has increased since 
1967 when catch per net day was only 0.05 to 
0.22 in 1968 and finally to 0.91 in 1969. White 
crappie had been absent in the sample for two 
years, but 0.38 per net day were taken in 1969 . 
Abundance of gizzard shad, plains and highfin 
carpsuckers increased slightly in 1968, while 
other species exhibited no important changes . 

White bass in Beaver increased from .73 
in 1968 to 6.02 per net day in 1969, becoming 
the most abundant species in the sample. This 
increase was due to the strong 1968 year class . 
Except for a sharp decrease in 1967, white 
bass numbers have progressively increased 
through 5 years of sampling and now dominate 
the catch. With this change, the gill net catch 
composition in Beaver has become similar to 
that of Bull Shoals . 

In the January 1969 sample, gizzard shad 
was the second most abundant species, with 2.62 
captured per net day. Carp were third in 
abundance, but showed a decrease to less than 
one -half the 1968 catch. White crappie appeared 
for the first time in 1968 when 0.09 per net day 
were captured. In 1969, there was an increase 
to 0.16 per net day. Black crappie reached peak 
abundance in 1966, when 0.46 per net day were 
captured. They have progressively decreased 
since, with only 0.02 captured per net day this 
year . Numbers of walleye were greater than in 
1968 , but lower than in the three previous years . 



Estimates on Beaver through 1966-1969 have 
been used to estimate annual production of 0- 
age shad. Production values have been computed 
for periods starting in the summer as soon as 
shad have grown large enough to be effectively 
captured in the midwater trawls and continued to 
the end of the year. 

Production in Beaver during the 4 -year 
period is shown graphically as the area under 
the curves in Figures 1 and 2. Estimates of 
production reveal enormous variation from year 
to year. Threadfin shad production in 1966 was 
2.76 grams per square meter, 0.07 in 1967, 
6.86 in 1968, and 1.09 in 1969. 

Gizzard shad production in 1966 was 2.52 
grams per square meter, too small to measure 
in 1967, then 4.39 in 1968, and 0.15 in 1969. 

Comparison of white bass growth and shad 
production shows a direct relation. When shad 
production is high, white bass growth is good; 
when it is low, as in 1967, white bass growth is 
extremely poor. 



S t 
SI 2 



19(6 1967 
Vo_D « S 


\* 
\ 1968 

V. 


1969 



2 



3 12 

MEAN WEIGHT IN GRAMS 



Figure 1. — Monthly changes in population 
numbers and average individual weights of 
0-age threadfin shad in Beaver Reservoir, 
1966-1969. 



247 



b 




M 






4 


1966 
June 




1968 


1969 


3 


\ J 


J 






2 
1 




\j 


\^ 






\a 

\lO_D 




\d 


' L. S D 



1 2 



3 12 3 4 
MEAN WEIGHT IN GRAMS 



1 2 



Figure 2. — Monthly changes in population 
numbers and average individual weights of 
0-age gizzard shad in Beaver Reservoir, 
1966-1969. 



Cooperative study 

Additional fish population studies using 
midvirater trawls were conducted on Barren 
River and Nolin River Reservoirs in Kentucky 
in July. The study by the Kentucky Department 
of Fish and Wildlife Resources and Western 
Kentucky University under supervision of the 
Sport Fishing Institute is designed to demon- 
strate effects of high level and low level water 
releases on fish populations, fishing, plankton, 
benthos and water quality. Our midwater trawl 
sampling was to define vertical distribution of 
fish in the pelagic zones and estimate shad 
populations . 



begun in Bull Shoals . Blue catfish were recovered 
for the first time since their introduction in 1967. 

The reproduction or survival and growth of 
young -of -year largemouth bass was lower in 1969 
than in 1968 . While the growth rate of young 
spotted bass remained about the same, reproduc- 
tion or survival slightly decreased. With the 
exception of the bluegill, young-of-year sunfishes 
reproduction or survival decreased. Intermedi- 
ate and adult sunfish production also showed 
decreases from that of 1968 . 

Standing crop estimates from cove retonone 
samples in Beaver suggest slower growth and 
lower production of young-of-year largemouth 
bass than in 1968 , and a decrease in intermediate 
and adult largemouth bass . Growth of young-of- 
year spotted bass was slightly faster, although 
production of young-of-year, intermediate and 
adults remained about the same. Intermediate 
and adult channel catfish decreased slightly from 
last year. With the exception of the bluegill, 
young-of-year sunfish production decreased. 
Intermediate and adult bluegill and longear sun- 
fish increased and green sunfish decreased. 

Young-of-year threadfin shad crops reached 
an all-time high in 1969 of 42.8 lbs. /acre. The 
increase in total standing crop from 402 .4 lbs ./ 
acre in 1968 to 444 .4 lbs. /acre in 1969 is attri- 
buted to larger adult gizzard shad and young-of- 
year threadfin shad crops . 

Largemouth bass population estimates 



Alfred Houser 



Cove rotenone sampling 



The total standing crop estimate derived 
from 1969 cove rotenone sampling on Bull 
Shoals showed a decrease from 1968 . This 
difference was due primarily to a decrease ui 
adult gizzard shad. Increases were noted In the 
Intermediate and adult largemouth bass popula- 
tion. The young-of-year threadfin shad crop 
was at its highest since 1966, equaling 6.7 lbs./ 
acre . The carp standing crop also reached its 
highest since 1966. The standing crop of Inter- 
mediate and adult channel catfish reached an 
all-time high since cove rotenone sampling was 



Attempts were made In 1968 and 1969 to 
estimate the largemouth bass population in Beaver 
by the Schnabel mark and recapture method along 
2.4 miles of a 75 -acre cove shoreline. We used 
a boom -type shocker with a 230 volt a .c . genera- 
tor to capture the fish, and a Floy FD-67 tag on 
fish over 200 mm. Fish less than 200 mm. were 
marked with a caudal fui clip. Eight nights of 
capture, mark and recapture began April 28 and 
ended May 15 . 

After 5 nights of tagging and recapture , 267 
fish over 200 mm . were tagged and 24 percent 
recaptured, yielding an estimate of 672 (280/ 
shoreline -mile). After 6 nights of shocking, 
238 fish less than 200 mm . were marked and 



24 percent recaptured, yielding an estimate of 
868 (360/shoreline-mile). 

In comparison, estimates from the same 
Beaver cove shoreline in May, 1968 showed 105 
fewer bass greater than 200 mm , and 700 fewer 
bass less than 200 mm. The latter estimate 
provides dramatic evidence of the highly sue - 
cessful 1968 year class of largemouth bass 
associated with rising spring water levels and 
great numbers of young-of-year shad. 

In Bull Shoals we selected a much larger 
cove of 395 acres with a shoreline of 8.9 miles 
to estimate the largemouth bass population by 
the Petersen method. This cove required 4 
nights (April 7 -10) of tagging and marking to 
cover the entire shoreline and 4 nights (April 
14-21) of recovery of marked fish to estimate 
the population. As in Beaver, separate esti- 
mates were made of fish over and under 200 



For fish over 200 mm . , we tagged 283 fish 
and 23 percent recaptured, yielding an estimate 
of 1,174 fish (132/shoreline-mile). For fish 
less than 200 mm . , 485 were marked and 21 
percent recaptured, providing an estimate of 
2,510 fish (237/shoreline-mile). 

Considering the time involved per mile of 
shoreline and the percentage of recovery of 
marked fish, the Petersen method of estimating 
the population seems more practical than the 
Schnabel method. Shorter sampling periods 
should reduce errors introduced by extensive 
fish movement . 

Age and growth of largemouth bass 

In conjunction with the cove population 
estimates in 1968 and 1969 in both reservoirs, 
we collected largemouth bass scale samples 
for age and growth data. During 1969, we read 
1,045 scales . The data were entered on IBM 
cards and a 7040 computer was used to calculate 
length -weight and body scale relations, and 
growth . 

Horace E . Bryant 



Exploratory sampling for young-of-year fish 

Exploratory sampling continued into its 
second and final year. Objectives were to find 
(1) sampling techniques for age group fish 
suitable for White River reservoirs; (2) distri- 
bution patterns for the major species; and (3) 
population estimation methods for young fish. 

The 1969 effort concentrated on meter net 
sampling with a modified sampling design based 
on 1968 results . Intermittent collections began 
March 27, with a regular weekly sampling sched- 
ule from April 23 to July 24 . Except for inter- 
mittent collections in the upper end of the reser- 
voir and a reservoir -wide series made in one 
night, all sampling was in the Prairie Creek 
arm near the middle of Beaver reservoir. One 
night each week was spent sampling from the 
upper end of the Prairie Creek arm, the following 
night from the main channel at the mouth of 
Prairie Creek. Three samples were taken each 
night from each of the following: surface along 
shore, surface in mid -channel, 5 meters, 10 
meters, and at 15 meters in the main channel 
area where depth permitted. Sampling sequence 
was random and hauls were standardized at 5 
minutes each at 1500 rpm . Each haul filtered 
approximately 360 cubic meters of water at a 
towing speed of approximately 3 .4 miles per 
hour. 

Catch rates for all species varied consider- 
ably with date, depth, and even within replicates, 
but enough consistency was obtained for the 
major species taken to determine approximate 
spawning period, gross distribution patterns, 
early growth rates and an index of numbers pre - 
sent. 

Species composition, dates captured and the 
date of highest mean density are shown in Table 
1. Composition is similar to the 1968 meter net 
catch. 

The spawning period was estimated for both 
shad species by back plotting growth curves . 
Shad pro larvae were not taken consistently in 
the Prairie Creek samples . The catch was 
apparently influenced by larvae drift into and out 
of the sampling area. Gizzard shad spawned 
from the second week of April to the third week 



249 



Table 1. — Composition, first and last dates captures, and week and mean density of highest 
catch of identifiable larval fishes captured by meter net in the Prairie Creek 
area of Beaver Reservoir, Arkansas, April 23 to July 24, 1969. Based on 120,796 
fish from 357 hauls. 





Pe 


rcent of 


Dates 


captured 


Maximum mean 


density 


Species 


total catch 


First 


Last 


Dates 


Numb 


;r/l 


000 m-^ 


Gizzard shad 




46.7 


4-30 


7-24 


5-14/15 






1955 


Threadfin shad 




32.5 


5-21 


7-24 


6-18/19 






893 


Lepomis, sp. 




13.7 


5-21* 


7-24 


6-18/19 






464 


Pomoxis sp. 




5.3 


4-30 


7-24 


5-14/15 






247 


Brook silversides 




1.0 


5-28* 


7-24 


7-16/17 






31 


White bass 




0.5 


4-30 


6-19 


5-14/15 






25 


Log perch 




0.1 


4-23 


5-22 


4-30/31 






16 


Micropterus sp . 




■(;** 


5-21 


5-29 


5-21/22 






2 


Carp 




t 


5-7 


7-10 


5-28/29, 


6-11/12 


t* 


Channel catfish 




t 


6-18 


7-24 


6-18/19 






t 


Black bullhead 




t 


- 


- 


7-2/3 only 




t 


Flathead catfisn 




t 


- 


- 


6-25/26 


only 




t 



* Age group I + taken earlier; this is the first date larval were captured. 

3 3 

** Less than 0.1 percent of total catch, or less 1/1000 m . (1,000 m equals 0.81 acre- 
foot . ) 



of June and threadfin from the first week of May 
to about July 1. This was a longer spawning 
period for both species than in 1968 and could 
be due to warming in the reservoir. Surface 
temperatures increased steadily and rapidly to 
83° F . on May 29 . Temperatures then dropped 
to 75° F. on July 5 and remained in the mid-70's 
throughout June but then increased rapidly into 
the 80's again about July 1. 

We collected white bass eggs in the extreme 
upper end of Beaver on March 27 (the earliest 
sample taken) but the first prolarvae were not 
taken until April 10. Spawning continued through 
the third week of April . Crappie spawned from 
about mid -April until late June. Sunfish and 
brook silversides began spawning about mid- 
May and continued throughout the remainder of 
the sampling period. 

Distribution patterns have not been deter- 
mined for all species, but gizzard shad (Figure 
3) seem to show a progressive seasonal change 
from concentration at the surface of both shore- 
line and mid-channel areas in late April and 
early May; to surface at the shoreline, and 
surface at mid-channel and 5 -meter depths in 
mid -May; to the 5 -meter depth for the remainder 



of the period. An exception to this pattern 
occurred on June 25 and 26, when numbers at 5 
meters dropped drastically, but an increase was 
noted at the 15 -meter depth. Several days of 
very high winds which completely mixed the 
upper 30 feet of water preceded this distribution 
shift. 



mmM 



APR MAY JUN JUI 

Figure 3. — Depth distribution of gizzard 
shad in the Prairie Creek area of Beaver 
Reservoir, by alternate weeks from April 
30 to July 24, 1969. Mean number/1000 m3 
depict from left to right: surface along 
shore; mid-channel surface, 5 meters, 10 
meters, and 15 meters. 



250 



2332 

Q 



^ 



28-29 
MAY 



a 



1549 

a 



(L 



11-12 25-26 

JUNE 



^: 



9-10 23-24 

JULY 



Figure 4. — Depth distribution of threadfin 
shad in the Prairie Creek area of Beaver 
Reservoir, by alternate weeks from May 28 
to July 24, 1969. Mean number/1000 m^ 
bars for each week depict from left to 
right: surface along shore; mid-channel 
surface, 5 meters, 10 meters, and 15 
meters . 

Threadfin shad occurred in greatest 
numbers in samples along the shoreline in May 
after which peak abundance alternated between 
the shoreline, surface and 5 meter samples for 
the remainder of the sampling period (Figure 4). 
Highest density occurred at the 5 -meter depth 
on June 25-26. During the same period, there 
was a noticeable drop in the surface catch in 
mid -channel, due to movement caused by the 
wind and mixing conditions mentioned previously. 
The density at 10 and 15 meters was always less 
than at any of the shallower depths. 

Analysis of variance of gizzard shad density 
and distribution showed significant differences 
between weeks and between depths but no differ- 
ence between locations (main channel compared 
to tributary arm). There was interaction be- 
tween week and location and between week and 
depth , Taking each week individually, and 
comparing locations by depth, significant differ- 
ences were obtained only three weeks at the sur- 
face and at 5 meters. Comparing both the main 
channel and tributary arm, differences between 
depths were obtained in 7 of the 11 weeks. 

Nerval F . Netsch 



Beaver Reservoir sport fish catch 

Estimations of angler effort and harvest 
on Beaver Reservoir continued during the fifth 
year in cooperation with the Arkansas Game and 
Fish Commission and the U.S. Corps of 
Engineers . 

From June 1968 - May 1969 , anglers spent 
521,600 hours, or 122,800 angler -days, harvest- 
ing about 461,900 fish weighing 518,700 pounds. 
This is a 17 percent increase in weight over the 
previous 12 months, even though estimated total 
effort was slightly less this year (Figure 5). 






1964 ' 1965 ' 1966 ' 1967 ' 1968 ' 1969 

Figure 5. — Annual fishing effort in angler 
days per acre (front) and yield in pounds 
per acre (rear) on Beaver Reservoir, 
Arkansas, from June 1, 1964 through 
May 31, 1969. The reservoir was impounded 
in December, 1963. 

Twenty-eight percent of total angler activity 
occurred from June through August , 13 percent 
during the fall, 2 percent during the winter, and 
56 percent during the spring. 

Yields of largemouth bass and crappies 
increased over the previous census year, but 
harvest of other species declined (Figure 6). 
During the white bass spawning run this spring 
many were caught in the upper reaches of the 
reservoir beyond the aerial count route and 
docks visited by the creel clerk. Estimates for 
white bass are therefore conservative. 

Beaver Reservoir is following the same 
general pattern of yield reported by Missouri 
Conservation Commission biologists during the 
early years of Table Rock and Bull Shoals 
Reservoirs (Figures 7 and 8). Harvest estimates 
on Table Rock and Bull Shoals were conducted on 



251 



largemouth 
Bass 

Spotted Bass 




1964 ' 1965 ' 1966 ' 1967 ' 1968 ' 1969 

Figure 6. --Annual harvest of various sport 
fishes, in pounds per acre, from Beaver 
Reservoir, June 1964 - May 1969. 



/\- 




1 



3 4 5 6 7 

Age of reservoir in years 



8 



Figure 7. --Harvest estimates from Beaver 
Reservoir compared with adjusted harvest 
estimates (see text) from Bull Shoals and 
Table Rock Reservoirs during their early 
years of existence. 

selected major arms and upstream areas but 
adjusted to account for the fact that the censuses 
did not cover (Missouri D-J reports by Burress, 
Hanson, Funk and Fry). These areas typically 
have shallower mean depths, higher relative 
shoreline lengths , higher dissolved solids , and 
are more heavily fished than downstream , open 
water areas in Beaver , The proportion of the 




BLACK BASSES 

ANGLER HARVEST 



\- 

\ 

0- I I I I I I . 

1 2 3 4 5 6 7 8 

Age of reservoir in years 

Figure 8. --Black bass harvest estimates 

from Beaver Reservoir compared with adjust- 
ed black bass harvest estimates (see text) 
from Bull Shoals and Table Rock Reservoirs 
during their early years. 

total harvest accounted for by the upstream cen- 
sus zone of Beaver (comprising one -fourth of the 
total reservoir area) has increased with age of 
impoundment. Factors used for converting pre- 
vious harvest estimates in arms and upstream 
areas of Bull Shoals and Table Rock to total 
reservoir harvest per acre were drawn from the 
Beaver data as follows: first year of impound- 
ment, 1.00; second year, 0.96; third year, 0.80; 
fourth and later years, 0.50. 

David 1. Morals 

LIMNOLOGY 

Physicochemical limnology 

Monitoring of selected physical and chemical 
parameters continued on both impoundments . 
Sampling in Beaver was handled through contract 
with the University of Arkansas . Winter and 
spring water levels were well into flood pool on 
both reservoirs . Specific conductance and 
Secchi transparencies were generally lower 
than at comparable times in previous years , 
particularly during January and February. 
Water levels began falling in May and conduct- 
ance and transparency readings generally 
increased throughout the remainder of the year. 



252 



_0.0 0.2 0.4 0.0 0.2 0.4 0.6 0.8 1.0 



Uptake -- 
Downlake - 





,r"-' 


E " 


\ \ 














sz 


1 N 


■f-t 




Q. 




(D 




3 30 






BEAVER 
\ 


40 


\ 


50 






0.0 02 0.4 0.0 0.2 0.4 0.6 0.8 1.0 

Dry weight (g/m^) 

Figure 9. — Average profundal benthic bio- 
mass estimates of uplake and downlake 
transects on Beaver and Bull Shoals 
Reservoirs, as indicated by Petersen 
dredge collections, January-June, 1969. 

Macroscopic profundal bottom fauna 

Field collections were completed on a one 
year survey of the profundal benthos in Beaver 
and Bull Shoals . Comparisons of uplake and 
downlake regions of both impoundments were 
emphasized. Results from the January through 
June collections indicate a higher standing crop 
in the uplake region of both impoundments 
(Figure 9). A winter maximum in profundal 
benthic biomass appears typical for these 
impoundments . 

The abundance of profundal organisms 
appeared to vary with the thickness of bottom 
sediments. Along the edges of the old river 
channel, and in areas with a steep sloping 
bottom , the benthos was poor . This may have 
involved sampling efficiency, as the lake bottom 
in these areas was often sufficiently compact to 
prevent dredges from biting deeply. 

Immature stages of Chaoborus sp. and 
Chironomus attenuatus were abundant in the 



uplake region of both impoundments , but only 
meagerly represented in the downlake areas. 
Oligochaetes dominated collections from the 
downlake transects . Vertical movements were 
common among larvae of Chaoborus and C . 
attenuatus during the warmer portions of the 
year. 

A comparison of the littoral macroscopic bottom 
fauna of Beaver and Bull Shoals reservoirs 

Extreme structural heterogeneity in the 
littoral of both impoundments has produced 
rather severe sampling limitations. Convention- 
al dredging has been ineffective. Shallow ceram- 
ic pots (12" inside diameter) filled with natural 
substrate and exposed for 28 days have been 
tested and used. Approximately 160 of these 
devices were set out during the late summer and 
100 percent recovery was obtained using SCUBA. 

These samplers have some limitations. 
Cold water imposes a seasonal SCUBA limitation 
which prevents 12 -month studies. At best, field 
collections can be conducted 9 months of the year. 
SCUBA also limits the maximum depth at which 
these samplers can be used. However, the 
sampler appears well suited to comparative 
studies as it offers a sampling unit of remark- 
ably uniform dimension and will function over a 
wide range of substrates. To date, studies 
involving ceramic pots have been designed to: 

(1) Measure chironomid species diversity 
from selected littoral substrate as a 
measure of benthic community develop- 
ment and stability in impoundments of 
varying ages; 

(2) Evaluate fish predation effects on 
the littoral benthic community; 

(3) Monitor long-term changes 
associated with aging of White River 
impoundments . 

Identification problems with some immature 
chironomids have delayed the analysis of ben- 
thos samples designed to measure chironomid 
species diversity. Samples from coarse rubble, 
gravel, sand, and silt have been collected. 
These are compared with regard to chironomid 



253 



Table 2. — Mean dry weight (g/m^) of benthic biomass, and percent deviation from the 
control, of ceramic-pot collections in which fish were differentially 
excluded. 



Beaver Reservoir 



Bull Shoals Reservoir 
Weight Percent deviation Weight Percent deviation 



Control (no frame J 
Frame only 



Frame with 1/4' 
mesh top 



Frame with 1/4" 
mesh excluder 



.105 



.060 



.141 



- 7 
-43 



.100 
.151 
.067 

.190 



+ 51 
- 33 

+ 90 



Frame with 5/8" 
mesh excluder 



Frame with 1" 
mesh excluder 



.195 



.119 



+ 84 



+ 97 



species diversity, and general levels of benthos 
standing crop in each substrate . 

Mass chironomid rearing was conducted at 
intervals throughout the year with approximate- 
ly 30 associations having been obtained to date. 
This work will be continued on an expanded bas- 
is during the late winter and spring months of 
1970. A chironomid reference collection is 
being assembled. When completed, this will 
include permanent slides of all life stages and 
keys to identification of reservoir species . 

Tests designed to evaluate the effects of 
fish predation on littoral benthic organisms 
were conducted during the late summer . Small 
frames (16 x 16 x 12 inches), some of which 
were covered with various sized nylon net 
material, were used to exclude fish. These 
were placed over the ceramic pots buried in 
silt at water depths of 5 meters in both reser- 
voirs and recovered after 28 days exposure. 
Structural barriers to fish predation resulted in 
an increase in benthos standing crop of near 100 
percent in several instances (Table 2). An ex- 
cluder of 5/8" bar mesh appeared most desir- 
able in these tests . A one -inch mesh excluded 
sunfish over 70 mm. total length. Attempts to 
shade areas without providing protection from 
predation resulted in a decrease in benthic 



standing crop . Small sunfish were numerous in 
the study area of both impoundments. Shading 
provided protection for sunfish, and probably 
fostered increased predation. There was con- 
siderable evidence of carp predation in Beaver 
Reservoir. This may explain the increase in 
benthic standing crop where frames only were 
placed over sampling devices. Chironomids, 
Stenonema and Caenis increased in abundance 
where protection from predation was provided. 
Large burrowing forms, including Hexagenia and 
some oligochaetes , showed little difference, 
indicating selective predation. Additional 
attempts to evaluate predation effects are 
planned for 1970. 

Littoral benthos samples were collected 
along transects during the late summer in the 
mid-lake regions of both impoundments. Stand- 
ing crops of benthic invertebrates were highest 
near the shorelines and generally declined lake- 
ward (Figure 10) . In Bull Shoals , Stenonema and 
Caenis naiads were abundant at depths of 1-3 
meters and declined rapidly lakeward. Naiads 
of Hexagenia were encountered wherever silty 
areas occurred within the littoral region. In 
Beaver Reservoir, the mayfly fauna was more 
poorly developed. Chironomids were the most 
abundant forms in both impoundments. However, 
the mean size of these organisms was small and 



254 



some estimate of production rates will be 
needed before their contribution to the total 
benthos biomass can be assessed. In Bull Shoals 
Reservoir, chironomid abundance was highest 
near the shoreline (1 meter) and in the upper 
IX)rtion of the thermocline (9 meters). Chirono- 
mids were most abundant at 3 meters depth in 
Beaver Reservoir and reflected a rapid rate of 
shoreline erosion and shallow redeposition in 
this recently created impoundment, Chironomid 
abundance appeared to vary directly with the 
amount of siltation in Beaver Reservoir. Chao - 
borus larvae were more abundant in Beaver 
littoral samples than in Bull Shoals samples . 

Larry R. Aggus 

LIFE HISTORY 

Underwater studies 

The weekly underwater SCUBA monitoring 
transects in Bull Shoals and Beaver which began 
experimentally in 1968 were expanded for the 
purpose of determining similarities and differ- 
ences in reproductive requirements and spawn- 
ing behavior of largemouth, smallmouth and 
spotted bass . 

Observations in Bull Shoals began on April 
15 when the water temperature reached 57° F . 
at 10 feet. Water level at the onset of spawning 
was approximately the same as in 1968 and 21 
feet higher than when spawning began in 1967 . 
As in 1968, no bass nesting was observed in the 
800 -yard steep bluff study area, a preferred 
spawning habitat of spotted bass in 1965, 1966, 
and 1967 . Avoidance of bluff habitat for spawn- 
ing by spotted bass is correlated with high water 
level, because during each of the 3 years of 
observation before 1968, water level at beginning 
of spawning was at least 15 feet lower . Nests of 
spotted bass in coves occurred at expected 
densities along with largemouth and smallmouth 
bass, suggesting that the increased cover avail- 
able in coves where dense vegetation was inun- 
dated may have created an equally attractive 
spawning habitat. 

Spotted bass were first observed spawning 
in Bull Shoals during 1969 on April 16 when the 
water temperature was 59° F . at nest depth . 



a 
« 



2 


' 1 r- T » 




/ ^^ 








\ \ 




\ \ 


4 


\ ^ 




\ \ 




\ \ 




\ / 




\ / 


6 


\ / 
\ / 




\/ 




/\ 




\ 




8 


- 


\ 

\ 




/ 




/ 


10 


/ 




/ 




/ 


14 


1 • ■ 1 



0.0 0.2 0.4 

Dry weight (g /m^) 



0.6 



Figure 10. — Mean littoral benthic biomass 
estimates from transects in the mid-lake 
region of Beaver and Bull Shoals Reser- 
voirs, as indicated by collections in 
ceramic pots, July-August, 1969. 

Largemouth and smallmouth bass nests were 
found one week later when the water temperature 
was 60° F. Reproductive activity continued 
through May for all three species with break-up 
of the last fry schools during the first week of 
June. 

Four cove transects in Bull Shoals each week 
covered approximately 2,300 yards of habitat 
typical of the lower one-third of the reservoir. 
Within this shoreline distance, 53 fresh bass 
nests were found between April 16 and May 20. 
No preference among the three species for nest- 
ing substrate was apparent. However, there 
was some indication the species were selective 



-Numbers and depths of centrarchid nests encountered during 
weekly underwater transects of 2,300 yards of cove habitat 
in Bull Shoals during April and May, 1969. 





Nest depth 


Average 


Number of 


range 


nest depth 


nests 


(feet) 


(feet) 



Largemouth bass 
Spotted bass 
Smallmouth bass 
White crappie 
Black crappie 



31 
13 
32 



2.5- 5 

4 -13 

5 -10 
7 -15 
5 -13 



6.5 
7 
10 



in nest depths (Table 3). These differences in 
nest depth preference may be minimal since 
wSLter transparency was relatively low and nests 
may have been concentrated at unusually shal- 
low levels . Data previously collected indicated 
greater depths are utilized for nesting when 
water transparence is high. 

An 11 -foot drop in water level in Bull 
Shoals during May appeared to adversely affect 
survival of fry schools. The densities of nests 
in egg and larval stages were similar to those 
observed in 1968, but the number of subsequent 
fry schools was much lower. Most guarded fry 
schools were observed for a shorter duration 
than in 1968 , which suggests they may have 
suffered heavy mortalities from predation as 
the falling water forced them from cover . 

In addition to observations of bass nesting, 
white and black crappie nests encountered dur- 
ing the cove transects were enumerated (Table 
3) . Black crappie nests had not been observed 
during the preceding four years . 

Weekly underwater observations in Beaver 
Reservoir included two cove transects of 330 
yards each and one of 320 yards on bluff habitat. 
Thirteen largemouth and 6 spotted bass nests 
were found in the cove transects while only 1 
largemouth and 1 spotted bass nest were 
observed on the bluff between April 24 and May 
29 . No smallmouth bass or crappie nests were 
found . 

Louis E . Vogele 



Identification keys for larval and juvenile fishes 

We were successful in artificial rearing of 
white bass to 45 millimeters . Before the 
stripping and fertilization operation on April 11, 
1969 , larvae had survived for only limited 
periods after hatching. Eggs were stripped and 
fertilized directly into a plastic hatching jar 
containing a shad tube and a piece of snug -fitting 
2 -inch thick treated matting. Neither bentonite 
nor rennet was used to separate eggs . The 
water used for incubation was filtered through 
fine gravel . The filter reduced the copepods to 
a low level, drastically reducing predation dur- 
ing the first four days after hatching. 

Water temperatures in the hatchery system 
indicate larval white bass are sensitive to tem- 
perature drops of 5° F. (2.2° C). Mortality 
attributed to temperature drops was estimated 
at 50 percent per lot, although the larger, more 
aggressive larvae appeared to survive. 

Transportation of eggs from spawning 
grounds, where they are stripped and fertilized, 
to the experimental hatchery must be done by 
boat or vehicle. Neither is desirable due to 
vibration and its effect on eggs , even those which 
are water -hardened. The viable eggs were 
transported by boat on calm waters . 

Feeding began between the seventh and tenth 
days when larvae assumed a horizontal swimming 
position (about 4 .2 millimeters total length). 
Very finely ground, dry prepared meal (ground 
fines) was used initially. The larvae were 
observed to skim the surface a few moments 
after the food introduction, eatiag some of the 



finer particles . This meal was also introduced 
wet, but did not appear to be as acceptable. 
When the larvae reached about 4 .5 millimeters 
total length (12th day) diey were provided a 
small amount of natural food collected in a 
No . 10 mesh meter net . They readily accepted 
this food. Copepods present in the plankton 
catch were not observed to prey on the white 
bass larvae. Shad larvae were also taken in the 
tow and were eaten by white bass larvae. A 
few weeks later, larval shad captured by mid- 
water trawl were fed to the white bass. Many, 
however, were dead or dying and, although 
several were consumed, most were rejected. 
Later an attempt was made to feed young brook 
silversides to white bass; they were not eaten. 
It was our impression that the older larval 
shad and the brook silversides were too large 
to be acceptable . Larval carp were also fed to 
white bass and rejected. 

Black and white crappie were hybridized 
and reared successfully. We agree with biolo- 
gists of the Illinois Natural History Survey that 
hybrid crappie are more abundant in nature 
than previously believed. Cliaracters are so 
similar that a hybrid parent may have been 
used in this experiment. 

We obtained a few northern pike fry from 
the Arkansas Game and Fish Commission and 
reared them in our barge -mounted hatchery. 
When about 60 mm . long, these fish were fed 
two young carp (about 25 mm . total length) 
per day. 

Studies of changes in morphometric char- 
acters of white bass during larval development 
were begun. A series of photomacrographs 
were taken of a specimen from each sample 
collected. 

Movements of sport fishes in Beaver Reservoir 

We began mark and recapture study of 
several species of sport fish in Beaver Reser- 
voir in the fall of 1967. Trap nets and electro- 
fishing equipment , the principal gears used to 
capture fish for marking, were fished from fall 
to spring. Four trap nets were used in 1967-68 
and six in 1968-69. The six trap nets in 1968- 
69 were fished in the mid -reservoir region. 



and in two major tributary arms of Beaver 
Reservoir. We used electro -fishing on the 
spawning grounds and in areas immediately 
below the spawning grounds . Hook and line 
fishing in early February several miles below 
the spawning grounds accounted for 106 white 
bass tagged, plus two recaptures from the other 
jxjints of marking. A summary of mark and 
recapture results is presented in Table 4 . 

In 1968-69, over twice as many white bass 
were marked as in 1967 -68 . Trap nets accounted 
for 1,276 white bass in 1967-68 and 1,660 in 
1968-69 . Electro -fishing on the spawning 
grounds produced 342 white bass in early 1968 
and 1,694 in early 1969. It is apparent that 
electro -fishing effort on the spawning grounds is 
the most productive method. Trap nets were 
fished 710 net -days and yielded 2.3 white bass/ 
net day, while electro -fishing yielded 169 white 
bass/day. A trap net day is 24 hours of fishing 
per trap net while an average electro -fishing 
day is 4 hours . Trap nets produced 289 channel 
catfish, 77 flathead catfish, and 18 walleye dur- 
ing the 1968-69 period. Electro -fishing 
produced 10 walleye and 9 channel catfish during 
the spring of 1969 . 

White bass returns from the 1968-69 mark- 
ing totaled 378 or 10.5 percent. Twenty white 
bass marked in the 1967-68 season were 
returned during the 1968-69 season, or 1.2 per- 
cent, for a total of 106 (6.6 percent) for fish 
tagged in 1967-68. 

White bass marked from traps and 
recovered on the spawning grounds in 1969 had a 
median upstream migration of 0.21 miles per 
day, with extremes of 0.08 to 0.94 miles per 
day for 60 recaptures. For white bass marked 
on the spawning grounds and recovered down- 
stream (beyond 5 miles and before July 15, 1969) 
the median distance was 0.50 miles per day, 
with extremes of 0.10 to 1.31 miles per day. 
One fish tagged in upper White River was caught 
47 days later 44 .5 miles down reservoir (0.94 
miles/day) and within 3 .5 miles of the dam . 
Six white bass were recovered by fishermen 
within 3 miles of the dam, while another 11 white 
bass were recaptured between 3 and 5 miles 
above the dam . 



257 



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258 



Table 5. — Growth of nine marked white bass with information on date and lengths at 
marking and recapture. 



Date 
tagged 



l/19/b8 

1/9/68 

1/3/68 

2/23/68 

1/15/68 

4/9/69 

12/23/68 

2/7/69 

1/27/69 



Days 
out 



461 
45 7 
419 
388 
330 
271 
180 
164 
54 



Total length 

(millimeters) 

at tagging 



Total length 

(millimeters) 

at tagging 



225 
250 
255 
245 
264 
322 
257 
340 
210 



303 
315 
325 
330 
327 
330 
269 
345 
213 



Growth in 
millimeters 



78 

65 

70 

85 

63 

8 

12 

5 

3 



Analysis recoveries by anglers without 
regard to size, shows a pattern of migration 
down the reservoir from the first of May to 
middle of August in 1969 . Between March 29 to 
May 4 , the heaviest recovery of tags came from 
the up-reservoir spawning grounds . Between 
May 10 to June 24 , returns were heavy from the 
mid-reservoir region near the Highway 12 
Bridge in the Prairie Creek arm area, while in 
mid- to late August a group of returns came 
from the vicinity of the mouth of Clifty Creek 
arm about 5 miles above the damsite. Fishing 
for white bass slacks off between mid -September 
and January . 

Several white bass from the 1967-68 mark- 
ing were recaptured by our gear during the 
1968-69 season. Measurements taken indicate 
good growth of fish tagged with the Floy FD-67 
tag (Table 5) . 

During the 1968 -69 season we marked 298 
channel catfish. There were 29 recaptures for 
a 9.7 percent return. The maximum distance 
traveled was 13 miles by a 336 mm . fish. 

Trap nets caught a fairly large percentage 
of young channel catfish, many of which were 
too small to be tagged. Of the 298 marked, 
196 (65.8 percent) were less than 375 mm. and 
65 (21.8 percent) were less than 300 mm. total 
length. The median length was 370 mm. with 
extremes of 220 to 710 mm. No channel catfish 
marked in 1967 -68 were recaptured during the 
1968-69 season. 



Fewer flathead catfish were marked in 
1968-69. Of the 77 tagged, 8 (10.4 percent) 
were recaptured during the year . The median 
length was 750 mm. with extremes of 400 and 
1,020 mm. The maximum distance of a recap- 
ture was 14.25 miles downstream from the 
point of tagging, 69 days after marking. This 
would be a minimum rate of 0.21 miles per day 
by the shortest route . One flathead catfish 
marked in April , 1968 , was recovered 7 -3/4 
miles from the point of tagging after 494 days of 
freedom . 

Five times more walleye were marked dur- 
ing 1968-69 than the previous year. Eighteen 
were marked from trap nets and an equal number 
from the spawning grounds . Nine of the spawn- 
ing ground walleye marked were collected in 
gill nets or by electro -fishing by the Arkansas 
Game and Fish Commission. Their operations 
also recovered five walleye marked in our trap 
nets . Some white bass and walleye marked in 
trap nets fished about 2-1/2 miles above the 
confluence of the War Eagle Creek arm and White 
River arm were recovered on the War Eagle 
Creek spawning grounds . This indicates a hom- 
ing tendency in these species in Beaver. 

We frequently heard of fishermen who had 
caught marked fish but did not return the tags . 
Since little factual evidence was available, a 
series of tag recovery report forms were 
serially numbered and distributed in sporting 
goods stores, and other businesses frequented 
by fishermen. One location, a bait shop near 



259 



the major white bass spawning ground on the 
White River, distributed many forms to fisher- 
men with tagged fish in possession. Of the 51 
serially numbered forms, 27 (52.9 percent) 
were returned to this office, and 24 (47.1 per - 
cent) were not returned. Only seven (1.4 per- 
cent) of 484 tagged white bass reported by 
anglers did not supply complete information. 

The successful return of tags was attri- 
buted to heavy saturation of radio and newspaper 
media in northwest Arkansas , along with 
especially prepared posters in fluorescent red 
letters placed at docks. In addition, a 1/8 
ounce doll fly was given in return for letters 
providing information on where and when tagged 
and distance traveled . When tags were returned 
to our office, Information on the total white bass 
catch and number of tagged fish was requested. 
There was one tagged white bass per 36.9 fish 
caught, based on 14 tag recoveries from 517 
white bass reported as total catch. 

Thomas O. Duncan 

CONTRACT RESEARCH 

Food habits of the white and black crappie in 
Beaver Reservoir 

A study comparing the food habits of the 
black and white crappie in Beaver Reservoir 
greater than 30 mm. in total length was initi- 
ated in June. From July to October, monthly 
samples were collected with an 8 -foot mid- 
water trawl and a few in gill nets . Beginning in 
November, larger crappie were captured with 
trap nets. Gill netting, trawling and electro - 
shocking are being substituted for trap netting 
as necessary to obtain crappie during the win- 
ter and spring. 



present in Beaver in 1969. Young -of -year shad 
were the only fish found in the stomachs of the 
larger white crappie, and constituted the major 
food item by volume . Larvae and pupae of the 
phantom midge ( Chaoborus) are the most numer- 
ous food organisms , but the volume of shad is 
much greater . 

Robert L . Ball and Raj V . Kilambi 

Limnetic zooplankton population dynamics 

Monthly sampling of the zooplankton popu- 
lations in Beaver and Bull Shoals Reservoirs 
began in August, 1969 . Six stations on Beaver 
and seven stations on Bull Shoals were chosen 
for study. Collections were made with oblique 
tows of a Miller sampler from the surface to 
50 feet. 

Quantitative data are incomplete at this 
time as only 3 months of samples have been 
studied. In general. Bull Shoals has shown little 
change from an earlier 1964-1966 study. Beaver, 
now fully impounded, shows a higher zooplank- 
ton density at the downstream stations, which 
decreases in both diversity and density in the 
middle and upper reaches of the impoundment. 
This contradicts the results of an earlier 1964 - 
1966 study, but could be only seasonal variation. 

Dominant organisms in Bull Shoals Reservoir 
are the cyclopoid copepods, Bosmina , Daphnia, 
and the rotifers , Keratella and Asplanchna . 
In Beaver, the dominant cladoceran was Bosmina , 
with some Diaphanosoma and few Daphnia . 
Both (palanoid and cyclopoid copepods were pre- 
sent and Keratella and Asplanchna were the 
dominant rotifers . 

Sam Damico and C. E. Hoffman 



Analysis of the crappie stomachs completed 
to date indicates a strong preference of yearling 
and older crappie for young -of -year shad, 
particularly threadfin shad, from July through 
September. A comparison of the stomach con- 
tents of black crappie caught in July and August 
of 1965 with those caught during the same mon 
months of 1969 indicates a definite increase in 
the number of shad consumed, undoubtedly re- 
lated to the greater number of threadfin shad 



Beaver Reservoir physico -chemistry 

Monitoring of selected physical and chemi- 
cal parameters at 6 permanent study sites on 
Beaver Reservoir continued. Emphasis was 
placed on measuring nitrogen, phosphates, and 
total carbon for use in the prediction of eutro- 
phication rates . Temperature, dissolved oxy- 
gen , transparency and conductance data were 
collected on a continuing basis. Bacteriological 



and phytoplankton sampling continued on a 
reduced scale during the last half of 1969 . 

A severe summer hypolimnetic oxygen 
deficit occurred in the uplake one -third of the 
reservoir. Water transparency in this region 
was generally low. Both dissolved oxygen con- 
centration and water transparency increased in 
the downlake two -thirds of the reservoir. 

High specific conductances were recorded 
in the uplake region during the late summer. 
Inflowing waters, primarily from the White 
River, remained in an identifiable mass which 
moved to the mid-lake area as a narrow density 
flow. The identity of this water was lost as 



thermal stratification began breaking up in 
October and November. Domestic pollution 
coupled with increased mineral concentrations 
as surface flows decreased, probably accounted 
for the high conductance of this stratum . 

A summary report for the period July 1968 - 
June 1969 has been completed (M.S. thesis by 
Wayne Bennett) . Most nutrient concentrations 
decreased during this period of study. Iron 
showed a 10-fold increase. However, multi- 
variate analysis indicated no linear correlation 
between 15 chemical parameters . 

Randall Bayliss and Robert A. Gearheart 



261 



TECHNICAL COMMUNICATIONS 

Publications, manuscripts in press, special reports, and major addresses 

Acton, R. T., E, E. Evans, P. F. Weinheimer, H. K. Dupree, and J. C. Bennett. Phylogeny of 
Ig M antibodies . Abstract submitted for publication in Federation Proceedings . In press , 

Aggus, Larry R. Bottom fauna development in Beaver Reservoir, Northwest Arkansas, during the 
period of filling 1964-1966. Ph.D. Dissertation. Auburn University. 124 p. 

Allen, John L. GLC determination of quinaldine residue in fish. Presented at the 83rd Annual 
Meeting of the Association of Official Analytical Chemists. Washington, D. C. October. 

. Chemistry of quinaldine and detection of quinaldine residues . Chemistry Seminar 



Seminar, Auburn University, Auburn, Ala. October. 
, and Paul D. Harmon. Control of pH to MS -222 anesthetic solutions. The 



Progressive Fish-Culturist. In press. 



, Charles W. Luhning, and Paul D. Harmon. Investigations in fish control: 



Identification of MS -222 residues in selected fish tissue by thin layer chromatography. U.S. 
Bureau of Sport Fisheries and Wildlife. In press . 

, and Joe B. Sills. GLC determination of quinaldine residue in fish. Journal of 



the Association of Official Analytical Chemists. In press. 
Amend, Donald F. Retention of mercury by salmon. The Progressive Fish-Culturist. In press. 
. Myxobacterial infections of salmonids: prevention and treatment. American 



Fisheries Society. Symposium on Diseases of Fish and Shellfi^. In press. 

. Control of infectious hematopoietic necrosis (IHN) virus disease by elevating the 



water temperature . Journal of the Fisheries Research Board of Canada . In press . 

. Oxytetracycltne (Terramycin) for control of Aeromonas salmonicida infections 



in coho salmon Oncorhynchus kisutch, Technical Papers, BSFW, No. 36, 6 p. 

, J. L. Fryer, and K. S. Pilcher. Studies of certain sulfonamide drugs for use in 



juvenile chinook salmon. The Progressive Fish-Culturist, 31(4): 202-206. 

, and Avron J. Ross. Experimental control of columnaris disease with a new 



nitrofuran drug (P-7138) . The Progressive Fish-Culturist . In press . 



262 



Amend, Donald F., William T. Yasutake, and Robert W. Mead. A hematopoietic virus disease of 
rainbow trout and sockeye salmon. Transactions of the American Fisheries Society, 98(4): 796- 
804. 

, William T. Yasutake, and Reginald Morgan. Some factors influencing suscepti- 



bility of rainbow trout to the acute toxicity of an ethyl mercury phosphate formulation (Timsan) . 
Transactions of the American Fisheries Society, 98(3): 419-425 . 

Applegate, Richard L. , and James W . MuUan. Ecology of Daphnia in Bull Shoals Reservoir. 
Bureau of Sport Fisheries and WUdlife Research Report 74 , 23 p. 

Banks, Joe L. Effect of different rearing temperatures on growth of chinook finger lings , Northwest 
Fish Cultural Conference, Olympia, Wa. December 3-4. 

Benson, Norman G. Some effects of water management on biological production in Missouri River 
main stem reservoirs . Proceedings of American Society of Civil Engineers Specialty Conference 
on "Current research into the effects of reservoirs on water quality" . Technical Report 17 , 
Department of Environmental and Water Resources Engineering, Vanderbilt University. 307- 
321. 

Berger, Bernard L. A synergic mixture of MS -222 and quinaldine sulfate as an anesthetic for 
freshwater fish. Presented at the 31st Midwest Fish and Wildlife Conference. St. Paul, 
Minn. December. 

, Robert E. Lennon, and James W. Hogan. Investigations in fish control: 26. 



Laboratory studies on antimycin A as a fish toxicant. Bureau of Sport Fisheries and Wildlife. 
21 p. 

Billi, James L. , and K . Wolf. Quantitative comparison of peritoneal washes and feces for detecting 
infectious pancreatic necrosis (IPN) virus in carrier brook trout. Journal of the Fisheries 
Research Board of Canada, 26(6): 1459-1465 . 

Brauhn, J. L. Bacterial disease in redear sunfish. The Progressive Fish-Culturist. In press. 

Bryant, Horace E., and Alfred Houser. Growth of threadfin shad in Bull Shoals Reservoir. 
Proceedings of the Twenty-second Annual Conference, Southeastern Association of Game and 
Fish Commissioners. In press. 

, and David I. Morals. Identification of ingested gizzard shad and threadfin shad 



by gizzard dimensions. Bureau of Sport Fisheries and Wildlife, Technical Paper. In press. 

Bullock, G. L. Identification of fish pathogenic bacteria. Textbook of Fish Diseases . TFH 
Publications . In press . 

, and Diane Collis . Oxytetracycime sensitivity of selected fish pathogens . Bureau 



of Sport Fisheries and Wildlife, Technical Paper 32: 3-9. 
, D. Conroy, and S. F. Snieszko. Bacterial diseases. Textbook of Fish Diseases. 



TFH Publications . In press . 



263 



Bullock, G. L., and J, J. A. McLaughlin. Advances in knowledge concerning bacteria pathogenic 
to fishes (1954-1968), Symposium on Diseases of Fishes and Shellfishes, American Fisheries 
Society. In press. 

_, and S . F . Snieszko . Bacteria in blood and kidney of apparently healthy hatchery 



trout. Transactions of the American Fisheries Society 98(2): 268-271. 

Burress, Ralph M . The use of antimycin in fish control. Presented at the 2nd Annual Conference 
of Fishery Biologists, Fisheries Division, State Game and Fish Commission, Macon, Ga, 
February. 

, and Charles W . Luhning. Investigations in fish control: 25. Field trials of 



antimycin as a selective toxicant in channel catfish ponds . Bureau of Sport Fisheries and 
Wildlife, 12 p. 

, and Charles W. Luhning. Investigations in fish control: 28. Use of antimycin 



for selective thinning of sunfish populations in ponds . Bureau of Sport Fisheries and Wildlife. 
10 p. 

Burrows, Foger E. Water reuse and recirculation systems. Great Plains Fisheries Association 
Workshop, Rapid City, S, D. February 4-5, 

. Research developments of the Salmon -Cultural Laboratory, Spearfish Training 



School, Spearfish, S. D. February 6. 

. Current status of programs of Abernathy Salmon-Cultural Laboratory^ Oregon 

Fish-Commission, Clackamas, Oregon. May 23. 

, Hatchery water reconditioning systems. Conference of Association of Conserva- 



tion Engineers, Portland, Oregon. October 14. 
. Impact of environmental control on hatchery operations. Northwest Salmon 



Canners Association, Gleneden Beach, Ore. October 21. 

. Adult survival of salmon reared under environmental control^ Northwest Fish- 



Cultural Conference, Olympia, Wash, December 3-4. 
. The influence of fingerling quality on adult salmon survivals . Transactions of 



the American Fisheries Society, 98(4): 777-784 , 
, and Harry H, Chenoweth, The rectangular -circulating rearing pond. The 



Progressive Fish-Culturist. In press. 

Campbell, J. B., and Ken Wolf, Plaque assay and nucleic acid type of Egtved virus (virus of viral 
hemorrhagic septicemia of rainbow trout), Canadian Journal of Microbiology, 15: 635-637. 

Clark, John. Thermal pollution and aquatic life. Scientific American, 220(3). 

. Heat pollution. National Parks Magazine, 43(267): 4-8, 

, and Malcolm Silverman. The thermal pollution controversy. Proceedings of 



Pennsylvania Water Conference. In press . 

264 



Clark, Jolui, W. G. Smith, Arthur W. Kendall, Jr., and Michael P. Fahay. Studies of Esturine 
dependence of Atlantic coastal fishes. Data Report I: Northern section, Cape Cod to Cape 
Lookout. R/V Dolphin cruises 1965-66; zooplankton volumes, mid -water trawl collections, 
temperatures and salinities. Bureau of Sport Fisheries and Wildlife, Technical Paper 28. 132 p. 

Cope, Oliver B., J. P. McCraren, and L. EUer. Effects of dichlobenil on two fishpond environ- 
ments. Weed Science. In press. 

Cruea, Darrell D. Some chemical and physical characteristics offish sperm. Transactions of 
the American Fisheries Society, 98(4): 785-788. 

, L. L. Eller, and N. Priddy. A new stain for fish sperm. The Progressive Fish- 



Culturist. In press. 

Curran, D., and R. L. Herman. Oxytetracycline efficacy as a pretreatment against columnaris 
and furunculosis in coho salmon. Bureau of Sport Fisheries and Wildlife, Technical Paper 
34: 1-6. 

Dunbar, C. E . Pathological calcification in visceral granuloma of brook trout and nephrocele Lnos is 
in rainbow trout. Northeast Fish and Wildlife Conference, White Sulphur Springs, W. Va. 
February. 

Dupree , Harry K . Influence of corn oil and beef tallow on growth of channel catfish . Bureau of 
Sport Fisheries and Wildlife, Technical Paper 27. 13 p. 

. Basic nutrition of channel catfish. Proceedings of Fish Farming Conference, 



Texas A & M University, College Station. October 7-8. In press. 

. Nutrition of channel catfish. Address to the First Annual Convention, Catfish 



Farmers of America, New Orleans, La. February 6-8. 
, O. L. Green, and Kermit E . Sneed. Growth and survival of fingerling channel 



catfish fed "complete" and "incomplete" feed in ponds and troughs. The Progressive Fish- 
Culturist. In press. 

, and John E. Halver. Amino acids essential for the growth of channel catfish. 



Transactions of the American Fishery Society, 99(1): 90-92. 

Eller, Lafayette L. Pathology in redear sunfish exposed to H 191. Transactions of the American 
Fishery Society. In press. 

Elliott, Joseph W. The oxygen requirements of chinook salmon. The Progressive Fish-Culturist, 
31(2): 67-73. 

Elrod, Joseph H., and T. J. Hassler. Estimates of some vital statistics of northern pike, walleye, 
and sauger populations in Lake Sharpe, South Dakota. Bureau of Sport Fisheries and Wildlife, 
Technical Paper 30. In press . 

Fowler, Laurie G. Progress report on the Abernathy dry diet. Northwest Fish-Cultural Confer- 
ence, Olympia, Wash. December 3-4. 



265 



Fowler, Laurie G., and Joe L. Banks. Tests of vitamin supplements and formula changes in the 
Abernathy salmon diet, 1966-67. Bureau of Sport Fisheries and Wildlife, Technical Paper 26. 
19 p. 

, and Joe L. Banks. The Abernathy salmon diet: tests of fish meal, dried, skim 



milk, and vegetable oil substitutes. Bureau of Sport Fisheries and Wildlife, Technical Paper. 
In press . 

Fribourgh, James H., Jordan A. Robinson, and Fred P. Meyer. Oxytetracycline residues in 
tissues of blue and channel catfishes . Bureau of Sport Fisheries and Wildlife, Technical 
Paper 38 . 7 p . 

, Jordan A, Robinson, and Fred P. Meyer. Oxytetracycline levels produced in 



catfish serum by three methods of treatment. Bureau of Sport Fisheries and Wildlife, Technical 
Paper 39 . 6 p . 

, Fred P. Meyer, and Jordan A. Robinson. Oxytetracycline leaching from medi- 



cated fish feeds. Bureau of Sport Fisheries and Wildlife, Technical Paper 40. 7 p. 

Gilderhus, Philip A. The use of fluorescent dyes in water dispersion studies . Presented at 
Mississippi River Research Consortium, La Crosse, Wis. June. 

. Stream reclamation techniques. Seminar presented to Nebraska Fishery 



Biologists, Lincoln, Neb. February. 



The critical problems of water and air pollution. Presented to the Biology Club, 



Wisconsin State University, La Crosse, Wis . December. 
, Bernard L. Berger, and Robert E. Lennon. Investigations in fish control: 27. 



Field trials of antimycin A as a fish toxicant. Bureau of Sport Fisheries and Wildlife. 21 p. 

Giudice, John J. Improving channel catfish through crossbreeding. Proceedings of Fish Farming 
Conference, Texas A & M University, College Station. October 7-8. In press. 

Grant, F. B., K. T. P., and R. W. Griffith. The twenty-four hour seminal hydration response in 
goldfish ( Carassius Auratus ) - I. Sodium, potassium, calcium, magnesium, chloride, and 
osmolality of serum and seminal fluid. Comparative Biochemistry and Physiology, 30: 273-280. 

Green, O. L. Intensive culture of fingerling catfish in small ponds. The Catfish Farmer, 1(4): 
21 and 37 . 

. Fingerlings to food fish. Proceedings of Conference on Commercial Fish 



Farming, January 27-28, 1969. University of Georgia, Athens, p. 7-12. 
. Culture of catfish fingerlings. Address to the First Annual Convention, Catfish 



Farmers of America, New Orleans, La. February 6-8. 
. Fingerling production. Proceedings of Fish Farming Conference, Texas A & M 



University. October 7-8. In press. 

Halver, J. E. Aflatoxicosis and trout hepatoma. Bulletin of the Office of International Epizootics, 
69:1249-1278. 

266 



Halver, J. E. Chapter X: Aflatoxicosis and trout hepatoma. In Aflatoxin(L. A. Goldblatt, ed), 
Academic Press, New York, p. 265-306. 

. Nutrition in marine aquiculture. Marine Aquiculture Symposium, Oregon State 



University. In press, 



Trout for test systems for cancer. American Cancer Society's Eleventh Annual 



Science Writers' Seminar, New Orleans, La. March 28. Abstract. 
. Vitamin requirements. In Fish in Research (O. Neuhaus and J. E . Halver, 



eds.), Academic Press, New York, p. 209-232. 
, and L. M. Ashley (eds .). Trout hepatomagenes is : Supplement to Final Report, 



NCl-FS-64-14 . Government Printing Office, Seattle, Wash. 10 p. 
, L. M. Ashley, and R. R. Smith. Aflatoxicosis in coho salmon. National Cancer 



Institute Monograph, 31: 141-155, 



, L. M. Ashley, and R. R. Smith. Ascorbic acid requirements of coho salmon 



and rainbow trout. Transactions of the American Fisheries Society, 4: 762-771. 
, L. M. Ashley, and R. R. Smith. L -Ascorbic acid and collagen synthesis in 



salmonids. Vlllth International Congress of Nutrition, Prague, Czechoslovakia. August 28- 
September 5 . Abstract . 

. Micro pellets for sea fish culture . Canterbury-Kent, England. August 16. 

. Fish nutrition research for mariculture. Aberdeen,, Scotland. August 21. 

. Scientific salmon husbandry. Winchester, England. August 23. 

. Fish hepatoma. Erlangen, Germany. August 26. 

, Fish nutritional requirements . Scharf ling, Austria. August 29 . 



Enigma in sea fish husbandry. Northwest Fish Culture Conference, Olympia, 



Wash. December 3-4, 



, R. G. Klein, E. T. Mertz, and W. M. Beeson. Arginine and histidine require- 



ments of coho salmon. Federation Proceedings , 28: 249. 

Hassler, Thomas J. Growth, year-class strength, maturity, and sex ratios of northern pike in 
Oahe Reservoir, South and North Dakota, 1959 through 1965 . Bureau of Sport Fisheries and 
Wildlife, Technical Paper 29. In press. 

. Environmental influences on early development and year -class strength of 



nortJiern pike in Lakes Oahe and Sharpe, South Dakota. Transactions of the American Fisheries 
Society. In press. 

Hastings, W. H. Channel catfish growth response to test feeds. Proceedings of Commercial Fish 
Farming Conference, University of Georgia, Athens. January 27 -28 . p. 22-35. 



267 



Hastings, W. H. Fish farming and the use of fishery products in fish feeds. American Fishes and 
U. S. Trout News, 14(3): 5-6, 

, Nutritional score. In Fish in Research, Academic Press, New York, p. 263-292. 



Catfish nutrition. Address to the Nutrition Council of the American Feed Manu- 



facturers Association, Chicago, 111. December 2. 

. Formula feeds for catfish. Address to the First Annual Convention, Catfish 



Farmers of America, New Orleans, La. February 6-8. 

. Report on coldwater fish nutritional requirements and feed technology. Report 
to European Inland Fisheries Advisory Committee (EIFAC), FAO, Alvkarleo, Sweden. 
November 23-26. 

, and Harry K. Dupree. Formula feeds for channel catfish. The Progressive 



Fish-Culturist, 31(4): 187-196. 



Fish farming and fish meal utilization in fish feeds . Address to the National 



Fisheries Institute, Inc., Washington, D. C. March 19 . 

Heimstra, Norman W., David K. Damkot, and Norman G. Benson. Some effects of silt turbidity 
on behavior of juvenile largemouth bass and green sunfish. Bureau of Sport Fisheries and 
Wildlife, Technical Paper 20. 9 p. 

Herman, R. L. Oxytetracycline in fish culture: a review. Bureau of Sport Fisheries and Wildlife , 
Technical Paper 31: 1-9. 

. Toxicity of oxytetracycline to trout. Bureau of Sport Fisheries and Wildlife, 



Technical Paper 33: 1-4 . 

. Prevention and control of fish diseases in hatcheries . Symposium on Diseases 
of fishes and shellfishes. American Fisheries Society. In press. 

. Abstract of doctoral dissertation, "Some physiological and histological effects 



of gossypol on rainbow trout (Salmo gaixdneri) ." Dissertation Abstracts . In press . 

. Chemotherapy of fish diseases . Wildlife Disease Association, Ames, la. June. 



Lymphomas of brook trout. Fourth International-Symposium on Comparative 



Leukemia Research, Philadelphia, Pa. September. 

. Diseases in fish under laboratory conditions . Armed Forces Institute of 



Pathology, Walter Reed Army Medical Center. September. 

, D. Collis, and G. L. Bullock. Oxytetracycline residues in different tissues of 
trout. Bureau of Sport Fisheries and Wildlife, Technical Paper 37:1-6. 

Hobson, E . S . Daylight, darkness and feeding in tropical reef fishes . American Museum of 
Natural History Coral Reef Symposium at Bimini, B. W. I. March. 



Hobson, E . S . Feeding behavior of inshore fishes. Presented to the Fellows of the San Diego 
Natural History Museum, San Diego, Calif. April. 

. Possible advantages to the blenny Runula azalea in aggregating with the wrasse 



Thalassoma lucasanum in the eastern Pacific. Copeia, 1969(1): 191-193. 

. First California record of the Guadalupe cardinal fish, Apogon guadalupensis . 



California Fish and Game, 55(2): 149-151. 



Submergence times, cleaning symbiosis, and the shark threat in the Galapagos 



marine iguana. Copeia, 1969(2): 401-402. 



The parrotfishes of the eastern Pacific, with a generic rearrangement of the 



Scarinae. (With R. H. Rosenblatt, Scripps Institution of Oceanography) Copeia, 1969(3): 434- 

453. 

. Observations on Dandraster excentricus, a sand dollar of western Nortli America, 



(With R. Merrill, University of California, Santa Barbara) American Midland Naturalist. 
In press . 

Hoffman, G. L. Intercontinental and transcontinental dissemination and transformation of fish 

parasites, with emphasis on whirling disease ( Myxosoma cerebralis) . Wildlife Disease Associa- 
tion, Ames, la. June. 

■ . Ciurrent status of whirling disease in salmonids in the United States. American 



Fishes and U.S. Trout News. November -December, 10, 12, 20. 

. Intercontinental and transcontinental dissemination and transfaunation of fish 



parasites with emphasis on whirling disease ( Myxosoma cerebralis) . Symposium on Diseases 
of Fishes and Shellfishes, American Fisheries Society. In press. 

, C. E. Dunbar, K. E. Wolf, and L. O. Zwillenberg. Epitheliocystis, a new 



infectious disease of the bluegill (Lepomis macrochirus ). Antonie Van Leeuwenhoek Journal of 
Microbiology and Serology, 35(2): 146-158. 

, and R. E. Putz. Host susceptibility and the effect of aging, freezing, heat, and 



chemicals on spores of Myxosoma cerebralis . The Progressive Fish-Culturist, 31(1): 35-37. 

Hogan, James W. Investigations in fish control: Toxicity of Hyamine 3500 to fish. Bureau of 
Sport Fisheries and Wildlife . In press . 

Holway, J. E., and G. W. Klontz. A procedure for testing the antigenicity of vaccines for the 
immunization of fish against furunculosis . The Progressive Fish-Culturist. In press. 

Houser, Alfred, and Horace E. Bryant. Age, growth, sex composition and maturity of white bass 
in Bull Shoals Reservoir. Bureau of Sport Fisheries and Wildlife, Technical Paper. In press. 

Howland, Robert M. Investigations in fish control: Laboratory studies on possible fish -collecting 
aids, with some toxicities for the isomers of cresol. Bureau of Sport Fisheries and Wildlife. 
In press. 



269 



Rowland, Robert M. Interaction of antimycin A and rotenone in fish bioassays . The Progressive 
Fish-Culturist, 31(1): 33-34. 

, and Richard A. Schoettger. Investigations in fish control: 29. Efficacy of 



methylpentynol as an anesthetic on four salmonids. Bureau of Sport Fisheries and Wildlife, 
Up. 

. TRANSLATIONS. 



Askerov, T. A. 1968 . A method for control of saprolegnial fungus . (Metod Bor'by s Saproleg- 
nievym Gribkom.) Rybnoe Khozyaistvo, Moscow, p. 23-24. October 10. 

Balon, Eugen K. 1966 . Ichthyomass and abundance of the fish of an inundated arm of the 
Danube below Bratislava with a description of the course of poisoning with toxaphene. 
(Ichtyomasa a Abundancia Ryb Dunajskeho Inundacneho Ramena pod Bratislavou s Opisom 
Priebehu Otravy Toxafenom.) Biologia, Bratislava, p. 295-306. April 21. 

Brik, I. L. 1969. Properties of acetylcholinesterase in the brain of the carp. (Svoistva 
Atsetilkholinesterazy Golovnogo Mozga Karpa.) Biokhimiya, 34(1): 90-94. Nauka, Moscow. 

Danyulite, G. P., and G. A. Malyukina. 1967. Investigation of the physiological mechanism 
of action of a direct -current electrical field on fish. (Issledovanie Fiziologicheskogo Mekhanizma 
Deistviya Polya Postoyannogo Elektroforicheskogo Toka na Ryb.) Povedenie i Retseptsii Ryb. 
Akademiya Nauk SSSR, Ministerstvo Rybnogo Khozyaistva SSSR, Ikhtiologicheskaya K., Nauka, 
Moscow, p. 56-62. 

Grigor'eva, M. B. 1967. The influence of the shoaling habit on gas exchange in fish. (Vliyanie 
Stainosti na Gazoobmen Ryb.) Povedenie i Retseptsii Ryb. Akademiya Nauk SSSR, Ministerstvo 
Rybnogo Khozyaistva SSSR, Ikhtiologicheskaya Komissiya, Nauka, Moscow, p. 37-41. 

Grinberg, M. M. 1967. A study of innervation of the body musculature in fish with different 
ecology on an example of the trout and carp. (Issledovanie Innervatsii Tulovishchnoi Muskula- 
tury u Ryb s Razlichnoi Ekologiei na Primere Foreli i Karpa.) Povedenie i Retseptsii Ryb. 
Akademiya Nauk SSSR, Ministerstvo Rybnogo Khozyaistva SSSR, Ikhtiologicheskaya Komissiya, 
Nauka, Moscow, p. 127-133. 

Ivanova, M.N. 1968. Nutritive rations and food coefficients of predatory fishes in Rybinsk 
Reservoir. (Pishchevye Ratsiony i Kormovye Koeffitsienty Khishchnykh Ryb v Rybinskom 
Vodokhranilishche.) Biologiya i Troficheskie svyazi Presnovodnykh Bespozvonochnykh i Ryb. 
Sbornik State I. Akademiya Nauk SSSR, Institut Biologii Vnutrennikh Vod, Trudy, Nauka, 
Leningrad, 17(20):180-198 . 

Ivasik, V. M., O. I. Stryzhak, and V.N. Turkevich. 1968. On diplostomatosis in the trout. 
(O Diplostomatoze Foreli.) Rybnoe Khozyaistvo, November 11, p. 27-28. 

Ivleva, I. v., and M.I. Popenkina. 1968. On the temperature dependence of metabolism in 
poikilothermic animals. (O Temperaturnoi Zavisimosti Obmena u Poikilotermnykh Zhivotnykh.) 
Fiziologicheskie Osnovy Ekologii Vodnykh Zhivotnykh. Seriya Biologiya Morya Vyp. 15. 
Institut Biologiya Yuzhnykh Morei Im. A. O. Kovalevskogo, Akademiya Nauk Ukrainskoi SSR, 
Naukova Dumka, Kiev, p. 29-51. 



Howland, Robert M. TRANSLATIONS. 

Kamshilov, M. M. 1967. Selection for Increased resistance to ultraviolet rays in different 
lines of flagellates. (Otbor na Povyshennuyu Ustoichivost' k Ul'trafioletovym Lucham v 
Razlichnykh Liniyakh Zhgutikonostesev.) From: Radiant factors in the life of water organisms. 
(Luchistye faktory zhizni vodnykh organizmov.) Akademiya Nauk SSSR, Institut Biologii 
Vnutrennikh Vod. Trudy, Nauka, Leningrad, 14(17): 54-83. 

Karamyan, A. I., I. V. Malyukova, and B. F. Sergeev. 1967. Participation of the telence- 
phalon of bony fish in the accomplishment of complex conditioned -reflex and general -behavior 
reactions. (Uchastie Konechnogo Mozga Kostistykh Ryb v Osushchestvlenii Slozhnykh Uslovnore- 
flektornykh i Obshchepovedencheskikh Reaktsii.) Povedenie i Retseptsii Ryb. Akademiya Nauk 
SSSR, Ministerstvo Rybnogo Khozyaistva SSSR, Dchtiologicheskaya Komissiya. Nauka, Moscow, 
p. 109-114. 

Khung, Nguen Kim. 1968. The content of free amino acids in the muscles of the Black Sea 
grey mullet in relation to water salinity. (Soderzhanie Svobodnykh Aminokislot v Myshtsakh 
Chernomorskoi Kefali v Zavisimosti ot Solenosti Vody.) Rybnoe Khozyaistvo, September 9, 
Moscow, p. 7. 

Korzhuev, P. A. 1958. Ecological -physiological peculiarities of certain species offish. 
(Ekologo-Fiziologicheskie Osobennosti Nekotorykh Vidov Ryb.) Trudy Soveshchanii Dchtiol. 
Komis. Akad. Nauk SSSR. 8: 364-371. 

Korzhuev, P. A., and T.N. Glazova . 1968. Comparative physiological characteristics of the 
blood and hematopoietic organs of fish and aquatic mammals. (Sravnitel'no-Fiziologicheskaya 
Kharakteristika Krovi i Krovotvornykh organov Ryb i Vodnykh Mlekopitayushchikh.) Fisiologi- 
cheskie Osnovy Ekologii Vodnykh Zhivotnykh. Seriya Biologiya Morya Vyp. 15. Institut 
Biologii Yuzhnykh Morei Im. A. O. Kovalevskogo , Akademiya Nauk Ukrainskoi SSR. 
Naukova Dumka, Kiev, p. 131-146. 

KulLkova, N. I. 1968. Characteristics of the blood protein composition of horse mackerels of 
southern seas. (Osobennosti Belkovogo Sostava Krovi Stavrid Yuzhnykh Morei.) Fiziologicheskie 
Osnovy Ekologii Vodnykh Zhivotnykh. Seriya Biologiya Morya Vyp. 15. Institut Biologii 
Yuzhnykh Morei Im. A. O. Kovalevskogo, Akademiya Nauk Ukrainskoi SSSR, Nuakova Dumka, 
Kiev, p. 147-158. 

Kuperman, B. I. 1969. Triaenophorosis in fish and measures for its prevention. (Trienoforoz 
Ryb i Mery Dlya Ego Preduprezhdeniya.) Rybnoe Khozyaistvo, Moscow, January 1, p. 27-28. 

Malyukina, G. A., and G. V. Yurkevich. 1969. On functional pecularities of the peripheral 
apparatus of the olfactory system in fish. (O Funktsional'nykh Osobennostyakh Perifericheskogo 
Apparata Obonyatel'noi Sistemy Ryb.) Povedenie i Retseptsii Ryb, Akademiya Nauk SSSR, 
Ministerstvo Rybnogo Khozyaistva SSSR, Dchtiologicheskaya Komissiya, Nauka, Moscow, p. 114- 
120. 

Monakov, A. V. 1968. The cyclopid fauna of the littoral zone of Rybinsk Reservoir. (Fauna 
Tsiklopid Pribrezhnoi Zony Rybinskogo Vodokhranilishcha.) Biologiya i Troficheskie Svyazi 
Presnovodnykh Bespozvonochnykh i Ryb. Sbornik Statei. Akademiya Nauk SSSR, Institut 
Biologii Vnutrennikh Vod, Trudy, Nauka, Leningrad, 17(20): 33-40. 



271 



Rowland, Robert M. TRANSLATIONS. 

Nikol'skii, V. V. 1964 . Concerning a method of obtaining a primary culture of carp kidney 
cells . (O Metodike Polucheniya Pervicluioi Kul'tury Pochechnykh Kletok Karpov .) Materialy 
Vsesoyuznoi Konferentsii po Voprosam Veterinarnoi Virusologii, p. 66-67. 

Panov, D. A. 1968 . Importance of provision with food for the survival of fish larvae (on an 
example of the bream of Rybinsk Reservoir). (Znachenie Obespechennosti Pishchei Dlya Vyzhi- 
vaniya Lichinok Ryb (Na Primere Leshcha Rybinskogo Vodokhranilishcha.) Biologiya i Trofich- 
eskie Svyazi Presnovodnykh Bespozvonochnykh i Ryb. Sbornik Statei. Akademiya Nauk SSR, 
Institut Biologii Vnutrennikh Vod, Trudy, Nauka, Leningrad, p. 199-221. 

Pavlov, D. S., and Yu. N. Sbikin. 1967. Study of the spectral and threshold sensitivity of 
vision in fish by a method of optometer reaction. (Izuchenie Spektral'noi i Porogovoi Chuvstvitel' 
nosti Zreniya Ryb Metodom Optomotornoi Reaktsii.) Povedenie i Retseptsii Ryb. Akademiya 
NaukSSSR, Ministerstvo Rybnogo Khozyaistva SSSR, Ikhtiologicheskaya Komissiya, Nauka, 
Moscow, p. 74-79. 

Pavlov, D. S., Yu. N. Sbikin, and D. S. Uspenskii. 1967. The influence of temperature on 
certain functional peculiarities of vision in fish. (Vliyanie Temperatury na Nekotorye Funkt- 
sional'nye Osobennosti Zreniya Ryb.) Povedenie i Retseptsii Ryb. Akademiya Nauk SSSR, 
Ministerstvo Rybnogo Khozyaistva SSSR, Ikhtiologicheskaya Komissiya, Nauka, Moscow, p. 86- 
89. 

Piskunov, I. A., and A. M. Kharchenko. 1968. Commercial investigations of tuna in the 
Indian Ocean. (Promyslovye Issledovaniya Tuntsov v Indiiskom Okeane.) Trudy Vsesoyuznogo 
Nauchno-Issledovatel'skogo Instituta Morskogo Rybnogo Khozyaistva i Okeanografii (Vinro), 
64: 344-373. Trudy Azovo -chernomorskogo Nauchno-Issledovatel'skogo Instituta Morskogo 
Rybnogo Khozyaistva i Okeanografii (Azcherniro), 28: 1968. 

Prazdnikova, N. V. 1967. Peculiarities of the distinction of visual images by fish. (Osobennosti 
Razlicheniya Zritel'nykh Izobrazhenii Rybami.) Povedenie i Retseptsii Ryb. Akademiya Nauk 
SSSR, Ministerstvo Rybnogo Khozyaistva SSSR, Ikhtiologicheskaya Komissiya, Nauka, Moscow, 
p. 79-86. 

Rodova, R. A. 1968. Chironomid females I. (Samki Khironomid I.) Biologiya i Troficheskie 
Svyazi Presnovodnykh Bespozvonochnykh i Ryb. Sbornik Statei. Akademiya Nauk SSSR, Institut 
Biologii Vnutrennikh Vod, Trudy, Nauka, Leningrad, 17(20): 124-144. 

Semenova, L. M. 1968 . Some data on the biology of Bosmina coregoni Baird in Rybinsk 
Reservoir. (Nekotorye Dannye po Biologii Bosmina coregoni Baird v Rybinskom Vodokhranx- 
lishche.) Biologiya i Troficheskie Svyazi Presnovodnykh Bespozvonochnykh i Ryb. Sbornik 
Statei. Akademiya NaukSSSR, Institut Biologii Vnutrennikh Vod, Nauka, Leningrad, 17(20):21- 
26. 

Sharonov, I. V. 1968. Dynamics of abundance of generations and the growth of the bream in 
Kuibyshev Reservoir. (Dinamika Chislennosti Pokolenii i Rost Leshcha v Kuibyshevskom Vodo- 
khranilishche.) Biologiya i Troficheskie Svyazi Presnovodnykh Bespozvonochnykh i Ryb. Sbornik 
Statei. Akademiya Nauk SSSR, Institut Biologii Vnutrennikh Vod, Trudy, Nauka, Leningrad, 
17(20): 151-179. 



Rowland, Robert M. TRANSLATIONS. 

Shul'man, G. E., and L. M. Kokoz . 1968. Peculiarities of protein growth and fat accumulation 
in Black Sea fishes. (Osobennosti Belkovogo Rosta i Zhironakopleniya u Chernomorskikh Ryb.) 
Fiziologicheskie Osnovy Ekologii Vodnykh Zhivotnykh. Seriya Biologiya Morya Vyp. 15. 
Akademiya Nauk Ukrainskoi SSR, Institut Biologii Yuzhnykh Morei Im . A. O. Kovalevskogo , 
Naukova Dumka, Kiev, p. 159-206. 

Skabichevskii, A. P. 1948. On tlie soaring of non-motile planktonic algae. (O Parenii Nepod- 
vizhnykh Planktomiykh Vodoroslei.) Uspekhi Sovremennoi Biologii, 26(4), p. 615-618. 

Titarev,E. 1964. Preservation of fish scraps by means of sodium pyrosulfite. (Konserviro- 
vanie Rybnykh Otkliodov Pirosul'fitom Natriya.) Rybovodstvo i Rybolovstvo, 5(14), p. 14. 

Vinberg, G. G. 1968. Interdependence between intensity of metabolism and rate of growth in 
animals. (Vzaimozvisimost' Intensivnosti Obmena i Skorosti Rosta u Zhivotnykh.) Fiziologiche- 
skie Osnovy Ekologii Vodnykh Zhivotnykh. Seriya Biologiya Morya Vyp. 15. Institut Biologii 
Yuzhnykh Morei Im A. O. Kovalevskogo, Akademiya Nauk Ukrainskoi SSR. Naukova Dumka, 
Kiev, p. 5-15. 

Volodin, V. M. 1968. Fertility of the burbot ( Lota lota L.) in Rybinsk Reservoir. (Plodovitost' 
Nalima (Lota lota L.) v Rybinskom Vodokhranilishche.) Biologiya i Troficheskie Svyazi 
Presnovodnykh Bespozvonochnykh i Ryb. Sbornik State! . Akademiya Nauk SSSR, Institut Biologii 
Vnutrennikh Vod, Trudy, Nauka, Leningrad, 17(20): 222-229. 

Volodin, V. M., and M.N. Ivanova . 1968. Way of life, growth, and feeding of the young 
burbot in Rybinsk Reservoir. (Obraz zhizni, rost i Pitanie Molodi Nalima v Rybinskom Vodo- 
khranilishche.) Biologiya i Troficheskie Svyazi Presnovodnykh Bespozvonochnykh i Ryb. Sbornik 
Statei. Akademiya Nauk SSSR, Institut Biologii Vnutrennikh Vod, Trudy, Nauka, Leningrad, 
17(20): 230-240. 

Zusser, S. G. 1967. Concerning study of the reasons for the attraction of fish to light. 
(Ob Izuchenii Prichin Privlecheniya Ryb na Svet.) Povedenie i Retseptsii Ryb. Akademiya Nauk 
SSSR, Ministerstvo Rybnogo Khozyaistva SSSR, Ikhtiologicheskaya Komissiya, Nauka, Moscow, 
p. 95-99. 

Hunn, Joseph B. Fish in research. Seminar presentedto Marquette University School of Medicine, 
Milwaukee, Wis. January. 

. Chemical composition of rainbow trout urine following acute hypoxic stress. 



Transactions of the American Fisheries Society, 98(1): 20-22. 
. Inorganic composition of gallbladder bile from fasted rainbow trout. The 



Progressive Fish-Culturist, 31(4): 221-222. 
. Investigations in fish control: Dynamics of MS -222 in the blood and brain of 



freshwater fishes during anesthesia . Bureau of Sport Fisheries and Wildlife . In press . 
, and Wayne A. Willford. Flow rates and chemical composition of urine from 



rainbow trout, Salmo gairdneri , after MS-222 or methylpentynol anesthesia. Comparative 
Biochemistry and Physiology. In press. 



273 



Jenkins, Robert M. "Big Reservoirs," a chapter in the book FISH AND FISHING. Bureau of 
Sport Fisheries and Wildlife . In press . 

. A discussion of a paper, "Measurement of economic values in sport fishing: 



An economist's views on validity, usefulness and propriety," by J. B. Stevens. Transactions of 
the American Fisheries Society, 98(2): 357-359. 

. "Reservoir Fish Management," a chapter in the American Fisheries Society 



Centennial volume, "100 Years of Fisheries in North America." In press. 
. Large reservoirs- -management possibilities. Proceedings of the 36th Annual 



Meeting, Midwest Association of Fish and Game Commissioners. In press. 
. The influence of engineering design and operation and other environmental 



factors on reservoir fishery resources . Proceedings of the 5th Annual American Water 
Resources Conference , In press . 

Jenkins, Thomas M., Jr. Observations on color changes of brown and rainbow trout (Salmo trutta 
and Salmo gairdneri ) in stream habitats, with description of an unusual color pattern in brown 
trout. Transactions of the American Fisheries Society, 98(3): 517-519. 

, and Aaron Klain. A regulated temperature electric tool for marking fish. 



Transactions of the American Fisheries Society, 98(2): 338-340. 
. Night feeding of brown and rainbow trout in an experimental stream channel. 



Journal Fisheries Research Board of Canada, 26(12). In press. 

Johnson, B. T. Mechanism for the degradation of DDT by micro-organisms. Bacteriology 
Proceedings . Abstract A103 16 . 

, and CO. Knowles . Microbial degradation of the acaricide N'-(4-chloro-o-tolyl)- 



N,N -dim ethyl -formamidine. Bulletin of Environmental Contamination Toxicology. In press. 

June, Fred C. Atresia and year -class abundance of northern pike, Esox lucius, in two Missouri 
River impoundments . Journal of the Fisheries Research Board of Canada . In press . 

and F. T. Carlson. Food of young Atlantic menhaden, Brevoortia tyrannus , in 



relation to metamorphosis . Bureau of Commercial Fisheries, Fishery Bulletin. In press . 

Kennedy, H. D., and D. F. Walsh. Effects of malathion on two warm -water fishes and aquatic 
invertebrates in ponds. Bureau of Sport Fisheries and Wildlife, Technical Paper. In press. 

, L. L. Eller, and D. F. Walsh. Chronic effects of methoxychlor on bluegills and 



aquatic invertebrattes . Bureau of Sport Fisheries and Wildlife , Technical Paper . In press . 

Kilambi, Raj V., and Raymond E. Baglin, Jr. Fecundity of the gizzard shad, Borosoma cepedianum 
(LeSueur), in Beaver and Bull Shoals Reservoirs. The American Midland Naturalist, 84(2): 444- 
449. (Contract No. 14-16-0008-959 research results.) 

, and Raymond E . Baglin, Jr. Fecundity of the threadfin shad, Dorosoma petenense, 



in Beaver and Bull Shoals Reservoirs. Transactions of the American Fisheries Society, 98(2): 
320-322. 

274 



Kinisey, J. B. Recreational aspects of oceanography. In Proceedings of Symposium, Marine 
Sciences and Business Potentials, Transference of Technology Series No. 3, The University of 
Texas, p. 159-164. 

Klontz, George W., and Douglas P. Anderson. Fluorescent antibody studies of isolates of 

Aeromonas salmonicida . Bulletin de 'Office International des Epizooties, 69(7-8): 1149-1157. 

, and Douglas P. Anderson. Oral immunization of salmonids: A review. American 



Fisheries Society. Symposium on Diseases of Fish and Shellfish. In press. 

Lane, Thomas H., and Howard M. Jackson. Investigations in fish control: Voidance time for 23 
species of bioassay fish. Bureau of Sport Fisheries and Wildlife. In press. 

Lennon, Robert E. Fishery science grows up. In Sport Fishing USA. In press . 

, Fishes that are pests. In Vertebrates in pest situations: an appraisal. Vol. 6. 



Plant and Animal Pest Control. National Academy of Sciences, Washington, D. C. In press. 
. Research in fish control. Seminar presented to Trainee Class, Spearfish 



Fisheries Center, S . D. February. 



. Fish Control Laboratory activities --and FINTROL. Presented at the 18th Annual 



Great Plains Fishery Workers Association Meeting, Rapid City, S. D. February, 
. Pollution. Presented to the Western Wisconsin Chapter Society of Professional 



Engineers, La Crosse, Wis. December. 
, and Bernard L. Berger. Investigations in fish control: A resume on field 



applications of antimycin A. to control fish. Bureau of Sport Fisheries and Wildlife. In press. 

Macek, K.J. Biological magnification of pesticide residues in food chains. Presented at the 

Symposium on the Biological Impact of Pesticides in the Environment, Corvallis, Ore. In press. 

, and H. O. Sanders. Biological variation in the susceptibility of fish and aquatic 



invertebrates to DDT. In press. 

McCabe, Robert A., Edward L. Kozicky, and Robert E. Lennon. A scientific position on predator 
management. Presented at the 31st Midwest Fish and Wildlife Conference, St. Paul, Minn. 
December . 

McCartney, Thomas H. The determination of the effect of a pyridoxine deficiency on the serum 
lipids of fingerling brook trout. Fisheries Research Bulletin No, 32, p. 6-11. State of New 
York Conservation Department, Albany. 

. The effect of a dietary pyridoxine deficiency on the inorganic composition of 

fingerling brook trout. Fisheries Research Bulletin No. 32, p. 12-13. State of New York Con- 
servation Department, Albany. 

. The effect of dietary carbohydrate level and supplemental phosphorus on the 



liver glycogen of fingerling brown trout. Fisheries Research Bulletin No. 32, p. 26-31. State 
of New York Conservation Department, Albany. 



275 



McCartney, Thomas H. The chemical composition of the trout erythrocyte. Fisheries Research 
Bulletin No, 32, p. 32-33. State of New York Conservation Department, Albany. 

. The effect of dietary safflower oil on the serum lipids of fingerling brown trout. 



Fisheries Research Bulletin No. 32, p. 34-40. State of New York Conservation Department, 
Albany. 

McCraren, Joseph P., O. B. Cope, and L. Eller. Some chronic effects of Diuron^^^ on bluegills . 
Weed Science. In press. 

MacPhee, Craig, and Richard Ruelle. A chemical selectively lethal to squawfish (Ptychocheilus 
oregonensis and P. umpquae) . Transactions of the American Fisheries Society, 98(4): 676-684. 

Marking, Leif L. ^Toxicological assays with fish. Bulletin of the Wildlife Disease Association, 
5(2): 291-294. 

. Toxicological assays with fish. Presented at the Annual Wildlife Disease 



Conference, Ames, la. June. 

. Toxicity and degradation of potential fish toxicants under diverse pH conditions . 

Presented at the 31st Midwest Fish and Wildlife Conference, St. Paul, Minn. December. 

. Investigations in fish control: A method for rating chemicals for potency against 



fish and other organisms . Bureau of Sport Fisheries and Wildlife . In press . 
. Juglone (5 -hydroxy-1, 4 -naphthoquinone) as a fish toxicant. Transactions of the 



American Fisheries Society. In press, 



Investigations in fish control: 23. Toxicity of quinaldine to selected fishes, 



Bureau of Sport Fisheries and Wildlife. 10 p. 



Investigations in fish control: 30. Toxicity of methylpentynol to selected fishes. 



Bureau of Sport Fisheries and Wildlife. 7 p. 



Toxicity of rhodamine B and fluorescein sodium to fish and their compatibility 



with antimycin A. > The Progressive Fish-Culturist, 31(3): 139-142. 
, Everett L. King, Charles R. Walker, and John H. Howell. Investigations in fish 



control: Toxicity of 3'chloro-3-nitrosalicylanilide (33NCS) to freshwater fish and sea lamprey. 
Bureau of Sport Fisheries and Wildlife. In press . 

, and Wayne A. Willford. Investigations in fish control: Comparative toxicity of 



twenty -nine nitrosalicylanilides and related compounds to eight species of fish. Bureau of Sport 
Fisheries and Wildlife. In press . 

Martin, J. Mayo. Possible ways to increase production. American Fishes and U. S. Trout News, 
13(8): 20-21. 

. New happenings in farm raised catfish industry. American Fishes and U. S. 



Trout News, 13(6): 8 and 23-25. 



276 



Meyer, Fred P. A potential control for leeches. The Progressive Fish-Culturist, 31(3): 160-163. 
. Commercial fish production in the U.S. and its relation to the feed industry. 



Feedstuffs, 47(7): 27-28. 

. Where do we go from here. The Catfish Farmer, 1(1): 25, 



. Dylox as a control for ectoparasites of fish. Proceedings, 22nd Annual Confer- 
ence of Southeastern Game and Fish Commissioners, Baltimore, Md. October 21-23. In press. 

. Seasonal fluctuations in the incidence of disease on fish farms. In Special 



Publication No. 5. A Symposium on Diseases of Fish and Shellfish. The American Fisheries 
Society. In press. 

. Disease in warmwater pond fish. Journal of the Wildlife Disease Association. 



In press . 



Factors associated with the outbreak of diseases. Proceedings of Fish Farming 



Conference, Texas A & M University, College Station. October 7-8. In press. 
. Where do we stand ? Proceedings of Fish Farming Conference, Texas A & M 



University, College Station. October 7-8. In press. 

Mullan, James W . , and Richard L. Applegate. Centrarchid food habits in a new and old reservoir 
during and following bass spawning. Proceedings of the Twenty-first Annual Conference, 
Southeastern Association of Game and Fish Commissioners: 332-342. 

, and Richard L. Applegate, Notes on drowning of bobwhites in a large reservoir. 



Wilson Bulletin, 81(4): 467. 



, and Richard L. Applegate. Use of an echosounder in measuring distribution of 



reservoir fishes. Bureau of Sport Fisheries and Wildlife, Technical Paper 19. 16 p. 
, David I. Morals, and Richard L. Applegate. Thermal, oxygen and conductance 



characteristics of a new and old Ozark reservoir. Bureau of Sport Fisheries and Wildlife, 
Technical Paper . In press. 

Nelson, William R. Biological characteristics of the sauger population in Lewis and Clark Lake. 
Bureau of Sport Fisheries and Wildlife, Technical Paper 21. 11 p. 

Netsch, Norval F. The catch of wire traps in Old Hickory Reservoir, Tennessee. Proceedings of 
the Twenty-second Annual Conference, Southeastern Association of Game and Fish Commis- 
sioners . In press . 

Neuhaus, O. W., and J. E. Halver (eds .). Fish in research. Academic Press, New York, 311 p. 

Oshima, K., C. L. Johnson, and A. Gorbman. Relations between prolonged hyperthyroidism and 
electroneurophysiological events in trout, Salmo gairdnerii. Effects of replacement dosages of 
thyroxine. Journal of Neuroendocrinology. In press. 

Ogren, Larry, and James Chess. A marine kill on New Jersey wrecks. Underwater Naturalist 
Bulletin of the American Littoral Society, 6(2): 4-12. 



011a, B. L., R. Wicklund, and S. Wilk. Behavior of winter flounder in a natural habitat. Trans- 
actions of the American Fisheries Society, 98(4): 717. 

, H. M. Katz, and A. L. Studholme. Prey capture and feeding motivation in the 



bluefish, Pomatomus saltatrix . Copeia. In press. 

Pearce, Jack B. Marine biogeography and change --natural and man induced. Ward's Bulletin. 
In press . 

Phillips, Arthur M., Jr. Nutrition, digestion, and energy utilization. Chapter 7, Fish Physiology, 
Vol. I, edited by W. S. Hoar and D.J. Randall, p. 391-432. Academic Press, N. Y. 

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. Effect of formalin on the level of dietary ascorbic acid and on brook trout 



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Effects of massive doses of vitamin Do on fingerling brook trout. Fisheries 



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. Correlation of fatty acid composition of diets and livers of brown trout finger - 



lings. Fisheries Research Bulletin No. 32, p. 51-62. State of New York Conservation 
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. Effects of exposure of brown trout eggs to a low concentration of estrogenic 



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, Donald L. Livingston, and Arthur M. Phillips, Jr. The effect of source of dietary 



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, Donald L. Livingston, and Arthur M. Phillips, Jr. The effect of supplemental 



choline and methionine upon the utilization of fat by brown trout. Fisheries Research Bulletin 
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Prager, J. C, and J. B. Mahoney. Annulment of aziridine (Apho late) --induced growth inhibition 
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, J. E. Martin, and V. Brassier. Vibrio anquillarum from an epizootic in rainbow 



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. Pesticide toxicities to tadpoles of the Western chorus frog Pseudacris triseriata 



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. Biology of the white crappie in Lewis and Clark Lake. Bureau of Sport Fisheries 



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279 



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Smith, W. G., and Michael P. Fahay. A description of eggs and larvae of the summer flounder, 
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Sneed, Kermit E . A stop-gap breeding program for catfish farmers . The Catfish Farmer, 1(2): 
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Snieszko, S. F., and A. J. Ross. Columnaris disease of fishes. BSFW, Fish Disease Leaflet, 

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. Contemporary status of fish epizootiology. Northeast Fish and Wildlife 



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. Immunization of fishes . Wildlife Disease Association, Ames, la. June, 



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. Abundance of fishes off the California coast as determined by observations from 



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. Observations on cumulative bottom' drift in Monterey Bay using sea bed drifters. 



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. A note on phosphorus changes in pond soils. Proceedings, 22nd Annual Confer- 



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. Viewpoint of the U.S. Bureau of Sport Fisheries and Wildlife. California 



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Thomas, Allan E. Mortality due to leach infestation in an incubation channel. The Progressive 
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, Joseph W. Elliott, and Joe L. Banks. Hematological and chemical characteristics 



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, Joe L . Banks , and Donald C . Greenland , Effect of yolk sac absorption on the 



swimming ability of fall chinook salmon. Transactions of the American Fisheries Society, 
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. The ecology of William Snyder Pond and problems in management of the sport 

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. Fishery management of Lake Pend Oreille and opportunities for service projects 



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281 



Walker, Charles R. Aquatic herbicide residues in fish and the expanding fresh water fisheries. 
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. Opportunities for cooperative projects between fishery research laboratories and 



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. Use of herbicides for fisheries management. 23rd Annual Meeting of the North- 



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. Problems in clearance and registration of chemical tools used by fish culturists 



and fishery biologists. 99th Annual Meeting of the American Fisheries Society, New Orleans, 
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. Some views on research needed for providing urban sport fishing opportunities . 



13th Annual Coordination Meeting of the Cooperative Wildlife Research Units, Washington, D. C. 
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. Program aids for scouters (Training and Activities Committee). 34th North 



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. Stress -induced ascorbic acid depletion and Cortisol production in two salmonid 



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. The role of stress in the disease resistance of fishes. American Fisheries 



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, A. J. Ross, and Lynwood Smith. Some metabolic effects of bacterial endotoxins 



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Wicklund, R. Commensalism between sharks and pelagic fishes . Underwater Naturalist, 6(1). 

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. Observations on spawning of the lane snapper. Underwater Naturalist, 6(2). 

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, Joe B. Sills, and Everett W. Whealdon. Chlorinated hydrocarbons in the young of 



Lake Michigan coho salmon. The Progressive Fish-Culturist, 31(4): 220. 



282 



Wolf, K. Guidelines for virological examination of fishes. Symposium on Diseases of Fishes and 
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infectious pancreatic necrosis viruses in doubly infected cultures of RTG-2 cells. Archiv flir 
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salmon fingerlings. The Progressive Fish -Culturist. In press. 

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response of adult trouts to inoculation with live virus . Journal of the Fisheries Research Board 
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, M. C. Quimby, and C. P. Carlson. Infectious pancreatic necrosis virus: 



lyophilization and subsequent stability in storage at 4° C. Applied Microbiology, 17(4): 623-624 . 

Yasutake, William T. Comparative histopathology of epizootic salmonid virus diseases. Symposium 
on Diseases of Fish and Shellfish. American Fisheries Society. In press . 

, and C.J. Rasmussen. Histopathogenesis of experimentally induced viral 



hemorrhagic septicemia in fingerling rainbow trout (Salmo gairdneri ). Bulletin de 'Office 
International des Epizootics, 69(7-8): 977-984. 

Zaugg, W . S . Comments on the relationship between gill ATPase activities , migration and salt 
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, and L. R. McLain. Adenosine triphosphatase activity in gills of salmonids: 



seasonal variations and salt water influence in coho salmon, Oncorhynchus kisutch. 
Comparative Biochemistry and Physiology. In press . 

, and L. R. McLain. Inorganic salt effects on growth, salt water adaption and 



gill ATPase of Pacific salmon. In Fish in Research (O . Neuhaus and J . E . Halver , eds .) . 
Academic Press, N. Y., p. 293-306. 



283 



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DIRECTORY 



ATLANTIC MARINE GAME FISH RESEARCH 
Dr. L, A. Walford 
P. O. Box 428 
Highlands, New Jersey 07732 

PACIFIC MARINE GAME FISH RESEARCH 
Gerald B. Talbot 
P. O. Box 98 
Tiburon, California 94920 

GULF MARINE FISH RESEARCH 
P. O. Box 4218 
Panama City, Florida 32401 

NATIONAL RESERVOIR RESEARCH PROGRAM 
Robert M . Jenkins 
113 S . East Street 
Fayetteville, Arkansas 72701 

WARMWATER FISH CULTURE RESEARCH 
Kermit E. Sneed 
P. O. Box 860 
Stuttgart, Arkansas 72160 

FBH DISEASE RESEARCH 
Dr. S. F. Snieszko 
Leetown(P. O. KearneysvUle) 
West Virginia 25430 

Dr. Robert R. Rucker 
Building 204 , Sand Point NAS 
Seattle, Washington 98115 



FISH CONTROL RESEARCH 
Dr. Robert E. Leimon 
P. O. Box 862 
La Crosse, Wisconsin 54602 

FISH GENETICS RESEARCH 
Bruno von Limbach 
Beulah, Wyoming 82712 

FBH-PESTICIDE RESEARCH 

Dr. Richard A. Schoettger 

Route 1 

Columbia, Missouri 65201 

SIERRA NEVADA AQUATIC RESEARCH 
Norman Reimers 
Star Route 3, Box 198 
Bishop, California 93514 

SALMON CULTURE RESEARCH 
Roger E . Burrows 
1440 Abernathy Road 
Longview, Washington 98632 

FISH NUTRITION RESEARCH 

Dr. Arthur M. Phillips, Jr. 
Cortland, New York 13045 

Dr. John E. Halver 
Cook, Washington 98605 




3 9088 01018 6195 



the Deyartment of the Interior 

— a Department of Conservation — 

is concerned luith the management, 

conservation, and development 

of the 'Nation's water, wildlife, 

mineral, forest, and park 

and recreational resources. 

It also has major 

responsibilities for 

Indian and Territorial affairs. 

As the Nations principal 

conservation agency, 

the Department works to assure 

that nonrenewable resources 

are developed and used wisely, 

that park and recreational resources 

are conserved for the future, 

and that reneivable resources 

make their fidl contribution 

to the progress, 

prosperity, and security 

of the United States — 

now and in the future.