QMJFORNIAI
FTSH-GAME
"CONSERVATION OF WILDLIFE THROUGH EDUCATION"
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u
1
1
VOLUME 61
JANUARY 1975
NUMBER 1
Published Quarterly by
STATE OF CALIFORNIA
THE RESOURCES AGENCY
DEPARTMENT OF FISH AND GAME
STATE OF CALIFORNIA
EDMUND G. BROWN JR., Governor
THE RESOURCES AGENCY
CLAIRE T. DEDRICK, Secretary for Resources
FISH AND GAME COMMISSION
TIMOTHY M. DOHENY, President, Los Angeles
JOSEPH RUSS III, Vice President PETER T. FLETCHER, Member
Ferndole Roncho Santa Fe
BERGER C. BENSON, Member SHERMAN CHICKERING, Member
San Mateo San Francisco
DEPARTMENT OF FISH AND GAME
G. RAY ARNETT, Director
1416 9th Street
Sacramento 95814
CALIFORNIA FISH AND GAME
Editorial Staff
ROBSON A. COLLINS, Editor-In-Chlef long Beach
KENNETH A. HASHAGEN, Editor for Inland Flsheriei Sacramento
CAROL M. FERREL, Editor for Wildlife Sacramento
ROBERT N. TASTO, Editor for Marine Resources Menio Park
PAUL M. HUBBELL, Editor for Salmon and Steeiheod Sacramento
HAROLD K. CHADWICK, Editor for Striped Bass, Sturgeon, and Shod Stockton
(2)
CONTENTS
A Black Bear Population Study in Northern California
William Piekielek and Timothy S. Burton 4
Early Larvae of the Diamond Turbot, Hypsopsetta guttulata
Maxwell B. Eldridge 26
The Food of Neomysis mercedis Holmes in the Sacramento-San
Joaquin Estuary Angela L. Baldo Kost and Allen W. Knight 35
Note on the Ecology of the Ratfish, Hydrolagus collei, in the Gulf
of California C. P. Mathews 47
Notes
An Unusually Fast Growth Bate for Tilapia zillii
William, J. Hauser 54
Notes on Some Fishes Collected off the Outer Coast of Baja Cali-
fornia Eric H. Knaggs, John S. Sunada, and Robert N. Lea 56
Occurrence of the Prowfish, Zaprora silenus Jordan, 1896 in Mon-
terey Bay, California Gregor M. Calliet and M. Eric Anderson 60
Book Reviews 63
(3)
Calif. Fish and Game 61(1) : 4-25. 1975.
A BLACK BEAR POPULATION STUDY IN
NORTHERN CALIFORNIA^
WILLIAM PIEKIELEK
School of Forestry and Conservation, University of California, Berkeley
and
TIMOTHY S. BURTON
Wildlife Management Branch
California Department of Fish and Game
Forty-three wild bears were culvert trapped, immobilized, and tagged
in a limited area in Trinity County, California, during the summer
and fall of 1972. Eleven depredation bears were trapped and tagged
throughout the county. Sex and age distribution and physical charac-
teristics of these 54 animals are summarized.
Summer movements and home ranges of the marked bears were
small. Average known maximum summer movement was 1.85 miles
(2.97 km), increasing in fall to 6.1 miles (9.8 km). Adult females with
cubs appeared to have smaller yearly ranges than other sex and age
classes. Summer density of the bear population in the study area was
approximately two bears per square mile (2.6 km^). Thirty-six percent
of the adult females were with cubs, the average litter 1.67. Summer
food habits are reported, based on analysis of 106 scats.
INTRODUCTION
The black bear, Ursiis amcricanus, is receivinjr inereasint; recognition
as an integral part of our forest environment and as an important game
species. Improved methods of handling and tagging large animals have
facilitated black bear population studies in the last 2 decades. This
paper reports the initial phase of a long term black bear population
study in California. Emphasis in the first year of the project was on
determining population composition and density, movements, food
habits, and individual physical characteristics of black bears in a rep-
resentative habitat in northern California.
STUDY AREA
A study area of approximately 115 square miles (298 km^) was
selected east and south of Clair Engle Lake, Trinity County (Figure
1). Most of the study area is contained within the Shasta-Trinity Na-
tional Forest. This part of the national forest is in "checker board"
ownership; alternate sections are privately owned. The study area sup-
ports a relatively high density of bears and is intersected by numerous
logging roads providing easy access. Although major emphasis was
given to tlie study area outlined, depredation bears (garbage dump,
campground, and other nuisance bears) captured elsewehere in Trinity
County are included in the analyses.
The study area lies at the south base of the Trinity Alps, one of the
principal mountain ranges of this area. Elevations range from 1,800 ft
(549 m) in the Lewiston area to 8,091 ft (2,468 m) at Granite Peak.
The area consists almost entirely of timbered or brushy gulches divided
^ This study was supported in part by Federal aid in Wildlife Restoration projects
W-51-R "Big Game Studies" and W-52-R "Wildlife Investigations Laboratory."
Accepted for publication July 1974.
(4)
BLACK BEAR STUDY
Lewiston Lake
Lewiston
FIGURE 1. Principal bear study area west of Clair Engle Lake, Trinity County, California,
showing summer trapping sites (o), and fall trapping sites (•) near Lewiston.
by sharp ridges, with local elevation changes of 1,000 (305 m) to 2,000
ft (610 m). At the immediate base of the Trinity Alps, precipitous
local elevation changes approach 6,000 ft (1,830 m).
The climate of the area is typical of the Pacific Coast with local con-
ditions influenced by elevation and exposure. Summers are dry and
warm ; winters are cool and wet. Snowfall may vary greatly from year
to year with a range of 10 (25.4 cm) to 70 (177.8 cm) inches recorded
at Weaverville. Higher elevations receive greater amounts of precipi-
6
CALIFORNIA FISH AND GAME
tation in the form of snow. The spring of 1972 was unusually dry and
the fall months of 1972 were unusually wet.
Most of the study area is covered by a pine-fir forest; dominant
species are Douglas fir {Pseudotsuga menziesii) and yellow pine (Pniws
pondcrosa) with lesser numbers of sugar pine (P. lamhrrfifina) and
incense cedar {Lihocedrus dccurrens) (Figure 2). Understory trees in
the conifer forest include Pacific madrone (Arbutus menziesii) , bigleaf
maple {Acer macrophyllus) and Pacific dogwood (Cornus nutiallii).
Oak woodland and manzanita communities are on some soutli facing
slopes; principal species are Oregon white oak (Qucrcus garryana),
California black oak {Q. kelloggii), interior live oak {Q. wislizcnii),
green leaf manzanita {Arctostaphylos patula), and white leaf man-
zanita (A. viscida). Some stands of digger pine (P. sahiniay^a) are at
lower elevations. A few small wet meadows occur at higher elevations,
about 4,000 ft (1,220 m). Scientific names of plants were taken from
Munz and Keck (1959).
FIGURE 2. General view of part of the bear study area, showing intermixture of conifer
timber and brush fields (largely manzanita).
Commercial logging plays a major role in the ecology of the study
area. An estimated 40 to 50% of the study area has been at least par-
tially logged since 1950. The completion of tlie Trinity and Lewiston
dams in 1962 had an important effect on the physical aspects of the
area. Clair Engle Lake, formed by the Trinity Dam, inundated much
of the lowland watershed of the Trinity River and some of its major
tributaries, which were previously winter deer range. Tlie upstream
spawning run of the king salmon {Oncorhytichus tshawytscha) was
stopped at the breast of the Lewiston Dam.
Another recent impact on the study area is the great influx of
summer recreationists. Within the study area there are 11 national
BLACK BEAR STUDY
forest campgrounds and one major private resort. However, there are
few year-round residents in the study area.
METHODS
Trapping Methods
Trapping took place in two different time periods. A summer period,
using 18 trapsites (Figure 1), extended from June 29 to September 6,
1972. Limited fall trapping was undertaken at a salmon spawning area
near Lewiston between October 2 and October 13, 1972. Depredation
bear trapping was done throughout the summer and into the fall.
Essentially all trapping was done with culvert traps. Emphasis was
placed on capturing bears in natural settings in a defined local area.
Traps were located on or near old logging roads. "Call baits," consist-
ing of fish (wrapped in burlap) or road killed deer hanging in trees,
were used at these trapsites. Trapsites were chosen on the basis of bear
sign in the area or the response to a test "call bait" placed in the area.
Traps for nuisance bears were set when needed at campgrounds, private
homes and resorts throughout the county. Trap bait consisted of canned
fish base catfood, strawberry jam and marshmallows. Aldrich snare
settings were tested as a trapping method the last two nights of the
summer trapping period.
Trapping success was expressed in terms of bear captures per trap
night. During the summer period 58 captures of 38 different bears were
made in 156 culvert trap nights, for a 37% capture rate. During the
fall period four captures of four different bears were made in 21 cul-
vert trap nights, for a 19% capture rate. Fifteen depredation bear
captures of 14 different bears were made in 94 culvert trap nights for a
16% capture rate. Eleven of the latter were immobilized, tagged, and
transplanted. One bear was captured by a snare trap in six trap nights
for a 17% capture rate.
FIGURE 3. Immobilized bear being processed outside of trop.
8 CALIFORNIA FISH AND GAME
Immobilization, Handling and Tagging
Trapped bears were immobilized with Sernylan (phencyclidine
hydrochloride) injected manually using a syringe with a 3 ft (0.9 m)
fiberglass extension rod. Dosages were administered at the level of 1
mg of Sernylan per 3 (1.30 kg) to 4 lb. (1.81 kg) of estimated body
weight. Once techniques were established, average time from first injec-
tion to immobilization was approximately 30 min with a range of 3 to
85 min. Average time from bear immobilization to bear arousal was
approximately 60 min and ranged from 20 to 154 min. No lasting ill
effects of the drug were noted, and the immobilization method was con-
sidered satisfactory.
Once a bear was immobilized biological data were recorded (Figure
3). All animals were then marked in each ear with metal ear tags wdth
attached colored plastic streamers which identified each bear individu-
ally. Some bears were also tatooed in the ear. Retention of the metal ear
tags and streamers was good; only one metal ear tag and four streamers
were known lost. Six bears were also fitted with radio collars.
After marking, bears were given an injection of Procaine Penicillin G
as a general prophylaxis.
INDIVIDUAL BLACK BEAR CHARACTERISTICS
Color
Of 54 bears handled and three cubs observed during the handling of
their mothers, 33 (58%) Avere black or predominantly black with only
small patches of another color, such as a white chest blaze. Twenty -one
bears (37%) were predominantly a shade of bro\vn (Figure 5). One
bear was about equally brown and black. Two bears were predominantly
blonde. In all, eight bears, three of the black phase and five of the
brown phase, had white breast marks.
Color phases of the black bear vary from region to region. In the
eastern United States most bears are of the black phase. Black (1958)
reported that of 184 bears handled in New York all were black phase.
In Pennsylvania the situation is similar with only a few cinnamon
colored bears reported (Pennsylvania Game Commission 1952). In
western North America there is a greater mixture of color phases.
Records compiled from fur posts in British Columbia, Washington,
Oregon and Idaho between 1825 and 1857 (Cowan 1938) indicated
color phase ratios from 63% brown — 37% black in Idaho to 100% black
on Vancouver Island (Figure 4). In the Northwest Pacific area there
was a pronounced increase in the proportion of black phase bears from
south to north and also from east to west. In California, Grinnell et al.
(1937) reported that bears in the Sierra Nevada were predominantly
of the brown phase. The Trinity County ratio of 37% brown — 58%
black corresponds with the geographic trends in color reported by
Cowan.
There was no correlation between color phase and sex in the Trinity
study area. However, there did seem to be an unexplained correlation
between color and age. Of five cubs handled or se^n by the authors, all
were black. Of six yearlings handled, five were black. Thus, of 11 cubs
and yearlings 91% were black while of the total sampled population
58% were black, and of the sampled adult bears only 39% were black
or predominantly black. If these samples are representative of the popu-
BLACK BEAR STUDY
FIGURE 5. Sub-adult bear of brown phase recovering from immobilizing drug. Note ear
markings,
lation, the question is raised whether a portion of the population
changes with age from black to a lighter color phase. We have no proof
that such change occurs.
Measurements
The following measurements were taken (in inches) from immobilized
bears: body length, from nose tip to tail bone end; shoulder height,
from top of shoulder to base of ankle; tail length-, from base of tail
to end of tail bone ; neck girth ; chest girth ; head length ; head width ;
head circumference ; hind foot length ; hind foot width ; hind toe width ;
forefoot length; forefoot width; fore toe width, (see Figure 3 for il-
lustration of foot measurements) ; ear height from notch ; and ear height
from crown. A summary of all measurements is given in the senior au-
thor's unpublished M. S. thesis, 1973, University of California,
Berkeley.
Sexual dimorphism in size among the bears in the Trinity study area
was pronounced. There was little overlap in any of the linear measure-
ments of adult males and females, and where present was largely at-
tributed to age differences. The average chest girth for adult male bears
10
CALIFORNIA FISH AND GAME
Black color phase
r~^ Brown color phase
FIGURE 4. Color composition of black bear populations in the Pacific northwest. Data largely
from Cowan, 1938.
was 41.7 (105.9 cm) inches compared to 34.5 (87.6 cm) inches for adult
female bears. Size dimorphism apparently starts soon after birth, as
yearlings exhibited a size difference between sexes.
Adult male depredation bears averaged larger than other adult male
bears. A part of this average size difference was probably due to a
BLACK BEAR STUDY
11
larger percentage of older males in the depredation sample than in the
wild bear sample.
A strong positive correlation was found between bear weight and
composite foot measurements (Figures 6 and 7). The log-log form of
plotting the data fit well to a straight line of the equation :
FIGURE 6. Foot measurements of black bears. A + B + C + D-I-E+ F gives the sum
of composite foot measurements plotted in Figure 7.
Log (weight) = — 2.73 + 3.5 log (sum of foot measurements). The
correlation coefficient for this plot is 0.974.
Several field observations showed that a composite foot measurement
sum obtained from a track in light dust was about 10% less than the
true sum, obtained from the animal. Track measurements thus might
be used to derive rough estimates of population composition.
Weights
The average weight of the adult male depredation bear is more than
other wild males (Table 1). Bears captured in the fall appeared by
12
CALIFORNIA FISH AND GAME
C
O
o
CD
-r \^\y
/
o
0 / °
o <^o° o
^8
200 —
oA°
■ / o
■ y o
■ /
o4o
K
100 —
■f
■
80-
/ °
/ o
60-
40-
/■ o-Males
/ ■- Females
30-
o
<
>
1 1 1
20
30
Sum of composite foot measurements (inches)
FIGURE 7. Correlation of body weight and composite foot measurements of Trinity County
bears.
visual inspection to be fatter than summer captured bears. However, no
bear captured in the summer was recaptured in the fall, so no actual
weight gain could be determined.
Trinity County bears are similar in weight to those reported by
Jonkel and Cowan (1971) in Montana, but are considerably lighter than
those found in the eastern United States (Table 2). Because some of the
weights given for the eastern states are probably late fall weights, it is
difficult to make exact comparisons. Nevertheless, it seems apparent that
Trinity County bears are smaller. Of 149 bears that Black (1958)
handled in one summer, six male bears exceeded 400 lb. (181.6 kg) with
BLACK BEAE STUDY
13
the largest two weighing 562 (255.1 kg) and 599 lb. (271.9 kg). His
maximum weight for a female was 361 lb. (163.9 kg). None of the
Trinity bears approach these figures. The largest male, weighed 324 lb.
(147.1 kg) and the largest female 162 lb. (73.5 kg).
TABLE 1.— Average Weights (pounds) of Trinity County Black Bears, 1972
Class
No.
Range
X
SD
All adult males
30
8
11
2
1
3
2
116-324
190-295
112-162
99-104
87
58-64
43-44
215.0
243.6
127.6
101.5
87.0
61.0
43.5
55.0
Depredation adult males
Adult females
38.8
18.0
Sub-adult males
Sub-adult females
Male yearlings
Female yearlings
TABLE 2. — Average Black Bear Weights from Several Different Localities
Location
Average weights (pounds)
Adults
Year-
lings
Source
Males
Females
Cubs
Jonkel and Cowan (1971)
Montana
211
304
324
276
215
125
189
200
196
128
45
94
54
22
Harlow (1961)
Florida -
Harlow (1961)..
New Hampshire
New York
Black (1958)
38
This study.. ...
Trinity County
29
LIFE HISTORY
Summer Movements and Home Range
Recaptures and radio locations of 13 bears (6 males and 7 female)
yielded data on summer movements. All movements were computed as
minimum linear distances between known location points. The average
movement shown by male bears was 1.7 miles (2.7 km), while for
females the average was 2.0 miles (3.2 km). The overall average summer
movement was 1.9 (3.1 km) miles, both sexes included. The maximum
movement recorded by recapture was 2.8 miles (4.5 km). During sum-
mer, the maximum distances moved by three radio-collared bears were
2.2 (3.5 km), 3.0 (4.8 km) and 4.5 miles (7.2 km). The average maxi-
mum number of days between known locations for bears showing move-
ment was 24.5 days.
Trapsites were not located in such a pattern or in adequate numbers
that a reliable home range size could be plotted on the basis of recap-
tures alone. However, two radio-collared bears — number 10, an adult
male, and number 61, an adult female with cubs — were located fre-
14
CALIFORNIA FISH AND GAME
quently enough to enable an accurate estimation of their summer home
range (Figure 8). A third bear, number 14, an adult female, was located
only a few times before losing her collar.
FIGURE 8. Movements of three Trinity County bears fitted with radio collars.
Bear number 10 was located 20 times over 56 days in an area of less
than 5 square miles (12.9 km-) before he moved a distance of approxi-
mately 7 miles (11.3 km) from his summer range. The latter movement
was considered a seasonal migration. Bear number 61 was located six
times over a period of 15 days in an area of less than 7 square miles
BLACK BEAR STUDY 15
(18.1 km^). Bear number 14 was located four times in a period of 28
days in an area of less than 4 square miles (10.4 km^). Her collar was
then recovered 23 days after the last known location approximately 3.5
miles (5.6 km) from the center of the area of her previously known
locations.
From these data, summer home ranges were estimated to be fairly
FIGURE 9. Seasonal movements of Trinity County bears as shown by recapture, sighting,
and hunter kill. One kill site (SW corner) was actually 7 miles (11.3 km) farther
to the Southwest, ofF the map.
16
CALIFORNIA FISH AND GAME
small, most being approximately 5 (12.9 km-) to 10 square miles (25.9
km-) in size. Summer home range size did not appear to be different-
iated by sex or age class.
Fall Movements
On the basis of radio collar locations, sightings, trapping, and hunter
tag returns, fall movements of 10 bears were known (Figure 9). The
average movement of nine bears trapped in the s\immer and located in
the fall was 6.1 miles (9.8 km) from the original summer capture site.
Movements fell into two distinct categories.
Four of the bears apparently had not, at the time of the fall location,
left or moved far from their summer home range. Eadio-collar bear
number 61, a female with cubs, stayed in the area of her summer home
range until she was shot on October 18. On October 17, an adult female
with a cub was sighted 2.0 miles (3.2 km) from her capture site of
September 1. On September 23, an adult male was shot illegally 1.5
miles (2.4 km) from his original summer (July 25) capture site.
On October 24, a yearling female was sighted 0.5 miles (.8 km) from
her original summer (July 26) point of capture. It is not known if any
of these bears would have moved or did move from their summer home
ranges later in the fall.
The other five bears, captured in the summer and located in the fall,
were found an average of 9.0 miles (14.5 km) from their original cap-
ture site. These fall locations were determined between September 11
and November 4. Eadio-coUared bear number 10 moved from his sum-
mer home range and then stayed on a small fall home range for at least
30 days (Figure 8). It is not known whether other bears located a
relatively large distance from their original capture sites were staying
in a newly defined home range or were wandering.
In summary, average fall movements were greater than average sum-
mer movements, but not all of the animals moved from their summer
home ranges.
Comparison With Other Studies of Black Bear Mobility
Movement data from other reports (Table 3) show two important
trends in bear movement habits. First, most studies report a larger
average movement in the faU than in the summer. And second, male
bears show larger average movement than females.
TABLE 3. — Average Movements of Black Bears According to Season and Sex
Minimum average movement (miles)
Summer
Fall
All year
Location and source
Males
Females
Michigan — Erickson and Petrides (1964)..
Montana — Jonkel and Cowan (1971)
Virginia — Stickley (1961)
2.1
1.3
1.85
6.7
7.6
6.10
5.4
3.9
10.0
3.67
1.4
1.6
1.8
Trinity County (1972) ...
3.13
BLACK BEAR STUDY 17
A greater average movement in the fall suggests an extension of the
summer home range, or movement to a different fall home range, or
possibly fall nomadism. Increased fall movement can be a result of
bears taking advantage of local food abundance (Spencer 1955). In
Montana, Jonkel and Cowan (1971) reported that throughout the year
a small home range was used by all bears, except transient sub-adults.
They believed that the large diversity of climate, topography and veg-
etation in a small area made it possible for bears in the Montana area
to maintain small yearly home ranges.
In this study, bears seemed to have an extremely small summer home
range, but part of the population moved in fall to new food supplies.
By the latter half of September the supply of manzanita berries, the
major summer food, had been exhausted in the summer trapping area.
There appeared to be no mast crops, berry crops, or other easily avail-
able or plentiful food sources in the area to replace manzanita berries.
There were plentiful food sources in the form of spawning salmon,
acorn crops and manzanita berries in the areas to which bears were
known to move.
Despite poor food conditions a segment of the study population did
not move far from their summer home range, or possibly they moved
later in the fall. That portion of the study population that stayed
close to their summer home range was largely made up of sows with
cubs or immature bears. Sows with cubs are generally expected to stay
on small home ranges. Jonkel and Cowan (1971) reported that dis-
persal was pronounced in yearling bears in Montana. However, there
was no evidence that this was the case with yearling bears in the
Trinity study area.
Contrary to other reports, movement data from the Trinity study
area were not clearly differentiated according to sex. The average max-
imum known summer movement of females was slightly greater than
that of males. However, it appears that adult females with cubs make
significantly shorter fall movements than either lone adult females or
adult males.
Food Habits
Seats were collected from July through October of 1972. All scat
samples were analyzed, most in the dry state, at the California Fish
and Game laboratory.
Scat samples usually were not collected unless they could be dated
to within approximately a week. During July and August most samples
were collected along roads, around trapsites and bait stations, and from
traps during regular trapping activities. Trap bait did not appear in
scats taken from traps. All of the samples in July and August came
from the summer trapping area. In September and October a system
of trails and roads was checked periodically for scats. Part of this
system was within the summer trapping area. The remainder was
around Lewiston Lake, in an area with a high proportion of Manzanita
thickets and oak woodland.
Table 4 summarizes the major food items found in 106 scat samples.
Volumes of food items were estimated, but because volume composition
in a scat is not necessarily indicative of the volume eaten, final data
18 CALIFORNIA FISH AND GAME
"were expressed in terms of frequency of occurrence, with general vol-
ume trands noted. These data are presented only as a food index and
a supplement to other data in the study.
Many of the September and October samples came from a king
salmon [Oncorhxjnclxus tshawtscha) spawning area on the Trinity
River near the breast of Lewiston Dam. Although bears were seen
feeding on salmon, scats dropped in the area contained mostly acorns
and manzanita berries apparently eaten in the surrounding area.
Bears in the study area depended primarily on manzanita berries
from July through August (Table 4). Thirty four of 35 scat samples
contained manzanita berries, and a large majority of these samples
were essentially 100% manzanita berries with other items in trace
amounts. Grasses and forbs were the next most common food item in
July and August, but they were a relatively small volume of the
samples in which they occurred. Dogwood seed occurred in 14% of the
August scats, usually as a major volume item.
In September and October manzanita berries remained a major food.
By late September and into October acorns became a dominant food
item in the Lewiston Lake area. Although acorns were found in 38%
of the October scats, none occurred in any of the scats from the summer
trapping area. Grasses and forbes continued to be found frequently but
in small amounts.
Deer hair was found in 5 of 106 samples.
Reproduction
Of all adult female bears examined during the summer trapping
period, two were in estrus. These bears were captured on July 17 and
July 18. Of three adult female bears captured after July 18 that were
believed to be without cubs, none were observed in heat. The beginning
of the breeding season could not be estimated because trapping did not
begin until the last week in June.
Four of the 11 adult females captured (36%) were known to have a
litter of the year. Three of these litters were either handled or seen.
The other litter was not observed during the handling of the mother,
but was sighted with the mother several weeks later. Two other females
unaccompanied by cubs during capture were lactating.
The average litter size in Trinity County was 1.67 cubs, based on six
litters handled or seen.
The female black bear has seasonally constant estrus with ovulation
induced following mating. The mating season can vary but usually
occurs during June and July (Erickson and Nellor 1964). Grinnell
et al. (1937) reported a pair of California black bears mating on June
25. Of eight females trapped by Stickley (1961) in Virginia in one
summer, three were in heat in June, three in July and two in August.
Jonkel and Cowan (1971) found in Montana that bears were in estrus
as early as May 25 and as late as August 10, with a peak in June. Data
indicated that most mating in Trinity County is over by mid-July.
Black bear litters seem to run slightly over two cubs in the eastern
United States. Average litter size was reported as 2.4 in Maine (Spencer
1955), 2.2 in Florida (Harlow 1961) and 2.15 in Michigan (Erickson
1964). In the western United States reported average litter size is
usually below two cubs. Average cubs per litter has been reported as
BLACK BEAR STUDY
19
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20 CALIFORNIA FISH AND GAME
1.68 in Idaho (Kiist 1946), 1.8 in Yellowstone National Park (Bray
1967) and 1.6 in Montana (Jonkel and Co-wan 1971). Although the
sample was small in Trinity County the average litter size of 1.67 com-
pares closely with other areas in the West.
POPULATION CHARACTERISTICS
Density
Thirty-eight bears, which included two cubs, were trapped and tagged
in the main part of the summer trapping area. In addition, four cubs
were known to accompany three sows which were tagged. The average
radius of movement for bears in the summer trapping area was 1.85
miles (2.9 km). If it is assumed that on the average bears were drawn
a maximum of 1.85 miles from a trapsite, then the trapping covered an
area of 44 square miles (113.9 km-). If no emigration took place during
the summer, the minimum density of the marked population in the main
summer trapping area was 42 bears on 44 square miles or approxi-
mately one bear per square mile (2.6 km^). This computation takes no
cognizance of the unmarked portion of the population.
Three methods were used to estimate the total population, including
marked and unmarked animals. Two utilized the Lincoln Index method
with different types of sampling; the other fitted the frequencies of
capture and recapture to a geometric model.
After the trapping period there were seven sightings of individual
bears or family groups in the main summer trapping area. Three of
these were marked. Using this as an estimate of the percentage of the
total population marked in the area, it can be calculated that there
were 84 individual bears and family groups in the area. If 14% of the
population were cubs (see section on population structure) then the
total population would be 98 bears.
If August 29 is arbitrarily chosen as the end of the marking period
and the beginning of a sampling by capture period, the total population
based on capture-recapture is estimated as 103 bears using a simple
Lincoln Index.
The geometric model for the frequency of capture distribution (Ed-
wards and Eberhardt 1967) uses as an estimator of total population
the equation,
N = "^
1 - (n/t)
where n = total number of individuals captured and
t = total number of captures.
Using this method we estimated the population to be 121 bears. Edwards
and Eberhardt believed this computation gives estimates that are
slightly high.
Comparing the results of these three methods of determining total
population, we believe that a conservative estimate of the total popula-
tion in the main trapping area during the summer of 1972 was between
80 and 90 bears. This Avould be a density of roughly two bears per
square mile. It is thought that local densities in the trapping area may
have been even higher. Of 42 known bears in the trapping area, 31 were
known to be located in the northern half of the area.
BLACK BEAR STUDY 21
Fall densities were not estimated for the main part of the summer
trapping area or the total study area. From the decrease in bear sign
in the main summer trapping area after mid-September and the data
on fall movement patterns, it is postulated that the population density
in the main summer trapping area decreased greatly in the fall.
Although five marked bears were reported shot during the 1972 bear
season, no attempt was made to use the kill of marked and unmarked
animals to estimate a fall population density-. The relatively large dis-
persal movements shown by three of the marked hunter-killed bears
would make it very difficult to determine over what area a Lincoln
Index should be applied.
Spencer (1955) used a cruise line method to calculate a density for
the total bear range in Maine of one bear per 5.56 square miles (14.5
km^). In Virginia, Stickley (1957), cited by Bray and Barnes (1967),
distributed questionnaires to game wardens and estimated the black
bear density to be one per 3.9 square miles (10.1 km^). In Michigan,
Erickson and Petrides (1964) calculated, from marked-unmarked ratios
among hunter-killed bears in their study area, a bear densitj^ of one
per 3.4 square miles (8.8 km-), although the researchers considered this
calculated density to be low.
In the "West, in that part of Yellowstone National Park studied by
Bray (1967), the black bear density was estimated to be one per 5.2
square miles (13.5 km-). In the best habitat of Bray's study the density
was reported as one per 1.4 square miles (3.6 km-). In Montana in the
Bear Creek study area Jonkel and Cowan (1971), using tagging and
observation data, estimated the bear density to be one per 0.8 square
mile (2.1 km-) in 1961. After increased hunting pressure in the area,
they calculated the density to be one per 1.7 square miles (4.4 km^) in
1966. In Alberta, Kemp (1972) reported the density of an unhunted
bear population as one bear per 1.02 square miles (2.6 km^).
The estimated summer bear density in the summer trapping area in
Trinity County is about one bear per 0.5 square miles (1.3 km^) which
is almost twice that of any other reported in the literature. Even the
absolute minimum density of one marked bear per square mile is close
to the highest density given in the literature. We acknowledge that
this may represent a seasonal concentration that could vary from year
to year with shifting availability of food.
Sex and Age Structure
During the summer trapping period the sex ratio of trapped bears
was 14 females to 25 males, or 36% females to 64% males. Statistically,
this ratio was not significantly different at the 5% level from a one-
to-one sex ratio. All four of the bears captured during the fall trapping
period were males. Of 11 depredation bears tagged, 10 were males. Most
previous studies have shown a preponderance of males in trapped
samples, but Kemp (1972) suggests that this might derive from the
higher mobility of males. The sex ratio of 88 hunter killed bears in
Trinity County during the 1972-73 season was 42% females to 58%
males. More data are needed to verify the actual sex ratio in the popu-
lation.
The age was estimated by toothwear and body size. Cubs and yearlings
were accurately classified. For analysis purposes, all other bears were
placed in a combined subadult and adult classification. For the known
22
CALIFORNIA FISH AND GAME
population of 43 bears, the general age structure was as follows: six
cubs; five yearlings; 32 subadults and adults. As suggested before, there
may have been some cubs that were not seen that belong to this sample
population.
Table 5 summarizes the age structure of other black bear populations,
in comparison with that found in the Trinity study area. The age struc-
ture of the Trinity population was almost exactly that reported for a
stable unhunted population in Alberta (Kemp 1972). It is also very
similar to that of a slightly decreasing population in Montana (Jonkel
and Cowan 1971). Bears in the Trinity study were not accurately
aged by a tooth sectioning technique, so no calculation of mortality rate
according to age class can be derived.
TABLE 5. — Age structures of Several Black Bear Populations
Location and source
Colorado — Bray and Barnes (1967) citing
GUbert (1951)
Montana — Jonkel and Cowan (1971)
Virginia— Stickley (1961) - -
Michigan — Erickson and Petrides (1964)
Alberta— Kemp (1972)
Trinity County (1972)
Cubs
No.
44
18
2
42
21
6
%
19
12
2
36
15
14
Yearlings
No.
53
26
27
27
18
5
%
23
17
29
23
13
12
Older bears
No.
133
HI
65
48
104
32
%
58
71
69
41
72
74
Hunter Caused Mortality
Five of the 54 bears in the tagged populations were killed during the
hunting season from October 14, 1972 to January 1, 1973. This is a 9%
hunter caused mortality. However, if we exclude the tagged depreda-
tion bears, which were scattered throughout the county, and consider
only the other tagged bears, the hunter caused mortality was five of 43
bears or almost 12%. It must be stressed that this is a minimum
estimate since the hunting kill is not fully reported in Trinity County.
The reported kill in the county was 88, which was close to the 5 year
average of 91 bears, from 1967-68 to 1972-73.
Jonkel and Cowan (1971) reported a 3% hunter kill of tagged bears
after the tirst year of trapping. This increased to 13% the following
year when hunting was encouraged in the area. Erickson and Petrides
(1964) in Michigan reported a minimum annual mortality rate by hunt-
ing of 19%. Stickley (1961) in Virginia found that hunters took 33%
of his tagged bears the first fall after tagging. The Trinity County
hunter kill percentage of 12% is relatively low compared to these
reported figures, but as mentioned before the accuracy of this figure
is in doubt.
DEPREDATION BEARS
Depredation bears are such a distinctive segment of the total bear
population that a separate discussion is warranted. Of 11 depredation
bears tagged, nine were adult males. One was a female subadult and
one was a yearling male. It is not unusual that males comprise such a
BLACK BEAR STUDY 23
high percentage of the depredation bear sample. Black (1958) in New
York found that of bears classified as dump bears, 75% were males.
Similarly, Erickson and Petrides (1964) reported that 84% of 30
captured dump bears were males.
The average weight of adult male depredation bears (summer cap-
tured) was larger (243.6 lb. [110.6 kg]) than the average weight of
summer captured wild bears (198.9 lb. [90.2 kg]) in the study. Most
of the depredation adult males tagged were estimated to be 5 to 6 years
old or older. Manj- of the wild adult male bears captured were estimated
to be between 3 years and 6 years old. Black bears have been reported
as not attaining full body growth until the sixth or seventh year (Ger-
stelll939).
A subadult female depredation bear captured in a campground on
July 6 was transplanted 14 miles (22.5 km) to the north. By late
August this bear had moved 7 miles (11.3 km) southeast and has become
a nuisance around a housing development and had to be removed. An
adult male was captured at a private dump on June 27 and was trans-
planted approximately 25 miles (40.2 km) to the northeast. Two days
later a tagged bear was reported seen about half way between the point
of capture and point of release. On July 5 he was sighted and iden-
tified by us at the dump where he was originally captured.
In Michigan, of 19 bears transplanted an average of 39.7 miles
(63.9 km) only two showed homing behavior (Erickson and Petrides
1964). However, in New York, Sauer et al. (1969) report that of 52
bears transferred from 8.2 (13.2 km) to 66.6 miles (107.2 km) from the
capture site, 22 returned to the vicinity of capture. The longest distance
from which a bear returned to its home range was 56 miles (90.1 km).
Sauer et al. thought that this homing behavior was not due to a homing
instinct but rather to the familiarity of many bears with a relatively
large area around their home range.
The dense bear population in the summer trapping area coexisted
with a high population of recreationists. Yet, in 1972 only two summer
nuisance bears were reported in campgrounds although bear depreda-
tion in the county as a whole was high. Summer bear nuisances at the
resort in the area were few and not troublesome. This situation might
have been due to the concentration of the recreation activity along the
main roads and around the lake shore, rather than being scattered
throughout the area. However, field observations and radio collar loca-
tions showed that it was not unusual for bears to pass within a few
hundred yards of campsites. Yet, few recreationists ever sighted a bear
in the area. Some were surprised to learn that bears were common in
the area.
The question of what causes a bear to become a nuisance is a complex
one. It would be suspected that overcoming a fear of man is one of the
major factors. Likewise, natural food conditions probably infiuence the
incidence of nuisance behavior. Bear trouble in the Trinity area was
low in the summer of 1972 when manzanita berries were plentiful. In
the fall when bear food became scarce in the summer trapping area,
bear nuisance reports increased for a time, even though human use of
the area had greatly decreased and it was thought that bear density
had greatly decreased. This leads one to postulate that natural food
conditions in the area to which a depredation bear is transplanted may
24 CALIFORNIA FISH AND GAME
be a major factor in dotcrmininp: whether tliat bear becomes a nuisance
bear again.
As human population density and recreational use increase in Trinity
County, conflicts between bears and human interests will increase. More
information on the factors which cause a bear to become a nuisance
bear is needed. Also, methods of handling a troublesome bear will have
to be improved so that the probability of nuisance recurrence by the
bear will remain low.
ACKNOWLEDGEMENTS
We gratefully acknowledge aid from several members of the Califor-
nia Department of Fish and Game, including Wallace G. Macgregor
and Dick Weaver who provided supervision and assistance during the
field work ; Bruce Browning who assisted with the food habits study ;
Walt Stienecker who analyzed most of the seat samples ; Brian Hunter
and Bill Clark who trained us in immobilization techniques; and Herb
Hagen who provided assistance with radio telemetry equipment and
methods.
Don Foster served as field consultant during development of trap-
ping techniques.
Gene Christman of the Museum of Vertebrate Zoology prepared the
figures for this publication.
A. Starker Leopold was of invaluable help in the preparation of the
final manuscript.
LITERATURE CITED
Black. H. C. 1958. Black bear research in New York. Trans. N. Am. Wildl.
Conf. 23 : 443^61.
Bray, O. E. 1967. A population study of the black bear in Yellowstone National
Park. M. S. Thesis. Colorado State Univ. 102 p.
Bray, O. E., and V. G. Barnes. 1967. A literature review on black bear popula-
tions and activities. National Park Service and Colorado Cooperative Wildlife
Research Unit. 34 p.
Cowan, I. M. 1938. Geographic distribution of color phases of the red fox and
black bear in the Pacific Northwest. J. Mammal. 19(2) : 202-206.
Edwards, W. R., and L. Eberhardt. 1967. Estimating cotton-tail abundance from
live trapping data. J. Wildl. Manage. 31 : 87-96.
Erickson, A. W. 1964. An analysis of black bear kill statistics for Michigan. In
The black bear in Michigan. Mich. St. Univ. Res. Bull. 4:68-102.
, and J. E. Nellor. 1964. Breeding biology of the black boar. In The
black bear in Michigan. Mich. St. Univ. Res. Bull. 4: 1-45.
-, and G. A. Petrides. 1964. Population structures, movements and mortality
of tagged black bears iu Michigan. In The black bear in Michigan. Mich. St.
Univ. Res. Bull. 4:46-67.
Gilbert, D. L. 1951. Economics and related biology of the black bear in Colorado.
M. S. Thesis. Colorado A. and M. Coll. 164 p.
Gerstell, R. 1939. The growth and size of Pennsylvania black bears. Pa. Game
News. 10(8) : 4-7.
Grinnell, J., J. S. Dixon, and J. M. Linsdale. 1937. Furbearing mammals of
California. Vol. 1. Univ. Calif. Press. Berkeley, Calif. 377 p.
Harlow, R. F. 1961. Characteristics and status of Florida black bear. Trans.
N. Am. Wildl. Nat. Res. Conf. 26 : 481-495.
Jonkel, C. J., and I. McT. Cowan. 1971. The black bear in the spruce-fir forest.
Wildlife Monogr. 27 : 1-57.
Kemp, G. A. 1972. Black bear population dynamics at Cold Lake, Alberta, 1968-
70. In Bears, their biology and management. Ed. by S. Herrero. Interna-
tional Union for Conservation of Nature and Natural Resources, Merges, Switzer-
land, p. 26-31.
BLACK BEAR STUDY 25
Munz, P. A., and D. P. Keck. 1959. A California Flora. Univ. Calif. Press.
Berkeley, Calif. 681 p.
Pennsylvania Game Commission. 1952. The black bear in Pennsylvania. Pa.
Game News 23(4) : 11-18.
Rust, H. J. 1946. Mammals of northern Idaho. J. Mammal. 27(4) : 308-327.
Sauer, P. R., S. L. Free, and S. D. Brown. 1969. Movements of tagged bears
in the Adirondacks. N. Y. Fish and Game J. 16(2) : 205-223.
Spencer, H. E., Jr. 1955. The black bear and its status in Maine. Maine Dept.
Inl. Fish. Game. Bull. 4 : 1-55.
Stickley, A. R., Jr. 1957. The status and characteristics of the black bear in
Virginia. M. S. Thesis. Virginia Polytechnic Inst. 141 p.
. 1961. A black bear tagging study in Virginia. Proc. Ann. Conf. S. E.
Assoc. Game Fish Comm. 15 : 43-54.
Calif. Fish and Game 61(1) : 26-34. 1975.
EARLY LARVAE OF THE DIAMOND TURBOT,
HYPSOPSETTA GUTTULATA^
MAXWELL B. ELDRIDGE
National Marine Fisheries Service
Tiburon Fisheries Laboratory
A developmental series of larvae of Hypsopsetta guttulata collected
in Son Francisco Bay is described. These larvae are very similar to
Pleuronichthys turbots and distinguishing characters which separate
larval forms of Hypsopsetta from Pleuronichthys are discussed. Occur-
rences of H. guttulata eggs and larvae indicate an extended spawn-
ing period from early June through mid-October.
INTRODUCTION
The most abundant pleuronectid larva collected to date in a current
study of the fish eggs and larvae of Richardson Bay, California, pre-
sented a problem. At first the larvae, especially the specimens with
the yolk-sac absorbed, appeared to be one of the Pleuronichthys species,
of which two (P. decurrens and P. verticalis) were known to be in the
San Francisco Bay. Many identifying characters for Pleuronichthys
spp. established by Budd (1940), however, did not agree with my speci-
mens. The most obvious were the small size of yolk-sac larvae and the
presence of oil globules in the yolk. The dilemma was presented to E. H.
Ahlstrom of the NMFS Southwest Fisheries Center, who was able to
identify the series of specimens as larvae of the diamond turbot,
Hypsopsetta guttulata.
The diamond turbot is not tabulated separately in commercial land-
ings but is included with turbots of the genus Pleuronichthys. Together
they constitute a minor part of the commercial catch. The diamond
turbot is often caught by coastal sport fishermen. This reflects the fish's
habitat; it is commonly found in shallow bays and tidal flats and on
muddy or sandy bottoms (Baxter 1960). This species ranges from Cape
Mendocino to Cape San Lucas, Baja California, and in the Gulf of
California. The larval specimens described herein are from the northern
extent of the range of H. guttulata but early records (Jordan and Gil-
bert 1880) show that it has long been a resident of San Francisco Bay.
Compared to the Pleuronichthys turbots, little is known of the life
history of the diamond turbot, especially its reproductive habits.
Limbaugh (1955) stated that the pelagic eggs are released during
summer and fall. Eggs from running ripe diamond turbots were taken
by Limbaugh during the summer and similar eggs were taken repeatedly
in plankton collections made off the Scripps Institution of Ocean-
ography pier during the summer of 1952 (Orton and Limbaugh 1953).
The purpose of this paper is to describe the early life history stages
of H. guttulata and to give characters that Avill readily separate it from
the larvae of the two Pleuronichthys species whose adults occur in San
Francisco Bay. The description is handicapped by the lack of a complete
developmental series. There were no specimens obtained between 5.8 mm
1 Accepted for publication July 1974.
(26)
DIAMOND TURBOT LARVAE 27
and 11.4 mm (0.23 and 0.45 inch). Therefore, the study concentrates on
the younger larvae. Juvenile and adult specimens used in this study
were obtained from field collections in San Francisco Bay and from the
collection of the California Academy of Sciences.
METHODS
The larval specimens used for this description were collected in
Richardson Bay, California, which is an approximate 11.0 km^ (4.25
mile-) shallow embayment located immediately to the north of the en-
trance to and within San Francisco Bay. Two methods were used to
catch the diamond turbot. A standard 0.5 meter plankton net was towed
at randomly selected stations throughout Richardson Bay, and two sta-
tionary channel nets, modified from a design of Lewis, et al (1970),
were fished simultaneously. One channel net was positioned midway up
the Bay and the other near the entrance to the Bay. All nets had a mesh
aperture size of 333 micra.
A total of 135 specimens were examined in this study, 95 of which
were larvae. The larvae were preserved in 5% buffered formalin, while
the juvenile and adult fish were preserved in 40% isopropyl alcohol.
Morphometric measurements followed those described by Ahlstrom and
Ball (1954) and were made with an ocular micrometer. I selected the
illustrated specimens to represent stages of development. The illustra-
tions are literal, drawn by means of a camera lucida.
The meristic data were taken from either specimens stained with
alizarin or from x-ray photographs.
The following description is organized by character according to the
approach used by Ahlstrom and Ball (1954). Each character is fol-
lowed through its development. Pigmentation is presented first followed
by morphology and meristics.
PIGMENTATION
The discussion on pigmentation is limited to those melanophores
visible in the preserved specimens. It is possible other body pigments
are present in diamond turbot larvae but are lost in formalin preserva-
tion. The pigmentation varied within any given size class as might be
expected for a species with heavy pigmentation. Throughout the entire
series the larvae exhibited generally heavy body pigmentation on the
anterior f 's of the body of yolk-sac larvae and extending f's of the
body length in 5 mm larvae. The most notable variation in pigment
was the range of development of patches of scattered fine melanophores
located along the dorsal and ventral midlines posterior to the anus. In
younger forms, these patches ranged from barely detectable spots on
the bases of the finfolds to occasionally a definite triangular patch in
one or both finfolds. The older larvae did not exhibit any patches ex-
tending onto the finfold, but dark strips of fine spots were clearly
visible.
Newly hatched larvae (Figure la) completely lacked eye pigment.
The head and body were pigmented. The head melanophores were dis-
crete stellate units while the body exhibited fine stippling at 50 x
magnification. The yolk-sac was devoid of pigment except for ap-
proximately 10-15 stellate melanophores on the surface of the large oil
globule.
28
CALIFORNIA FISH AND GAME
B
FIGURE 1. Diamond turbot. A, 1.7 mm; B, 212 mm; C, 216 mm.
As the yolk was absorbed and the put became functional, the pigment
spread ventrally over the yolk-sac. The hindgut enlarged and pigment
was seen over its ventral flexion to the anus. Melanophores persisted on
the oil globule. An interconnecting network of stellate melanophores
Avas present over most of the anterior half of the body. The postanal
patches on the dorsal and ventral midlines were now visible. In most
specimens these were seen only as intensification of the fine pigment
spots near the base of the finfold.
Eye pigmentation developed along the dorsal rim of the eye (Figure
lb). There was still some yolk visible at this stage and the mouth was
well developed with up to 10 stellate melanophores along the margin of
DIAMOND TURBOT LARVAE
29
the dentary. The past-anal patches lessened in size in larger specimens
and were routinely seen as concentrations of midline pigment (Figure
Ic). The body became covered with discrete large stellate melanophores.
Several spots were also visible in the isthmus. This general pattern con-
tinued into larger specimens (Figure 2a).
B
FIGURE 2. Diamond turbot larvae. A, 3.8 mm; B, 4.9 mm; C, 5.8 mm.
The more developed larvae around 4.0 to 4.9 mm w^ere distinguished
by the elongate patches which now were densely pigmented but still
confined to the base of the developing vertical fin anlage. The head had
less surface pigment spots but imbedded melanophores were visible,
especially at the nape.
30 CALIFORNIA FISH AND GAME
The metamorphosing harvae (Figure 2c) continued these pigment
patterns. Tlie median patches -were more extensive, spreading onto the
pterygiophore bases of the dorsal and anal fins. The specimens at this
stage of development presented different appearances depending on
the extent of expansion or contraction of the melanophores. Almost
the entire body exclusive of the outer fin margins and the posterior
portion of the body was covered Avith stellate melanophores.
Meristic characters easily distinguish metamorphosed juveniles. These
characters are presented in Table 1. All juvenile specimens had a total
of 35 vertebrae ; 12 abdominal and 23 caudal. The dorsal fin averaged
71 rays and the anal fin 50 rays. The caudal fin averaged 19 rays. The
eyed side was densely pigmented over the entire body. Dark spots were
scattered on both sides and ended prior to the caudal penduncle. Pig-
ment extended onto the vertical fins.
MORPHOMETRY AND MERISTICS
The newly hatched larvae averaged 1.6 mm (0.063 inch) standard
length (s.L.) and appeared deep bodied because of the large yolk-sac.
The oval shaped yolk-sac contained unsegmented yolk with numerous
oil globules, the largest positioned to the rear of the yolk-sac. The single
large oil globules averaged 0.14 mm (0.005 inch) in diameter. As the
yolk was absorbed, the yolk-sac appeared more ovate and the head and
hindgut more outlined. By approximately 2.2 mm (0.087 inch) s.L., the
yolk was more than ^ absorbed. The oil globule now averaged around
0.06 mm (0.002 inch). Larvae ranging 2.3 to 2.4 mm (0.090 to 0.094
inch) had consumed nearly all their yolk.
As the yolk was consumed, the gut and mouth became more de-
veloped. Newly hatched larvae had no functional mouth and the hind-
gut leading to the anus appeared as a thin transparent tube extending
ventrally through the finfold. Gut development was most evident in the
bulging or enlargement proceeding ventrallj' to the anus, accompanied
by heavy gut pigmentation. By 2.3-2.4 mm (0.090 to 0.094 inch) s.L.,
the gut was functional and food was seen in the intestine. In general,
the gut length shortened relative to body length in the larvae ; at
metamorphosis the snout to anus length was approximately 35% s.L.
(Figures).
Body shape became more fusiform as yolk absorption progressed.
Some specimens slightly hunched over the yolk-sac, but this disappeared
with yolk absorption. With the thickening of the gut, the development
of the mouth and enlargement of the head, the body deepened in rela-
tion to its length (Figure 3). The specimens around 3.8 mm to 4.9 mm
began to exhibit the compressed flatfish form. The illustrated larvae
display the gradual rotation of the gut anteroventrally with a character-
istic sag to the stomach. The metamorphic specimens had a rounded
appearance to the gut. Their bodies were more compressed. Throughout
the developmental series the myomeres were difficult to see mostly
because of the intense pigmentation.
The head of the hatchling showed a midbrain bulge separated from
forebrain and medulla which is typical of many pleuronectid larvae.
By 2.4 mm, it appeared as a large dome which continued throughout
the series. The fore and hindbrain sections could be seen also at these
sizes. The head increased in overall relative size throughout develop-
ment finally reaching approximately ^ of the body length, then it
DIAMOND TURBOT LABVAE
31
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32
CALIFORNIA FISH AND GAME
decreased slightly as the body deepened (Fip:ure 2). The mouth was
inferior in position until 3.5-3.9 mm when it became terminal. The
larvae around 5.8 mm exhibited asymmetric growth, with the left eye
20-1
10-
40-
30-
20-
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^ 60H
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T ' 1 — ' I ' I ' r
—I —
0.2
1 — ' I • I •! I • I • I ' I •
* 4.
I
I f
f *+ -
HEAD LENGTH
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BODY DEPTH
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SNOUT TO ANUS LENGTH
T — ' I MM
T ' 1 — ' I ' I '!
0.4 0£ 0.8 1.0 2.0 4.0 6.0aOIO
—I • — I MM'
20 40 60 80
(mm)
Morphometric proportions (in logorithmic scale) of the diamond turbot, plotted
OS percentages of standard length.
DIAMOND TURBOT LARVAE 33
in the midst of migration to the right side. Eye diameters remained
much the same in relation to body length throughout development
(Figures).
The finfold began at the forehead and extended posteriorly around
the tail and forward to the yolk-sac or gut. It remained complete and
translucent throughout development until around 3.8 mm when the
anlagen of the dorsal and anal fins and the caudal fin were seen form-
ing. At hatching the pectoral fin bud was visible on the dorsal aspects
of the yolk-sac. By approximately 2.4 mm, the pectoral fins appeared
as small lateral projections.
The 4.9 mm larvae possessed nearly developed dorsal and anal fins
but the fin ray counts were not complete. Likewise, the metamorphosing
larvae did not have complete dorsal and anal fin development, but the
rays were more discernible. The caudal fin developed simultaneously
with the dorsal and anal fins. The upward flexion of the caudal noto-
chord occurs at about 4.0 mm s.l. The hypural cartilages and the full
complement of caudal rays were visible in the metamorphic specimens
(Figure 2c). In these advanced larvae, the pterygiophore primordia
appeared as longitudinal ridges along the bases of these fins. The
smallest juvenile specimen (11.5 mm) did show complete vertical fin
ray development.
DISCUSSION
From occurrences of the larvae, Hypsopsetta guttulata appeared to
have an extended spawning period. Larvae, and what I believe to be
the pelagic eggs of the diamond turbot, were collected from early June
through mid-October.
These eggs averaged 0.80 mm in diameter with usually one large oil
globule (average 0.14 mm diameter) and numerous other globules
scattered throughout the yolk. They can easily be distinguished from
Pletoronichthys eggs by the absence of the hexagonal pattern on the
chorion and the presence of oil globules.
It is very easy to confuse H. guttulata larvae with Pleuronichthys
larvae, especially with the similarity in pigmentation and morphology.
There are no other known larvae in this geographical area which have
such heavy pigmentation and which might be confused with turbot
larvae. So differentiation needs to be made between the larvae of the
different turbots which might occur in the San Francisco Bay area.
In general, the Pleuronichthys larvae are larger than Hypsopsetta
larvae in the early stages of development. P. verticalis is the smallest
at hatching being 3.16 mm (0.12 inch) long (Budd 1940). Even allow-
ing for shrinkage during preservation, Hypsopsetta larvae would not
exceed about 2.00 mm (0.08) at hatching. Yolk-sac larvae of P. verticalis
have a notable crest not as pronounced in the diamond turbot. Another
distinguishing characteristic for the young is the presence of oil globules
in the yolk. The finfold pigment patches found in both P. verticalis
and P. decurrens are not as developed or as consistently present in the
diamond turbot. Only the very small Hypsopsetta larvae (2.4 mm)
had finfold patches. The mottled turbot, P. coenosus, is separated most
easily because it is very large at hatching (5.54 mm) and has heavy
pigmentation throughout its finfold.
34 CALIFORNIA FISH AND GAME
It can be seen that various turbot larvae are best separated by pig-
mentation (especially in the finfold), and relative size at which struc-
tures develop in post yolk-sac larvae.
ACKNOWLEDGEMENTS
I wish to acknowledge the valuable advice, instruction, and generous
time E. H. Ahlstrom and H. G. Moser of the Southwest Fisheries
Oceanography Center oiTered me during the course of this study. I
also would like to thank the California Academy of Sciences, especially
Lillian Dempster, for providing equipment and specimens.
REFERENCES
Ahlstrom, E. H.. and O. P. Ball. 1954. Description of eggs and larvae of jack
mackerel (Trachurus symmetricus) and distribution and abundance of larvae in
1950 and 1951. U.S. Fish Wildl. Serv., Fish. Bull. 56(97) : 209-245.
Baxter, J. L. 1960. Inshore fishes of California. Calif. Dep. Fish and Game.
Sacramento : 80 p.
Budd, P. L. 1940. Development of the eggs and early larvae of six California
fishes. Calif. Dep. Fish and Game, Fish. Bull. (56) : 1-50.
Jordan, D. S., and C. H. Gilbert. 1880. List of the fishes of the Pacific coast of
the United States, with a table showing the distribution of species. Proc. U.S.
Nat. Mus., 3(1880) : 452-458.
Lewis, R. M., W. F. Hettler, Jr., E. P. H. Wilkens, and G. N. Johnson. 1970. A
channel net for catching larval fishes. Ches. Sci., 11(3) : 196-197.
Limbaugh, C. 1955. Fish life in the kelp beds and the effects of kelp harvesting.
Univ. of Calif., Institute of Marine Resources, Ref. 55-9, 158 p.
Orton, G. L., and C. Limbaugh. 1953. Occurrence of an oil globule in eggs of
pleuronectid flatfishes. Copeia 1953 (2) : 114-115.
Calif. Fish and Game 61(1) : 35-46. 1975.
THE FOOD OF NEOMYSIS MERCEDIS HOLMES IN
THE SACRAMENTO-SAN JOAQUIN ESTUARY
ANGELA L. BALDO KOST ^ and ALLEN W. KNIGHT
Deportment of Water Science and Engineering
University of California, Davis
ABSTRACT
Gut contents were determined in approximately 1500 opossum
shrimp, Neomysis mercedis Holmes, from the Sacramento-San Joaquin
Estuary. The shrimp, obtained from 12 stations over a 13-month period,
were 2 to 17 mm (0.08 to 0.67 inch) long.
The most abundant items in the gut were detritus and diatoms. The
percentage of detritus relative to diatoms was greater in winter than
in summer, and increased with shrimp size.
Forty kinds of diatoms were found in the gut. Certain diatom genera
predominated in shrimp from particular locations and in shrimp col-
lected during particular times of the year.
Animal fragments and other items also encountered were much less
abundant than detritus and diatoms.
Thus, the shrimp appears to eat a variety of food items.
INTRODUCTION
This study was initiated, along with others on the opossum shrimp,
Neomysis mercedis Holmes, to improve understanding of environmental
relationships in the Sacramento-San Joaquin Estuary which might be
affected by water development projects. The present study is an im-
portant component of an extensive investigation into many aspects of
the biology and ecology of N. mercedis and the striped bass, Morone
saxatilis.
N. mercedis is an important component of the trophic structure of
the Sacramento-San Joaquin Estuary. This shrimp is the major food
item in the diet of young striped bass in all seasons of the year (Stevens
1966). This study involved the gut contents of approximately 1500
opossum shrimp collected from Suisun Bay and the Delta from March
1970 through March 1971. Very little previous information was avail-
able on the feeding habits of this shrimp.
MATERIALS AND METHODS
Sampling Stations
The opossum shrimp were collected by the California Department of
Fish and Game, Bay-Delta Fishery Project, from 12 stations extendin^
from Suisun Bay up the Sacramento River to Rio Vista, and up the
San Joaquin River almost to Stockton (Figure 1). The station numbers
used in this study are those of the California Department of Fish and
Game.
1 Present address: 9321 Discovery Way, Apt. H, La Jolla, California 92037. Accepted
August 1974.
( 35 )
36
CALIFORNIA FISH AND GAME
Sampling Procedure
Each month from March 1970 to March 1971 a sample was obtained
from each of the 12 stations, for a total of 156 samples. Monthly-
sampling was conducted during three consecutive days between one-
half hour before and one hour after high neap tide.
Samples were taken with a cone-shaped plankton net of silk bolting
cloth with 23 meshes per inch. The net opening was 0.1 m- (1.07 ft^).
A diagonal tow was made from the bottom to the surface, and each
tow took approximately 10 minutes.
Each sample was preserved with 5-10% formalin, along with enough
Rose Bengal dye to stain the shrimp.
Five pair of shrimp were selected from each sample. The shrimp
were selected to obtain a wide range of sizes (2-17 mm from the anterior
STOCKTON
SACRAMENTO -SAN JOAQUIN
BAY DELTA
NEOMYSIS SAMPLING STATIONS
FIGURE 1. Sacramento-San Joaquin Bay-Delta Estuary System, Neomysis sampling stations.
NEOMYSIS MERCEDIS FOOD
37
end of the eyestalk to the base of the telson). The sex was determined
for each organism 7 mm and longer. Shrimp shorter than 7 mm could
not be sexed and were considered as juveniles. Shrimp of the same
size and sex were chosen for each pair, and their gut contents were
pooled.
Shrimp Dissection and Slide Preparation
The stomach and intestine were removed from each shrimp with two
fine needles under a dissecting microscope. The full gut was located
readily since it did not take up the stain. The thin exoskeleton was
teased apart along the dorsal surface of the organism from the head to
the base of the telson, and the gut was then carefully lifted out.
Each pair of pooled guts was placed on a glass microscope slide in a
drop of water. The stomach and intestine were gently broken open
with the needles, and the contents were dispersed and stirred in the
water.
The slide was then air-dried, a drop of Permount mounting medium
was applied, and a 1 cm^ glass coverslip was placed on the slide. The
preparation was dried overnight.
Enumeration of Gut Contents
Items present in the mounted gut contents were counted and iden-
tified with a compound microscope at 400 X- Every item was enumerated
except when more than 1000 algal cells were present on a slide. In such
cases (about half of the total), enumeration was terminated at 1000
cells. According to Javornicky (1958) counting 1000 cells limits the
expected error to ±6.3% (with a probability of 0.95).
TABLE 1. — Diatoms Encountered in Neomysis Gut Contents
Diatom
Total
number
counted
Diatom
Total
number
counted
Coscinodiscus sp. - _-
196,633
166.380
57.206
16,893
11,882
7,173
6,450
4.661
4,412
3,547
2,002
1.808
1,182
446
414
288
285
250
223
174
Rhopalodia sp.
159
Melosira sp. _-
Gomphonema sp. No. 1
Surirella sp. No. 2
143
Cvclotella ST>. _
96
Nitzschia paradoxa
Nitzschia sp. No. 4
88
Tabellaria sp.
Pinnularia sp.
85
Diatoma sp. . _
Stauroneis sp
45
Fragilaria sp. No. 1
Eunotia sp. . _. .-
32
Stephanodiscus sp.
Fragilaria sp. No. 2
22
Synedra sp. ..--. .--.
Actinoptychus sp
18
Asterionella sp.
Pleurosigma sp.
15
Epithemia sp. .
Meridian sp.
13
Naviciila sp.. .
Acnanthes sp --
9
Triceratium sp. _
Gyrosigma sp.
6
Cocconeis sp.
Amphora sp. _ .
5
Cymbella sp. . . ..
Fragilaria arcus
5
Nitzschia sp. No. 2 .
Skeletonema sp..
4
Surirella sp. No. 1 .
Lepidodiscus sp.
3
Rhoicosphenia sp ..
Frust ula sp
1
Nitzschia sp. No. 3 _. __
Gomphonema sp. No. 2
Nedium 9p.
1
Diploneis sp.
1
38
CALIFORNIA FISH AND GAME
Algae were identified to the generic level, but many animal fragments
could not be identified and were included in the general category
"animal fragments".
Detritus was enumerated by using a microscope ocular attachment
which divided the field into 100 squares, 0.0258 mm on a side, at 400 X-
The quantity of detritus was approximated by counting the number of
squares filled in each field examined. The portion of the field occupied
by diatoms was also estimated, according to the detailed procedure
described elsewhere (Baldo, 1972).
RESULTS
The most abundant of the materials found in the gut were detritus
and diatoms. Each varied in importance with station, time of year,
and size of shrimp. Of the identifiable material, a total of 40 diatoms
were encountered (Table 1). In addition there were 2 genera of green
algae, one dinoflagellate, rotifer loricas, tintinid loricas, crustacean
fragments, sponge spicules, pollen grains, and (apparently) fragments
of higher plants (Table 2).
TABLE 2. — Additionol Items Encountered in Neomysis Gut Contents
Item
Total number
counted
Green algae
Scenedesmus
Pediastrum
Dinoflagellate
Ceralium
Rotifer loricas
Tintined lociras
Crustacean fragments. .
Sponge spicules
Pollen grains
Higher-plant fragments
38
20
252
129
739
129
252
10
Detritus
The majority of the guts examined contained a significant amount of
unidentifiable material. This unidentifiable material was classified as
detritus. It was usually a gold-brown color. Some of this material ap-
peared to be homogeneous, but it was generally mixed with particles or
objects of different sizes and shapes of unknown origin. This material
was probably either organic debris (e.g., peat or plant material) that
the shrimp had ingested, or partially digested algal material. Its actual
origin was not determined.
Comparison of the relative amounts of detritus and diatoms in the
guts showed that detritus was more important during the winter (De-
cember to March), while diatoms were more important during the sum-
mer and early fall (Figure 2).
NEOMYSIS MERCEDIS FOOD
39
DETRITUS
DIATOMS
8 9 1.0
MONTHS
11 12
FIGURE 2. The percentage of total diatoms and detritus relative to each other. Gut contents
from all 12 stations combined for each month from March 1970 through March
1971.
Over the shrimp size range evaluated, the relative amounts of detritus
and diatoms differed markedly. Diatoms were more plentiful in small
shrimp than in large ones. On the other hand, detritus was more
abundant in the larger shrimp (Figure 3). Shrimp 16 to 17 mm long
were excluded because only one of each was examined. Calculations for
most of the other sizes were based on more than 80 individuals. The
increase in percentage of detritus with size was rather uniform except
for 2 mm shrimp (which included only 9 individuals).
%
lOOn
SO-
SO-
70
60
50-
40-
iO\
20
lOJ
0
lllllllllll DIATOMS
■1^ DETRITUS
5 6 7 8 9
SHRIMP SIZE IN MM
10
12
15
FIGURE 3. The percentage of total diatoms and detritus relative to each other in the gut
of shrimp of different sizes (2 to 15 mm), all stations and months combined.
40
CALIFORNIA FISH AND GAME
Diatoms
Of the 40 kinds of diatoms t'lieountorod in tho guts of N. mercedis,
certain genera predominated (Table 1). Two diatoms, Coscinodiscus
and Melosira, were far more abundant than the rest. Coscinodiscus was
MEL05IRA
CYCLOTELLA
TABELLARIA
NITZSCHIA
PARADOXA
DIATOMA
FRAGILARIA
STEPHANOOISCUS
SYNEORA
ASTEHIONELLA
EPITHEMIA
NAVICULA
THICERATIUM
24 44 34 52
58 62 68
STATIONS
74 80 88 92 102
FIGURE 4.
Variation in the 13 most common diatom genera encountered in the gut of
shrimp from each of the 12 Bay-Delta stations, oil months combined. Each
genus is represented as its percent of total diatoms. Diatoms not included con-
stituted less than 1% of the total.
NEOMYSIS MERCEDIS FOOD
41
CYCLOTELLA
TABELLARIA
NITZSCHIA
PARADOXA
DIATOMA
FRAGILARIA
STEPHANODISCUS
SYNEDRA
ASTERIONELLA
TRICERATIUM
3456789 10 11 12 1 23
MONTHS
FIGURE 5. Variation in the 13 most common diatom genera encountered in the gut of
shrimp from March 1970 through March T977, all stations combined. Each genus
is represented as its percent of the total diatoms.
the most important diatom in guts of shrimp from the lower Delta
and Suisun Bay stations (Figure 4). At these downstream stations it
often constituted 90 to 99% of the total diatoms. The diatom Melosira
replaced Coscinodiscns as the most abundant diatom in shrimp from
upper Delta stations during most of the year. Cyclotella was also im-
42
CALIFORNIA FISH AND GAME
portant at eastern stations, especially at station 92, near Stockton.
These geographical variations in the relative abundance of the various
diatoms were greater than seasonal variations in relative abundance
(Figures).
Coscincxiiscus
7 8 9
MONTHS
FIGURE 6. Variation in the diatom Coscinodiscus sp., represented as its percent of the total
diatoms in the gut for each month from March 1970 through March 1971 at 12
Bay-Delta stations.
Figures 6, 7, and 8 are three-dimensional graphs showing the spatial
and temporal distribution of the 3 most common diatoms. Each diatom
is represented as its percent of the total diatoms in all the guts ex-
amined from each station and each month. It is again evident that
Coscinodiscus was the most abundant diatom in the gut from the lower
Delta. It was replaced by Melosira as the most common diatom in the
upper Delta. The percentage of Coscinodiscus in shrimp from stations
in the upper Delta is greater from June to August than during the
Melosira
3 4 5 6 7 8 9 10 11 12 1 2 ._
MONTHS
FIGURE 7. Variation in the diatom Melosira sp., represented as its percent of the total
diatoms in the gut for each month from March 1970 through March 1971 at 12
Boy-Delta stations.
NEOMYSIS MERCEDIS FOOD
43
rest of the year (Figure 6). This increase appears to be related to the
salinity, which increases upstream during the summer when the flow
in the rivers is decreased (Figure 9).
Distribution of the remaining diatoms in the guts also varied geo-
graphically and seasonally. For example, Triceratium appeared pre-
dominantly at station 102 during most of the year whereas Tdbellaria
appeared at station 68 during the late spring and early summer. For
a more complete description of the distribution of the less common dia-
toms, seeBaldo (1972).
Animal Fragments and Other Gut Contents
Many guts contained fragments (mostly appendages) of unidentified
crustaceans. A copepod was encountered which was nearly intact. The
Cyclotella
MONTHS
FIGURE 8. Variation in the diatom Cyclofella sp., represented as its percent of the total
diatoms in the gut for each month from March 1970 through March 1971 at
12 Bay-Delta stations.
1(^000
ELECTRICAL
CONDUCTIVITY
MONTHS
FIGURE 9. Variation in electrical conductivity in umhos of water at 12 Bay-Delta stations
for each month from May 1970 through March 1971. Data are from Knight,
Biggar, and Tanji, 1972.
44 CALIFORNIA FISH AND GAME
crustacean fragments found increased in number with shrimp size, but
so few crustaceans were found that the validity of this observation is
questionable.
Rotifer loricas which appeared to be of the genus Kcratella were
found in a number of shrimp. Tintinid loricas were less common. The
number of rotifers or tintinids present was not correlated with shrimp
size.
At least two varieties of sponge spicules were present in the gut of
a number of shrimp.
Two genera of green algae, Scenedesmus and Pcdiastrum, were en-
countered in very small numbers. A single dinoflagellate, Ceratiiim,
was found in a shrimp from Suisun Bay.
Pollen grains were present in very small numbers at every station.
Fragments of higher plants were only minor contributions.
For more information on the spatial and temporal distribution of
these items, see Baldo (1972).
DISCUSSION
Many investigators (e.g., Esterly 1916, Wilson 1951, Mecom and
Cummins 1964, Hart 1934) have noted that recognizable items in the
gut may not be the sole source of nutrition. In some cases the items
may not even be a source of nutrition. The hard skeletons of items
such as diatoms and crustaceans may be the main reason for their
retention and recognition in the gut. Many kinds of algae such as
greens and blue-greens would be less likely to retain their original
structure after being eaten and partially or totally digested. Items such
as bacteria, either free in the water or surrounding detritus particles,
and other nanoplankters which would be difficult to identify in the
guts, may or may not play a significant role in the nutrition of these
shrimp.
Data were obtained from the Federal Bureau of Reclamation in
Sacramento on the phytoplankton present at Delta stations during the
same period. Many of the diatoms found in the shrimp guts were
similar to those in the phytoplankton samples. A number of Chloro-
phyta, Cyanophyta, and Crytophyta. however, which were present in
the phytoplankton samples were not in the shrimp guts. It was not
possible to determine from the gut contents examined whether the
shrimp ingested these green algae and other forms and digested them
beyond identification, or whether they selected against these forms.
The seasonal changes in the relative occurrence of detritus and dia-
toms in the guts noted in this study presumably reflect changes in their
relative availability. Diatoms are several times more abundant in the
environment during the summer than in the winter (Delta Fish and
Wildlife Protection Study, 1972). Conversely, detritus may be more
abundant during the winter, when increased runoff likely carries greater
amounts of organic debris into the Estuary. Both of these probable
changes parallel the changes in relative abundance observed in the
shrimp guts.
This study does indicate that N. mercedis is able to ingest a wide
variety of foods. It is reasonable to assume that it utilizes whatever
food is available at any particular place or time, whether it be detritus
or one kind of diatom or another.
NEOMYSIS MERCEDIS FOOD 45
Mauchline (1967) indicated similar results for the mysid Schistomysis
spiritis. That shrimp extracts suspended matter indiscriminately from
the water and must therefore use a large variety of foods. In guts of
S. spiritis he found fine particulate matter mixed with sand grains,
various diatoms, dinoflagellates, filamentous algae, some leaf fragments,
spores, and seeds of terrestrial origin. In addition, Mauchline
(1971a, b) found that the mysid, Paramysis arenosa and Neomysis inte-
ger could utilize many food types when available, including plant and
animal matter, detritus, and inorganic particles. I?aymont et al (1964)
stated that mysids take whatever food is more or less immediately
available. They indicated that detritus is important in the nutrition of
N. integer, especially in estuarine conditions where there is normally a
constant supply of organic matter. They observed Neomysis stirring up
detritus on the bottom with its appendages and ingesting it. Lasenby
and Langford (1973) found that My sis relicta in two Canadian lakes
is potentially omnivorous.
Wilson (1951) examined the stomach contents of Neomysis mercedis
Holmes in British Columbia, and found diatoms, dinoflagellates, blue-
green algae, vascular plant material, and animal material consisting of
mainly copepod and mysidacean remains.
Tattersall (1951) indicates that most mysidacea, including N. integer,
filter-feed microscopic plants and animals and detritus. They are able
to pounce on living copepods and ingest them and have been seen carry-
ing around dead mysids and amphipods of their own size while eating
them. Acanthomysis scidpta will readily eat injured or freshly killed
members of its own species and anything else it can capture (Green
1970). N. mercedis has been seen in the lab eating dead or weak mem-
bers of its own species.
It is probable that shifts in environmental quality would alter the
food supply available to A'^. mercedis. Changes in water chemistry
(salinity, pollutants, etc.) would favor certain forms of algae rather
than others. Increased turbidity could inhibit algal growth. However,
since N. mercedis appears to utilize a diversity of items, food will
probably not be limiting to the shrimp as long as either detritus or
some form of algae is present in sufficient quantity.
SUMAAARY
1. Detritus and diatoms were the major food items found in the gut
of N. mercedis from the Sacramento-San Joaquin Delta. Animal frag-
ments and other items were less abundant.
2. The relative abundance of detritus and diatoms in the gut varied
during the year. Diatoms increased in relative amounts in summer, and
detritus increased in the winter months.
3. The relative importance of detritus increased in the gut of larger
shrimp, and, conversely the relative importance of diatoms increased
in the gut of smaller shrimp.
4. Previous reports indicate that mysid shrimp are capable of utiliz-
ing a wide variety of foods. The results of this study are consistent with
those reports. The shrimp N. mercedis appears to be omnivorous.
ACKNOWLEDGEMENTS
This research was supported in part by a grant from the Water
Resources Center, project number W243. We thank Harold Chadwick
46 CALIFORNIA FISH AND GAME
and staff of the California Fish and Game Department-Delta Study
group for providing the opossum shrimp and extending many courtesies
and conveniences. Gerald J. Kost was of considerable assistance in
computer analysis of these data. The authors are grateful to Mary Ann
Simmons for her assistance in preparation of this manuscript.
REFERENCES
Baldo, A. L. 1972. The food of Neotnysis aicatschensis in the Sacramento-San
Joaquin Delta. Masters Thesis, University of California at Davis. Davis, Cali-
fornia.
Delta Fish and Wildlife Protection Study. 1972. Dissolved Oxygen Dynamics
Sacramento-San Joaquin Delta and Suisun Bay. California Departments of
Water Resources and Fish and Game. 129 pp.
Esterly, J. L. 1916. Feeding habits and food of pelagic copepods and the question
of nutrition by organic substances in solution in water. Universitv of California
Publ. Zool. 16 : 171-184.
Green, J. W. 1970. Observations on the behavior and larval development of
Acanthomysis sculpta (Tattersall) (Mysidacea). Canadian J. Zool. 48:289-292.
Hart, T. J. 1934. On the phytoplankton of the south west Atlantic and Belling-
shaussen Sea 1929-1931. Discovery Rep. 8 : 1-268.
Javornicky, Pavel. 1958. Revision of some methods of quantative estimation of
phvtoplankton. Scientific papers of the Chemical Engineering School. 1958. Fac.
Technol. Fuels and Water 2 : 283-367.
Knight, A. W., J. W. Biggar and K. K. Tanji. 1972. Bay Delta Water Chemistry
Study, unpublished data. Dept. of Water Science and Engineering, U. C. Davis,
Davis, California.
Lasenby, D. C, and R. R. Langford. 1973. Feeding and assimilation of Mysis
relicta. Limnol. Oceanogr. 18 : 280-285.
Mauchline, J. 1967. The biology of Schistomysis spiritus (Crustacea, Mysidacea).
J. Mar. Biol. Assoc. U. K. 47 : 383-396.
Mauchline, J. 1971a. The biology of Paramysis arenosa (Crustacea, Mysidacea).
J. Mar. Biol. Assoc. U. K. 51 : 339-346.
Mauchline, J. 1971b. The biology of Neomysis integer (Crustacea. Mysidacea).
J. Mar. Biol. Assoc. U. K. 51 : 347-354.
Mecom, J. O., and K. W. Cummins. 19(>4. A preliminary study of the trophic
relationships of the larvae of Brachycentrus americanus (Banks). Trans. Amer.
Microscop. Soc. 83 : 239-250.
Raymont, J. E. C, J. Austin and E. Linford. 1964. Biochemical studies on marine
zooplankton. I. The biochemical composition of Neomysis integer. J. Conseil
Perm. Intern. Exploration Mer. 28 : 354-363.
Stevens, Donald E. 1966. Food habits of striped bass, Roccus saxatilis, in the
Sacramento-San Joaquin Delta. Calif. Dept. Fish and Game, Fish Bull. 136 :
68-96.
Tattersall, W. M., and O. S. Tattersall. 1951. The British Mysidacea. Lond.
Ray Society. 460 p.
Wilson, R. R. 1951. Distribution, growth, feeding habits, abundance, thermal
and salinitj' relations of Neomysis mercedes (Holmes) from Xicomekl and
Serpentine Rivers, British Columbia. M. A. Thesis, U. of British Columbia,
Vancouver,
Calif. Fish and Game 61(1) : 47-53. 1975.
NOTE ON THE ECOLOGY OF THE RATFISH,
HYDROLAGUS COLLEI, IN THE GULF OF CALIFORNIA^
C. p. MATHEWS
FAO/INP
AP M-10, 778
Mexico (1) D.F. Mexico^
Hydrolagus collei, the ratflsh, has been taken frequently in the north-
ern Gulf of California. This species shows a marked migratory pattern
being relatively abundant and widely distributed in this area in Febru-
ary-March, and found at few stations and in low numbers in June
and August. Males appear to grow more slowly than females and are
less frequent in the catches. The breeding season must be several
months before or after the period of spring abundance in the northern
Gulf.
Hydrolagus coffei, el pez llamado pez rata de California, ha side
capturado frecuentemente en el norte del Golfo de California. Esta
especie demuestra un patr6n migratorio; es relativamente abundante
en esta zona en febrero y marzo y muy restringido en su distribuci6n
y en abundancias muy bajas en junio y en agosto. La estaci6n de repro-
duccion debe de estar varies meses antes a despuis del periodo de
abundancias altas en el norte del Golfo de California.
INTRODUCTION
Hydrolagus collei has been known to occur in eastern Pacific tropical
waters from western Alaska to northern Baja California ; Johnson and
Horton (1972) have described some aspects of the ecology of this
species. It is the object of this paper to present some of the results of
the exploratory and prospective fishing cruises of the Alejandro de
Humboldt, during which Hydrolagus collei was found to be fairly
widespread although usually in low abundances, at certain times of the
year in the northern Gulf of California. During a series of cruises con-
ducted by the K/V Alejandro de Humboldt of the Instituto Nacional
de Pesca of Mexico, between June, 1971 and March, 1972, suflScient data
were gathered for the bathymetric and geographic distributions of this
species to be known in the area from Guaymas to Isla Tiburon and in
the zone north of Isla Tiburon and Isla Angel de la Guarda. During
cruises conducted from April 1971 to December 1971, in other parts of
the Gulf of California no ratfish were taken although on all cruises the
same depths (100-600 m) (328-1,968 ft) were sampled.
METHODS
The Alejandro de Humboldt is a 42 m (138 foot), 450 gross ton stern
trawler equipped as a research vessel. The usual sampling tool was an
otter-trawl net, with a 41 m (136 feet) headline, and cod-ends with
mesh sizes of 4.5 cm (1.8 inches) and 5.5 cm (2.2 inches). The smaller
1 These views do not necessarily reflect those of FAO. Accepted for publication June
1974.
* Present address : Department of Fisheries Oceanography, Escuela Superior de
Ciencias Marinas, Ensenada, B.C., Mexico.
(47)
48
CALIFORNIA FISH AND GAME
mesh cod-end was employed only from July 1971 onwards, but is not
thought to have increased the vulnerability of ratfish to the net during
this period.
Specimens of ratfish were separated from the catch, and were usually
measured (total body length in cm) and sexed.
RESULTS
Ratfish were taken from the mid-Gulf northward, but the area of
greatest concentration was to the north of Isla Angel de la Guarda.
rJune 1S71
August 19 71
a February-March 19 72
30° Lot N
100 fathom Isobath (183 m)
200 fathom isobath (366 m)
— . - • 400 fathom Isobath (732 m)
SCALC in nautical MItC S .
FIGURE 1. Distribution of Hydrolagus colUi in the Northern Gulf of California.
GULF OF CALIFORNIA RATFISH
49
TABLE 1 . — Stations at Which Hydrolagus eollei was Captured
by the "Alejandro de Humboldt"
Number of
specimens
Total length
in cms.
Depth (m)
Date 1971
19 June
20 June
21 June
23 August...
1 September
Date 1972
23 February.
23 February.
23 February.
23 February.
24 February.
25 February.
28 February.
28 February.
28 February.
28 February.
29 February,
29 February.
29 February.
29 February.
29 February.
1 March
2 March
3 March
10 March...
10 March
6
1
4
1
1
4
3
23
33
3
11
112
76
17
4
4
4
15
75
40-50
7
17
2
6
58
40
51
42-49
38-55
33-50
40-42
25-51
2&-49
36-45
38-50
39-51
46-48
39-49
30-50
38-51
43-55
50-51
36-44
36-44
412-446
502-506
290-310
540-560
294-296
196
304-307
390-394
309-312
192-220
366-415
288-292
304-332
250-298
201-226
300m
330
290
292-296
282-360
268-274
264-321
398-400
420-434
341-348
Barely some specimens were found between Guaymas and Isla Tiburon.
Ratfish were far more abundant in February-March 1972 than in
June or August 1971 (Figure 1, Table 1).
In interpreting these data, it is important to remember that in June
and August-September 1971, approximately 50 hours of fishing were
spent in the area in which ratfish were subsequently found in February-
March 1972, when about 60 hours were fished. Therefore, the amount
of fishing effort expended in the summer of 1971 and early spring,
1972 was approximately equal and the marked differences in abundance
and distribution are not caused by differences in fishing effort expended.
They are probably due to migratory movements of the fish themselves,
either towards depths the Alexandre de Humboldt could not sample, or
out of the Gulf of California.
Most stations (16 out of 19) at which ratfish were found were situated
from 270-430 m deep.
Abundances, expressed in numbers of fish per hectare, varied from
0.1 fish/ha to 2.9 fish/ha (Figure 2).
These depths also contain all stations at which abundances exceeded
two individuals per hectare. However, ratfish were found up to 196 m
deep in low abundances (0.2 or less/ha).
The envelope curve for the stations at which ratfish were found in
summer 1971, is based on only five occurrences, but three of these were
50
CALIFORNIA FISH AND GAME
ABUNDANCE. NUMBERS /ha.
100-
200-
E
Ql
Q
3 00-
3
_i
500-
FIGURE 2. Bathymetric distribution and abundance of Hydrolagus collei.
GULF OP CALIFORNIA RATFISH
51
in deeper waters than any of the spring 1972 occurrences (Table 1),
and all five occurrences were in low abundances (0.1-0.4 fish/ha). This
suggests that in summer (June-September) ratfish move out of the
northern Gulf of California into deeper waters and return at the latest
by the end of winter (February), probably earlier.
A total of 448 ratfish was measured and sexed on the Alexandre de
Humboldt in February and March 1972 (Figure 3). Two modes are
present, at 38-39 cm and at 47 cm, corresponding to the maximum
occurrence of male and female fish. It is unlikely that there is any ques-
tion of sex reversal in this species, so it may be concluded that females
grow to a larger size than males. From 45-55 cm 10 fish were males and
168 females, giving a sex ratio of 94.4% females, with no males from
52-55 cm. On the other hand, from 35-44 cm, 131 males and 104
females were found, giving a sex ratio of 44.3% females. Females pre-
dominate in the catch, of which 67.2% were females and 42.8% males.
Twenty-seven females, all taken in spring 1971, from 36-55 cm in
length, were opened and their gonads were examined. Two stages were
recognized :
i) Ovaries moderately developed, include at least one clear yellow,
yolky egg 2.0-2.5 cm in diameter; frequently other, smaller and
similar bodies were present.
ii) Immature, when the ovaries are small and undeveloped (Table 2).
TABLE 2.— Maturity in Female Ratfish
Total body length
(cm)
State of ovaries
Immature
With eggs
36-40
Three immature fish
3
1
6
0
0
41-45
46-50*
51-55
One fish with eggs, one fish immature
Five fish with eggs, six fish immature
Eleven fish with eggs
1
5
11
* Longest immature female: 47 cm.
These rather sparse data indicate that female ratfish mature at
lengths between 41-47 cm, and that fish 51 cm and over are always
mature.
It was not possible to distinguish any stages of maturation in the
male gonads : these were inconspicuous and showed no signs of sperm.
The state of the female gonads, and especially the male gonads, sug-
gests that reproduction takes place several months before or after the
sampling period (February 1972). At any rate, no ripe animals were
taken. Unfortunately, none of the fish taken in June or August 1972,
were dissected.
An attempt to examine the stomach contents was made, but this
species has no clearly defined stomach and the area which corresponds
to the stomach in other fish was empty in the fish examined. The spiral
valves of four were opened ; while three of these were empty, the fourth
contained what appeared to be some sand.
52
CALIFORNIA FISH AND GAME
V o
9
o
o
E
3
Z
n n
25
35 40 45
ToTol Body Length cms.
50
55
60
FIGURE 3. Size frequency distribution of the males and females of Hydrolagus collei.
SHADED BARS = MALES
DISCUSSION AND CONCLUSIONS
Ratfish show a distinct migratory movement, being more abundant
and more widespread in the northern Gulf of California in February-
March, than in June-September. They do not appear to reproduce dur-
ing the period of peak abundance, but this requires further investiga-
tion. Females predominate in the catch and this could be because of
greater vulnerability to the net, as females are on the average larger,
but could also be due to females migrating more readily, or even to a
natural difference in sex ratio. However, the pattern of an increasing
proportion of females in larger fish is a very widespread one and on
close investigation is usually found to be accompanied by increasing
mortality selective against males. There is no good reason to believe this
process does not operate on the Gulf of California population of ratfish.
The cause of the migratory movements of ratfish is unknown, but
most of the fish species in the northern Gulf of California are more
abundant in early spring, so a casual agent with a rather generalized
action should be looked for ; quite possibly temperature, oxygen con-
centration and currents are of great importance.
A different mesh size was used in spring 1972 (4.5 cm) and June
1971 (5.5 cm), so the ratfish caught were subject to different net vul-
nerabilities at different sampling periods. However, there is no reason
to believe that the marked seasonal differences in distribution are
caused by biased sampling arising from the different equipment used,
GULP OF CALIFORNIA RATFISH 53
as the material collected in August-September 1971 was also collected
with the finer mesh cod-end (4.5 cm) as opposed to the courser mesh
used to gather the material collected in June 1971. There were no sig-
nificant differences in distribution or abundance recorded between June
and August 1971 ; therefore, the change in mesh size did not signifi-
cantly affect the vulnerability to the net of the fish present.
ACKNOWLEDGEMENTS
I wish to acknowledge the help of the Captain, F. Hernandez
Ascensio, and crew of the Alejandro de Humboldt who made the work
of collection so much easier and more agreeable by their friendly
participation. I also wish to acknowledge the help of Biol. H. Chavez,
Sr. Humberto Pedraza and T. P. Armando Arias, who were instru-
mental in helping to collect the data on which this paper is based.
REFERENCES
Johnson, A. G., and Horton, H. F. (1972). "Length, weight, relationships, food-
habits, parasite and sex and age determinations of the ratfish, Hydrolagus collei
(Lay and Bernett)" Fishery Bulletin 70 (2) : 1972.
Calif. Fish and Game 61(1) : 54-63. 1975.
NOTES
AN UNUSUALLY FAST GROWTH RATE
FOR TILAPIA ZILLII
TUapia zillii is an herbivorous cichlid from East Africa, and it is
one of many species of TUapia introduced into the United States for
the biological control of aquatic weeds (SchefPer 1960; Avault, Smith-
erman, and Shell 1968). It was authorized for introduction into Cali-
fornia waters in 1971 (Pelzman 1973). Any successful method of bio-
logical control of aquatic weeds in the irrigation systems in southern
California would be welcomed. Large sums of money are spent annually
for the mechanical removal of aquatic weeds since chemical controls
cannot be applied because irrigation water also provides the potable
water supply.
On 5 May 1972, the California Department of Fish and Game re-
leased 250 T. zillii in an irrigation drainage ditch near the southeastern
edge of Imperial Valley, approximately 15 miles east of Calexico, Cali-
fornia. No other T. zillii have been stocked in this drainage ditch since
the initial introduction. At the time of stocking, the fish averaged 5.7 g
(5 per oz) (F. G. Hoover, California Department of Fish and Game,
personal communication) and approximately 70 mm (2.75 inches) (un-
published data).
Eecently, nine large T. zillii were captured in this drain, probably
individuals from the original introduction. They were collected on 16
January and 13 March 1974 by seining and throw-netting. Scale
samples were taken from a dorso-lateral location near the base of the
caudal peduncle. The scales were mounted between two glass slides
and examined with a binocular microscope at 10 power magnification.
Distances between annuli were measured at least twice with an ocular
micrometer.
The specimens ranged from 257 to 315 mm (10.1 to 12.4 inches) tl
and weighed 380 to 709 g (0.84 to 1.56 lb) (Table 1). All were 2 years
old. Back-calculated lengths ranged from 133 to 185 mm (5.2 to 7.3
inches) and averaged 164 mm (6.5 inches) at the end of the first year.
At the end of the second year of growth, the range w^as 225-300 mm
(8.9 to 11.8 inches) and the average, 249 mm (9.8 inches).
Chimits (1957) reported a faster growth rate for T zillii, but most
reports indicate that this species requires 4 to 6 years to reach approxi-
mately 300 mm (11.8 inches) in length (El Zarka 1961; Fryer and
lies 1972). Lowe (McConnell) (1955) reported a 2-year old T. zillii
weighing 765 g (1.69 lb), but she does not indicate whether the fish
grew under wild or cultured conditions. The maximum reported length
and weight for T. zillii is 350 mm (13.8 inches) and 800 g (1.76 lb),
respectively, (Chimits 1957) although there is a single report of one
which weighed 2948 g (6.50 lb) (Anon. 1955). In addition, the fish I
collected grew faster than nearly all TUapia sp. reported by lies (1971)
and Fryer and lies ( 1972 ) .
(54)
NOTES
55
The largest fish I collected were males. Ben-Tuvia (1959), El Bolock
and Koura (1960), El Zarka (1961) and Fryer and lies (1972) also
reported that males were usually longer than females, particularly
after they matured.
Unfortunately, this growth rate does not represent the growth rate
of all T. zillii in California waters, but rather, is an example of the
growth potential of this species when released into an environment
with a long growing season, little competition, and abundant food. This
growth rate most likely will not be sustained as the population in-
creases.
TABLE 1. — Size at the time of capture, sex, and growth of Tilapla zillii in a south-
ern California irrigation drainage ditch.
Sex
Length
(mm)
Weight
(g)
Length at age
Date
I
II
13 Mtrch 1974
M
M
M
F
M
F
F
315
301
297
290
285
280
278
271
257
286
(11.3
inches)
709
608
595
572
522
508
587
438
380
547
(1.201b.)
185
161
178
133
174
171
173
157
140
164
(6.5
inches)
300
13 March 1974
244
13 March 1974
242
13 March 1974
240
13 March 1974
253
16 January 1974.
245
16 January 1974
244
13 March 1974
244
13 March 1974
225
Average
249
(9.8
inches)
REFERENCES
Anonymous. 1955. East African Freshwater Fisheries Research Organization
Annual Report 1954/1955. Uganda Argus, Ltd., Kampala. 1-40.
Avault, J., Jr., R. Smitherman, and E. Shell. 1968. Evaluation of eight species
of fish for aquatic weed control. FAO Fisheries Report 44. VII/E3 : 109-122.
Ben-Tuvia, A. 1959. The biology of the cichlid fishes of Lakes Tiberias and Huleh.
Bull. Res. Counc. Israel. 8B : 153-188.
Chimits, P. 1957. The tilapias and their culture. FAO Fisheries Bull. 10(1) :
1-24.
El Bolock, A., and R. Koura. 1960. Age, growth and breeding season of Tilapia
zillii Gervais in Egyptian experimental ponds. Notes and Memoirs No. 49. Alex-
andria Institute of Hydrobiology : 1-36.
El Zarka, S. 1961. Tilapia fisheries investigation in Egyptian lakes. II. A
biological study of Tilapia zillii G. in Lake Quarum, Egypt, U.A.R. Notes and
Memoirs No. 66. Alexandria Institute of Hydrobiology : 1-44.
Fryer, G., and T. lies. 1972. The cichlid fishes of the great lakes of Africa.
Oliver and Boyd, Edinburgh. 641 p. '
lies, T. 1971. Ecological aspects of growth in African cichlid fishes. J. Cons.
Int. Explor. Mer. 33(3) : 363-385.
Lowe (McConnell), R. 1955. Species of tilapia in East African dams, with a key
for their identification. East African Agric. Jour. 20(4) : 256-262.
Pelzman, R. 1973. A review of the life history of Tilapia zillii with a reassess-
ment of its desirability in California. Inland Fisheries Admin. Rep. 74-1 : 1-9.
Scheffer, P. 1960. Factual information concerning the use of tilapia in the bio-
logical control of algae and aquatic weeds in Arizona farm ponds, reservoirs and
ditches. U. S. Dep. of Agric. Soil Conserv. Service. Technical Notes. 21 p.
56
CALIFORNIA FISH AND GAME
William J. Hauscr, University of Califortiia-Riverside, Imperial Valley
Field Station, 1004 East Bolton Road, El Centro, CA 92243. Funds
for this and related research were provided hy Imperial Irrigation
District, Coachella Valley County Irrigation District, and Palo Verde
Irrigation District, Research Grant Number CAL/ICP. Accepted
June 1974.
NOTES ON SOME FISHES COLLECTED OFF THE
OUTER COAST OF BAJA CALIFORNIA
The 12 fishes listed in this report represent geographic range ex-
tensions, definite collection localities, or they are taken so infrequently
as to warrant a published record. The fishes were collected by the au-
thors aboard the Department of Fish and Game research vessel Alaska.
Previously unpublished data, from fish collected during other Depart-
mental research cruises, are also included. Latitudes and longitudes
have been included for all collecting localities (Table 1). Miles are in
nautical miles.
TABLE 1. — Latitudes and Longitudes of Localities of Capture
(Arranged from North to South)
Locality
Latitude
Longitude
Baja California
Todos Santos Bay
San Martin Island
Pt. Canoas
rt. Canoas (33.3 km W)
Playa Maria Bay
Sebastidn Vizcaino Bay (27.8 km SW of Playa
Maria Bay)
Cedros Island (12.9 km W. of northern end)
Cedros Island (17.6 km NNW of northern end)
San Benito Islands
Lagoon Head
Sebastidn Vizcaino Bay (22 fathom spot)
Sebastidn Vizcaino Bay (27.8 km E. of Pt. Eugenia)
Turtle Bay (14.8 km SW of Turtle Bay)
San Cristobal Bay
San Pablo Point
San Hipoiito Point (11.1 km SE)
31° 46.6' N.
30° 28.8' N.
29° 44.0' N.
29° 27.8' N.
28° 56.2' N.
28° 49.7' N.
28° 23.7' N.
28° 21.2' N.
28° 20.3' N.
28° 14.9' N.
28° 6.0' N.
27° 50.0' N.
27° 36.2' N.
27° 22.4' N.
27° 12.9' N.
26° 52.0' N.
116° 45.3' W.
116° 2.7' W.
115° 50.0' W.
115° 31.5' W.
114° 31.7' W.
114°
115°
115°
115°
114°
114°
114°
115"
114°
114°
113°
48.2' W.
21.0' W.
17.9' W.
31.6' W.
5.5' W.
23.0' W.
50.0' W.
1.0' W.
37.8' W.
30.5' W.
52.0' W.
Eptatretus stoutii (Lockington) — Pacific hagfish
On three separate occasions, a total of four Pacific hagfish was cap-
tured off the coast of central Baja California: (i) 27.8 km (15 miles)
SW of Plava Maria Bav on October 2, 1970, (ii) 33.3 km (18 miles) W
of Pt. Canoas on October 3, 1970, and (iii) on June 21, 1971 o& San
Pablo Point. These fish ranged from 178 to 420 mm (7.0 to 16.5 inches)
total length (tl). Our identification was confirmed by Carl L. Hubbs,
Scripps Institution of Oceanography, La Jolla, California. Two of these
hagfish taken on October 2 and 3, 1970, are now in the ichthyological
collection at Scripps Institution of Oceanography (SIO 73-373 and
SIO 73-374). The hagfish, taken on June 21, 1971, is catalogued as
SIO 71-164.
E. stoutii also was captured 12.9 km (7 miles) W of the northern end
of Cedros Island in 278 to 281.6 m (152 to 154 fm) of water on Janu-
ary 17, 1959 by John Seapin. This previous southern limit to the range
NOTES 57
was never published. The hagfish captured off San Pablo Point extends
the range south a distance of approximately 148.3 km (80 miles) from
off Cedros Island to San Pablo Point.
Hexanchus griseus (Bonnaterre) — Sixgill shark
On October 6, 1970, a sixgill shark measuring 850 mm (33.6 inches)
TL was captured in a midwater trawl in Todos Santos Bay. The trawl
was fished from surface to a depth of 14.6 m (48 ft) in water 38.1 m
(125 ft) deep. This is the first record of H. griseus from Mexican
waters. The specimen is deposited in the Natural History Museum of
Los Angeles County (LACM 31679-1).
Hydrolagus collie'i (Lay and Bennett) — Raffish
Six raffish were collected in a bottom trawl off Point Canoas on
June 26, 1971, in 58.5 m (32 fm) of water. These fish ranged from 370
to 450 mm (14.6 to 17.7 inches) tl. The vertebral column of a small
Hydrolagus had been found in the stomach of a giant sea bass, Stereo-
lepis gigas, taken at the "22 fathom spot" in Sebastian Vizcaino Bay,
two days earlier. Unfortunately, our evidence was inadvertently washed
overboard. Two H. colliei were captured on January 17, 1959, approxi-
mately 17.6 km (9.5 miles) NNW of northern end Cedros Island in
182.9 to 183.2 m (100 to 101 fm) of water. These two specimens were
360 and 462 mm (14.2 and 18.2 inches) tl.
The occurrence of the raffish off Cedros Island extends the range
south along the outer coast of Baja California 389.2 km (210 miles)
from Santo Tomas to Cedros Island and evidently Sebastian Vizcaino
Bay. Although the specimens captured off Point Canoas are now de-
posited at the Natural History Museum of Los Angeles County, they
have not been catalogued at this time.
Anchoa exigua (Jordan and Gilbert) — "Anchovy"
A number of these engraulids was collected at three separate localities
in Sebastian Vizcaino Bay. Our first collection was made 27.8 km
(15 miles) E of Point Eugenia in Sebastian Vizcaino Bay on October
1, 1970, where the fish were dip-netted from tide pools. The subsequent
capture localities were at Lagoon Head (Oct. 2, 1970) and Playa Maria
Bay (Oct. 3, 1970). These fish were captured by beach seine and ranged
in size from 52 to 60 mm (2.0 to 2.4 inches) standard length (sl).
Clearing and staining facilitated identification of these fishes and
meristics corroborated with those given by Hildebrand (1943). Speci-
mens from the above collections are deposited at California Academy of
Sciences (CAS 28745 and 28746).
These fish extend the known range northward approximately 370.6
km (200 miles) from San Juanico Bay (McHugh and Fitch 1951) to
Playa Maria Bay.
Physiculus rasfrelliger Gilbert — Hundred-fathom codling
Eight Physiculus rastrelliger, ranging from 127 to 178 mm (5.0 to
7.0 inches) sl, were captured in prawn traps on June 21, 1971, from a
depth of 182.9 m (100 fm) off San Pablo Point. This collection is near
the type locality for this species as reported by Fitch and Barker
(1972). Their occurrence seems noteworthy, however, because this
58 CALIFORNIA FISH AND GAME
species is by no means common. All eight specimens (2 whole and 6
skeletonized) are now deposited at the Natural History Museum of Los
Angeles County ( LACM 32755-1 ) .
Anoplopoma fimbria (Pallas) — Sablefish
Two sablefish were captured on June 23, 1971, in prawn traps off
San Benito Islands. The traps were set in 219.4 m (120 fm) of water
and these fish measured 380 and 403 mm (14.9 and 15.9 inches) sl.
Fitch and Lavenberg (1971) note Cedros Island as the southern limit
for this species. San Benito Islands are at a latitude equivalent to
Cedros Island. These specimens are deposited at the Natural History
Museum of Los Angeles County (LACM 32700-1).
Zaniolepis latipinnis Girard — Longspine combfish
Eleven longspine combfish were collected in a bottom trawl off San
Cristobal Bay on June 22, 1971. The specimens ranged from 65 to 150
mm (2.6 to 5.9 inches) sl. Fitch (1953) recorded the southern limits as
2.8 km (1.5 miles) southwest of San Martin Island; thus, the present
specimens extend the southern limits 222 km (120 miles).
Zaniolepis frenata Eigenmann — Shortspine combfish
A single shortspine combfish, 57 mm (2.2 inches) sl, was taken 14.8
km (8 miles) SW of Turtle Bay in a midwater trawl on June 22, 1971.
The specimen captured off Turtle Bay extends the range southward a
distance of 105.5 km (57 miles).
Agonopsis sterletus (Gilbert) — Southern spearnose
Two southern spearnose poachers were taken in a bottom trawl SE of
San Martin Island. These fish were captured at a depth of 4.2 m (23
fm) on June 28, 1971, and measured 56 and 123 mm (2.2 and 4.8
inches) sl.
While searching for other individuals of this species, we found an
A. sterletus deposited at the Natural History Museum of Los Angeles
County (LACM 20819) which had been captured 11.1 km (6 miles) SE
of San Hipolito Point. This fish measured 106.5 mm (4.2 inches) sl and
was netted in 65.8 to 71.3 m (36 to 39 fm) of water on April 29, 1950.
Jordan and Everman (1896) report the southern limit for this species
to be Los Coronados Islands. The capture at San Hipolito Point extends
the range southward 685.6 km (370 miles).
Epinephelus niveatus (Valenciennes) — Snowy grouper
A snowy grouper was captured with a bottom trawl in San Cristobal
Bay. This fish, netted at a depth of 67.7 m (37 fm) on June 22, 1971,
measured 104 mm (4.1 inches) sl. Although this capture is within E.
niveatus range, it is captured so infrequently, that this netting satis-
fies much needed catch localities of this species. This fish is deposited at
California Academy of Sciences (CAS 28420).
Parophrys vetulus Girard — English sole
Four English sole were caught in a bottom trawl fished at a depth of
67.7 m (37 fm) in San Cristobal Bay on June 22, 1971. These fish
ranged from 119 to 147 mm (4.7 to 5.8 inches) sl. The southern limit
is extended from Cedros Island approximately 92.5 km (50 miles) south-
ward by this collection.
NOTES 59
Microstomus pacificus (Lockington) — Dover sole
Two dover sole, 158 and 203 mm (6.2 and 8.0 inches) sl, were cap-
tured in a bottom trawl on June 22, 1971, in San Cristobal Bay. The
southern limit of this speci'^s has been recorded as San Quintin Bay,
Baja California (Fitch and Lavenberg 1971), and Guadalupe Island
(Roedel 1953). The specimens caught in San Cristobal Bay extend the
known range over 185.3 km (100 miles) southward.
ACKNOWLEDGEMENTS
The authors gratefully acknowledge the assistance of Andrew
Felando, Frank McCumiskey, Earl Andreassen, and the rest of the
crew on the ALASKA. We especially wish to express our thanks to
John Fitch for his field notes of previously unpublished material and
his suggestions concerning the manuscript. Mickey Wolfe, Pat Barnett,
and Gayle Jones are to be commended for their patience in typing our
many versions of this paper.
REFERENCES
Fitch, John E. 1953. Extensions to known geographical distributions of some
marine fishes on the Pacific coast. Calif. Fish Game 39 (4) : 539-552.
Fitch, John E., and L. W. Barker. 1972. The fish family Moridae in the eastern
north Pacific with notes on morid otoliths, caudal skeletons, and the fossil record.
U. S. Nat. Mar. Fish. Serv., Fish. Bull. 70(3) : 565-584.
Fitch, John E., and R. J. Lavenberg. 1971. Marine food and game fishes of Cali-
fornia. Univ. of Calif. Press, Berkeley. 179 p.
Hildebrand, Samuel F. 1943. A review of the American anchovies (family En-
graulidae). Bingham Oceanogr. Collection, Bull. 8(2) : 1-165.
Jordan, David S., and B. W. Evermann. 1896. A check-list of the fishes and
fish-like vertebrates of North and Middle America. U. S. Comm. Fish. Kept, for
1895 : 207-584.
McHugh, J. L., and J. E. Fitch. 1951. An annotated list of the clupeoid fishes
of the Pacific coast, from Alaska to Cape San Lucas, Baja California. Calif. Fish
Game 37(4) : 491-495.
Roedel, Phil M. 1953. Common ocean fishes of the California coast. Calif. Dep.
Fish and Game, Fish Bull. (91) : 1-184.
Eric H. Knaggs, John S. Sunada and Robert N. Lea, Marine Resources
Region, California Dcpariment of Fish and Game, 350 Golden Shore,
Long Beach, Calif. 90802. Robert N. Lea's present address, University
of Miami, Rosenstiel School of Marine and Atmospheric Sciences,
10 Rickenhacker Causeway, Miami, Florida 33149. This study was
conducted in cooperation with the Department of Commerce, National
Oceanic and Atmospheric Administration, National Marine Fisher-
ies Service, under Public Law 88-309, Project 6-3-R. Accepted Au-
gust 1974.
OCCURRENCE OF THE PROWFISH ZAPRORA SILENUS
JORDAN, 1896 IN MONTEREY BAY, CALIFORNIA
On the morning of October 15, 1973, a 50.1 cm (19.8 inch) Standard
Length (sl) specimen of the rare proA\-fish, Zaprora silcnus Jordan,
1896 was collected by John Fumotara on the trawler New Janet Ann.
It was taken at 118 m (390 ft) on the north shelf of the Monterey-
Submarine Canyon at lat 36° 50' N, long 121° 59' W. This represents
a southward range extension of approximately 161 km (100 miles)
since it has recently been reported from Bodega Bay (Fitch and Laven-
berg 1971 ; Miller and Lea 1972) .
The specimen was brought to the vertebrate museum at the Moss
Landing Marine Laboratories where all measurements, counts and
photographs were taken. It has subsequently been deposited in the
ichthyology collection at the California Academy of Sciences (CAS
30693).
Information on the monotypic prowfish is scarce because most refer-
ences consist chiefly of notes on range extensions, some with meristic
and morphometric data presented (Kendall 1914; Dymond 1928;
Schultz 1934; Scheffer 1940; Schultz and Haryey 1945). However,
Chapman and Townsend (1938) reviewed the osteology and early life
history of the prowfish based on 36 specimens collected in the north-
east Pacific off Washington, British Columbia and Alaska. Fitch and
Lavenberg (1971) presented natural history notes summarizing the
TABLE 1. — Meristic and morphometric data from Zaprora silenus (CAS 30693).
Measurements
Total length.- ..-
Standard length (SL)
Head length (HL)
Body depth
Bony interorbital space
Snout length
Orbit diameter -
Maxillary length
Depth caudal peduncle
Predorsal length
Preanal length
Length longest pectoral ray
cm
50.1
41.8
8.7
11
3
2
1
3
4
7
23
8.0
%SL
119.9
20.8
27.8
8.
4.
4.
7.
11,
17.0
56.5
19.1
.9
.8
.1
.9
.2
%HL
575.9
480.5
133.3
42.5
23.0
19.5
37.9
54.0
81.6
271.3
91.6
Counts
Dorsal fin rays. .
Anal fin rays
Pelvic fin rays..
Pectoral fm rays
Branchiostegals.
Gill rakers
LVI
IV 26
absent
23
6
8-18
(60)
NOTES 61
known information on this species. McAllister and Krejsa (1961)
reviewed its enigmatic taxonomic position, finally placing the family
Zaproridae in the superfamily Stichaeoidae. Greenwood et al. (1966)
have further placed the family in the suborder Blennioidei. Because
little is known of this fish, even where it is more abundant to the
north, the specimen was examined in detail to contribute as much
information to its life history as possible.
The meristic and morphometric data (Table 1) compare favorably
with published information on northern specimens (Kendall 1914; Dy-
mond 1928; Chapman and Townsend 1938; Scheffer 1940) with the
exception that our specimen, when carefully dissected and examined
by X-ray, had four anal spines and 26 soft rays.
The right sagitta (otolith) was removed and measured 4.1 mm across
its longest axis and exhibited three winter rings, with the last on the
distal margin not quite complete, indicating that this fish was in its
third year. As determined by serial sections of the gonad, our specimen
was found to be an immature female with developing ova, indicating
the possibility of spawning during the next season. Thus our specimen
would probably have spawned in its fourth year, which agrees with
growth zone readings on the otolith from a 33-inch male by Fitch and
Lavenberg (1971). All of the juvenile specimens of Zaprora caught by
Chapman and Townsend (1938) off Alaska were taken during the
months of May, June and July, which may indicate a seasonality to
their spawning habits, and thus a seasonality in the abundance of
young prowfish in the plankton.
The stomach of our specimen was empty but the intestine contained
the remains of nine hyperiid amphipods. No trace was found of jelly-
fish remains as reported by Fitch and Lavenberg (1971). No external
or gill parasites were present. The specimen showed no unusual colora-
tion, appearing uniform grayish blue with a slightly lighter ventral
surface, and very noticeable light blue head pores,
ACKNOWLEDGEMENTS
We wish to thank John Fumotara for bringing us this interesting
fish, and James Gordon, California Academy of Sciences, for providing
a radiograph of the specimen for our counts.
REFERENCES
Chapman, W. M., and L. D. Townsend. 1938. The osteology of Zaprora silenus
Jordan, with notes on its distribution and early life-history. Ann. Mag. Xatur.
Hist. Ser. 11. 2(8) : 89-117.
Dymond, J. R. 1928. Another prowfish {Zaprora silenus) record. Copeia
(169) : 88-89.
Fitch, J. E., and R. J. Lavenberg. 1971. Marine food and game fishes of Cali-
fornia. Univ. of Calif. Press, Berkeley and Los Angeles, 179 pp.
Greenwood, P. H., D. E. Rosen, S. H. Weitzman, and G. S. Myers. 1966. Phy-
letic studies of teleostean fishes, with a provisional classification of living forms.
Am. Mus. Nat. Hist., Bull., 131(4) : 341^55.
Kendall, W. C. 1914. A new record for the prowfish. Copeia (12) : 1-2.
McAllister, D. E., and R. J. Krejsa. 1961. Placement of the prowfishes, Zapro-
ridae, in the superfamily Stichaeoidae. Can. Nat. Mus., Natur. Hist. Pap.
(11): 1-4.
Miller, D. J., and R. N. Lea. 1972. Guide to the coastal marine fishes of Cali-
fornia. Calif. Dept. Fish and Game, Fish Bull. (157) : 1-235.
62 CALIFORNIA FISH AND GAME
Scheffer, V. B. 1940. Two recent records of Zaprora siletius Jordan from the
Aleutian Islands. Copeia 1940(3) : 203.
Schultz, L. P. 1934. Zaprora silenus Jordan from Alaska. Copeia 1934(2) : 98.
Schultz, L. P., and E. W. Harvey. 1945. The flaccid fish, Zaprora silenus,
from off Newport, Oregon. Copeia 1945(4) : 237.
— Gregor M. Cailliet and M. Eric Anderson, Moss Landing Marine
Laboratories, Moss Landing, California 95039. Accepted September,
1974.
BOOK REVIEWS
Endemism in Fishes of the Clear Lake Region of Central California
By John D. Hopkirk; University of California Press, Berkeley, 1973; 135 p., illustrated in
black-and-white photos.
The largest freshwatfer fish province within California is the Sacramento province.
The Clear Lake region studied by Hopkirk encompasses all or part of 7 of the 10
districts within this province. It extends from 50-60 miles north and east of Clear
Lake, to the Golden Gate on the south and the Pacific Coast on the west.
Citing fluviolacustine speciation, the Clear Lake minnow {Endemichthys grandi-
pinnis), the Clear Lake splittail (Pogonichthys ciscoides), the Clear Lake hitch
{Lavinia exilicauda chi) , and the Clear Lake tuleperch {Hysterocarpus traskii
lagunae) are described from the Clear Lake basin, as is an unnamed subspecies of
Cottus asper. In addition, the tuleperch of the Russian River subprovince is now
recognized as a new subspecies, H. t. porno.
According to the author, the evidence from the fish fauna can now be added to
that of the moUuscan fauna, and that of the flora, in support of the thesis that the
Clear Lake area is a center of endemism. There will be arguments, however, as to
the strength of this evidence. The differences between these "endemics" and that
of their extrabasin congeners is small and the argument can be raised that, for
example, P. ciscoides deserves no more than subspecific recognition.
Endemichthys grandipinnis. a new genus and species, is based upon 12 specimens
collected in 1939 and 1940. The characteristics that distinguish this taxon from re-
lated taxa are minor indeed, and one might conclude we are dealing with hybrids
grandipinnis, between Lavinia exilicauda and Orthodon microlepidotus, as earlier
workers who examined this material have done. No less an authority than Dr. Carl
L. Hubbs, however, reportedly agrees with the author's diagnosis.
In any event, the author has compiled a considerable amount of data on native
fishes of the Clear Lake region and their distribution. Particularly valuable is a
listing of these fish (exclusive of Petromyzontidac, Acipenseridae, and Salmonidae)
in the collections of 7 ichthyological museums through about 1966. The systematic
discussion of each genus and species is especially detailed, but I would like to have
seen more graphical and statistical treatment of the data presented, particularly
where the new species and subspecies are concerned. The sections on geology, bio-
geography and zonation of fishes are brief but informative.
Not since Snyder's work on the fishes of the Lahontan system has there been a
comprehensive treatment ©f the native fishes of a major California region. Regard-
less of whether or not one agrees with its taxonomic conclusions, it is a welcome
addition to the sparce taxonomic literature on California's native freshwater fishes.
— Stephen J. Nicola
Western Trout Fly Tying Manual
By Jack Dennis; Snake River Books, Jackson Hole, WY 1974; 258 p., illustrated. $6.95
Finally, a book about western fly patterns ! The "west" in this case means Mon-
tana, Wyoming, Idaho, and Colorado but the patterns described include many pat-
terns commonly used in California.
Jack Dennis has written an extremely useful "How-to" book for both the beginner
and the more advanced tyer. Over sixty patterns are detailed in the Manual : Drys,
wets, streamers, nymphs, and a special section on hair flies for our more turbulent
western waters.
The origin of each fly is briefly described, the most commonly used sizes listed,
and information on how it would be fished is often illustrated with a personal
experience. A detailed list of materials is provided and finally, step-by-step photo-
graphs (black and white) of the actual tying process. As always, a picture is worth
a thousand words ; the photos are clear, the proportions obvious, and the photo
of the finished fly gives the novice tyer something to shoot at.
The Manual also has a brief chapter on materials and tools, a chapter on special
fly tying techniques, and a special section on the use of the whip finishing tool. The
author explains what equipment and hooks he prefers, and tells where they can be
obtained. Far too infrequently do authors provide enough information on brand
names and sources of supply ; this feature will be appreciated by the beginning tyer.
The Western Trout Fly Tying Manual is available in paperback at a price of
$6.95 ; there is also a special limited edition, signed and numbered by the author
for $35.00. — K. A. Hashagen, Jr.
(63)
A87003 — 800 11-74 5M
INSTRUCTIONS TO AUTHORS
EDITORIAL POLICY
The editorial staff will consider for publication original articles and
notes dealing with the conservation of the fauna and flora of California
and its adjacent ocean waters. Authors may submit two copies, each,
of manuscript, tables, and figures for consideration at any time,
MANUSCRIPTS: Authors should refer to the CBE Style Mamial (third
edition) for general guidance in preparing their manuscripts. Some
major points are given below.
1. Typing — ^All material submitted, including headings, footnotes,
and references must be typewritten double-spaced on white bond
paper. Papers shorter than 10 typewriten pages, including tables,
should follow the format for notes.
2. Citations — ^All citations should follow the name-and-year system.
The "library style" will be followed in listing references.
3. Abstracts — Each paper will be introduced by a short, concise
abstract. It should immediately follow the title and author's name
and be indented at both margins to set it off from the body of the
paper.
4. Abbreviations and numerals — ^Use approved abbreviations as listed
in the CBE Style Mamwil, In all other cases speU out the entire
word,
TABLES: Each table should be typewritten double-spaced throughout
with the heading centered at the top. Number tables with arable
numerals and place them together in the manuscript following the
references. Use only horizontal rules. See a recent issue of California
Fish and Game for format.
FIGURES: Submit figures at least twice final size so they may be reduced
for publication. Usable page size is 4f inches by 7f inches. All figures
should be tailored to this proportion. Photographs should be sub-
mitted on glossy paper with strong contrasts. AU figures should be
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figure number in the upper right corner. Markings on figures should
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PROOF AND REPRINTS: Galley proof will be sent to authors approxi-
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of charge to authors. Additional copies may be ordered through the
editor at the time the proof is submitted.
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