(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Children's Library | Biodiversity Heritage Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "Synopsis of biological data for the winter flounder Pseudopleuronectes americans (Walbaum) / Grace Klein-MacPhee"

C<$5. '3 -VW/5 c//?e <//</ 



414 



V \ 

o x :=*: r* 



*♦ 






o 



NOAA Technical Report NMFS Circular 414 

Synopsis of Biological Data 
for the Winter Flounder, 
Pseudopleuronectes americanus 
(Walbaum) 



November 1978 





FAO Fisheries 
Synopsis No. 117 

NMFS/S 117 

SAST - WINTER FLOUNDER 
.1.83(20)050,03 




lM*P\i ;1 ifiiT^J Jf.« 



U.S. DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 



^O^MOSP 




'l^fNT 0* 



NOAA Technical Report NMFS Circular 414 

Synopsis of Biological Data 
for the Winter Flounder, 
Pseudopleuronectes americanus 
(Walbaum) 



Grace Klein-MacPhee 



November 1978 



FAO Fisheries Synopsis No. 117 



8- 

>. 

w 
3 

I 

n. 
v 

a 

to 

a 



U.S. DEPARTMENT OF COMMERCE 

Juanita M. Kreps, Secretary 

National Oceanic and Atmospheric Administration 

Richard A. Frank, Administrator 

National Marine Fisheries Service 



National Marine Fisheries Service (NMFS) does not approve, rec- 

nmend or endorse any proprietary product or proprietary material 

itioned in this publication. No reference shall be made to NMFS, or 

to this publication furnished by NMFS, in any advertising or sales pro- 

jtion which would indicate or imply that NMFS approves, recommends 

or endorses any proprietary product or proprietary material mentioned 

herein, or which has as its purpose an intent to cause directly or indirectly 

the advertised product to be used or purchased because of this NMFS 

publication. 



CONTENTS 

Page 

Identity 1 

1.1 Nomenclature 1 

1.2 Taxonomy 1 

1.3 Morphology 2 

Distribution 3 

2.1 Total area 3 

2.2 Differential distribution 4 

2.3 Determinants of distribution 4 

2.4 Hybridization 5 

Bionomics and life history 5 

3.1 Reproduction 5 

3.2 Preadult phase 6 

3.3 Adult phase 9 

3.4 Nutrition and growth 12 

3.5 Behavior 23 

Population 25 

4.1 Structure 25 

4.2 Abundance and density 26 

4.3 Natality and recruitment 29 

4.4 Mortality and morbidity 30 

4.5 Dynamics of the population as a whole 31 

4.6 The population in the community and the ecosystem 31 

Fishing 34 

5.1 Fishing equipment 34 

5.2 Fishing areas 35 

5.3 Fishing seasons 35 

5.4 Fishing operations and results 36 

Protection and management 36 

6.1 Regulatory (legislative) measures 36 

6.3 Control or alteration of chemical features of the environment 36 

6.4 Control or alteration of the biological features of the environment 39 

Pond fish culture 39 

7.1 Procurement of stock 39 

7.2 Spawning 39 



in 



Synopsis of Biological Data for the Winter 
Flounder, Pseudopleuronectes americanus (Walbaum) 



GRACE KLEIN-MacPHEE 1 



ABSTRACT 

This monograph contains a synopsis of selected pertinent papers covering biological and tech- 
nical data of the winter flounder, Pseudopleuronectes americanus, including life history, taxonomy, 
physiology, disease, ecology, population dynamics, commercial and sports fishery, behavior, environ- 
mental effects, and culture. One hundred and fifty-four published reports and 12 unpublished reports 
are covered. Twenty-one figures are included. Literature up to and including 1976 is covered. 



1 IDENTITY 

1.1 Nomenclature 

After Jordan et al. 1930:227 and Norman 1934:345. 

1.11 Valid scientific name 
Pseudopleuronectes americanus (Walbaum). 

1.12 Subjective synonomy 

Pleuronectes. Schoepf 1788. Schrift. Ges. Nat. Freunde 
Berlin, VIII, p. 148. 

Pleuronectes americanus Walbaum 1792. Artedi 
Ichth. (3), ed. 2, p. 113 (based on the flounder of 
Schoepf). 

Pleuronectes planus Mitchill 1814. Rep. Fishes New 
York, p. 8. 

Platessa plana. Storer 1893. Boston J. Nat. Hist., ii, p. 
475; Rep. Ichth. Mass., p. 140. 

Platessa pusilla De Kay 1842. Nat. Hist., New York 
(Fish), p. 296, pi. xivll; fig. 153 (New York). 

Pseudopleuronectes planus. Bleeker 1862. Versl. 
Akad. Wet. Amsterdam, xiii, p. 428. 

Pseudopleuronectes americanus. Gill 1864. Proc. 
Acad. Nat. Sci. Phila., xvi, p. 216. 

Pseudopleuronectes dignabilis Kendall 1912. Bull. 
U.S. Bur. Fish., xxx, (1910), p. 392, pi. lvii (Georges 
Bank). 

1.2 Taxonomy 

1.21 Affinities 

Suprageneric 
Phylum — Chordata 

Subphylum — Vertebrata 



'U.S. Environmental Protection Agency. Environmental Research 
Laboratory, South Ferry Road, Narragansett, RI 02882. 



Class — Osteichthys 

Order — Pleuronectiformes (Heterosomata) 
Family — Pleuronectidae 

Generic (data from Norman 1934) 

Pseudopleuronectes. Bleeker 1862. Versl. Akad. Wet. 

Amsterdam, xiii. p. 428. 
[Pleuronectes planus Mitchill]; Norman 1933, Ann. 

Mag. Nat. Hist. (10) xi, p. 220. 
Limandella. Jordan and Starks 1906. Proc. U.S. Natl. 

Mus., xxxi, p. 204. 
[Pleuronectes yokohamae Giinther.) 

Generic — Body ovate, compressed. Eyes on right side 
separated by narrow naked or scaled ridge, upper eye 
close to edge of head; postocular ridge, if present, rugose; 
snout and eyeballs not scaled. Olfactory laminae, paral- 
lel, without rachis. Mouth moderate sized, length of 
maxillary on blind side less than one-third that of head, 
jaws and dentition stronger on blind side, no more than 
■Mx teeth on ocular side of either jaw. teeth compact in- 
cisorlike, close-set, sometimes forming continuous cut- 
ting edge, not enlarged anteriorly, uniserial in both jaws; 
vomer toothless. Gill rakers few, lower pharyngeals nar- 
row. 120-180 mm in length, slender, not much ap- 
proximated anteriorly, inner edges evenly curved, each 
with widely separated rows of conical teeth. Dorsal fin 
less than 85 rays beginning behind posterior nostril of 
blind side and above eye; all rays simple, some scaled on 
ocular side; tip of first interhaemal spine projecting in 
front of anal fin which has less than 65 rays. Pectoral fin 
of ocular side usually larger than one on blind side; mid- 
dle rays branched. Caudal fin 13 or 14 branched rays; 
caudal peduncle short to moderate in length. Scales 
small, adherent, imbricate (at least anteriorly) ctenoid or 
cycloid; spinules, if present, short, few; no supplementary 
scales, lateral line curved above pectoral fin, supratem- 
poral branch is present without posterior prolongations. 
Vent median or slightly on blind side between pelvics. 
Intestine narrow, elongate, with three or more coils; 3+1 
pyloric appendages moderate or rather elongate. Three 



species, one from Atlantic coast of North America; two 

from Japan. 

Specific 
Pseudopleuronectes americanus (Walbaum 1792) (Fig. 1). 



A. Interorbital ridge nearly naked; tips of gill rakers 
sharply pointed; 68-75 scales in lateral line; den- 
tal formula 2 




Figure 1 .—Adult winter flounder. 
Type — not traced. 

Lateral line nearly straight, dorsal fin originates op- 
posite forward edge of eye and is nearly equal in height 
throughout its length. Ventral fins alike on two sides of 
body, both separated. Synopsis of the species is taken 
from Norman (1934:342). 

Synopsis of the Species 

I. Eyes separated by a ridge, which is naked or scaled, 
width less than one-fourth diameter of eye; postocular 
ridge rugose. 



+ 14-23 
2-6 + 19-24 



1. P. herzensteini. 



B. Interorbital ridge scaled; tips of gill rakers rounded 
or obtusely pointed; 75-90 scales in lateral line; 
dental formula 

0-3 + 8-16 2. P. yokohamae. 

0-4 + 12-20 

II. Interorbital space flat, scaled, width one-third to one- 
half diameter of eye; postocular ridge not rugose; 78- 
89 scales in lateral line 3. P. americanus. 

1.22 Taxonomic status 
Morpho — Species. 

1.23 Subspecies 
See section 1.31 

1.24 Standard common names, vernacular names 

Winter flounder, blackback, Georges Bank flounder, 
lemon sole, flounder, sole, flatfish, rough flounder, (Bige- 
low and Schroeder 1953). Plie rouge, carrelet (Leim and 
Scott 1966). 

1.3 Morphology 

1.31 External morphology 

Gill rakers 7-8 (lower anterior arch); lateral-line scales 
78-89; fin rays, dorsal 59-71(5 73), anal 47-54(x 46), pec- 
toral 10-11 (5-7 branched); caudal 19 (13 branched); ver- 
tebrae 36 (10+26); pyloric caecae 3+1; dental formula 

0-2 + 10-15 
0-2 + 10-17 



(Norman 1934). See also Table 1. 



1.32 Geographic variation 

In 1912 W. C. Kendall described the Georges Bank 
flounder as a new species, Pseudopleuronectes dig- 
nabilis. He stated that the most conspicuous differential 
characteristics of this "species" are shorter head, larger 
number of vertical fin rays, color, and larger size (Ken- 
dall 1912). There is also a different spawning season 
(April-May). 

Perlmutter (1947) compared counts of winter flounder 
north and south of Cape Cod and from Georges Bank. He 
felt that Georges Bank flounder had significantly dif- 
ferent dorsal, pectoral, and anal fin ray counts showing 
there was little mixing of this stock with other winter 
flounder stocks. 



'Dental formula occular side + blind side (upper jaw) 
occularside + blind side (lower jaw) 



Table 1. — Comparison of fin ray counts of winter flounder by several 
investigators. 







Pectoral 


Reference and 


Dorsal rays 


Anal rays 


rays 


locality 








Kendall (1909) 








P. dignabilis 


68-78 .f 70.6 


50-54 x 52.3 




(Georges Bank) 


61-67 x 64.7 


46-50 x 48 




P. americanus 
Perlmutter(1947) 


63.97 ± 2.51 


47.83 ± 1.82 


9.84 ± 0.68 


North of Cape Cod 


64.05 ±2.29 


47.73 ± 1.88 


10.08 ± 0.59 


South of Cape Cod 
Georges Bank 


68.93 ± 2.53 


51.30 ± 1.96 


10.58 ± 0.62 


(P. dignabilis) 




.V 


i 


Lux etal. (1970) 




64.94 


48.89 


Cape Cod Bay (North) 




66.87 


50.42 


East. Vineyard 
Sound (South) 


Date 






Georges Bank 


1963 


69.53 


51.94 


(P. dignabilis) 


1964 


69.58 


52.14 




1966 


70.28 


52.61 





Lux et al. (1970) compared dorsal and anal fin ray 
counts on winter flounder from inshore waters off 
Massachusetts north and south of Cape Cod and from 
Georges Bank. An examination of water temperature at 



spawning time (March-April) for 1940-56 in 
the National Marine Fisheries Service at V 
showed that, in March, water temperature range 



Wood 

" 

rere indicatec 
ear tl 



1.7° to 5.4°C. This is higher than at 
Gloucester, Mass. The Georges Ban 
spawn at higher temperatures w 
ray number. Norman (1934) 
represent a distinct race with a diffe 
as described by Kendall (1909) (Table 
Lobell (1939) believed racial groups \ 
Long Island Sound since recoveries 
localities occur simultaneously wit! 
points relatively distant. 

2 DISTRIBUTION 



2.1 Total area 

Atlantic coast of North America fro 
the offshore fishing banks (40-100 m 
ter flounder is common from the Strait 
North Shore of the Gulf of St. Lawren< • 
Bay. The extremes of distribution are .. 
of the Grand Banks, the northernrru 
gava Bay, Labrador (Kendall 1909); and V. 
Beaufort, N.C., the southernmost recc 
(Hildebrand and Schroeder 1928). 



Figure 2. — Range of winter flounder. 

3 



45° 



-40° 




2.2 Differential distribution 

2.21 Eggs, larvae, juveniles 

Marine Research, Inc.' mapped larval distribution in 
Narragansett Bay (Fig. 3). The most extensive work on 
differential distribution of eggs, larvae, and juveniles was 
done by Pearcy (1962a) in the Mystic River estuary, 
Conn. Spawning took place in the upper estuary. Young 
fish demonstrated both horizontal and vertical dif- 
ferences in distribution. 




Figure 3. — Distribution of winter flounder larvae in Narragansett 
Bay (Marine Research Inc. 1974, see text footnote 3). 



Horizontal distribution — During the early larval 
period ("March to April prior to metamorphosis), the den- 
sity of winter flounder larvae was 15 times greater in the 
upper Mystic River estuary than in the lower estuary. 
Later in spring, upper estuarine density declined. By 
May no larvae were caught in the upper estuary indicat- 
ing that larvae moved down into the lower estuary. In the 
early season there was no difference in average length of 
larvae from the upper or lower estuary. During March 



and April the smallest sizes were found in the lower es- 
tuary and by mid-April the largest sizes were taken here. 

Vertical distribution — Larvae had a passive sinking 
rate of 14 mm/s in seawater with a specific gravity of 
1.022, so they were nonbuoyant and located near the bot- 
tom, partially benthic. The small larvae are poor swim- 
mers which swim vertically in a 90° climb, stop, rotate 
180°, and sink passively (Pearcy 1962a). 

Perlmutter (1947) found the larvae spawn in shallow 
water in southern New England and New York. Larvae 
remain in shoal water near shores of bays and estuaries. 
As they grow older they tend to move into deeper water; 
entering the commercial and sport fisheries catch in the 
second and third years. 

De Sylva et al. (1962) 4 reported that in the Delaware 
River estuary, Indian River Bay seemed to be an impor- 
tant nursery ground for young which first appeared in 
early June. Larvae were collected in late winter. Work 
done by Derickson and Price (1973) in the Indian River 
Bay area of the Delaware River and by McCracken 
(1963) on movements of immature flounders in Passama- 
quoddy Bay, Canada, supported the statement that, in 
general, in northern waters immature flounder occur in- 
shore and move offshore during winter. 

Lux et al. (1970) collected spent and spawning females 
off Georges Bank, Mass. The population spawns off- 
shore and larvae and juveniles remain on the spawning 
area separated from nearby shore populations. 

2.22 Adults— See section 3.53 
2.3 Determination of distribution 

Perlmutter (1947) stated that the predominant phys- 
ical forces affecting movements of eggs and larvae in 
spawning habitats are wind and tide, but effects of these 
are reduced by eggs being demersal and adhesive, with 
early pelagic stages remaining in back waters of bays and 
inlets. 

Pearcy (1962a) attributed the larval distribution in- 
shore and close to the bottom to the fact that they are 
nonbuoyant. When not actually swimming they sink; 
and therefore, are not carried away by outward moving 
surface currents. The survival value of this is that it 
might reduce offshore dispersal, an important factor in 
loss rate for small larvae. 

McCracken's (1963) laboratory studies of winter floun- 
der reactions to light showed that small (60-90 mm TL 
(total length) ) immature flounders are positively photo- 
tropic; medium (120-180 mm TL) flounders avoid light. 
He theorized that where flounder are found in shallow 
water during summer, the differential distribution 
between young immature and older immature may result 
from a different behavior pattern with size and maturity 
in relation to light. 



Marine Research Inc. 1974. 19th Rome Point Investigations Narra- 
gansett Bay, Ichthyoplankton Survey Final Report to the Narragansett 
Electric Company. 



Me Sylva, D. P., F. A. Kalber, Jr., and C. N. Shuster, Jr. 1962. 
Fishes and ecological conditions in the shore zone of the Delaware River 
Estuary with notes on other species collected in deeper waters. Univ. 
Del. Mar. Lab., Inf. Ser. Pub!. No. 5, 164 p. 



Experiments by Huntsman and Sparks (1924) and 
Battle (1926) on resistance to temperature stress showed 
that younger fish were more tolerant of high tempera- 
tures (29°-30°C) than older fish, which might also ac- 
count for their being located in shallower waters in 
summer. 

2.4 Hybridization 

Nichols (1918) described a fish from the New York 
market believed to be a hybrid, Pseudopleuronectes 
americanus X Limanda ferruginea. Considering the 
Georges Bank flounder as a separate species, Morrow 
(1944) reported a record winter flounder (560 mm TL, 
2,649 g) which appeared to be intermediate between P. 
americanus and P. dignabilis. 

3 BIONOMICS AND LIFE HISTORY 

3.1 Reproduction 

3.11 Sexuality 

Winter flounder have separate sexes; there is little sex- 
ual dimorphism. Norman (1934) stated that scales on the 
blind side of males are ctenoid instead of cycloid, giving 
them a rough feeling. Perlmutter (1947) confirmed this 
generally, but mentioned that often large females have 
rough scaled blind sides. 

3.12 Maturity 

Winter flounder in the New York region mature at 2-3 
yr when they are 200-250 mm TL long (Perlmutter 1947). 
Kennedy and Steele (1971) gave the age of maturity of 
flounder from Canada as age VI for males and VII for 
females. Fifty percent of the females and males were 
mature at 250 and 210 mm, respectively. Maturity may 
be related to size and not age; therefore, northern floun- 
der may be older at maturity than southern ones. 

3.13 Mating 

No distinct pairing has been observed (Breder 1922). 
See 3.16. 

3.14 Fertilization external (Breder 1922) 

3.15 Gonads 

In Long Pond, Newfoundland, male gonads began to 
enlarge earlier than female and males reached spawning 
stage before females. Ripening began in September, 
progressed slowly during winter months, and spawning 
took place March-June (Kennedy and Steele 1971). 

Dunn and Tyler (1969) studied ovarian anatomy of 
winter flounder. They described the ovary as being an 
adaptation of the vertebrate compact ovary. It differs 
from most teleost ovaries in having a relatively short 
hilus and mesovarium. Ovaries are connected anteriorly 



to the peritoneum by a short mesovarium; arteries and 
veins pass through the hilus. Four oocyte types could be 
distinguished morphologically throughout the yearly 
cycle: 

1) Small immature — 10-80 p diameter, irregular in 
shape, sometimes angled, darkly staining (basophilic) 
containing no yolk or fat droplets; nucleus with one or 
two large nucleoli. 

2) Large immature — 80-150 M round, yolkless con- 
taining some fat droplets, granular looking cytoplasm. 
Nucleus with several darkly staining nucleoli around the 
periphery. 

3) Maturing oocytes — 150 ^ massive deutoplasm fat 
and yolk deposits, small protoplasm, prominent theca. 
Visible yolk deposition occurs at 150 ^ . At ovulation, 
diameter 40-850 ^ . 

4) Atretic or regressing oocytes — Shrinkage of zona 
radiata away from theca. Disorganized cellular struc- 
ture including rupture of the nucleus and wrinkling of 
the theca, resorption of yolk and fat which leaves a mass 
of folded theca often containing dark staining amor- 
phous material. 

Three states of ovary development based on biological 
examination of follicular development were present for 
fish held in tanks: 



1) Resting ovaries — Contain no oocytes with yolk 
deposits, have large intraovarian spaces, relatively thick 
walls. (Those on reduced rations often did not have thick 
walls). 

2) Ripening ovaries — Contained maturing oocytes as 
well as atretic and immature ones. 

3) Regressing ovaries — Portion of large immature 
oocyte had begun vitellogenesis normally but at the time 
of sampling were atretic. Ovaries less emaciated than 
resting types, immature oocytes more densely arranged. 
The frequency distribution of oocyte sizes in resting 
ovaries showed bimodal distribution. 

Dunn and Tyler (1969) hypothesized a 2- or 3-yr cycle. 
Dunn (1970) found individual fish vary in their state of 
development at any given time, strengthening the 3-yr- 
cycle hypothesis. He studied fish 340-450 mm TL from 
September to December, and presented evidence for 
autumn growth of yolkless oocytes which would tend to 
split oocytes into two size groups. The proportion of 
small immature oocytes remained low so few oocytes 
were added to immature follicles. Increase in proportion 
of eggs in larger size classes (80- 100 /i) with reduction in 
number of small eggs represented growth of a portion of 
the oocytes. Larger oocytes can be tentatively identified 
with those oocytes that in the following summer form the 
stock of large immature follicles which begin vitel- 
logenesis to be spawned the next spring. Three year 
cycle — year 1, at least small immature oocytes become 
recognizable; year II they become larger immature 
oocytes; year III yolk is deposited and they are spawned. 



Fecundity studies have been summarized in Table 2. 

Topp (. 1968) also measured ova density and found it 
ranged from 6.082 to 18.963 eggs/g of ovary with a mean 
of 10,595 eggs g of ovary. Egg diameter ranged from 0.33 
to 1.00 mm with a mean of 0.61 mm. There was no sig- 
nificant correlation between mean egg size and fish size; 
but egg size differed among age groups, age group three 
having the smallest eggs. 

Table 2.— Fecundity values for winter flounder. 



Number of eggs 


Age. weight or 




X 1.000 


size (TL) offish 


Investigator 


x 500 




Bigelowand 


Maximum 1.500 


1.531 g 


Schroeder(1953) 


435-3,329 


3 yr (300-400 mm) 
to 5 yr (400-450 mm) 


Topp (1968) 




210 g, 250 mm to 


Saila (1962a) 


93-1.340 


1,052 g, 430 mm 




x 610 


x 334 mm 






111 g, 220 mm to 


Kennedy and 


99-2.604 


1,300 g, 440 mm 


Steele (1971) 


x 590 


x 340 mm 





3.16 Spawning — Once a year (Table 3) 

- Spawning times vary, beginning earlier in the southern 
part of the fish's range and progressively later as one 
proceeds northward. 

Tagging experiments at Woods Hole and Waquoit, 
Mass.. performed by Nesbit (in Lobell 1939) showed that 
a significant number of fish returned to the same spawn- 
ing grounds two or more successive years. He was not 
able to tell if these fish remained in the bay throughout 
the regular season, or moved out and returned to spawn. 

Saila (1961) showed that winter flounder returned to 
the tagging locality with high frequency over the year of 
recovery data, after having left the area following the in- 
itial breeding season. (See section 3.51.) 

Breder (1922) described spawning habits from obser- 
vations made on fish held captive in large wooden tanks 



Table 3.- 



Dates of winter flounder spawning at different geographic 
locations from north to south. 



Dates 


Peak 


Area 


Investigator 


Mar. -June 





Long Pond, Con- 


Kennedy and 






ception Bay, 


Steele (1971) 






Newfoundland 




Mar. -May 


Apr. 


Booth Bay Harbor. 


Hahn (Pers. commun. 






Maine 


in Bigelow and 
Schroeder, 1953) 


Feb. -May 


— 


Eel Pond, Woods 


Sherwood and 






Hole, Mass. 


Edwards (1901) 


Jan. -Mav 


Feb. -Mar. 


South of Cape 


Bigelow and 






Cod and Massa- 


Schroeder (1953) 






chusetts Bay 




Mid Feb.- 


Mar. 


Mystic River 


Pearcy (1962a) 


Apr. 




estuary, Conn. 




Dec. -May 


Varies 


Southern New 


Perlmutter(1947) 




with water 


England — New 






temp. 


York 




Nov. -Apr. 


— 


Indian River Bay, 


Fairbanks et al. 






Del. 


(1971) 



at Woods Hole. Spawning occurred at night, between 
2200 and 0330, under artificial lights. Five fish, three 
males and two females, took part. Previous to spawning, 
they (especially females) exhibited a large amount of 
swimming activity. 

The fish swam rapidly in a circle about 1 ft in 
diameter, counterclockwise with vent outwards. As they 
swam, genital products were discharged. This took 10 s, 
then the fish swam to the bottom. During spawning, eggs 
were extruded from the female, flowed along the upper 
side of the anal fin and over the tail to spread out in all 
directions. Breder (1922) believed that females must 
release the eggs but males can hold the milt because, if 
frightened or alarmed, they do not take part in the ac- 
tivity. I can confirm this from personal observations. 

See section 3.51 for information on spawning migra- 
tion and section 7.2 for factors influencing maturation 
and spawning time. 

3.17 Eggs 

The eggs are demersal. Pearcy (1962b) showed that 
specific gravity with gum arabic and seawater was 1.085, 
and they sank in water of 30% o salinity. He believed 
that morphological similarities among adults, and 
characteristics of the larvae of those pleuronectids with 
demersal eggs, suggest they evolved from species with 
buoyant eggs. The adaptive value of demersal eggs is 
that they would remain in inshore nursery grounds where 
conditions for development are favorable. 

The eggs ranged from 0.71 to 0.86 mm in diameter with 
a mode of 0.81 mm. The spermatozoa are 0.030-0.035 mm 
long. Eggs are adhesive and clump together after fer- 
tilization, often becoming distorted and polyhedral in 
shape (Breder 1924). 

See also section 3.21. 

3.2 Preadult phase 

3.21 Embryonic phase 

Breder (1924) described the embryonic stages in eggs 
collected from ponds in the Woods Hole region during 
February when water temperature ranged from 1° to 2°C 
(Fig. 4). 

1) Blastodisc — Large and pale amber, yolk colorless 
with a finely tuberculate surface. 

2) First cleavage (temperature 21°C) 2V% h after fer- 
tilization. 

3) 24 h after fertilization blastoderm has many cells. 

4) 3rd day — Differentiation begins. 

5) 6th day — Premature segmentation and cephaliza- 
tion begins. In many eggs a small sphere similar to the oil 
globules in pelagic eggs was observed (I believe this is 
Kuppfers vessicle); a few had several. Beyond this stage 
they disappeared. Embryo is pale amber and oil globule 
colorless. 

6) 9 days — Embryo well differentiated, chrome yel- 
low chromatophores are scattered over the body. 






? igure 4. — Developmental stages of winter flounder. A. Unfertilized 
;gg. B. Egg with blastoderm of two cells. C. Egg with blastoderm 
>f four cells. D. Egg with blastoderm of eight cells. E. Egg with 
)lastoderm of many cells. F. Embryo in early stage of differentia- 
ion. G. Embryo further differentiated. Note small sphere similar 
o an oil globule. H. Embryo in an advanced stage of differentiation. 
. Egg about to hatch. (From Breder 1924.) 



7) 15 days — Chromatophores have the same ap- 
pearance but a concentration of them as a vertical band 
appeared in caudal region. The heart can be seen beat- 
ing and the cephalic region looks finely tuberculate. 
After 15 days, hatching began. After hatching, eyes were 
sometimes unpigmented and sometimes had chrome yel- 
low pigment. Pigment developed in all larvae within a 
few days. Later the pupils became tinged with green. 

8) 19 days after hatch — Pupil black and iris with 
metallic green iridescence. Eyes directed forward and 
down. Mouth is large and functional; yolk absorbed, 
animal symmetrical. Pigment is darker, almost orange. 

The temperature at which these eggs were incubated 
is not clear. The only temperature given (21°C) is lethal 
to winter flounder eggs. According to my experience, this 
timetable of events best corresponds to temperatures of 
6°-8°C. 

Sullivan (1915) observed hatching of eggs which had 
been stripped and fertilized in the laboratory. For a day 
or more before hatching, fish could move within the cap- 
sule. Movement occurred by a series of contractions from 
the posterior part which tended to push the fish forward 
and eventually ruptured the egg capsule at right angles 
to the long axis of the fish's body. The fish usually freed 
itself from the capsule within 10 min. Scott (1929) inves- 
tigated effects of salinity and temperature on hatching of 



eggs. At 4°-5°C, 70% hatched at a maximum average 
time of 26 days as compared with 21 days at 0°C, and 18 
days at 12°-17°C. At varying salinities (29.40 ± 2.2°/ 00 
control) the highest percent hatching occurred at 7/8 and 
1/8 parts salinity. The average percent hatching was 
lower for eggs in dilute seawater than control, and lower 
than the normal average. Percent hatch did not decrease 
linearly with decreasing salinity. He concluded that 
salinity has little effect on hatching but temperature is 
important. Rogers (1976) incubated winter flounder eggs 
under various conditions of temperature and salinity and 
found highest viable hatches occured at 3°C over a salini- 
ty range of 15-30°/ oo . She constructed a diagram depict- 
ing the qualitative effects of temperature and salinity on 
development and hatching of winter flounder embryos 
(Fig. 5) Salinity appeared to influence time of embryo 
mortality. At 35-45°/ 00 at all temperatures mortality 
usually occurred at gastrulation and abnormal develop- 
ment of the embryo was observed. At 5-10°/ O o embryos 
appeared to develop normally but died just prior to 
hatching; a fact which might be due to inability of the 
larvae to free themselves from their chorions. Analysis of 
variance showed salinity to be statistically more signifi- 
cant than temperature or the interaction of temperature 
and salinity. Oxygen effects were not considered. 

Williams (1975) studied the survival and duration of 
development of winter flounder eggs at several constant 
temperatures from — 1.8°C to 18°C with emphasis on 
development in the lower temperature range. Mean 
viable hatch was 33% for the lowest temperature tested 
(-1.8°C) and over 50% for 0°-10°C. Above 10°C sur- 
vival was lower and many embryos were abnormal with 
narrow fin folds, short tails, or crooked vertebral 
columns. Upper lethal limit was 15°C. Williams thought 
that the immediate cause of embryonic death at high 
temperatures was microbial infection as mortality was 
often synchronous within a dish, and dishes with more 
than 100 eggs had higher mortality. Oxygen depletion 
might also have had an effect. The median duration of 
days to hatching as related to temperature was de- 
scribed by the regression equation fitted to points from 
0° to 10°C (minimum mortality range) is \nx = 3.636 - 
0.158 t where x = number of days from fertilization to 
hatching, and t = temperature, Q 10 = 4.8. Low temper- 
ature adaptation in the embryo did not depend on large 
additions of antifreeze to the ova prior to spawning as 
suggested by the freezing points of mature ovaries 
(-0.86°-0.98°C). 

3.22 Larval phase 

Sullivan (1915) described the larva from hatching to 
the end of the second month and divided larval history 
into four stages which he chose in order to show all diag- 
nostic characteristics for identification (Fig. 6). 

Stage 1.— Hatching (Fig. 6a) length 3.5 mm, depth 
0.525 mm. A group of dark pigment spots on the pos- 
terior half of the body was the most important character 
for identification. Another pigment patch lay over the 







( "\ 






IX! 






U> 






O 


12 




U. 

O 

z 


10 




_] 
3 

z 


7 




5 

CL 
O 

_l 
UJ 

> 

UJ 


5 




o 

O 

2 


3 


• 


V ) 
MA.IORI 




MAJORITY OF HATCHED 
LARVAE NORMAL ■ 75.07o 



COLLAPSING EGGS 



5 



7.5 10 15 20 25 30 35 37.5 

SALINITY ( % ) 



40 



45 



Figure 5. — Effect of salinity and temperature on hatching of winter flounder eggs (from 

Rogers 1976). 







rectum posterior to the yolk. Notochord present as 
straight tube. Dorsal, anal, and caudal fins represented 
by unbroken finfold. Yolk absorption was gradual and 
varied with temperature. At 4°C, 12-14 days, at higher 
temperatures, 8 or 9 days. 

Stage 2 — Yolk absorption (Fig. 6b) 12 days (approxi- 
mately) length 5 mm. 

Between stage 2 and 3 several critical changes take 
place: 1) migration of eyes, 2) development of fin rays, 
and 3) differentiation of caudal fin accompanied by up- 
ward bending of notochord. 

Stage 3 — Metamorphosing larva (Fig. 6c) 5-7 wk old, 
5.8 mm long. After sixth week pigment on left side tend- 
ed to diminish in intensity. 

Stage 4 — Postlarva (Fig. 6d) about 8 wk old, 6.5 mm 
long, average depth 2.75 mm. 

In later stages there was loss of pigment on the left 
side and increase on the right. In 8 mm long fish the right 
side was devoid of pigment except for about 20 spots 
scattered near the snout. These were gone by the time 
the fish were 20 mm long. 

The medusae Sarsia tubulosa prey upon larvae (Pearcy 
1962a). Their distribution and time of relative abun- 
dance coincided with winter flounder larvae. Pearcy 
postulated a differential predation rate, assuming that 
small larvae have less ability to escape the medusa, 
which helps explain high mortality rates for small larvae. 
A density dependent numerical response seemed im- 
probable in spite of the fact that the numbers of Sarsia 

Figure 6. — Larval development in winter flounder. A. Pseudo- 
pleuronectes americanus at hatching (3.5 x 0.523 mm). B. P. 
americanus at 12 days (3.0 X 0.724 mm). C. P. americanus at 6 
weeks (3.8 X 1.33 mm). D. P. americanus at 8 weeks (6.5 X 2.75 
mm). (From Sullivan 1915.) 



8 



rose and fell with that of the flounder population because 
the medusae do not bud. He also felt a functional 
response was improbable because medusae have limited 
sensory and locomotory abilities. 

Sullivan (1915) described behavior of newly emerged 
larvae. The larvae exhibit intermittent swimming alter- 
nating with resting on the bottom. If fish were kept in 
continuous motion for 30 min, they showed no sign of 
fatigue; therefore, intermittent swimming appeared to be 
a behavioral characteristic of the newly hatched larvae. 

In fish under 10 days old, no preference was shown as 
to which side they rested on; after 10-12 days they 
favored the left side. Fish 2 wk old rested on the left side 
75% of the time. 

Food — See section 3.42. 

3.23 Adolescent phase 

Young-of-the-year remained in waters along shores of 
bays and estuaries where they were spawned (Perlmut- 
ter 1947). Poole (1966b) collected young-of-the-year 
flounder in Shinnecock and Peconic Bays, Long Island. 
He found that saltwater coves were preferred habitats of 
this age group in both bays. 

Several important commercial and sport fishes prey 
upon winter flounder juveniles. A list of predators is 
presented in Table 4. There are no real competitors of 

Table 4.— Predators of juvenile winter flounder. 



Table 5. — Dates of field collections of winter flounder eggs, larvae, 
and juveniles (from north to south). 



Predator 



Citation 



Summer flounder, Paralichthys 

den tat us 
Striped bass, Morone saxatilis 
Bluefish, Pomatomus saltatrix 
Toadfish, Opsanus tau 
Cormorant, Phalocrocorax auritus 

auritus 
Harbor seals, Phoca vitulina 

and Phoca groenlandica 



Pearcy (1962a) 
Derickson and Price (1973) 
Derickson and Price (1973) 
Pearcy (1962a) 

Pearcy (1962a) 

Fisher and MacKenzie (1955 1 



'Fisher, H. D., and B. A. MacKenzie. 1955. Food habits of seals in 
the Maritimes. Fish. Res. Board Can. Prog. Rep. (Atl.) 61:5-9. 

juvenile winter flounder reported (see The Population in 
the Community and the Ecosystem). A list of collec- 
tions of eggs, larvae, and juveniles with data, collectors, 
and geographical area is presented in Table 5. 
See also sections 3.4, 3.5, 3.53. 

3.3 Adult phase 

3.31 Longevity 

Saila et al. (1965) prepared age-length tables from fish 
caught in Charlestown Pond and Narragansett Bay, R.I. 
The oldest fish were estimated age XII. The average total 
length of these age XII fish was calculated as 379 mm for 
males and 441 mm for females. Calculations were made 
from otoliths and Walford plots for fish older than 3 yr. 
The largest recorded winter flounder (Bigelow and 
Schroeder 1953) was 570 mm TL and was probably con- 
siderably older than 12 yr. 



Field collections 



Eggs 



Larvae 



Juveniles 



Scott (1929); St. Andrews 


20 May- 






N. Brunswick Mud Flats 


6 June 






Haedrich and Haedrich 








June-Nov. 


(1974); Mystic River, 










Mass. 










Fairbanks et al. (1971); 


Feb. 


-May 


Mar. -June 




Cape Cod Canal, Mass. 










Breder (1924); Woods Hole 


Feb. 








Region Ponds, Mass. 










Herman (1963); Narragan- 






Feb. -June 




sett Bay, R.I. 






(3.24-7.20 mm) 




Marine Research Inc. 


Jan. 


-May 


Feb. -July 




(1974)' 










Pearcy (1962a); Upper 


Feb. 


(?) 


Mar. -June 


July-Feb. 


Mystic estuary, Conn. 


0.75-0.96 


(2.5-7.6 mm) 


(6-40 mm) 


Wheatland (1956); Long 






Mar. -June 




Island Sound 






(2.80-8.5 mm) 




Richards (1963); Long 








Year-round 


Island Sound 










Poole (1966b); Shinnecock 








June-Oct. 


and Peconic Bay, Long 










Island 










de Sylva et al. (1962) 2 ; 








Mar. -Nov. 


Delaware River estuary 










Richards and Castagna 








May-June 


(1970); Eastern Shore 








(27-80 mm) 


Virginia midway in 










channel and tidal creeks 











'Marine Research Inc. 1974. 19th Rome Point Investigations, 
Narragansett Bay Ichthyoplankton Survey Final Report to the Narragan- 
sett Electric Company. 

-de Sylva et al. 1962. Fishes and ecological conditions in the shore 
zone of the Delaware River estuary with notes on other species collected 
in deeper waters. Univ. Del. Mar. Lab., Inf. Ser. Publ. No. 5, 164 p. 

3.32 Hardiness 

Winter flounder are very hardy. They are commonly 
found in waters between 4 and 30% o salinity at 0°-25°C 
(Pearcy 1962a). 

Sometimes fish kills occur under extreme conditions. 
Nichols (1918) reported a large kill in St. Moriches Bay, 
Long Island, when the temperature rose to about 30°C. 
Bigelow and Schroeder (1953) mentioned that fish may 
be killed by anchor ice in winter if they are trapped in 
shallow water by a sudden freeze. 

3.33 Competitors — See section 4.6 

3.34 Predators 

Dickie and McCracken (1955) listed monkfish 
(Lophius piscatorius), dogfish (Squalus acanthias), and 
sea raven (Hemitripterus americanus) as predators of 
winter flounder in Canadian waters. Tyler 6 listed sea 
raven and two species of birds — blue heron and os- 
prey — but did not say whether these prey on juveniles or 
adults. 



'Tyler, A. V. 1971. Monthly changes in stomach contents of demer- 
sal fishes in Passamaquoddy Bay, N.B. Fish. Res. Board Can., Tech. 
Rep. 288, 114 p. 



: J6 Parasites, diseases, injuries, and abnormali- 
ties 

Parasites — The principal work on parasites of winter 
flounder was done by Linton (1901, 1914, 1921, 1924, 
1934. 1941). Heller, 6 and Ronald (1957, 1958a, 
1958b, 1959. 1960. 1963) (Table 6). 



Diseases — Levin et al. (1972) reported methods for 
isolating and identifying the bacteria Vibrio 
anguillarium, how to identify vibriolike organisms as 
either V. anguillarium or V. variable, and how to diag- 



h Heller, A. F. 1949. Parasites of cod and other marine fish from the 
Baie de Chaleur region. Fish. Res. Board Can., Tech. Rep. 261, 23 p. 



Table 6. — Parasites of winter flounder. 



Parasite 



Site of Infestation 



Geographic Region 



Reference 



Protozoa 

Glugea microspora stephani 

Trichodinid 
Platyhelminthes 

Trematoda 

Derogenes carious 

Distomum appendieulatum 

D. grandiparum 

D. globeparum (?) 

D. citellosum 

D. aerolatum 

Stephanostomum baccatum 
Stephanostomum hystria 
Steringophorous furciger 
Podocotyle atomon 
Cnptocotyle lingua 
Hemiuris sp. 

Cestoda 

Bothrimonus intermedius 

Diplocotyle olrikii 

Bothriocephalus clavipes 

Bothriocephalus scorpii 

Tetrarhynchus bisculcatus 

Tetrarhynchus sp. 
Aschelminthes 

Nematoda 

Ascaris 

Ascaris acutus 

Contracaecum aduncum 

C. gadi 

Grillotia erinaceus 

Lacistorhynchus tenuis 

Scolex pleuronectis 

Terranova sp. 

Stomachinae larvae 

Acanthocephala 

Echinorhynchus laurentianus 

E. acus 
E. gadi 

E. sacealis 

Corynosoma sp. 

Cucullanus heterochrous 
Branchiura 

Argulus megalops 

A. funduli 

A. m. spinosus 

A. laticaudata 

Acanthochondria cornuta 

A. depressus 
Copepoda 

Caligus rapax 

I.epprjphtheirus hidpkni 
Isopoda 

Gnathia elongata 



intestine wal 
gills 



stomach and intestine 
stomach and intestine 
stomach and intestine 
stomach and intestine 
stomach and intestine 
stomach and intestine 
superficial musculature 
dermal surfaces 
stomach and intestine 
intestine 
skin 
intestine 

intestine 
intestine 
intestine 

stomach wall 
peritoneum 

stomach 
muscle intestine 
muscle intestine 
intestine, body cavity 
intestine, body walls 



axial musculature, body cavity exterior 
or pyloric caecae and intestine 

musculature, body cavity, surface 
external organs 

digestive tract 
intestine 



intestine 

skin body surface 

skin body surface 
not given 
not given 
not given 

not given 
not given 

not given 



Woods Hole Region 
Martha's Vineyard 
Bay of Fundy 

Canada 

Woods Hole 

Woods Hole 

Woods Hole 

Woods Hole 

Woods Hole 

Canada, Passamaquoddy Bay 

Canada 

Canada 

Long Island Sound 

Canada 



Passamaquoddy Bay 
Passamaquoddy Bay 

Woods Hole 
Woods Hole 



Woods Hole 
Long Island 
Canada 
Canada 
Woods Hole 
Woods Hole 
Woods Hole 
Canada 



Stunkard and Lux (1965) 

Lom and Laird (1969) 

Ronald (1960) 
Linton (1901) 
Linton (1901) 
Linton (1901) 
Linton (1901) 
Linton (1901) 
Wolfgang (1954a) 
Stafford (1904) 
Ronald (1960) 
Cooper (1915) 
Smith (1935) 
Ronald (1960) 

Cooper (1918) 
Ronald (1958b) 
Ronald (1958b) 
Leidy(1855) 
Linton (1901) 
Linton (1901) 



Linton (1901) 
Leidy(1904) 
Heller (1949)' 
Ronald (1963) 
Linton (1924) 
Linton (1924) 
Linton (1924) 
Ronald (1963) 

Ronald (1963) 



Gulf of St. Lawrence 


Ronald (1957) 


Gulf of St. Lawrence 


Linton (1901) 




Linton (1933) 




Stiles and Hassall (1894) 


Magdalin Island 


Montreuil(1955) 


Canada 


Ronald (1963) 


Canada 


Ronald (1958a) 


Canada 


Bere(1930) 


Canada 


Ronald (1958a) 




Rathbun(1885) 


Bay of Fundy 


Stock (1915) 


Woods Hole 


Wilson (1932) 


Woods Hole 


Wilson (1905) 


Woods Hole 


Ho (1962) 


Bay of Fundy 


Wallace (1919) 



Heller. A. F. 
23 p. 



1949. Parasites of cod and other marine fish from the Baie de Chaleur region. Fish. Res. Board Can. Tech. Rep. No. 261, 



10 



nose the disease vibriosis. Vibrio anguillarium was 
isolated from skin and muscle lesions of winter flounder 
from Narragansett Bay. External manifestations of dis- 
ease include dermal lesions usually accompanied by fin 
necrosis. These lesions included petichiae and ecchy- 
moses in their acute stage and frank ulceration in the 
more chronic manifestation. Necrosis of the fin began at 
the periphery and extended inwards including long rays. 
Microscopic lesions of the kidney also occurred. 
Characteristics of diagnostic importance to pathologists 
are dermal hemorrhage and ulceration, focal skeletal 
muscle necrosis, renal erythroblastic hyperplasia, and 
anemia. Organisms isolated from the lesions identified as 
aeromonads, plesiomonods, or vibrios by being Gram- 
negative, asporogenous, polar flagellate, oxidase-positive 
fermentative, anaerogenic rods. 

Stunkard and Lux (1965) described a common micro- 
sporidian infection of the digestive tract of winter floun- 
der. The disease was first reported by Linton (1901) in 
the Woods Hole region, and it may be identical with in- 
fections of European flounders caused by the parasite 
Nosema stephani (later transferred to the genus Glugea 
and referred to as G. stephani or G. hertwigi). Stunkard 
and Lux (1965) inspected over 1,000 winter flounder of 
different sizes taken from various locations in New Eng- 
land. Their results showed 3.5% of 751 flounder (length 
120-270 mm TL) collected from Woods Hole Harbor; 
16.7% of 126 flounder (length 210-500 mm TL) from Nan- 
tucket Shoals; 15.8% of 19 flounder (length 310-450 mm 
TL) from off Plymouth, Mass.; and 54.1% of small floun- 
der (length 41-110 mm TL) from Lake Tashmoo, Marthas 
Vineyard, were infected with this parasite. There was no 
effect of seasonal or sexual differences. The Georges 
Bank population (38 fish, 110-650 mm TL), isolated from 
the rest, showed no incidence of the disease. Infections 
were classified as heavy (infiltration massive, gut largely 
destroyed) or light (1-20 cysts in wall of intestine). Al- 
most all heavily infected fish were less than 80 mm long. 
Evidence indicates fish heavily infected during their first 
year of life do not survive. 

The site of infection was primarily the wall of the in- 
testine and pyloric areas. Other structures adjacent to or 
in contact with the gut such as the bile duct, liver, 
mesenterial lymph nodes, and ovary, may be involved. In 
light infections cysts were usually found on the external 
wall of the intestine; in heavy ones, the gut wall was 
largely supplanted by layers of cysts and the intestines 
had a chalk-white pebbled appearance with a rigid 
thickened wall. The cysts were spherical to oval and 
measures 0.6-1.0 mm in diameter. The walls were com- 
posed of laminated layers that had the structural appear- 
ance and staining reactions of host connective tissue. 
There were also masses or strands of spores scattered 
throughout the tissue of the gut wall often associated 
with distinct blood vessels. Below the connective capsule 
of the cyst was often a narrow layer of material contain- 
ing large oval, apparently pycnotic nucleii with frag- 
mented chromatin and distinct nucleoli. This suggested 
that cysts formed around a number of host cells whose 
cytoplasm had been consumed. Spores were oval to 



ovate measuring 4 X 2.5 . The basal wider end of the 
spore contained a large vesicle, the apical end a smaller 
one, the central part a band of chromatic material, and 
a single strand extending to the apical end. 

Attempts to obtain experimental infection of fishes by 
feeding them microsporidian cysts from gut walls of in- 
fected flounder embedded in pieces of clam were unsuc- 
cessful, so the life cycle is not known. Since fish become 
infected when only 50 mm in length when their diet con- 
sists of small invertebrates, a second intermediate host 
may be required in the parasite life cycle although no in- 
termediate host animals have yet been found for micro- 
sporidia. 

Another parasitic infection with metacercarial cyst of 
the trematode Stephanostomum baccatum has been 
studied by Wolfgang (1954a, b) in winter flounder from 
eastern Canada. He found that infection in inshore 
waters was greater near open water than on shoal 
grounds. Larger fish had heavier infections than small 
ones, the growth of the flounder was not impeded by 
heavy cyst infections, and no marked seasonal variation 
of the infection could be demonstrated. 

The life cycle of the parasite in eastern Canadian 
waters is as follows: mollusks, Buccinum undatum and 
Neptunea decemcostatum, primary intermediate hosts; 
six common pleuronectid species second intermediate 
hosts; Hemitripterus americanus and Hippoglossus com- 
mon definitive hosts. Experimental proof of relation- 
ships between S. baccatum adults in sea raven and the 
larvae in winter flounder was established. Experimental 
infections of winter flounder with S. baccatum cercariae 
dissected from infected snails was observed. The cer- 
cariae do not swim towards the flounder but wait until 
touched by the fish. They burrowed into a suitable site 
and encysted in muscle or connective tissue by secreting 
a hyaline cyst about themselves. 

Young-of-the-year flounders, seined in midsummer 
onshore and taken in surface tows near shore, were never 
infected. The smallest metamorphosed flounders (35 mm 
TL) were infected lightly at the end of August. Small fish 
(below 90 mm) taken during summer (age 0) date the 
earliest time at which a flounder may be infected. 

Because of the close nature of the association between 
hosts and the problems involved in eliminating any one 
of the hosts, control of the parasite is impractical. It does 
not slow the growth rate of flounder and does not harm 
man nor develop in him. 

Fish (1934) described a fungus disease of epidemic 
proportions in sea herring, Clupea harengus, and winter 
flounder throughout the Gulf of Maine. The causative 
agent was a species of fungus belonging to the genus 
Ichthyosporidium and the species was tentatively iden- 
tified as hoferi, first described in winter flounder by Ellis 
(1928). The organism is believed to be a normal parasite 
in herring, reaching epidemic proportions only when cer- 
tain unknown factors are operative. The epidemic, once 
initiated, increases in severity, reaches a peak, and sub- 
sides. Flounder may be an accidental host since infected 
flounder have been taken only in regions where large 
numbers of dead sea herring were available as food. Fish 



11 



I L934) believed the flounder acquired the infection by 
consumption of infected herring which acquire it by 
ingesting parasites liberated from fish in the same school; 
however, since winter flounder rarely eat fish and their 
mouths are too small to eat herring, this does not seem 
probable. It is more likely that scavenger organisms fed 
on the herring, after which flounder ate the scavengers, 
thus acquiring the parasites. The infection is believed to 
be established by way of the alimentary canal and spread 
throughout the host by the blood stream or lymphatics. 

There is no reason to believe this parasite capable o e 
infecting warm blooded animals. 

The complete life cycle of the organism is not known. 
The most common stage encountered in host tissues is 
the resting stage which appears as a spherical cell, com- 
posed of a heavy double wall enclosing the protoplast. 
Organisms ranged from 5 to 164.5 fj within which there 
appeared to be no difference in internal structure other 
than density of the cytoplasm and number of nucleii. 
From this stage (regardless of cell size), hyphal division 
may take place. The mycelium bores through surround- 
ing tissue and breaks up into a large number of daughter 
cells. The hyphal wall disintegrates and spores are 
liberated. 

Pathology — In flounder, internal lesions may occur in 
heart, liver, spleen, kidneys, intestinal tract, brain, and 
spinal chord. Macroscopic lesions appeared as white 
spherical firm masses or cysts. The viscera may be rid- 
dled with these from microscopic to bean-size cysts. In 
advanced lesions, firm cysts tended to disintegrate more 
pronouncedly in herring than in flounder. Micro- 
scopically, lesions were similar in all organs and hosts. 
An infiltration of mononuclear cells followed ingress of a 
single parasite. Tissue surrounding the parasite is replac- 
ed by an epithelioid type of tissue apparently derived 
from wandering monocytes. This was replaced even- 
tually by connective tissue believed to represent the 
host's chief defense mechanism to prevent spread of the 
parasite. As infection progresses, the parasites increased 
until the area once contained in the "tubercle" becomes 
a heterogeneous mass of parasites, infiltrating monocytes 
and epithelioid tissue, connective tissue, and necrotic 
debris. 

Mahoney et al. (1973) described a fin rot disease which 
reached epizootic proportions in 1967 in the New York 
Bight and has continued to occur annually. Winter floun- 
der were among the 22 principal species affected. The ex- 
ternal signs of disease were fin necrosis often accom- 
panied by skin hemorrhages, skin ulcers, and blindness. 
Bacteria of three genera, Aeromonas, Vibrio, and 
Pseudomonas were implicated as infective agents of dis- 
ease. Water pollution was thought to have a role in the 
disease as unsanitary conditions in aquaria are asso- 
ciated with similar epizootics, and the primary epizootic 
center is lower New York Harbor which is grossly 
polluted with sewage and industrial wastes. 

Infective bacteria are believed to be water borne. 
Disease incidence tended to parallel the seasonal regime 



of temperature increasing from low levels in spring, 
reaching highest levels from July to September, and de- 
creasing again in fall. 

Ziskowski and Murchelano (1975) reported the in- 
cidence of fin erosion in winter flounder from four areas: 
1) New York Bight Apex, heavily polluted by dumping of 
sewage, sludge, and acid wastes; 2) ocean outside of the 
Bight, unpolluted; 3) Sandy Hook-Raritan Bays, domes- 
tic and industrial pollution impacted area; 4) Great Bay, 
N.J., relatively unpolluted. Results showed there was a 
significantly greater incidence of disease in the Bight 
Apex (371 or 14.1 r r of the fish affected) than outside the 
apex (36 or 1.9%). 

Smith (1935) described a hyperplastic epidermal dis- 
ease in winter flounder which resembles a papillomatous 
disease called "carp pox" that affects cyprinids in Euro- 
pean waters. The disease occurred in two specimens of 
winter flounder from Long Island Sound and was charac- 
terized by grayish white, irregular slightly elevated 
patches on the pigmented surface of the body. The his- 
tological characteristics of disease are a hyperplasia of 
epithelial cells without keratinization. The chorium is 
slightly edematous and thickened but without inflam- 
matory cells. In many places irregular, elongated, fibrous 
bands extend from the chorium into the epithelium. 
There is a rich capillary blood supply in diseased areas 
and in some areas large nucous cells and cells with 
eosinophilic granules appear. Both of these fish were also 
infested with the parasite Cryptocotyle lingua, a 
trematode occurring as larvae encysted in the fishes' 
skin. Transplantation of diseased tissue into four nor- 
mal flounders was not successful. The disease is probably 
benign as invasion of underlying structures and 
metastases were not present. There was no direct 
evidence that encysted larvae acted as a causative agent. 

Abnormalities — An abnormal variety of black bellied 
fish was reported by the Rhode Island Fish Commission 
for 1900 (Sherwood and Edwards 1901). Thirty-three per- 
cent of the flounder were ambicolored in 1898, 4% in 
1900, and none by 1901. No reasons were given for this oc- 
currence. Abnormalities reported for winter flounder are 
presented in Table 7. 

3.4 Nutrition and growth 

3.41 Feeding 

Winter flounder are sight feeders. The importance of 
vision in juvenile feeding was studied by Pearcy (1962a). 
Fish fed in a dark room did not eat until zooplankton 
died and sank to the bottom. Field observations con- 
firmed that feeding occurs during the day. Stomachs 
emptied faster than indicated in laboratory experi- 
ments. 

Olla et al. (1969) also confirmed that winter flounder 
are sight feeders and active at day. At night they lie flat, 
heads resting on the bottom and eye turrets retracted, in 
a quiescent state. They assumed this state within 30 min 
after evening civil twilight and remained so until the 
beginning of morning civil sunrise. Relative volume of 



12 



Table 7. — Abnormalities in winter flounder. 



Table 8. — Food of winter flounder postlarvae to age I (Pearcy 1962a). 



Abnormality 



Remarks 



Source 



Albinism (partial) 



Reversal 



Tailless 



Ambicoloration 
(incomplete) 
(complete) 



Unpigmented spots 
on eyed side 



Dorsal wound 
Dorsal wound 
Abnormal squamation, 

loss of dorsal 

pterygiophores 



No hypural plate, only 
26 vertebrae, probably 
result of accident 

No other abnormalities 



Left eye just over dorsal 
crest, hooked dorsal 
fin, abnormal branching 
of lateral line 

4-13^ of 1959 year class 
from Georges Bank 
affected 



Breder(1938) 
Eisler(1963) 
Dawson (1962, 1967) 



Gudger(1935) 
Gudger(1945) 
Medcof(1946) 
Bishop (1946) 
MacPhee(1974)' 
Pearcy (1962c) 



Gudger(1934) 

Gudger(1934) 
Gudger(1934), 
Eisler(1963) 



Lux (1973) 



'Unpublished data. 

gut contents showed day feeding. Samples taken 
between 0800 and 1300 contained food, samples at 0415 
were empty indicating fish had not fed. Probable 
clearance time for the stomach is 7 to 11 h. 

Tyler (see footnote 5) reported on yearly feeding cycles 
of winter flounder in Passamaquoddy Bay. He found 
they had progressively more food in their stomachs after 
the first spring feeding in April when water temperature 
was between 3° and 4°C. The peak in quantity came at 
the end of May. Increased bottom temperatures during 
summer were accompanied by a decrease in stomach 
content volume. The lowest quantity was reached in 
November when some winter flounder ceased feeding. 
Water temperature at the onset of winter fasting had 
dropped to 5°-6°C from a peak of 10.1°C in September. 

Frame (1972) studied feeding habits and food of age I 
flounder in the Weweantic estuary, Mass. His findings 
were similar to Olla et al. (1969). He also found that the 
quantity of food consumed daily was variable. On cloudy 
days in summer, feeding may begin well after sunrise, so 
fish consume less. In winter, age I fish consumed less 
food, and their stomachs remained empty longer. 

3.42 Food 

Sullivan (1915) stated that until yolk absorption, lar- 
vae did not eat. Larvae up to 3 wk ate only diatoms, a lit- 
tle later they ate small crustaceans. 

Pearcy (1962a) gave a detailed account of larval and 
young juvenile feeding habits. He also cited S. W. 
Richards' unpublished data that dinoflagellates were the 
most frequent food eaten by larvae from Long Island 
Sound. Young flounder from the Mystic River estuary, 
Conn., fed largely on invertebrates (Table 8). Empty 
stomachs were found in 72% postlarvae, 25% metamor- 



Postlarvae 


Metamorphos 


ng 


Juveniles 


Age I 


3.4 mm 










Copepods 


Oopepods 




( 'i ipepods 


Polvchaetes 




(Harpacticoid) 






Phytoplankton 


Nauplii 




Eun'temura 


Neanthes 


(pennate and 






Diaptnmus 


Cirratulus 


filamentous) 






Paracalanus 






Polychaetes 




Am phi pods 


Amphipods 
Harmothoe 


Protozoanlike 


Nemerteans 




Ampelisca 




organism 






Cnrophium 
Polvchaetes 




Invertebrate eggs 


Ostracods 




Maldanids 
Clymnella 
Neanthes 
Cirratulus 


Ampelisca 
Corophium 



4-5 mm 
Nauplii 
6-8 mm 
Polychaetes 
Larval and small 



phosing larvae, and 0.6% juveniles. Juveniles are eury- 
phagus. Seventy-seven organisms from seven phyla were 
identified. There was a high degree of selectivity at cer- 
tain times of the year. Comparisons of food of flounder 
inhabiting shores vs. deep water showed that the major 
groups of animals were the same but genera differed. 

The time required for juveniles fed in the laboratory to 
evacuate stomachs was determined by preserving in- 
dividuals at different times (Table 9). The rate of feed- 
ing of juveniles 22-55 mm during four intervals (water 
temperature 20°-22°C) was approximately 2.0-3.4% body 
weight/day. The results are questionable because of 
rapid growth of individuals during the summer in the 
wild, and daily feeding rate shown for other juveniles 
(Pearcv 1962a). 



Table 9. — Stomach evacuation time of juvenile 
winter flounder (Pearcy 1962a). 


Length of 
fish (mm) 


Water temp. 

CO 


Number of hours 
Half empty Empty 


9-14 
10-15 
29-50 


13-15 

14-16 

20.5-22 


9 19 
7-10 13.5-18 
6-8 11-14 



Tyler 7 described the digestive tract of winter flounder 
as follows: narrow buccal cavity and pharynx; incisor- 
like teeth on premaxillary and dentary; stomach without 
fundus; four large pyloric caecae distal to pyloric valve; 
intestines coiled in coelome (viewed from blind side), two 
complete clockwise coils followed by one complete coun- 
terclockwise, situated between first two coils; intestinal- 
rectal valve present. Relative length of parts of the 
alimentary tract (expressed as percent of total tract 



Tyler, A. V. 1973. Alimentary tract morphology of selected North 
Atlantic fishes in relation to food habits. Fish. Res. Board Can., Tech. 
Rep. 361, 23 p. 



13 



length) are: 6.3. lips to first gill cleft; 4.9, first gill cleft to 
stomach: 10.1, stomach length: 69.8, pyloric valve to in- 
testinal-rectal valve; 8.9. rectum length. 

Winter flounder cease to feed in winter, fasting from 
November to April (Tyler 1972b). Olla et al. (1969) ob- 
served feeding behavior of winter flounder in their 
natural habitat by means of scuba. While actively feed- 
ing, the flounder lies with head raised off the bottom and 
12-17 rays of the dorsal fin braced vertically into the sub- 
strate. The left pelvic fin and several anal fin rays were 
used to support the head. In water currents of 20 cm/s the 
fish maintained its position by tucking the distal edges of 
the dorsal and anal fins into the bottom substrate. The 
eye turrets were extended and the eyes moved indepen- 
dently of one another. After sighting prey, the fish 
remained stationary pointed towards the prey, then 
lunged forward and downward covering about 10-15 cm 
to seize the prey. Mud, sand, and debris were expelled 
through the right branchial aperture. The fish then 
resumed the feeding position. If no food was sighted, the 
fish would swim to another location less than 1 m away 
and again resume feeding position. 

Adults — Throughout their range, winter flounder eat 
polychaete worms, amphipod and isopod crustaceans, 
pelecypods, and plant material. They are omnivorous 
and seem to be opportunistic, eating whatever is avail- 
able (Pearcy 1962a; Richards 1963; Mulkana 1966; 
MacPhee 1969; Frame 1972). 

Richards (1963) stated they ate a greater variety of 
food than any other demersal fish. Seasonal changes in 
the type of prey consumed were due partly to avail- 
ability of prey, and number and age of the predators. She 
also found that correlations between food diversity and 
total number of flounders were sometimes close, the 
highest numbers of flounders and number and varieties 
of amphipods, polychaetes, and molluscs occurring in 
spring and fall. 

Pearcy (1962a), Richards (1963), and Mulkana (1966) 
mentioned that with progressive increase in size, young 
winter flounder tend to prefer larger prey organisms. 

Frame (1972) compared species diversity in the 
stomach contents of age I winter flounder with contents 
of Petersen dredge hauls collected in the same area of the 
Weweantic estuary, Mass., from January to October. He 
used a modified percent overlap technique in an at- 
tempt to compare food utilization with prey diversity 
and availability. He found a low overlap value between 
dredge hauls and stomach contents in spring when the 
young flounder prefer planktonic copepods. By June the 
fish assumed a more benthic habit, and overlap values 
were higher. The value increased in July and October 
suggesting flounder adapt to a benthic existence by the 
midpoint of their first year. He proposed this dietary 
shift may be due to the animals' physiological require- 
ments rather than age alone. An example of this is that in 
spring, young flounder live at low salinities and tempera- 
tures which produce lower metabolic rates and conse- 
quently the fish uses less calories for metabolic mainten- 
ance; therefore, they survive on plankton. With increased 



temperatures and salinities later in the season, the meta- 
bolic rate increases requiring more calories. (See also 
section 3.44). 

Tyler (1972b) studied food resource division among 
northern marine fish predators in Passamaquoddy Bay. 
He showed that although over 100 prey species were in- 
cluded in stomachs of predators, each took only three or 
four principal species of prey which made up 70-99% of 
the mass of food for each predator. Winter flounder ate 
three principal species of polychaetes Nephtys, Lum- 
brinereis, and Praxillella. (See also section 4.6.) 

MacPhee (1969) showed that the most important 
category of food in the winter flounder's diet depends 
upon the type of bottom which the fish inhabits. The diet 
of flounder living on a predominantly rocky bottom is 
more variable than flounder living on a soft bottom. 
Frame (1972) agreed that winter flounder adapt their 
diet to environmental conditions. Fourteen phyla and 
260 species have been found in winter flounder stomachs 
by a series of investigators (Table 10). 

3.43 Growth rate 

Pearcy (1962a) gave comprehensive data on growth 
rates of age group flounder (Fig. 7). He pointed out 
there is a great deal of variation in average lengths within 
many months, which is partly due to difficulties in cal- 
culating a representative average length since prolonged 
spawning resulted in as much as 4 mo difference in age 
for a year class. Seasonal changes in growth were ap- 
parent. Growth is fast in spring and summer, slow in win- 
ter. Because metamorphosis of flounder was not com- 
pleted until June, the first 2 mo underestimated growth 
and were excluded from analysis. This decrease in stan- 
dard length often occurs during metamorphosis when 
caudal fin differentiation and body proportions change. 
Measurements of maximum length of otoliths of year 
class and maximum length of the opaque center com- 
pared with fish length at capture show that growth of the 



















• 


160- 






BEAM TRAWL 


YEAR -CLASS 

1958 1959 

• o 








i 


140- 






OTTER TRAWL 


■ D 






• / 


9 


120- 














A ■ 
7 




100- 










• 








80- 
60- 








■ 

x^ • ■ 

• • 










40- 


















20- 




















A 


M 


'j'j'a's'o 


'n'd'j'f'm'a 


M 


J 


j'a'b'o 


n'd'j 



MONTH 

Figure 7.— Growth curve of juvenile winter flounder (from Pearcy 
1962a). 



14 



Table 10.— Food organisms found in stomachs of winter flounder from different geographic areas. A. Long Island Sound (Richards 1963). B. Point 
Judith and Narrow River estuary, R.I. (Mulkana 1966). C. Mystic River, Conn. (Pearcy 1962a). D. Several— Cape Cod. Mass., to York, Maine 
(MacPhee 1969). E. Weweantic estuary, Mass. (Frame 1972). F. Conception Bay, Nova Scotia (Kennedy and Steele 1971). G. Bay of Fundy, Pas- 
samaquoddy Bay, N.B. (Wells et al. 1973). 



Organism 



Area 



Organism 



Area 



Chlorophyta 

Chaetomorplm linum 
Cladnphora serica 
Enteromorpha intestinalis 
Monostroma nxysperma 
Spongomorpha arcta 
I Iva lactuca 

Chrysophyta 
Diatoms 

Phaeophvta 

Ascophyllum nodosum 
Ectocarpus siliculosis 
Leathesia difformis 
P^'laiella littoralis 

Rhodophyta 

Acrosiphonia arcta 
Ahnfeltia plicata 
Asparagopsis hamifera 
Callithamnion byssoides 
Ceramium rubrum 
Chondrus crispus 
Corallina officinalis 
Dumontia incrassata 
Euthora cristata 
Polysiphonia lanosa 
Rhodymenia palmata 

Porifera 

Grantia sp. 

Coelenterata 

Diphasia fall ax 
Obelia enseralis 

Nemertinea 

Cephalothorax linearis 
Cerebratulus luridus 

Nematoda 

Annelida 
Oligochaeta 

Clitella arenarius (?) 
Enchytraeus albidus 
Polychaeta 

Ammotrypane acuta 
Ampharete acutifrons 
Amphicora fabricii 
Amphitrite johnstoni 
Antinoe sarsi 
Arabella tricolor 
Arenicola marina 
Aricidea fragilis 
Autolytus cornutus 
Capitella capitata 
Cirratulus cirratus 
Cistenides grandis 

C. gouldi 

Clymnella torquata 
Dodecaceria concharum 
Drilonereis elizabethae 

D. longa 
Eteone arctica 

E. longa 

E. trilineata 
Eudora truncata 
Eulalia uiridis 
Eumida sanguinea 
Eunoa nodosa 
Eupomatus dianthus 





Eusullis tubifex 


D 


Fabricia sabella 


G' 


Flabelligera affinis 


G' 


Glycera americana 


1) 


G. dibranchiata 


1) 


Goniada gracilis 


D 


Harmothoe extenuata 




H. imbricata 


A,D 


Lepidonotus squamatus 




L. variabilis 


D 


Lumbrinereis 


G' 


L. fragilis 


D 


L. tenuis 


G' 


Maldanopsis elongata 




Marphysa belli 


G' 


Megalona papillicornis 


h 


Neanthes caudata 


D 


N. succinea 


li 


N. uirens 


D 


Nephtys caeca 


1) 


N. incisa 


I) 


N. picta 


I) 


Nereis ciliata 


D 


N. furcata 


I) 


TV. me gal ops 


D 


N. pelagica 




N. tenuis 


A,D 


N. uirens 




Nicolea zostericola 


B,D,G 


Ninoe nigripes 


G 


Ophelia radiata 




Pectinaria gouldi 


B,D 


Peloscolex benedeni 


A 


Phyllodoce fragilis 


<; 


P. groenlandica 




P. maculata 




Poly cirrus exemus 


A,B,D 


Polydora ligni 


A,D 


Potamilla neglecta 




Praxillella gracilis 


G 


P. praetermissa 


A 


Prionospio malmgreni 


A 


Pygiospio elegans 


G 


Scalabregma inflatum 


F,G 


Scolopus armiger 


B-E.G 


Spirorbis borealis 


F 


Sthenelais gracilis 


D,G 


Stylaroides arenosa 


B,D,G 


Syllis gracilis 


B,D 


Terrebelloides stroemi 


D 


Tharyx acuta 


A,C 


Sipunculoidea 


A,G 


Phaslosoma procerum 


D 


Mollusca 


D 


Amphineura 


D 


Ischnochiton ruber 


A 


Lepidochiton marmorea 


F 


Gastropoda 


D,G 


Acmea testudinalis 


F 


Anoba aculeas 


G 


Bitteum alternatum 


D,F,G 


Buccinium undatus 


B,D 


Cerastoderma pinnulatum 


D 


Crepidula fornicata 


A,C,E 


Crucibulum striatum 



F 

[)' 

A 2 

A,E,G 

A 

A 

D 

A,C,D,G ' 

A 

D 

A,B,G 

A,G 3 ' 

E 

B 

I) 

A 

A.BJL 

A-E " 

A,B 6 

A 

A,B,G 26 

D 

A 

I) 

D 

A.D.F* 

D 

D,G,F ' ' 

D 3 

G 

F 

E,F 

G 1 

A,D 

I) 

IV 

A 

I) 

A,D 

A,G 

A.G 

B» 

A,B,G 

A 

A,D,F 

D,G 

A 

D 

A,F,G 2 

G 

A,G 

I) 



F,G 
D,F 

A,D,G 
D 
E 
D 

K 
I> 
E 



15 



Table 10.— Continued. 



Organism 



Area 



Organism 



Area 



Hydrobia mi nut a 

Lacuna pallidula 

Littorina littorea 

L. palliata 

L. saxitilis 

Lunatia heros 

Sfargarites grnenlandica 

M. helicinus 

\felampus bidentatus 

Mitrella lunata 

Sassarius trivitatta 

Xatica pusilla 

Xeptunea decemcostatum 

Puncturella noachina 

Retusa canaliculata 

Sella adamsi 

Skenea planorbis 

Thais lapiltos 

Turbonilla interrupta 
Pelecypoda 

Anomia aculeata 

A. simplex 

Bivalve siphons 

Cerastoderma pinnulatum 

Clinoeardium ciliatum 

Crenella faba 

Cyrtopleura costata 
. Ensis directis 

Gemma gemma 

Haminea solitaria 

Hiatella arctica 

Laevicardium mortoni 

Lyonsia hyalina 

Macoma baltica 

M. tenta 

Mercenaria mercenaria 

Mesodesma arctata 

Modiolus modiolus 

Mulinia lateralis 

Mya arenana 

Mytilus edulis 

Nucula proximo 

N. tenuis 

Nymphen grassipes 

Saxicava arctica 

Serripes groenlandicus 

Siliqua costata 

Solemya borealis 

S. velum 

Tellina agilis 

Yoldia sapotilla 

Y limatula 
Arthropoda 
Crustacea 
Amphipoda 

Aeginella longicornis 

Ampelisca spinipes 

A. macrocephala 

Amphithoe longimana 

A- rubricata 

Anonyx nugax 

Ratea catherinsis 

Byblis serrata 

Calliopius laeuiusculus 

Caprella geometrica 

C. linearis 

Carinogammarus mucronatus 

Casco biglowi 



G 4 


Corophium [volutator?) 


G 


C cylindricum 


D,G" 


C bonelli 


D 


Cymedusa filosa 


D 


Dexamine spinosa 


E,G 


Erichthonius brasiliensis 


D 


E difformis 


G 


Gammarus annulatus 


D 


G. lawrencianus 


E 


G. oceanicus 


A,D 


G. marinus 


A,E 


Grubia compta 


G 


Ischyrocerus anguipes 


G 


Jassa falcata 


E' 


J. marmorata 


A,E 


Lembos smithi 


D 


Leptochirus pinguis 


G 


Lysianopsis alba 


E 


Mclita dentata 




Mesometopa neglecta 


D 


Metopa pusilla 


1) 


Metopila carinata 


E J 


Microdeutopus gryllotalpa 


F 


Monnculodes edwardsi 


F 


Orchomenella minuta 


F 


Photis reinhardi 


E 


Phoxocephalus holbolli 


A,F 2 


Podocpropis nitida 


B,C 


Pontogeneia inermis 


C 


Stenothoe cypris 


F 


S. minuta 


F 2 


Sympleustes glaber 


A,C 


Typhosa pinguis 


D,E,G' 


Unicola irrorata 


E 


U. leucopis 


E 


Cirripedia 


D 


Ralanus balannides 


D 


Cladocera 


A,E 2 


Evadne nordmanni 


C,D,F,G" 


Podon leuckarti 


D,B" 


Copepoda 


B,D' 


Acartia sp. 


A,D,E 


Eurytemora sp. 


A 


Paracalanus sp. 


I) 


Pseudodiaptomus coronutus 


F 


Temora longicornis 


D 


Cumacea 


D 


Cyclaspis varians 


C,F 


Diastylis polita 


B,E' 


D. quadruspinosa 


1) 


Oxyrostylis smithi 


E 


Isopoda 




Chiridotea caeca 




Clathura polita cyathura 




Edotea triloba 


A-D 


E. montosa 


D 


Erichsonella attenuata 


AD' 


Idotea baltica 


D 


I metallica 


D,G' 


I phosphorea 


D 


I. viridis 


C 


■Jaera albifrons 


CD 


J. marina 


C,D S 


Leptochelia savignyi 


C 


Ostracoda 


A,D 


Cylindroleberis mariae 


B-D 


Pontocypris edwardsi 


G 


Pscudocytheretta edwardsi 



A,D,G !1 

C 

F' 

B,C 

F,G* 

A 

D 

B-D 

F,G' 

A,D,F,G" 

D 

D 

D,P 

D.G 

D J 

B-D« 

A,C,D,F,G' 

CD 

D.G 

F 

C 5 

F 

B,C 5 

A,F 

F* 

A 

A.C.D.G " 

A 2 

D,F 

A 

A 

F 

D 

A-D.G 

F 

A,C,F,G 

C 
C 

A,B 

C 5 

C 

A,C 

A,B,E,F 

AC 
D 
A 
A-C 

B,G 

A 

C 6 

A-CG 6 

D 

D 3 

D 

D 

B 

G 

D 

B-D" 

B,C» 
B,C 
C 



16 



Table 10.— Continued. 



Organism 



Area 



Organism 



Area 



Sarsiella americana 
Sarsiella zostericola 

Decapoda 

Cancer irroratus 
Crangon septimspinosus 
Neomysis americana 
Neopanope texana sayi 
Pagurus longicarpus 
Palaemonites vulgaris 
Polyonyx machrocheles 
Sabinea sarsii 
Upogebia affinis 

Insecta 
Insect larvae 

Invertebrate eggs 
Echinodermata 

Asteroidea 



B,C" 


Asterias forbesi 


A,C 


A. vulgaris 




Echinoidea 


F 


Arbacia punctulata 


A-C 7 


Strongylocen tratus droh bach iensis 


A,C 25 


Holothuroidea 


B 


Cucumaria frondosa 


A.D-F 


Ophiuroidea 


C 


Amphiphnlis xquamata 


B 


Ophiophalia aculeata 


A 


Chordata 


A 


Molgula manhattensis 




Didemnum candidum 


A.D-F 


Pisces 


B,D 


Fish remains 




Fish eggs 



D,F 

D 

D 

D,F,G 

D,G 

C-E 

I) 

CD 
G 

F 
D,F< 



'Wells et al. (1973) by percent weight. 
'Richards (1963) by occurrence and percent volume. 
'MaePhee (1969) numbers and occurrence. 
'Kennedy and Steele (1971) numbers plus volume. 



'Pearcy (1962a) by volume. 

'Mulkana (1966) by mean number/stomach and percent frequency 

occurrence. 
Frame (1972) numbers and occurrence. 



otolith after deposition of the opaque center was 
variable, and therefore exact age within the group can- 
not be determined by otolith characteristics. No cal- 
cified otoliths were found in fresh specimens until the left 
eye was in the median position (7.0 mm or greater). 

Growth in weight was calculated by Pearcy (1962a) 
from average length of flounder in millimeters at the 
beginning of each month converted to weight in grams by 
the formula: W = 0.000017L 3 (Fig. 8). 



AVERAGE WEIGHT 

INSTANTANEOUS GROWTH RATE 



I , ' . I o I „ I .. I „ I 



l .IJ, l , l . l .l Jl 



J J A s ON DJFMAMJ JASON J F 



Figure 8. — Average monthly weight gain in the Mystic River estuary 
in winter flounder (from Pearcy 1962a). 



phosis at 2°, 5°, and 8°C. The fish were reared in all 
black 38-liter aquaria at a stocking density of ap- 
proximately 13/liter. The aquaria were semiclosed and 
aerated. Salinity varied between 28 and 30% . Larvae 
were fed wild zooplankton (principally copepod nauplii 
at concentrations of 2,000/liter). Growth was measured 
weekly. Specific daily growth was calculated from the 
formula 



SG 



100 



log e WT -log e wt 
T 



* 1 

o 


where SG 
WT 


(S> 


wt 



specific growth 

dry weight at the end of the time interval 
dry weight at the beginning of the time 
interval 
T = time in days. 

Temperature strongly influenced growth of larvae and 
juveniles, growth being directly related to temperature. 
Regression analysis of the semilog arithmetic transfor- 
mation of growth on time gave the following linear 
equations: 



The instantaneous rates of growth {k = dw/dt) were 
calculated from relative growth by means of the for- 
mulas: 

b = (Wo i + 1 -Woi)/Woi 

where: Wo= average individual weight at beginning 
of month i 

b = relative growth and e k = 6 + 1. 

Laurence (1975) studied growth of laboratory reared 
winter flounder larvae from hatching through metamor- 



8°C: Log Y = 0.755 + 0.358X r = 0.99 
5°C: Log 7 = 0.840 + 0.213X r = 0.97 
2°C: Log y = 0.840 + 0.110X r = 0.85. 

Growth rate was significantly greater at 8°C than at 5°C, 
and greater at 5°C than at 2°C, but not significantly so. 
Larvae held at 2°C died before completing metamor- 
phosis. Time to metamorphosis was 49 days at 8°C and 
80 days at 5°C. Daily specific growth was greater at 
higher temperatures and was highly variable from week 
to week. Mean specific growth rates were 10.1%/day at 
8°C, 5.8%/day at 5°C, and 2.6%/day at 2°C. 



17 



Adults — Several authors have calculated growth rates 
of adults (Fig. 9). Kennedy and Steele (1971) calculated 
the age of Long Pond. Newfoundland, flounder from 
otoliths. They found no difference between growth curves 
o\ males and females until age IX when the females were 
much larger. This could be due to low numbers of 
females involved, or failure to age the fish correctly. The 
regression equations for the fish were: 

Females: Log W = 3.1441 log L - 2.0702 
Males: Log W = 2.9833 log L - 1.9041 

with L in centimeters and W in grams. 

Berry et al. (1965) determined age from otoliths and 
scales of winter flounder in Rhode Island. They found 
that scale markings were unreliable for making age 
determinations, and that otoliths provide fully reliable 
estimates only to age III, which agrees with Landers 
(1941). Their growth equations, based on the Walford 
plot, are: 

Females: / f+J = 395.7(0.34) + 0.66/, 
Males: / t+ , = 323.1(0.42) + 0.58/, 

where l t = length in millimeters at time t. 

They concluded a typical growth curve for winter 
flounder could not be developed because the species con- 
sisted of discrete stocks which were subject to variable 
rates of exploitation and environmental conditions; and 
that females grew faster than males. 

Poole (1966b) studied growth rates offish collected in 
several south shore bays of Long Island. He used otoliths 
and agreed with Berry's (1959) description of opaque 
band formation where the first opaque band useful for 
judging age appears in October and continues its growth 
to July when the fish is several months beyond age group 
I. Poole found that females grew faster than males and 
that the growth rate was different in certain bays. 



Lux (1973) calculated age and growth of winter floun- 
der on Georges Bank by means of scale analysis. Direct 
proportion growth calculations were made using the 
equation: 

L n = C + SJS[L - C] 

where L n = fish length (TL) at time of formation of 
nth annulus 
C = fish TL at scale formation 
S n = anterior scale radius to nth annulus 
S = anterior scale radius at capture 
L = fish TL at capture. 

He found growth was more rapid on Georges Bank than 
on inshore areas, fish from eastern Georges Bank grow- 
ing slightly faster than those from the western part. 
Females grew faster than males after age II. Growth 
equations were: 



It 



/°°(1 -exp[-K(t-t )}) 



where It = length in centimeters 

/ oo = theoretical maximum length 
K = rate of change in length increment 
to = age at which growth in length theoreti- 
cally begins 

Male: It = 550 (1 - exp [0.37 ( t + 0.05) ] ) 
Female: It = 630 (1 - exp [0.31 (t - 0.05)]) 

where It = length at age t. 

Howe and Coates (1975) described growth of winter 
flounder off the Massachusetts coast. They plotted 
"Walford lines": 

y = a + bx 

L, = (x) — length in millimeters at time t 




NEWFOUNDLAND 
NARRAGANSETT BAY 
WESTERN GEORGES BANK 
EASTERN GEORGES BANK 
GEORGES BANK 
NORTH OF CAPE COD 
SOUTH 8 EAST OF CAPE COO 



YEARS 



Figure 9. — Growth curves of adult winter flounders (from Saila et al. 1965; Poole 1966a; 
Kennedy and Steele 1971; Lux 1973; and Howe and Coates 1975). 



18 



L co = a — theoretical maximum length 
v = growth/month in millimeters 
b = rate of change in growth. 

There were significant growth differences between geo- 
graphic areas. The growth rates of females (F) south of 
Cape Cod were greater than those north of Cape Cod but 
less than those from Georges Bank. Males (M) grew 
faster on Georges Bank than south of Cape Cod. Females 
grew more rapidly than males south of Cape Cod but not 
on Georges Bank. The growth equations calculated for 
the fish are as follows: 



Ford -Waif or d Growth Equation 
L t+1 = 455.38(1 - 0.69) + 0.69L, 

L,+i = 476.76 (1 - 0.78) + 0.78L, 
L t+i = 487.38 (1 - 0.71) + 0.71L , 

Lt+i = 534.40 (1 - 0.69) + 0.69L, 
Lt+i = 622.38 (1 - 0.64) + 0.64L, 



Area 


Sex 


North of 


F 


Cape Cod 




East and 


M 


south of 


F 


Cape Cod 




Georges 


M 


Bank 


F 


where L = 


lc 


t 


ti 



length in millimeters 
= time in years. 



3.44 Metabolism 

Laurence (1975) studied metabolism of laboratory- 
reared larvae and juveniles. He used Warburg respirom- 
eters to measure oxygen consumption for 2-h periods. 
Absolute values of larval oxygen consumption increased 
until metamorphosis, at which time they declined. After 
metamorphosis, oxygen consumption again increased. 
Temperature directly affected oxygen consumption with 
higher consumption at higher temperatures. Metabolic 
rate on a unit weight basis decreased with increasing size 
from hatching through metamorphosis. Absolute values 
of routine metabolism expressed in liters of oxygen con- 
sumed, regressed on body weight were best described by 
a third degree polynomial. 



'W 



'W 



'W 



The metabolic rate of fish with respect to weight is 
usually described by the linearly related log transfor- 
mation log 10 oxygen consumption = a + b logioweight in 
which the slope value is approximately 0.80. 

Although larval winter flounder conformed to this type 
of relationship, metamorphosed juveniles did not. There- 
fore, continuous metabolism of this fish must be describ- 
ed by a different analysis than standard log-log transfor- 
mation. This change in metabolic patterns probably 
reflects changes in body shape and activity patterns oc- 



2°C: 


O > 


= 0.451 + 6.0 X 10 
+ 1.5 X 10" 1( W 3 


W- 


1.1 X 


10 


5°C: 


02 


= 0.601 + 3.3 X 10" 
+ 2.5 X \0~ W W 


V- 


1.7 x 


10 


8°C: 


2 


= 0.379 + 6.8 X 10" 
+ 7.6 X 10~ 10 W 3 


A w- 


4.3 X 


10 



curring at metamorphosis, and perhaps reflects phy- 
siological changes in the respiratory system. Salinity ef- 
fects were not examined. 

Frame (1973a) studied oxygen uptake rates of young 
winter flounder from the Weweantic River estuary, 
Mass., to determine the effects of estuarine conditions 
(salinity and temperature differences) on respiration and 
metabolic rates. He found that the quantity of O2 up- 
take (ml Q 2 /h per g) as a function of increased tempera- 
ture did not differ significantly between salinities of 10- 
20% o but is 40-50% higher at 30% c . Metabolic rates 
per gram did not differ between fish sizes used (10.0-13.5 
cm TL and 14.0-17.5 cm TL) or between sexes. Two fac- 
tors, temperature and weight, were necessary for calcula- 
tion of a fish's energy expenditure under routine metabol- 



~"Kj ° i5 
o 



e 10 




o Y=-O.I78 + 0I5X 
CONFIDENCE LIMITS 



16 20 24 

TEMPERATURE (°C) 



Figure 10. — Oxygen consumption (Y) of winter flounder at different 
temperatures and salinities and effect of weight (X) (from Frame 

1973a). 

ic conditions (Fig. 10). The expression for the equations 
in Figure 10 is: 

y = oxygen (ml 2 /h per g) 

X = temperature (°C) 

This is based on the assumption that 1.0 ml 2 is equiva- 
lent to 5.0 calories. Adjustment of the metabolic level by 
immature fish indicates the euryhaline nature of this 
species and suggests a physiological reason why young 
flounder are found in estuaries. 

Voyer and Morrison (1972) studied respiration of win- 
ter flounder at different temperatures and oxygen con- 
centrations. They found the average rate of oxygen con- 
sumed by flounder at 10° C was 35 and 55 mg (0 2 /kg body 
weight per hour at 3.5 and 8.6 mg dissolved oxygen 
(DO)/liter, respectively, (x fish weights 18.0-24.39 g for 
high 2 and 13.0-22.64 g for low 2 .) At 20°C the aver- 
age rate of 2 uptake was 70 at 8.2 mg DO/1 and 97 at 
6.3 mg DO/1. Oxygen consumption rates were signifi- 
cantly greater at 20°C than 10°C. In two of three ex- 
periments, rates of oxygen uptake were lower among 
groups of flounder maintained at reduced dissolved oxy- 
gen concentrations for 15-25 h. No dissolved oxygen-tem- 
perature interactions were apparent. 



19 



Huntsman and Sparks (1924) studied the effect of 9ize 
on respiratory rate which they measured by counting 
opercular movements per minute (Table 11). As the size 
of the fish increased, the respiratory rate decreased; the 
maximum movements showed the most regular decrease 
with increase in size. 

Table 11. — Effect of size on respiratory rate 
(opercular movements/minute) of winter floun- 
der (from Huntsman and Sparks 1924). 



Size (mm) 


Initial 


M 


iximum 


Final 


100 


141 




191 


130 


1 50 


100 




135 


103 


200 


76 




109 


51 


250 


86 




93 


61 


300 


73 




81 


53 



Horton et al. 8 determined oxygen consumption to be 
42.15 mg Q 2 /kg body weight per hour at a mean tem- 
perature of 13.4°C and salinity 30°/oo for mean body 
weight of 852 g. 

Frame (1973b) measured food intake and conversion 
efficiency for age I winter flounder under different tem- 
peratures and salinities. He defined conversion ef- 
ficiency as increase in the weight of a fish divided by the 
weight of food ingested for a given period of time. Only 
fish held at 12°C and 16°C in 20%>o salinity had a nor- 
mal growth rate. Conversion effiency ranged from 13.9 to 
19.0%. The regression equation relating daily growth in 
average body weight (Y) to daily ration/average body 
weight (X) was Y = 1.651 + 1.832X. Temperature 
rather than salinity appears to have caused stress con- 
ditions although metabolic factors such as lipid syn- 
thesis and protein loss may have masked the effect of 
salinity. Frame proposed flounder survival may be con- 
trolled by their ability to move gradually into favorable 
temperature-salinity environments. Unseasonal tem- 
perature-salinity regimes imposed on age I flounder may 
be fatal. 

Endocrine system and hormones — Phillips and Mul- 
row (1959) found that winter flounder corpuscles of Stan- 
nius, previously thought to be analagous to the adrenal 
cortex, were not concerned with the production of 
adrenocorticosteroids. They did not, however, suggest 
what the function of the corpuscles of Stannius might be. 

Grafflin (1935) studied kidney concentration of urea 
and urine flow in winter flounder. The highest urine 
plasma ratios fall in the lower range of urine flow (urea 
plasma milligrams percent in plasma x 12.0, range 8.5- 
18.4; in urine x 16.0, range 10.9-25.9; renal urine/plasma 
ratios x 1.3. range 1.0-1.8; urine flow cmVkg per 24 h x 
23.0, range 8.3-45.6). Considerable variation occurred in 
chloride concentration (0-87 millimoles/liter) and the ac- 
tual rate of urine flow. Grafflin concluded there was no 



'Horton. D. B., D. W. Bridges, and J. J. Cech, Jr. 1973. The de- 
velopment of biomedical procedures for establishing water quality criteria 
of marine fish. First Annu. Rep. to Environ. Prot. Agency, Contract 
R-80031, 48 p. 



direct relationship between rate of urine flow and urinary 
chloride concentration. 

Grafflin and Gould (1936) found that approximately 
one-half the normal total nitrogen of winter flounder 
urine could not be accounted for by ordinary nitrog- 
enous constituents. Percent of total nitrogen (N) (43.4 
mg N/100 cm 1 urine) of urine = urea 21.2%, ammonia N 
1.8%, uric acid 1.2%, total creatinine N 15%, amino acid 
N 4.2%, and undetermined 51.1%. Trimethylamine oxide 
was absent or present in very small concentrations in the 
urine. 

Maack and Kinter (1969) reported the first quan- 
titative evidence for transport of intact filtered proteins 
across the kidney tubules. Morphological observations 
obtained by Bulger and Frump" suggest that intact pro- 
tein is first transported across the brush border into the 
cell, from there to the intercellular spaces, and finally 
across the basement membrane to the peritubular space. 
Maack and Kinter (1969) speculated that transtubular 
transport of intact protein was the primary mechanism 
for handling normal protein loads, catabolism only oc- 
curring when an overload of protein is presented to the 
renal tubules. 

Kleinzeller and McAvoy (1973) conducted studies on 
the transport systems for sugars at the peritubular face of 
the renal tubular cells to obtain information on the reab- 
sorptive process using various sugars as inhibitors. A 
three carrier mediated pathway of sugar transport at the 
antiluminal cell face of the flounder renal tubule seemed 
to be operating: the pathway of the nonmetabolizable a 
methyl D-galactoside (not shared by D-glucose); the 
pathway shared by D-galactose and D-glucose; the path- 
way shared by the D-galactose and 2-deoxy-D-galactose. 

Ammonia is the primary nitrogenous excretory 
product in teleosts. For the most part, ammonia is 
produced from precursers in the liver, transported by the 
blood to the gills, and excreted by diffusion (Janicki and 
Lingis 1970). Liver homogenates from winter flounder 
produce ammonia from L-aspartate and L-glutamate at 
the rate of 2.7 ± 0.8 M moles NH/g tissue wet weight per 
hour at 25°C for the former and 10.0 ± 0.9 V- moles NH : ,/g 
tissue wet weight per hour at 25°C for the latter. Mito- 
chondrial and cytoplasmic fractions combined, produced 
ammonia from L-aspartate but single nuclear mitochon- 
drial and cytoplasmic fractions did not. Results are con- 
sistent with a general scheme in which the amino group 
of L-aspartate undergoes transamination with a keto- 
glutarate to form L-glutamate by action of L-aspartate 
aminotransferase, and ammonia is liberated from L- 
glutamic acid by L-glutamic acid dehydrogenase. How- 
ever, it is not clear which transaminase is involved. 

Goldstein and Forster (1965) studied urea production 
in winter flounder. Although teleosts are considered am- 
moniotelic, teleost blood contains significant quan- 
tities of urea (the origin of which is unknown since the 
complete cycle for synthesizing urea is not present in liv- 
ing teleost fishes). Activity of the uricolytic pathway 



"Bulger and Frump. Pers. commun., mentioned in Maack and Kinter 
1969. 



20 



(uric acid-urea) was assayed in slices from winter floun- 
der livers. The rate of conversion of uric acid to urea was 
23 ji moles urea/g per hour. Allantoin and allantoic acid 
were also converted to urea at the same rate. Uric acid 
could be converted to urea by a three step process: urate 
-allantoin-allantoicicate^urea. Purines are, therefore, a 
source of urea in fishes. 

Hormones — Donahue (1941) tested extracts of winter 
flounder ovaries for their estrogenic properties and found 
that the extracts contained estrogen but in quantities 
less than one standard rat unit. This might be useful for 
comparison to mammals but it is not clear how this 
relates to fish. 

3.45 Physiology 

Pesch (1970) studied the electrophoretic profiles of 
plasma protein (thought to be reliable indicators of phys- 



iological well being). Variations are related to changes 
in the body's metabolic requirements, defense against in- 
vasion and injury, maintenance of body pH, osmotic 
pressure, and regulation of cellular activity and func- 
tion. 

Plasma protein concentration in flounder was 3-4 g/100 
ml of plasma, the slow and medium group being most 
prominent. In both sexes the concentration of individual 
fractions differed according to stage of gonad matura- 
tion. Total concentration was greater in mature than in 
immature fish. In females, the slow fraction was respon- 
sible for the increase and was due to addition of vitellin 
which forms yolk protein. In males, the fast fraction was 
responsible for the increase, which could be due to the 
transport property of the fast fraction or it could be serv- 
ing as a source of amino acids. An immature male with 
tail rot had low plasma protein concentrations of about 
one-half normal. Aging is associated with increased 
plasma protein concentration, especially of slow and 



Table 12. — Blood chemistry values for winter flounder. 



Component 



Values 



Miscellaneous 



Source 



Plasma chloride 

Plasma protein 
Erythrocyte content 

Hemoglobin 



Freezing point 

depression 
Serum osmolality' 

(mOsm/1) 
Serum sodium 

(mmoles/1) 
Serum chloride 

(mmoles/1) 
Serum potassium 

(mmoles/1) 
Serum protein 

(g/100 ml) 
Erythrocytes 

(X 107mm 3 ) 
Hematocrit (%) 
Hemoglobin 

(g/100 ml) 



149.7-158.4 mOsm/1 
x = 154.2 mOsm/1 

3-4g/100ml 
235-372 mmYlO' 

x = 294 mm 3 
6.16-10.44 g/100 ml 
x = 8.93 g/100 ml 

Summer 
x = -0.63°C 

405.0 ± 7.0(12) 

185.8 ± 3.6 (12) 

157.9 ± 1.3(12) 
5.2 ± 0.3(12) 
5.5 ±0.3(12) 

2.25 ± 0.19(12) 

22.3 ± 1.6 (12) 
8.44 ± 0.16(12) 



Winter 



i = -1.15°C 
2 426.0± 6.0 (9) 
185.4 ± 4.5 (9) 
152.0 ± 3.5 (9) 

2 4.0 ± 0.2 (9) 

3 3.1 ± 0.2 (10) 

2.01 ± 0.10(10) 

22.9 ± 1.2 (10) 
3 5.1 ±0.40(10) 



Mean length offish 
203 mm 



Grafflin(1935) 

Pesch (1970) 
Eislerf 1965a) 



Pearcy (1961) 

Umminger and 
Mahoney (1972) 



Freezing point (°C) 



Melting point (°C) 

Melting point- 
freezing point (°C) 

Sodium (mMl ) 

Chloride (mMI -1 ) 

% due to NaCl 





Dialysed 


Serum 


serum 


-1.37 ±0.31? 


-0.65 


-0.69 ± 0.07 


— 


-0.75 ± 0.03 


-0.01 


-0.67 ± 0.07 


— 


0.62 ± 0.35 


0.64 


0.02 ± 0.001 


— 


250 ± 12 


— 


194 ± 6 


— 


178 ± 6 


0.0 


147 ± 14 


— 


58.1 


— 


94.0 


— 



Dialysate 
-0.72 



-0.70 



0.02 



172 



March (watertemp. -1.2°C, Duman and 
total no. fish 12) De Vries (1974) 

August (water temp. +17°C, 
total no. fish 8) 

March 

August 

March 
August 
March 
August 
March 
August 
March 
August 



21 



Table 12.— Continued. 



Component 




Values 




Miscellaneous 


Source 






Confidence 


Number 








Mean 


limits 


used 
86 


iSLof fish 24.7 ± 1.1(98) 




Red blood cell count 


1.81 X 107mm' 


± 0.13 


Hortonet al. 


Hemoglobin 


5.5 g^ 


± 0.4 


91 


Total value 


(1973)' 


concentration 












Hematocrit 


19% 


± 2 


92 


Total value 




Thrombocyte count 


135.5X 107mm 3 


±26.6 


26 


Total value 




Erythrocytic 


1.4cm/h 


± 0.3 


59 


Total value 




sedimentation 












Corpuscular 


112JU 3 


±13 


88 


Mean value 




volume (RBC) 












Corpuscular hemoglobin 


34 picograms 


± 3 


88 


Mean value 




Corpuscular hemoglobin 


31 g% 


± 2 


91 


Mean value 




concentration 












White blood cell count 


40.8X 107mm 3 


± 5.4 


82 


Total % of WBC 




Lymphocytes 


51% 


± 4 


92 


Total % of WBC 




Thrombocyte 


39^ 


± 3 


92 


Total % of WBC 




Neutrophil 


9% 


± 2 


92 


Total % of WBC 




Basophil 


<1% 


i<l 


92 


Total % of WBC 




Blast form 


<1% 


i<l 


92 


Total % of WBC 




Mature erythrocyte 












Total 


96^0 


± 2 


92 


% of RBC 




Winter 


100<~r 


±C1 


37 


% of RBC 




Spring 


95^ 


± 4 


55 


% of RBC 




Immature red blood cell 












Total 


4\ 


± 2 


92 


% of RBC 




Winter 


<1% 


±<1 


37 


% of RBC 




Spring 


7% 


± 4 


55 


% of RBC 




Clotting time 


2.44 min 


± 0.31 




Whole blood from start of 
sample withdrawal 




Plasma protein 


5.22 g% 


± 0.33 








concentration 












Condition offish 


2 


±cl 


91 


Code 0-5 worst to best 




(external! 








appearing 





Data expressed as mean ± standard error. Numbers in parentheses indicate the number of specimens used to obtain means. 
-Highly significantly different (P<0.0001). 

Significantly different (P<0.05). 
•Horton, D. B., D. W. Bridges, and J. J. Cech, Jr. 1973. First Annu. Rep. to Environ. Prot. Agency. Contract R-8003. 



medium fractions (Pesch 1970). (In trout this is thought 
to be due to the increase in globulin antibody produc- 
tion as the animal is exposed to various diseases.) 

Seasonal cycles in osmotic pressure of winter flounder 
serum and in four of eight blood characteristics (Um- 
minger and Mahoney 1972) occur (Table 12). In winter 
flounder, serum osmolality was highest when they were 
sexually mature, which is opposite to the condition 
usually found in fishes. 

Studies on laboratory acclimated winter flounder 
showed that temperatures ranging from —1° to 15°C had 
no effect on serum osmolality; therefore, seasonal change 
in serum osmolality of winter flounder in nature is 
probably not temperature controlled. 

Pearcy (1961) found that the freezing point depression 
of winter flounder serum averaged more in winter than in 
summer. This seasonal difference was later verified by 
Duman and De Vries (1974) (Table 12). The possible 
adaptive value might be as protection against freezing in 
shallow water during cold weather. 

3.46 Biochemistry 
Brooke et al. (1962) did biochemical analyses offish 



fillets and offal (bones, scales, and organs) and their 
seasonal variation in Gulf of Maine winter flounder 

(Table 13). Skeletal structure and scales are responsible 
for high ash in offal, and liver is important in high oil 
values. 

The properties and composition of winter flounder oils 
were presented by Ackman and Ke (1968). There is some 
commercial value for the oil and it is sometimes used as a 

replacement for cod liver oil. It is chiefly notable for a low 
proportion of C 2 2 relative to C 2u and C i6 (Table 14). 



Table 13.— Biochemical analysis of winter flounder fillets (based on 
Brooke et al. 1962). Symbols: — = not related to season, * = higher 
than 5% confidence level, *** = higher than 17c confidence level. 





Protein 


Oil 


Ash 


Moisture 




(%) 


(%) 


(%) 


(%) 


Fillets 


18.8 ± 1.5 


0.15 ± 0.09 


1.3 ± 0.14 


79.9 ± 1.5 


Offal 


16.9 ± 1.6 


3.20 ± 1.20 


5.1 ±0.1 


74.2 ± 1.8 


Seasonal 


variations 








Fillets 


— 


* 


— 


* 


Offal 


* + * 


— 


— 


* 



22 



Table 14. — Properties and fatty acid composi- 
tions of commercially produced winter flounder 
oils (from Ackman and Ke 1968). 



IMMATURE WINTER FLOUNDERS 
1945 YEAR-CLASS AGE I 



Oil 






Year produced: 


1964(a) 


1964(b) 


Iodine value (Wijs): 


141 


150 


Non-saponifiables (%): 


1.14 


1.03 


Free fatty acid (%): 


2.84 


1.35 


Composition in terms of 


major chain 


lengths 


and certain ratios of fatty acid 


.ypes 


Chain length 


1964(a) 


1964(b) 


( ' 14 


5.9 


6.6 


C,6 


28.3 


25.4 


Cl8 


22.9 


23.2 


C 20 


23.8 


25.5 


C 22 


15.9 


15.3 


% polyunsaturates 






Experimental 1 


25.3 


27.2 


Calculated" 


24.9 


27.6 


16:0 as c \ of saturated 


52.2 


46.4 


16:1 + 18:1 


32.2 


29.1 


16:0/(16:1 + 18:1) 


0.32 


0.34 



'By gas layer chromatography (GLC). 
'From formula: r r poly = 10.7 + 0.337 (oil 
I. V.- 100). 



3.5 Behavior 

3.51 Migration and local movements 

McCracken (1963) has done a great deal of work on 
migration of winter flounder in Canadian waters and has 
summarized the work of Lobell (1939), Perlmutter 
(1947), and Merriman and Warfel (1948), showing that 
winter flounder make regular migrations. 

During summer, mature flounders leave the shore zone 
in areas where temperatures rise above about 15° C but 
not where bottom temperatures do not reach this level. 
This movement toward cooler water is restricted to 
depths at which the temperature does not go below 12°C. 
Flounders return to the shore zone in fall after the tem- 
perature decreases below 15°C. In spring, immature and 
mature fish are both along shore with spawning fish con- 
centrated in shallow water when the temperature warms 
to 3°-4°C. 

North of Cape Cod flounders move deeper in winter. 
To the south, spawning condition is reached earlier, and 
mature flounders may remain in shallow water during 
the cold period. Figure 11 shows depth distribution by 
depth, age, and month of immature and mature floun- 
ders caught in Passamaquoddy Bay. 

Aside from local onshore-offshore migration, results of 
tagging experiments have shown that the winter floun- 
der is a stationary fish. Lobell (1939) showed summering 
concentrations in the Block Island region are composed 
of individuals from Long Island bays and sounds. Perl- 
mutter (1947) compared fish north and south of Cape 
Cod and from Georges Bank meristically and found there 
was little intermixing. He concluded that most popu- 
lations are the result of local spawning and comprise 
more or less discrete populations. 





5 - 

10 - 
15 - 
20 


"— -, | 


CO 




1945 rEAR-CLASS AGE R 




o 
I 
(- 

2 

z 


5- 

10- 

20- 


1 1 


,t 


T 




1944 AND EARLIER YEAR-CLASSES AGE IE AND 


OVf R 


Q. 

LU 

Q 


5- 

10- 

20 - 


ft * ♦ , 


J 



19-27 12-17 16-25 2-10 

MAY JUNE JULY SEPT 



MATURE WINTER FLOUNDERS 
1944 YEAR- CLASS AGE IV 



21-22 6 23 6-16 

NOV JAN MAR APR 

i o 

SCALE i 1 FISH 














1943 YEAR-CLASS AGE 2 




10- 

15- 


1 


1 




JL 




19' 


t2 


AND 


EARLIER YEAR-CLASSES AGE 21 AND OVER 




19-27 12-17 16-25 2 - 10 21-22 6 23 6 - 16 

MAY JUNE JULY SEPT NOV JAN MAR APRIL 

I 10 
SCALE' 1 FISH 

Figure 11. — Depth distribution of immature and mature winter 
flounder in Passamaquoddy Bay, April-May 1947, by age, month, and 
depth (from McCracken 1963). 

Howe and Coates (1975) reported results of a 10-yr tag- 
ging study off Massachusetts. Flounder tagged at 21 
locations showed the following movements: north of 
Cape Cod they were localized and confined to inshore 
waters, south of Cape Cod seasonally dispersed in a 
southeast direction beyond the territorial limit, and lit- 
tle mixing between Georges Bank and inshore area. 
Movements appear to be related to water temperature; 
they moved out when water temperatures climbed above 
15°C. The steep continental shelf east of outer Cape Cod 
appears to limit winter flounder distribution to within 5 
km of the coast. 

Massachusetts Division of Marine Fisheries (1961) 10 
tagging program in Quincy Bay showed that large fish (3c 
= 350 mm TL) congregate in shoal water for spawning. 
As the temperature increased in summer, they dispersed 



'"Massachusetts Division of Marine Fisheries. 1961. Annual report 
fiscal year July 1, 1960-June 30. 1961. Submitted by the director to the 
commission and Board of Natural Resources, Commonwealth of Massa- 
chusetts, 70 p. 



23 



to deeper waters. Young up to age IV remained in the 
harbor but moved deeper in summer. Fish 5 yr old or 
more (over 350 mm) tended to move out of the harbor 
completely in summer, and some travelled a long dis- 
tance to form offshore populations. 

A report (Anonymous 1964) described winter flounder 
populations containing a large number of abnormally 
pigmented individuals, all of the same age. This isolated 
group supports the fact that a population remains 
together and does not migrate. 

Tyler (1972a) studied surges of winter flounder into the 
intertidal zone in the Passamaquoddy Bay region by 
means of underwater television. He found that they 
entered the intertidal zone with the rising tide. Peak 
movement occurred 2.0-2.5 h after low tide and fell off 3.5 
h after the tide began to rise. Flounder occupied the area 
for 0-8 h then surged back to the sublittoral 2.5-0.5 h 
before the next low tide. Small (40-150 mm) and large 
(250-490 mm) flounders moved with the same synchrony 
but small ones tended to make short movements up and 
down the beach with net movement away from shore 
when the tide is falling, while large ones were more strict- 
ly directional. Intermediate sized flounder were absent 
from the intertidal region. He suggested that the adap- 
tive value of this movement is that the intertidal zone is 
a good feeding area. 

Saila (1961) conducted tagging experiments at Green 
Hill Pond, Charlestown, R.I., in an attempt to explain 
return of winter flounder to coastal breeding grounds on 
the basis of a model for diasporic nonoriented migration 
(a reassembly of animals dispersed over a strip of ocean 
bounded on one side by a straight coast running east- 
west and on the other by a reflecting barrier, the 20- 
fathom depth contour, beyond which no tagged fish were 
recaptured). The results showed flounder return to the 
same area to spawn each year. Approximately 75% 
returns to shore were achieved after 90 days of searching 
with a maximum strip width of 15 mi. If the barrier is 10 
mi, the probability is 90% return after 90 days. This time 
period was within the time flounder were observed to 
enter Green Hill Pond and is less than the observed 
breeding season; therefore, diasporic migration with no 
assumptions about orientation to outside stimuli seems a 
reasonable explanation for movement back to the coast. 



mer, showed a photonegative response. He thought light 
intensity might be another factor which is related to 
movement of young fish out of the shoals in fall and win- 
ter, or to differences in vertical distribution. 

Sullivan (1915) found larvae strongly phototactic. 

Olla et al. (1969) found a relationship between am- 
bient temperature and activity. Divers observed floun- 
der in Great South Bay, Long Island. Bottom tem- 
peratures ranged from 17.2° to 24.0°C. Flounders were 
active up to 22.2°C, but became inactive at higher tem- 
peratures with heads resting on the bottom. At 23° C all 
flounders found at 1100 h were buried in the sand with 
only their eyes protruding. Temperatures 50-60 mm be- 
low the sand surface were 19.8°-20.0°C, even in the shal- 
lowest part of the basin. Flounder evidently avoid high 
temperatures by burying themselves in the sand. 

Radle (1971) showed that high temperatures near ther- 
mal effluent from a power plant in Indian River Bay, 
Del., estuary inhibited feeding of juvenile flounder. 
Those collected from stations with bottom temperatures 
26.5°-27.0°C had less full stomachs than flounder from 
those stations with lower temperatures. Flounder from 
stations with temperatures 27.0°-27.5°C were not feed- 
ing at all. 

Sherwood and Edwards (1901) observed a sudden fall 
in water temperature at Great Harbor and Waquoit Bay 
(Cape Cod region) on 23 February 1900 from 1° to 
— 2.7°C. The flounder then disappeared from the harbor 
and none were taken again until 6 March when the water 
temperature rose to 0°C again. 

Beamish (1966) tested swimming endurance of winter 
flounder at different temperatures against currents of 
different velocities (Table 15). Endurance was measured 
as the time a fish maintained its position against a cur- 
rent of known velocity. 

Davis and Bardach (1965) reported on prefeeding ac- 
tivities of some marine fishes which had been con- 
ditioned to feed at certain time of day shortly after the 
start of their light period. After acclimation, most fishes 
increased locomotion 1-3 h before feeding. Trials with 
winter flounder showed that they did not exhibit this 
response, even after having been conditioned to feed at 
one particular time for over 23 days. 



3.52 Schooling 

Winter flounder do not school. 

3.53 Response to stimuli 

Response to light may affect depth distribution. 
McCracken (1963) showed from evidence in the labora- 
tory and distribution offish in Passamaquoddy Bay, that 
immature flounder of intermediate size perferred lower 
light intensities than mature or small immature floun- 
der, and suggested that behavior in relation to light may 
change at sexual maturity. 

Pearcy (1962a) found that small group flounder are 
least photonegative and that age group I, during sum- 



Table 15. — Swimming endurance of winter flounder at dif- 
ferent current velocities (from Beamish 1966). 



Temp, tested 


Swimming speed 


Endurance ± SE 


(°C) 


(cm/B) 


(min) 


14 


75 


25.4 ± 3.3 




135 


5.3 ± 1.2 


] 1 


75 


10.0 ± 1.2 




105 


3.2 ± 0.4 




135 


1.4 ± 0.2 


8 


75 


10.3 ± 1.0 




105 


5.8 ± 0.7 




135 


1.7 ± 0.2 


5 


75 


14.1 ± 1.5 




105 


5.8 ± 0.6 




135 


1.9 ± 0.3 



24 



Sutterlin (1975) tested the attractiveness of 25 dif- 
ferent chemical compounds to winter flounder by releas- 
ing seawater solutions of the compounds (10~ 3 molar 
concentration) through a plastic delivery tube in an area 
in front of the Biological Station in St. Andrews, New 
Brunswick, where winter flounder feed. Behavior of the 
flounder upon exposure to these compounds was 
monitored by an underwater television camera and the 
observers comments recorded on tape. Glycine was the 
most effective compound tested followed by alanine, 
methionine, asparagine, cysteine, glutamic acid, and 
leucine to a lesser extent. No amines or amino alcohols 
tested were attractants to flounder. During the fall the 
flounders were not attracted to any of the chemicals, 
probably as a result of behavioral or physiological states. 
Attraction was manifested by the fish circling the 
delivery tube, picking up pieces of clam shell and eject- 
ing them, making digging undulations, or snapping at 
the spout. 

Huntsman and Sparks (1924) studied temperature 
resistance ability of winter flounder of different sizes. 
They found that lethal temperature varied with age. Al- 
though differences were not great, there was an increase 
in susceptibility to high temperature with increase in 
size (100-200 mm, 29.1°-30.4°C; 200-300 mm, 27.8°- 
29.8°C). 

Battle (1926) studied the effects of heat stress on the 
loss of functional activity in the muscle tissue of large 
and small winter flounder. She found in both large and 
small individuals: 1) an automatic mechanism of the 
heart was lost first, 2) cessation of propagated wave in 
the heart and peristalsis in smooth muscle of the 
stomach and ilium occurred second, and 3) finally, loss of 
functional activity upon electrical stimulation, in order, 
of somatic muscle, smooth muscle, and cardiac muscle. 

Hoff and Westman (1966) calculated temperature 
tolerance of winter flounder by calculating median 
tolerance limits for various exposure times over a range of 
acclimation temperatures, and plotting lethal tem- 
peratures against acclimation temperature: cold limits 
0°-l°C; heat 29.3°C total lethal maximum (TLM) at 
48 h. 

The behavior of fish when transferred from the ac- 
climation tank to the high temperature tank was: 1) in- 
crease in general activity, 2) disturbances in equilibrium, 
and 3) increased respiratory movement. The behavior of 
fish transferred to cold temperature was: 1) loss of 
equilibrium, 2) initial increase in respiratory move- 
ments, and 3) violent convulsive spurts and spasms. 
Winter flounder frequently recovered from cold shock 
but never from heat shock. 

Duman and De Vries (1974) examined freezing-melt- 
ing point behavior of serum from winter flounder col- 
lected in St. Margaret's Bay, Nova Scotia, to determine 
the mechanism of freezing resistance. Freezing-melting 
points were determined by a capillary technique. For a 
NaCl solution the temperatures of freezing and melting 
points were within 0.02° C of each other. Winter flounder 
serum collected in March had widely separated freezing 
and melting points (thermal hysteresis). Serum col- 



lected in August did not show this property (Table 12). 
The serum of an Antarctic fish (Trematomous borch- 
grevink) has an unusually low freezing point because a 
group of glycoproteins act as an antifreeze. Winter floun- 
der serum was examined to see if such compounds were 
responsible for the low winter freezing point since in- 
creased NaCl could only account for 58% of the serum 
freezing point depression. The antifreeze compound was 
associated with the colloidal portion of serum. It was 
stable at a temperature of 100°C, soluble in 10% tri- 
chloracetic acid, and had a molecular weight greater 
than 3,500 daltons. The mechanism of action of the com- 
pounds was similar to that of glycoproteins of the Antarc- 
tic fish; however, results of gel electrophoresis and amino 
acid analysis indicated thev were not the same chemical- 
ly. 

4 POPULATION 

4.1 Structure 

4.11 Sex ratio (Table 16) 

Table 16. — Sex ratio of winter flounder. 



Sex ratio 




Number of 




* 


6 


Area of Capture 


fish 


Source 


7:3 




Green Hill Pond, 
Charlestown, R.I. 


(ii)l 


Saila (1962a) 


3:2 




Narragansett Bay, R.I. 


940 


Saila (1962b) 


3:1 




Fishing grounds south 
of Rhode Island and Mass 


2,118 


Lux (1969) 


1:1 




Long Pond, 

Newfoundland 


227 


Kennedy and 
Steele (1971) 


1:1 




Mystic River, Mass. 




Haedrich and 
Haedrich(1974) 


2.3:1 




Massachusetts 


12,151 


Howe and Coates 
(1975) 



Saila (1962a, b) compared sex ratios of fish in 
Narragansett Bay, R.I., with those from Charlestown 
Pond, R.I., and concluded that the higher proportion of 
females was due to catch selectivity for larger fish, since 
females were considerably larger and market preference 
is for large fish. 

4.12 Age composition 

Age composition has been studied by a number of 
authors based on analysis of otoliths (Table 17). 

4.13 Size composition 

Numerous authors have presented data on length fre- 
quencies of winter flounder from different areas. One of 
the most extensive works was done on the Canadian At- 
lantic area by Kohler et al." This work is too long to con- 



"Kohler. A. C, D. N. Fitzgerald, R. G. Halliday, J. S. Scott, and A. V. 
Tyler. 1970. Length weight relationships of marine fishes of the Cana- 
dian Atlantic region. Fish. Res. Board Can., Tech. Rep. 16, 199 p. 



25 



Table 17. — Calculated age distribution of winter flounder population. 





Saila 

Chad 


et al. (1965) 
>stown Pond 


Narragansett 
Bay 




Poole (1966b) 

1 .mil; Nland ba\- 




Dickie and McCracken 

(1955) St. Marys Bay, 

N.S. 1948-53 




Kennedy and Steele (1971) 
Newfoundland 


Age 


Great 
South 


Moriches 


Shinne- 
cock 


Peconic 


Nov. 
Dec. 


Mar. Apr. 


May- 
June July 


Sept.- 
Oct. 


I 





1 


56 


89 


3 


1 





2 














11 


15 


7.8 


159 


199 


29 


50 


22 


26 










1% 




III 


;>3 


236 


211 


316 


126 


69 


98 


54 




42 






5% 6% 


4% 


rv 


100 


241 


171 


312 


82 


77 


99 


86 




110 


18% 


18% 


12% 17% 


2% 


V 


45 


82 


110 


128 


17 


35 


38 


62 




137 


19% 


45% 


20% 25% 


16% 


VI 


16 


25 


25 


37 


5 


7 


3 


11 




136 


22% 


28% 2% 


12% 23% 


22% 


\1I 


4 


7 


13 


27 





1 





2 




103 


17% 


5% 10% 


23% 4% 


18% 


\tti 


1 


5 


1 


12 












68 


15% 


2% 10% 


13% 4% 


23% 


IX 
X 


12(9+) 8(9+1) 


14 


26 












41 

14 


14% 


2% 45% 
30% 


5% 15% 

4% 5% 


12% 

1% 


\ 




















14 2% 
£(76) 


3% 
(35) (27) 


6% 1% 
(179) (49) 


1% 
(66) 



NANTUCKET SHOALS 



WATCH HILL 



POINT JUDITH 






UJ 

O 

or 

LlI 

Cl 



AUG 1927 
OTTER TRAWL 
N = 200 





MAR-AUG 1941 
OTTER TRAWL 
N=2775 



NANTUCKET SOUND 

SEPT 1941 

OTTER TRAWL 

N= 156 



4 - 





OCT -NOV 1941 

OTTER TRAWL 

N=283 




APR -MAY 1942 

OTTER TRAWL 

N = 235 



-r- 
20 




25 30 35 40 45 50 55 
CENTIMETERS 




20 25 30 35 40 45 50 20 25 30 35 40 45 
CENTIMETERS 



Figure 12.— Size composition of winter flounder from Nantucket Shoals, Watch Hill, and Point Judith, R.I. Data smoothed by moving average of 

threes (from Perlmutter 1947). 



dense; therefore, interested readers should consult the 
original reference. Other work has been done by Perl- 
mutter (1947) (Fig. 12), de Sylva et al. (see footnote 3), 
Lux (1969), Tyler (1972a), and Kennedy and Steele 
(1971) (Fig. 13). Changes in length composition with 
depth were calculated by McCracken (1963) and are also 
discussed under sections 2.2, 2.3, and 3.1 (Fig. 14). 



4.2 Abundance and density 
4.21 Average abundance 



The results of authors who estimated average abun- 
dance of winter flounder are summarized in Table 18. 



26 



40 -i 



AUGUST 20-24 



OCT 20 AND NOV 10 



NOV." DEC. 
(77) 



i — r — i — i — i ' i *r 



MARCH 
(36) 



UJ 

< 



uj 
o 

UJ 

o_ 




SEPT.- OCT 
(67) 




o-"Vr — rh — i — i — r 



CD 



00 — 



CM 00 

C\J C\J 
i i 

O CD 

C\J C\J 



rO 
i 



O 

i 



CO 00 

ro ro 



CD 

i 



LENGTH - CM 



Figure 13. — Size composition of winter flounder from Newfoundland 
(from Kennedy and Steele 1971). 



Oviatt and Nixon (1973) determined by multiple 
regression analyses of fish numbers and biomass on 14 
environmental variables that only temperature and 
depth were factors influencing winter flounder abun- 






A 


BCD 






10 FATHOMS 


60^ 






40- 






20- 








A B C D 



A B C D 





A B C D 



A B C D 



SIZE GROUPS 

Figure 14. — Changes in length composition with depth of winter 
flounder in Northumberland Strait. Size groups are: A = 10-19 cm; 
B = 20-24 cm; C = 25-29 cm; and D = 30 cm and over. (From Mc- 
Cracken 1963.) 



dance. This is a reflection of tendency for fish to move 
out of the shallow waters as temperature warms in sum- 
mer and back in as the water cools in winter. 

Jeffries and Johnson (1974) reported on 7-yr variations 
in winter flounder abundance in Narragansett Bay. The 
relative abundance appeared to be associated with 
climatic trends but not with fishing pressure, but the an- 
nual abundance in the bay is reflected 2 to 3 yr later in 
the commercial catch. A major reduction in abundance 
of winter flounder was statistically related to a seemingly 
insignificant trend of temperature increase. Increased 
average temperatures in April were associated with a 
decrease in future catch, the 2- to 3-yr lag being almost 
equal to the period required for flounder to grow from lar- 
vae to catchable size. Jeffries and Johnson (1974) sug- 
gested that the chief effect of the temperature increase 
might be to hasten metamorphosis which takes place in 
April. This would cause the flounder to leave the plank- 
ton earlier and thereby encounter a set of predators 
qualitatively or quantitatively different from those ex- 
perienced by juvenile flounders of previous years. When 
a small change in the physical environment occurs over a 
period of several generations there is a much greater set 
of consequences resulting than would be predicted from 
physiological tolerances of each species involved. 



27 



Table 18.— Average density estimates of winter flounder. 





Life 








Area 


stage 


Density estimate 


Author 


Narragansett Bay 


Larvae 


0,0068/m 1 




Herman (1963) 


Long Pond, 


Adults 


14.9catch/man-h 




Kennedy and Steele 


Newfoundland 








(1971) 


Narragansett Bay 


Larvae 


x = 54.09/100 m 1 
Range (11. 1-107.1) 




Marine Res. Inc. 

(1974)' 


Mystic River, 


Adults 


Mar. 153/ha 


15,300/km' 


Haedrich and 


Boston. Mass. 




June 37/ha 
Aug. 180/ha 


300/km ! 

18,000/km 1 


Haedrich(1974) 






Nov. 368/ha 


36,800/km ! 


„ 


Delaware, 


Adults 


241.776 




Radle(1971) 


Indian River 










Cape Cod Canal 


Eggs 


Mar.-l June 


0.450/m J 


Fairbanks et al. 




Larvae 


Mar. -May 


0.035/m 1 


(1971) 


Buzzards Bay 


Eggs 


Feb. -May 


0.074/m 3 






Larvae 


Mar. -June 


0.113/m 3 





'Marine Research Inc. 1974. 19th Rome Point Investigations, Narragansett Bay 
Ichthyoplankton Survey Final Report to the Narragansett Electric Company. 




Smelt 



Alewife 



Flounder 



Figure 15.— Annual cycle of fish biomass in Mystic River, Mass. (from Haedrich and 

Haedrich 1974). 



4.22 Changes in abundance 



4.23 Density 



Seasonal abundance varies for reasons discussed in 
sections 2.2, 2.3, and 3.5. 



Greatest density of eggs occurs in February and 
March, of larvae in April and May, and of adults in win- 
ter and spring (Table 18). 



28 



4.24 Changes in density 

Haedrich and Haedrich (1974) (Fig. 15), Oviatt and 
Nixon (1973) (Fig. 16) and Pearcy (1962a) (Fig. 17) cal- 
culated seasonal changes in density of flounder popula- 
tions in the Mystic River, Mass., Narragansett Bay, and 
Mystic River, Conn., respectively. 



75 
50 
25 k 



250- 
200 
150 
100 
50 




(a) 



Winter flounder 
1971 



iyr<; i»n -r 



1972 



trtirtiiz 



1971 



/T^-S> 



Figure 16.— Biomass and numbers of winter flounder in Narragan- 
sett Bay (from Oviatt and Nixon 1973). 



4.3 Natality and recruitment 

4.31 Reproduction rates 

See section 3.1. 

Survival rates — Figure 18 is a survival curve for larval 
and juvenile winter flounder from Pearcy (1962a). 

4.32 Factors affecting reproduction 

Tyler and Dunn (1976) studied growth and measures of 
somatic and organ condition in relation to meal frequen- 
cy. Six ration levels were established by feeding fish a 
mixed diet of whole chopped clams and beef liver cubes 
at the following frequencies: one meal per day, one meal 
every other day, every 4th day, every 8th day, every 16th 
day, no food. The testing period was July through 
December. Food was supplied in excess of quantities 
eaten at each meal, water temperature was 7°C. 
Decrease in feeding frequencies resulted in increase in 
food consumption per meal but less food consumption 
per month. At two meals per month, fish did not eat 
more per meal. 

The maintenance ration was 7.9 cal/g per day. Weight 
loss during starvation equalled 2.14-2.05 g cal/g per day. 
Gross conversion efficiency ranged from 1 to 16°r and was 
positively correlated with ration. Net conversion ef- 
ficiency averaged 24.3°c and was not related to ration. 
Condition, liver weight, percent fat in the liver, and per- 
cent ovarian follicles with yolk were positively cor- 




Figure 17. 



-Average density of flounder in Mystic River, Conn, (from 
Pearcy 1962a). 



5- 



4 - 



rr 

Id 
DD 

5 
z 
o 

O 



2 - 



NUMBER 
LOG NUMBER 




Figure 18. — Survival curve for larval and juvenile winter flounder. 
Mystic River estuary. Conn, (from Pearcy 1962a). 



29 



related with mean calories consumed per day. The 
smaller proportion of oocytes with yolk in fish with 
decreased rations was due to the decrease in the num- 
bers of oocytes starting vitellogenesis. The field popula- 
tion from Passamoquoddy Bay, N.B., showed the same 
negative correlation between condition index and per- 
cent oocytes not undergoing vitellogenesis. This in- 
dicated that field fish were not getting all the food they 
could use. and the adaptive reproductive strategy in the 
face of the lack of food was to sacrifice egg production 
and maintain body weight so that when a good year came 
their bodies would be large and able to carry a large 
ovary. 

4.33 Recruitment 

Age or length at which flounders are recruited into the 
fishery varies. Briggs (1965) calculated sports fishery 
recruitment at 200 mm TL for South Shore bays, Long 
Island, and 260 mm TL for Gardeners and Peconic Bays. 
Dickie and McCracken (1955) gave commercial fishery 
data for St. Marys Bay, Nova Scotia, 3-4 yr, 363 g. Perl- 
mutter (1947) reported commercial and sport data for 
Long Island and New York. 180-200 mm, and Watch Hill 
and Point Judith, R.I., 170-220 mm. Saila et al. (1965) 
gave commercial data for Narragansett Bay and off- 
shore waters in Rhode Island: 18 mo (first entry) age III 
fully recruited and 250 mm. Factors influencing recruit- 
ment were size selection by fishermen, differences in 
depth distribution with age, mesh size of fishing net, and 
market preferences. 

See also section 4.5. 

4.4 Mortality and morbidity 

4.41 Mortality rates 

Pearcy (1962a) estimated loss rate for small larvae in a 
Connecticut estuary as 20%/day compared with 4%/day 
for postlarvae. Juvenile mortality rates were 0.31/mo for 



age and 0.084/mo for age I. Total mortality during lar- 
val and juvenile stages is approximately 99.98-99.99% 
(Table 19). 

A summary of mortality rate values for adult winter 
flounder calculated by several authors is presented in 
Table 20. 

Table 19.— Provisional life table for larval and juvenile stages of 
winter flounder (from Pearcy 1962a). 





Age 


Sur- 


Numbers 


Mortality 




in months 


vivors 


dying 


rate X 100 


Larvae 


0.7- 1.5 


100,000 


97,459 


97.46 




1.5- 2.4 


2,541 


1,099 


43.25 


Juveniles 


2.4-12.4 


1,442 


1,398 


96.95 




12.4-22.4 


44 


26 


59.09 




22.4- 


18 




99.982 



4.42 Factors causing or affecting mortality 

Pearcy (1962a) found that the most important factors 
affecting mortality of larvae were translocation and 
natural mortality. Translocation out of the estuary by 
seaward drift was significant and though little is known 
of the fate of these larvae, conditions were surmised to be 
more unfavorable offshore for larvae because of lack of 
suitable food. Predation was also thought to be the major 
cause of juvenile and larval mortality. There was no in- 
dication of accelerated mortality during the period of 
metamorphosis for the winter flounder (see Table 19) as 
mortality rates on a percentage basis were about the 
same. Mortality rates decreased with age. The average 
monthly survival rate for age group was about 69%; for 
age group I it was 92% (Fig. 18). 

Dickie and McCracken (1955) found that the leading 
cause of natural mortality of adult flounder in Pas- 
samaquoddy Bay was predation. The winter period was 
the most dangerous as 30% of the mortality occurred 
from November to April. 



Table 20. — Summary of mortality rate data of winter flounder. 



Natural 




Total 








mortality' 


Fishing 


annual 








rate 


mortality 


mortality 


Geographic location 


Year 


Source 


0.54 


0.24 


0.78 


Long Island Sound & bays 


1937 


Perlmutter (1947) 


0.33 


0.43 


0.76 


Long Island Sound & bays 




Figures calculated 
by Poole 




(instantaneous rate) 








0.321 


0.475 




St. Marys Bay, Nova Scotia 


1949-50 


Dickie and Mc- 
Cracken (1955) 


0.296 


0.272 

Males 


Females 


St. Marys Bay, Nova Scotia 


1952-53 






0.56 


0.65 


Charlestown Pond, R.I. 




Saila etal. (1965) 




0.51 


0.58 


Narragansett Bay 






H.Vi 


0.22 


0.72 


Great South Bay, N.Y. 


1964 


Poole (1969) 


0.52 


0.21 


0.73 


Great South Bay, N.Y. 


1965 




0.52 


0.20 
(instantaneous ra 


0.72 
te) 


Great South Bay, N.Y. 


1966 




0.273 


0.271 


0.474 


South of Cape Cod 


1964-66 


Howe and Coates 

(1975) 



30 



4.5 Dynamics of the population as a whole 

Dickie and McCracken (1955) analyzed a population of 
winter flounder in St. Marys Bay, western Nova Scotia, 
where a commercial flounder fishery began in 1948. This 
fishery showed a rapid rise in landings, a subsequent 
drop, and a stabilization as the catch appeared to reach a 
state of balance with production. Formulas used to cal- 
culate yield isopleth diagrams are: 

Growth 

W t _ t = W°°(l - exp[-k (* - t )] 3 

where W = weight in pounds 

W°° = upper asymptote of growth curve (2.43) 

k = slope (0.40) 

t = any age in years 

1 = time when length theoretically is 0. 

Values obtained 

W t _ t =2.38 (1 - exp[ -0.39U - t ))) 3 . 



Initial population size 



p=y/ M 



where P = population size 

Y = catch (weight in pounds) 
M = rate of exploitation. 

Yield equation 

pnII7 r ,, ,. . > -i ^&nexp[- nK(t - L)} 
Y„, = FRW<*> exp[-M (t n -t„ )]£ ^ 

p p ,.= o F+M+nK 

. (l - exp[-(F + M+nK(t K -t p ))] ) 
where n = +l,fti = -3, £2 2 = +3, fi 3 = -1 

F = instantaneous fishing mortality rate 

(0.251) 
R = recruitment (1,000,000 fish/yr) 
M = instantaneous mortality coefficient (0.36) 
t P ' = age of recruitment (3.0 yr) 
t K = maximum age by which time all flounders 

die(18yr) 
K = growth coefficient. 

The yield-isopleth diagram (Fig. 19) represented the 
situation believed to be closest to that of St. Marys Bay 
fishery. The sustained annual yield of over 0.5 million 
pounds predicted by the model agrees with the observed 
total landings for the past 3 yr. The model showed that 
catches will increase only if flounders are captured at 
smaller sizes and fished harder than at present. There- 
fore, there was little basis for restrictive regulation of the 
fishery as this would tend to lower the annual yield. 
Total fishing effort in the bay was limited by returns per 
unit effort. Therefore, St. Marys Bay flounder fishery is 



probably realizing the maximum sustained yield pos- 
sible under present market conditions. 

Saila et al. (1965) utilized available data on winter 
flounder vital statistics to get a preliminary theoretical 
estimate of the size of a population of juvenile winter 
flounder necessary to sustain or increase the yield of a 
commercial fishery for the species in Rhode Island 
Sound. Equations used to estimate equilibrium yield are: 



Y = T=T F T P T(o ) (i + exp[g - ZT\ ) 
E T=T r 2 

Y E = equilibrium yield 

T = successive intervals or periods in the life of the 

fish 

T r = tbe first period under consideration 

T — the last period under consideration 

F = instantaneous rate of fishing mortality 

Z = instantaneous rate of total mortality 

g = instantaneous rate of growth in weight. 



Coefficient values were derived from the data of Saila et 
al. (1965) and Pearcy (1962a). Fishing mortality was cal- 
culated on the basis of Rhode Island trawl landings for a 
10-yr period. Figure 20 illustrates three surfaces repre- 
senting the stock weights (in grams) of winter flounder at 
5 mo of age necessary to produce an equilibrium yield of 
approximately 2 million pounds. The lowest surface uses 
a conservative estimate of Z, the middle surface an 
average value, and the upper surface a slightly higher 
one. 

The stock weight of newly metamorphosed juveniles 
necessary to sustain the empirical average yield under 
average mortality coefficients for all life history stages 
was 6.5 X 10 6 g or 1.8 X 10'° individuals. The stock 
weight of juvenile flounder at an age of 5 mo was a signifi- 
cant proportion of the equilibrium yield. Growth ap- 
peared to be very rapid during the early life history 
stages and this provided for a significant early increase in 
biomass over and above the amount removed by natural 
mortality. The effect of natural mortality is more sig- 
nificant than the fishing mortality, and research on in- 
creasing the basic productivity of nursery areas would 
have a high probability of success in terms of improving 
the fishery. 

4.6 The population in the community and the 
ecosystem 

Dexter (1944) classified the winter flounder as a domi- 
nant which exerts control over the Strongylocentrotus- 
Buccinum community by occupying and holding space. 
The community extends from spring low water to a depth 
of about 27 m and latitudinally from the northern part of 
Cape Cod to the boundary of the cold Labrador Cur- 
rent off the coast of Maine. It is characterized by echino- 
derms, large gastropods, skates, sculpins, flounders, and 
decapod crustaceans. 



31 



200.000 



500.000 



600.000 




B 



.2 .4 .6 .8 10 12 14 1.6 18 £0 



a. 

3 
\- 
Q. 
< 
U 

H 



6.0 



5.0 



C 4.0 



3.0 



20 



yrVgrgr nC P 1.050.000 1.100.000 



1.160.000 




J I I I I L 



J L. 



.2 .4 .6 .8 IP 12 1.4 1.6 18 20 



-v 



MO.I5 
K-0.40 



J I 



5.0 



100 



60 
50 
4.0 
30 
2P 



V* 500.000 60OO00 



700000 



750.000 




D 



-L 



-L 



75O0O0 



J L I L 



.6 



.8 IP 12 14 16 18 2p 
F- INSTANTANEOUS RATE OF FISHING 



+■ 



MOl25 
K-CU5 



5.0 



J I 



IQO 



2. A 

Figure 19.— Yield isopleth diagrams for the St. Marys Bay flounder fishery (from Dickie and McCracken 1955). 



32 







r5.0 x 10* 




•4.5 x lO 6 ^^ / 




■4.0 xlO 6 / 


/ 2 
/ =i 

/ o 

/ z 


■3.5 xlO 6 / 


/ "? 




/ ti- 


■ZQ\\0*^f / 


/ / w 

/ / <" 




/ / < 

/ / * 


■2.5 xio 6 // J 


/ / o 

1 / m 








■2.0 x10 s / / 

/ / / 






1 1 / 

1.5 xlO 6 / 






/ / ^ 






► 1 . x V&s^'^ / 






L^y X44 






■0 5x10°/ 

/ "X28 M 


■" — 1 1 1 1 1 1 


y<20 
U2 



60 



.874 794 .714 .634 .554 474 .394 

F 

Figure 20. — Stock weights of winter flounder at age 5 mo required to 
produce an equilibrium yield of approximately 2 million pounds for 
three values of Z for the first 5 mo. Lowest surface, Z = 1.655; middle 
surface, Z = 1.855; and upper surface, Z = 2.055. (From Saila et al. 
1965.) 

Richards (1963) analyzed the demersal fish popula- 
tion of Long Island Sound from a sand-shell bottom and 
a mud bottom. The 10 most common species (of 37 
species, 3,949 individuals) constituted 93% of the total 
standing crop. The winter flounder was the most abun- 
dant species composing 67% of the standing crop in both 
bottom types. There were two groups of species, residents 
and migrants. The chief residents besides winter floun- 
der were the windowpane, Scophthalmus aquosus, and 
the hake, Merluccius bilinearis. The chief migrant was 
the scup, Stenotomus chrysops. In general, fishes were 
more abundant in fall, decreased early in winter, in- 
creased in late winter, and reached a low in summer. 

The sand-shell station was characterized by a high 
percentage of sand and gravel. It was occupied by a bio- 
mass of epifauna five times that of infauna of which the 
epifauna dominates the diets of prey species. Winter 
flounder dependence on polychaetes separated it from 
most other predators, and its omnivorous tendencies 
precluded extensive competition. Immigration of migra- 
tory predators increased chances for interspecific com- 



petition, but this was kept to a minimum (except for S. 
aquosus) by the abundant and well distributed food 
resources and absence of territoriality among the 
predators. The community was heterogeneous. Juvenile 
production was 0.06 g/m 2 per year. Trophic level conver- 
sion figures based on consumption of epi- and infauna 
showed infauna productivity was sufficient to support 
the species without additional epifauna but efficiency of 
food conversion was low, and it did not appear to make 
maximum use of available food (Richards 1963). 

Tyler (1971) described periodic and resident com- 
ponents of a northern Atlantic fish community located in 
Passamaquoddy Bay, New Brunswick. Temperature 
ranges for this area were 1.2°-10.1°C, salinity 29.5- 
22.3% o . The bottom was sloping, 38-55 m in depth, and 
covered with brown mud. Tyler concluded that in tem- 
perate regions, inshore deepwater fish communities are 
made up of three groups of species — one present during 
winter only, one during summer only, and a third 
throughout the year. The winter flounder was one of the 
most numerous members of the resident community. 
The population exhibited seasonal fluctuations in abun- 
dance related to spawning time, the maximum occurred 
in April and May. Tyler believed formation of temporal 
groups was mainly related to temperature regime, the 
greater the annual temperature fluctuation the more 
species in the temporal and the less in the regular com- 
ponent. Thus community stability was directly related to 
temperature stability. This was a food limited produc- 
tion system (Tyler 1972b) and there was, in general, over- 
lap in diets of the principal species of the community. 
The principal prey of the year-round residents were the 
same during the summer and winter except that four ad- 
ditional prey species were taken in summer. When win- 
ter seasonal species emigrated, the prey species were 
exploited by summer and year-round residents. When 
summer seasonals left, the principal species unique to 
them were unexploited. 

Derickson and Price (1973) studied the shore zone of 
Rehoboth and Indian River Bays, Delaware River. They 
collected 46 species and 41,286 individuals. The five most 
ecologically important species in order of abundance 
were Fundulus majalis, Menidia menidia, Fundulus 
heteroclitus, Pseudopleuronectes americanus, and 
Anchoa mitchilli. Combined average biomass estimates 
for the five SDecies were 5,500 kg/km 2 and 2,800 kg/km 2 
for Rehoboth Bay in 1968 and 1969, respectively, and 
7,600 kg/km 2 and 3,700 kg/km 2 for Indian River Bay in 
1968 and 1969, respectively. Greatest species diversity 
and abundance occurred in summer, probably because 
the bays were used as a nursery and feeding grounds. The 
numbers of individuals and species showed a direct rela- 
tionship to seasonal temperature. Winter flounder abun- 
dance showed no relationship to substrate type, vege- 
tation, and water current velocity, but water depth and 
temperature were important to various life stages of 
flounder. 



33 



Oviatt and Nixon (1973) described the community 
structure in Narragansett Bay. The 10 most important 
species made up 91% of the catch (Table 21). Winter 
flounder was the most abundant species. There was no 
clear pattern of fish abundance except for higher diver- 
sity at the mouth of the bay. Bay characteristics were: 
relatively unpolluted, covers 259 km 2 , has a small salini- 
ty range (24-30%o), temperature range from -0.5° to 
25°C, weak seasonal stratification, and depths up to 40 
m. East Passage is deeper than West Passage. Both were 
dominated by fine sediments with sand present at the 
mouth of the Bay and upper West Passage. The only 
year-round residents of the Bay were winter flounder and 
sand dab (windowpane). Scup, butterfish, weakfish, and 
sea robin were summer species only; winter species were 
sea herring, blue back herring, torn cod, and sculpin. The 
total species diversity expressed as the Shannon Weiner 
Index was 3.22. The high was in October and the low in 
January which is opposite to tnat reported by McErlean 
et al. (1973) for Chesapeake Bay. 

Table 21. — Important fish species by number and percent of two eco- 
systems. Species rank for 101 trawls at regular stations throughout 
the year. 







Percent 


Total 


Common name 


Scientific name 


of total 


number 




N'arragansett Bay, R.I.' 






Winter flounder 


Pseudopleuronectes 








americanus 


36 


3,361 


Windowpane 


Scophthalmus aquosus 


14 


1,287 


Scup 


Stenotomus chrysops 


10 


915 


Butterfish 


Peprilus triacanthus 


9 


871 


Weakfish 


Cynoscion regalis 


8 


718 


Northern sea robin 


Prionotus carolinus 


6 


f,i;.i 


Red hake 


Urophycis chuss 


3 


2? ■■ 


Barred sea robin 


Prionotus mart is 


2 


186 


Cunner 


Tautogolabrus adspersus 


2 


179 


Little skate 


Raja erinacea 
Mystic River estuary, Mass. 2 


1 


126 


Winter flounder 


Pseudopleuronectes 








americanus 


53 


1,465 


Rainbow smelt 


Osmerus mordax 


32 


890 


Alewife 


Alosa pseudoharengus 


7.6 


186 


Atlantic herring 


Clupea harengus 


5.9 


163 


Atlantic menhaden 


Brevoortia tyrannus 


0.9 


27 


Blueback herring 


Alosa aestiualis 


0.7 


19 


Ocean pout 


Macrozoarces americanus 


>0.1 


4 


Grubby 


Myoxocephalus aenaeus 


>0.1 


3 


Cunner 


Tautogolabrus adspersus 


>0.1 


3 


Atlantic mackerel 


Scomber scombrus 


>0.1 


3 



Oviatt and Nixon (1973). 
Haedrich and Haedrich (1974). 



the system, they might be important in regulating diver- 
sity and abundance of other members of the benthos. 

Haedrich and Haedrich (1974) surveyed fishes in the 
Mystic River estuary, Mass. It is a mixed, almost homo- 
geneous estuary with a tide range of 2-4 m, salinity 29- 
32% , and temperature 5°-18°C (bottom 3°-14°C). The 
lower 2 km of the estuary has been dredged. A power 
plant was located on the upper end of this stretch; heat- 
ing effects are minimal, but discharge may be 10° higher 
than the intake temperature. The midstream tempera- 
ture of water near the plant was rarely higher than 1° of 
that downstream. The estuary was highly polluted: DO 
1-6.8 ppm but generally less than 50% saturated, pH 6.5- 
8.0 with a high concentration of organic nutrient, and 
coliform counts in concentrations as high as 30,000 
cells/100 ml. Oily residues and hydrogen sulfide were pres- 
ent in the sediments. A benthic community analysis 
showed very low diversity dominated by the polychaete, 
Capitella capitata, a pollution indicator organism. Total 
number of fishes caught was 2,778 of 23 species; total 
weight was 1,631 kg. The 10 most abundant species are 
given in Table 21. This assemblage was similar to other 
northern fish communities with periodic and resident 
species; the winter flounder was a resident, completing 
its entire life cycle in the estuary. Catch rates for the es- 
tuary were lowest in June by numbers and weight and in- 
creased, thereafter, throughout the year. The mean rate 
of biomass caught was 24 kg/h or 2 g fish/m 2 . Diversity in 
numbers was at its highest in June and lowest in August; 
species diversity was greatest in November (see Fig. 15). 

Biomass diversity indicates complexity of energetic 
relations in the food web; in this estuary, diversity was 
low and winter flounder were major channels of energy 
flow at the fish trophic level. The community had a dy- 
namic period from November to August and a static one 
from summer to early winter. Food competition between 
major species was not likely as the three major fish 
species have very different food habits. They do not com- 
pete for space and the breeding time is different for all 
three species. Pooled annual diversity, a measure of com- 
munity structure designated H, was 1.19 on numbers and 
0.71 on weight. These values were low, but close to those 
obtained by McErlean et al. (1973) from the Patuxent 
River, Md.; suggesting this diversity level might be 
characteristic of temperate estuaries. 

5 FISHING 

5.1 Fishing equipment 



The winter flounder population was not aggregated 
(K = 1) and the maximum K value (a measure of ag- 
gregation) of 7.3 occurred in the fall. There was little dif- 
ference in seasonal means (spring 8,151/km 2 , summer 
6,669/km 2 , fall 7,163/km\ and winter 11,856/km 2 ). 
Trophic relationships were such that the two major 
species, winter flounder and windowpane, did not com- 
pete for food. The mean annual biomass of demersal 
fishes was 31,876 kg/m'. Although the abundance of 
demersal fishes was small with respect to other parts of 



5.11 Gears 

The most common gear used in the winter flounder 
fishery is the otter trawl (No. 35 Yankee). Dickie and 
McCracken (1955) gave the mesh size in the belly as 4 in 
(10.2 cm) between knot centers as purchased and in the 
cod end about 3 in (7.6 cm). Motte et al. 1973 12 described 



,2 Motte, G. A., A. J. Hillier, and R. P. Beckwith. 1973. Bottom 
trawl performance study. Univ. R.I. Mar. Tech. Rep. Ser. No. 7. Un- 
paged. 



34 



the trawl in detail (Table 22). Although there is a pound 
net fishery in the Chesapeake area and a fyke net fishery 
in the Middle Atlantic region, these fisheries are declin- 
ing. 

Perlmutter (1947) gave a history of the development of 
the fishery in the New York area. Before 1895 fish were 
taken by fyke net and traps. As consumer demand in- 
creased, more efficient gear was used. In 1895 the beam 

Table 22.— Description of Yankee 35 Otter Trawl (Motte et al. 1973). 





Length X 






Line 


diameter 


Material 


Attachments 


Headline 


52 ft 


Combination 


Floats: 8 or 19 X 8 


Bosom 


12 ft X 5/8 in 




in. diam. plastic 


Each wing 


20 ft X 5/8 in 






Footrope 


72 ft 


Chain 


Bobbin gear: 4-in 


Bosom 


10 ft X 3/8 in 




diam. rubber discs, 


Each wing 


31 ft X 3/7 in 




full length of 
footrope 


Hanging line 


89 ft X 5/8 in 


Polypropylene- 
Dacron 




Wing lines 


6 ft X 5/8 in 


Polypropylene- 
Dacron 




Wing bridles 








Upper 


60 ft X 3/8 in 


Steel wire chain 




Lower 


60 ft X 3/8 in 






Door legs 








Upper 


7 ft X 5/16 in 


Chain 


Doors: standard 


Lower 


7 ft X 5/16 in 


Chain 


rectangular 3 ft X 
6 ft X 1 to in 
236 lbs 


Towing warps 


7/16 in 


Steel wire 





Motte, G. A., A. J. Hillier, and R. P. Beckwith. 1973. Bottom trawl 
performance study. Univ. R.I. Mar. Tech. Rep. Ser. No. 7. Unpaged. 

trawl was introduced in the flounder fishery of 
Massachusetts. By 1915, the Cape Cod fishery had 
changed to otter trawls and there was a shift from sail to 
gasoline and diesel engines which made it possible to fish 
a greater area. By 1920 the winter flounder fishery was at 
its peak, but during the 1930's fishermen reported 
decreasing catches on major grounds; therefore, a mar- 
ket developed for yellowtail flounder, Limanda 
ferruginea. During the 1960's the winter flounder fishery 
increased again. 

5.12 Boats 

Dickie and McCracken (1955) described boats used in 
the Newfoundland winter flounder industry. Originally 
there were two types of boat: 1) large boats 40-45 ft long 
with gasoline engines, about 100 hp, which towed 50 ft 
"flounder drags" or No. 35 Yankee trawls; these boats 
began fishing earlier in spring, and 2) smaller Cape Is- 
land type open boats 30-40 ft long with gasoline marine 
engines and power-driven winches. By 1951 the large 
boats stopped fishing for winter flounder. 

Olsen and Stevenson 11 described commercial fishing 
boats used in Rhode Island waters. There were three 



"Olsen, S. B., and D. K. Stevenson. 1975. Commercial marine fish 
and fisheries of Rhode Island. Univ. R.I. Mar. Tech. Rep. 34, 117 p. 



groups of trawlers: 1) day boats 40-60 ft long fishing the 
nearshore grounds with a three-man crew, which leave 
and return to port the same day, 2) short-trip boats, es- 
sentially the same as day boats but making trips of 1-3 
days, and 3) long-trip boats 55-85 ft long fishing the off- 
shore grounds such as Nantucket shoals and Georges 
Bank, carrying a three- to six-man crew and making 3- to 
6-day trips. These boats had larger engines and were 
usually equipped with radar. 

5.2 Fishing areas 

5.21 General geographic distribution 

The general geographic distribution is the northwest 
Atlantic (FAO Statistical Area 21) on the coast of North 
America from Labrador to Cape Hatteras, N.C. (Fig. 2). 

5.22 Geographic range 

Winter flounder are found within 15 mi (24.2 km) of 
the shore and on offshore banks. They enter estuaries 
and may be found in brackish waters of many rivers. 
They are most abundant from Nova Scotia to New Jer- 
sey in inshore waters (Perlmutter 1947). There are also 
large populations on Georges Bank and Nantucket 
Shoals. 

5.23 Depth range 

Tide mark to 20 fathoms (40 m), they extend to 50 
fathoms on the offshore banks. The depth record is 70 
fathoms (Bigelow and Schroeder 1953). Variations of 
density with depth have been discussed in sections 4.12 
and 4.24. 

5.24 Conditions of the grounds 

Olsen and Stevenson (see footnote 13) stated that in 
Rhode Island waters, winter flounder can be caught over 
all types of bottom, but in salt ponds and estuaries they 
preferred muddy sand. Bigelow and Schroeder (1953) 
reported that on offshore banks they were common on 
hard bottom. 

5.3 Fishing seasons 

5.31 General pattern of seasons 
Early spring to late fall. 

5.32 Dates of beginning, peak, and end of season 
See Table 23. 

5.33 Variation in date or duration of season 

The season generally begins after adults have spawned 
and begun to move into deeper water. Factors affecting 
this are covered in sections 3.16 and 3.51. 



35 



Table 23.— Fishing seasons for winter flounder. 



Area 



Season 



Peak Minimum 



Author 



Long Island Feb. -June Apr. -May Lobell(1939) 

Rhode Island Year-round May -July Winter Olsen and 

Stevenson (1975)' 

Si MarysBay, Mar -Winter Apr. -July Winter Dickie and 

Nova Scotia McCracken (1955) 

Lone Island Mar. -Nov. Apr. -May Winter Briggs(1965) 

sports fishery 

Olsen. S. B.. and D. K. Stevenson. 1975. Commercial marine fish 
and fisheries of Rhode Island. Univ. R.I. Mar. Tech. Rep. 34, 117 p. 

5.4 Fishing operations and results 

5.41 Effort and intensity 

Dickie and McCracken (1955) calculated fishing effort 
in the St. Marys Bay, Nova Scotia, fishery by compiling 
average catch per 50-ft net per hour from boats which 
fished exclusively for flounder. To compare the drop in 
catch per effort with the history of the fishing intensity 
they divided the total landings of flounders from the 
catch by the catch per unit of effort by 50-ft nets. 

Edwards (1968) computed exploitation rate by cal- 
culating the average catch in pounds per tow for ICNAF 
Subarea 5 (New England) made by the 1963-66 ground- 
fish survey using a 36 Yankee Trawl with a 0.5-in (1.3- 
cm) cod end liner. The trawl had a bottom spread 35-40 
ft (10.7-12.2 m) and a maximum height of 7ft (2.1 m) at 
the middle. Biomass was calculated by applying a cor- 
rection factor of the number of square miles for the zone 
divided by area the net sweeps each tow (0.016 mi 2 ) to 
the catch per tow in pounds. 

Results of both calculations are presented in Table 24. 

Briggs (1965) calculated catch per unit effort of winter 
flounder by sportsmen fishing from five different facili- 
ties (bank and pier, rowboat, open boat, charter boat, 
and private boat) in four different locations around Long 
Island (Great South Bay, Shinnecock Bay, Gardiners 
Bay, and Moriches Bay) for each month in 1961-63. Open 

Table 24.— Fishing effort for winter flounder in St. Marys Bay and 
ICNAF subarea 5. 





Landings 


by 


Landings 


Propor- 


Total 




50-ft nets' 


by all 

nets' 


tion 
taken by 


effort by 




Catch/h 


50-ft 


Year 


Total 


in lbs 


(lbs) 


50-ft net' 


net 1 


1953 


253,111 


110 


421,071 


0.60 


3,828 


1952 


152,047 


105 


369,262 


0.41 


3,517 


1951 


99,636 


152 


586,111 


0.17 


3,856 


1950 


487,656 


188 


1,299,176 


0.38 


6,911 


1949 


354,024 


4 1 5 


737,403 


0.48 


1,777 


1948 


272,018 


476 


294,000 


0.93 


626 




Catch per unit tow in pour 


ids 2 




Southern 








Browns 


New E 


ngland Georges Bank 
Offshore Shoal Offshore 


Gulf of Maine 


Bank 


Inshore 


Shallow Middle Deep 




8.01 


4.99 


0.01 


11.44 


0.55 0.09 


0.13 



boat and charter boat anglers had the best catch per unit 
effort in the bays. Catch was highest in spring and lowest 
in summer (16-20 fish per angler per trip in spring, 10 or 
less in summer). Bank and pier anglers had the lowest 
catch per unit of effort. 

5.42 Selectivity 

Dickie and McCracken (1955) stated that nets with a 
mesh size of 4 in (102 mm) between knot centers in the 
belly and 3 in (76 mm) in the cod end take flounder down 
to 200 mm in size, but in the Nova Scotia fishery, fish 
plants place a minimum of 300 mm on flounder size. 

5.43 Catches 

Total annual yields in Table 25 include the world yield 
and the U.S. yield by states. For maximum equilibrium 
yield see section 4.5. 

Table 26 is the sports fishery yield of the United States 
by geographic section. 

6 PROTECTION AND MANAGEMENT 

6.1 Regulatory (legislative) measures 

Poole (1969) reported the State of New York Fish and 
Game Law prohibits buying, selling, or offering for sale, 
winter flounder less than 8 in (206 mm) long. 

Howe and Coates (1975) reported Massachusetts 
prohibits otter trawling at all times north of Boston and 
in Buzzards Bay. In most other areas trawling is 
prohibited from 1 April or 1 May to 31 October. 

Trawl regulations by the International Commission for 
the Northwest Atlantic Fisheries in relation to bottom 
fisheries, prohibit use of trawl nets with cod end meshes 
of dimensions less than 130 mm in manila twine netting 
or the equivalent when materials other than this are used 
to take winter flounder in subarea 4 (Bogdanov and Kon- 
stantinov 1973). See Figure 2. 

6.3 Control or alteration of chemical features of the 
environment 

Eisler (1965b) studied acute toxicity of alkyl benzene 
sulfonate (ABS), a surfactant present in detergent, to 
five estuarine fish species. The fishes, Menidia menidia, 
Fundulus heteroclitus, Mugil cephalus, Anguilla ros- 
trata, and Pseudopleuronectes americanus, were col- 
lected from New Jersey. Tide detergent, used as a source 
of ABS, contained 30.3% ABS. The winter flounder was 
intermediate in susceptibility; 8.2 ppm detergent was 
the L.C 50 after 96 h exposure at 20% o salinity and 20° C. 
After 12 wk in solution, the detergent retained its toxici- 
ty. 

Sprague and Carson 14 did preliminary screening tests 



Dickie and McCracken (1955). 
'Edwards 0968). 



"Sprague, J. B., and W. B. Carson. 1970. Toxicity tests with oil dis- 
persants in connection with oil spills at Chadabucto Bay, Nova Scotia. 
Fish. Res. Board Can., Tech. Rep. 201, 30 p. 



36 



Table 25. — Annual yield of winter flounder in world and U.S. commercial fish- 
eries.' 







1965 


1966 


1967 


1968 


1969 


1970 


1971 


1972 


1973 












1,000 t — - 




















Canada 




5.2 


3.3 


2.7 


1.2 


2.5 


— 


— 


— 


— 


U.S. 




11.6 


14.7 


12.3 


9r> 


11.3 


12.1 


11.6 


7.2 


9.7 


Total 




16.8 


18.0 


15.0 


10.7 


13.8 


12.1 


11.6 


7.2 


9.7 






New 


Massa- 




Con- 




New 












Hamp 


chu- 


Rhode 


necti- 


New 


Jer- 


Dela- 


Mary- 


Vir- 


Year 


Maine 


shire 


setts 


Island 


cut 


York 


sey 


ware 


land 


ginia 












1.00C 
































1973 


L86 


8 


10.914 


4,414 


844 


1,661 


160 


2 


2,200 


900 


1972 


280 


10 


11,344 


4,634 


38 


1,429 


94 


2 


3 


21 


1971 


146 


7 


14,542 


5,275 


817 


1,660 


79 


5 


17 


55 


1970 


298 


8 


15,898 


5,301 


789 


1,692 


146 


3 


•21 


123 


1969 


96 


4 


15,616 


4,300 


931 


1,444 


268 


2 


60 


394 


1968 


45 


— 


11,996 


3,362 


1,041 


1,826 


4 2 2 


3 


7-4 


824 


1967 


103 


— 


16,419 


3,844 


886 


2,931 


366 


19 


178 


798 


1966 


92 


— 


21,085 


4,275 


831 


3,259 


438 


50 


91 


220 


1965 


69 


— 


16,520 


3,638 


727 


2,245 


279 


38 


62 


122 


1964 


75 


— 


13,901 


4,080 


957 


1,441 


357 


4H 


26 


68 


1963 


45 


— 


11,786 


2,918 


983 


1,834 


185 


37 


10 


2 


1962 






















1961 


158 


— 


11,934 


2,028 


980 


1,695 


152 


20 


3 


1 



'From Fishery statistics of the United States. National Marine Fisheries Service, 
Statistical Digest numbers 54-56 for the years 1961-73. 



Table 26.- 



-Sports fishery statistics for winter flounder in 1970 and 1965 by survey re- 
gion (from Deuel 1973 and Deuel and Clark 1968). 



Year 



Region I North Atlantic 

New Engl and-New Jersey 

No. No. Wt. offish 

anglers fish (1,000 lbs) 



Region II Middle Atlantic 
New Jersey-Cape Hatteras 
No. No. Wt. offish 

anglers fish (1,000 lbs) 



Total 



1970 563 42,949 24,684 402 18,632 12,801 

1965 579 40,014 21,838 277 7,256 6,935 

Number of fishes of all species caught by U.S. salt water anglers in 1970 
21,581 7,496 



29,077 



of oil dispersants, manufactured for use in cleaning up oil 
spills, for acute toxicity to aquatic life. The test 
procedure used a static system with a given concen- 
tration of test mixture. Exposure continued for 7 days, 
after which several fish were removed and held in clean 
running water for 7 more days to check for delayed mor- 
tality. Test results gave an indication of acute lethal ef- 
fect only. There may be long-term or sublethal effects at 
concentrations of oil dispersants lower than those dis- 
cussed (Table 27). A classification scheme for "grade of 
toxicity" adapted from a report by the Joint Group of 
Experts on the Scientific Aspects of Marine Pollution 
(1969) was employed to describe toxicity (Table 27). 

Bunker C oil was "practically nontoxic" by 4-day 
criteria, but in 7-day tests, including 7-day postexperi- 
ment mortality, it was "slightly toxic" to winter floun- 
der (5°C 1,000-3,000 mg/liter). Corexit 8666 was "prac- 
tically nontoxic" as was its dispersion with Bunker C oil. 
An apparent toxicity during degradation should be in- 
vestigated before Corexit 8666 is considered for wide- 
scale use. Fish which died in Corexit alone had gill rakers 
and throats covered with white particles, apparently 



Corexit in mucus. This suggested Corexit caused mucus 
secretion around the affected areas and could be a factor 



Table 27. — Four-day median lethal concentrations of various oil 
dispersants, alone or mixed with Bunker C oil, to winter flounders 
and grading system used to describe toxicity at 5°C (from Sprague 
and Carson 1970).' 



Bunker C oil 
Corexit 8666 
Corexit 8666 and oil 
BP1100 + oil 
Disperaol SD 

Grade "Practically nontoxic" 

Grade 1 "Slightly toxic" 
Grade 2 "Moderately toxic" 
Grade 3 "Toxic" 
Grade 4 "Very toxic" 



> 10,000 mg/1 

> 10,000 mg/1 

> 10,000 mg/1 

32 mg/1 

> 1,000 mg/1 

Acute toxicity threshold 

above 10,000 mg/1 
Threshold 1,000-10,000 mg/1 
Threshold 100-1,000 mg/1 
Threshold 1-100 mg/1 
Threshold below 1 mg/1 



'Sprague, J. B., and W. B. Carson. 1970. Toxicity tests with oil 
dispersants in connection with oil spills at Chadabucto Bay, Nova Scotia. 
Fish. Res. Board Can. Tech. Rep. 201, 30 p. 



37 



in mortality, hut this could also have happened after the 
t'ish began dying. 

Smith and Cole (1970) examined the effects of 
chlorinated hydrocarbons DDT. heptachlor, dieldrin in- 
secticide residues, and two related breakdown products 
DDE and heptachlor epoxide, on winter flounder 
juveniles and adults from the Weweantic River estuary, 
Mass. Topp (1968) compared larval mortality of winter 
flounder in the Weweantic to that data compiled by 
Pearcy (1962a) for the Mystic River estuary, Conn., and 
found excessive mortality in the former. He felt this 
might be due to pesticide contamination which drained 
from cranberry bogs along the Weweantic River water- 
shed and from county mosquito control programs. 

Winter flounder contained residues of the above com- 
pounds in their tissues. In nonmigratory juveniles, 
seasonal patterns were demonstrated for DDT, hep- 
tachlor. DDE, and heptachlor epoxide. Peak concen- 
trations of parent compounds were more closely 
associated with high runoff conditions than with specific 
applications of pesticides in the drainage system. 
Dieldrin was present uniformly throughout the year. 
Migratory adult flounder present from October to May 
contained heptachlor and heptachlor oxide levels similar 
to juveniles but significantly less DDE (Table 28). Com- 
parisons of chromatographic patterns of these flounders 
with flounders from widely separated coastal popu- 
lations and offshore Georges Bank flounders showed that 
the Wew-eantic population had a unique pattern quite 
dissimilar from other populations inferring that local 
pesticide levels can establish area specific chroma- 
tographic patterns. Adult female flounder sequentially 
concentrated DDT, DDE, and heptachlor epoxide in 
their ripening ovaries as spawning season approached 
(Table 28). Ovarian concentrations of insecticide residue 
may have caused the high larval mortality at final yolk 
sac absorption reported by Topp (1968), because residues 
were bound to yolk fats where they remained inactive un- 
til those fats were metabolized by the developing egg. At 
this time DDT would be released and would cause death. 

Eisler (1970) reported juvenile winter flounder were in- 
termediate in susceptibility to endrin, p,p'-DDT, and 
heptachlor on the basis of LC 50 (96 h) tests conducted 
with 10 species of marine fishes. 



Janicki and Kinter (1971) reported inhibition of ATP - 
ase activity by DDT and its commercial solvents cyclo- 
hexanone and DMF (N,N dimethylformamide) in win- 
ter flounder from the Gulf of Maine. They found 
measurable inhibition of Na + , K + , Mg + + , ATP-ase ac- 
tivity in the intestinal mucosa at 1 ppm concentration 
DDT which was linear through 50 ppm. The gills tested 
with DMF and 50% ppm DDT showed ATP-ase activity 
54% inhibited. Cyclohexane completely inhibited ac- 
tivity. This inhibition of ATP-ase activity hindered ac- 
tive secretion of salt through gills which is important in 
maintaining tissue osmolarity. These observations may 
explain the sensitivity of teleosts to DDT. 

Baker (1969) experimented on histological and ultra- 
structural effects of high (3,200 and 1,000 fig/liter), 
medium (560^g/liter), and low (180A<g/liter) copper con- 
centrations on several organs, and the relationship of 
these effects to medical knowledge of copper metabolism. 
The results showed that high and medium levels of cop- 
per resulted in fatty metamorphosis in the liver, necrosis 
in the kidney, destruction of hemapoetic tissue, and 
gross changes in gill architecture. Somatic muscle, heart, 
stomach, duodenum, intestine, eyes, and brain showed 
no morphological changes. 

Pritchard et al. (1973) described metabolism and ex- 
cretion of DDT and Mirex, two highly persistent organo- 
chlorine pesticides, in winter flounder. Fish were in- 
jected with sublethal concentrations (100 g/kg) of labeled 
pesticide. Tissue and body fluids were analyzed. Because 
there was limited metabolism of parent pesticides to less 
toxic derivatives (90% of the DDT and 100% Mirex were 
unaltered after 1 wk), and excretion of both was very slow 
because of plasma binding, they concluded winter floun- 
der retain large fractions of pesticide which they are es- 
sentially unable to detoxify. Since fishes hold their pesti- 
cide burden primarily in muscle, the flesh of flounder 
from contaminated areas will be heavily loaded and is 
potentially dangerous for terminal consumers such as 
man. 

Freeman et al. (1974) determined mercury levels in 
fish from the Canadian Atlantic Coast. These results 
were 0.17-0.18 ppm mercury with a mean of 0.17 ± 0.01 
for dorsal muscle of male fish, 557 g average weight, and 
0.11-0.20 ppm mercury with a mean of 0.17 ± 0.03 for 



Table 28. — Average concentrations of insecticide residues in muscle tissue of win- 
ter flounder of various ages taken 25 January 1967, Weweantic River estuary (ppm 
wet weight). (From Smith and Cole 1970.) 





No. 






Hepta- 


Heptachlor 




Age 


fish 


DDT 


DDE 


chlor 


epoxide 


Dieldrin 


I 


5 


<0.01 


0.72 


1.55 


0.56 


< 0.01 


H 


7 


< 0.01 


1.07 


1.10 


<0.01 


< 0.01 


III 


4 


<0.01 


0.18 


1.27 


<0.01 


<0.01 


[\ 


3 


<0.01 


0.21 
Ovarian 


0.62 
tissue 


<0.01 


< 0.01 


30 Oct. 1966 


3 


0.11 


0.02 


0.07 


— 


< 0.01 


1967 


3 


0.16 


0.04 


<0.01 


<0.01 


<0.01 


29 Mar. 1967 


4 


0.40 


0.22 


<0.01 


0.65 


<0.01 



38 



female dorsal muscle. There was no significant dif- 
ference between mercury levels and sex or weight of the 
fish. Mercury limits allowed for commercial fish in the 
United States and Canada are 0.5 ppm. 

6.4 Control or alteration of biological features of the 
environment 

Hess et al. (1975) simulated the impact of the entrap- 
ment of winter flounder larvae at a nuclear power sta- 
tion, Millstone Point, Conn. Currents and water levels 
were simulated by a tidal hydrodynamic model, tidal 
currents, and diffusion by a computer. These provided 
input to a transport model which simulated the concen- 
tration of larvae to predict the numbers which could be 
entrained. Results indicated that the reduction in winter 
flounder larvae at the end of the pelagic stage when they 
are most likely to be entrained was less than 1% with the 
assumption that larvae will not return if lost from Mill- 
stone Bight. The effect of this 1% reduction in recruit- 
ment was simulated by a model in which year classes and 
total egg production were represented by compart- 
ments. Population parameters such as fecundity, natural 
and fishing mortality, and growth information was 
gathered from the literature. The effect of entrainment 
was incorporated by reducing the number of recruits to 
year class I that would result from a certain level of egg 
production. This indicated for a 1% reduction in recruit- 
ment, a potential 6 c r decrease in total population size 
after 35 yr of power plant operation (the average power 
plant life) (Fig. 21). 




20 30 40 50 60 70 

SIMULATED TIME IN YEARS 



Figure 21. — Simulated total population of winter flounder breeding 
in Niantic River with various levels of entrainment mortality (Mpl) 
(from Hess et al. 1975). 



Predicted values for which there was no local infor- 
mation such as currents, number of spawning adult win- 
ter flounder, and larval concentration are being verified 
by field work in progress. 

An overall assumption is made that some of the floun- 
der larvae spawned in the Niantic River and passing near 
the power plant will remain in the estuary. If all are lost 
to Long Island Sound the effect of entrainment of several 
percent of the larval population would be nil for winter 
flounder recruitment. 

7 POND FISH CULTURE 

Winter flounder were propagated and raised in fish 
hatcheries in the late 1800's in the United States because 
it was felt that the release of larvae would increase the 
flounder population, although the effectiveness was 
never established. The techniques for collecting adults, 
stripping and fertilizing eggs, and raising eggs and larvae 
were described by Brice (1898), Rathbun (1893), and 
Mead (1909). These techniques are mainly of historical 
interest, but they did have some interesting methods of 
dealing with the eggs which stick together in large 
clumps after fertilization. 

Eggs may be prevented from clumping by coating with 
diatomaceous earth (Smigielski and Arnold 1972). Eggs 
were stripped into a polyethylene dishpan 35 X 30 X 14 
cm. After the eggs were fertilized, they were covered by a 
dense slurry of diatomaceous earth suspension (50 g/1 of 
sterile seawater) and swirled in the suspension for several 
minutes. They were then rinsed by repeated dunking in 
clean seawater to remove excess diatomaceous earth, 
placed in plastic dishpans with screens fitted over holes 
cut in the sides and bottom, and incubated in flowing 
seawater. 

7.1 Procurement of stock 

Field collections of gravid adults by otter trawl 
(Smigielski and Arnold 1972). 

7.2 Spawning 

Smigielski (1975) studied responses of winter flounder 
to human chorionic gonadotropin (HCG), oxytocin, preg- 
nant mare serum gonadotropin (PMSG), deoxycortisone 
(DOCA), and freeze dried carp pituitary. Carp pituitary 
extract was successful, producing viable hatch in every 
case at dosages of 5 mg/454 mg body weight. The eggs 
and larvae were normal in every respect. 

HCG sometimes was successful when water tempera- 
tures were below 6°C and dosages were over 200 Inter- 
national Units. In general egg quality was poor and sur- 
vival low. The formation of membranous plugs and gross 
hydration caused death in several females. 

PMSG, DOCA, and oxytocin occasionally produced 
hydration but no ovulation. Water temperature appeared 
to be the most critical factor in producing ovulation in 
winter flounder. The majority of fish did not hydrate at 
temperatures over 6°C and had gonadosomal indices less 



39 



than 12^? even with hormone treatment. Observations 
reported in Bigelow and Schroeder (1953) in the Gulf of 
Maine showed that extensive spawning does not occur at 
water temperatures over 6°C. Hormone treatment exper- 
iments at water temperatures of 6°-7.5°C suggest that 
temperature above 6°C inhibit maturation of winter 
flounder eggs. Past observations showed that gravid 
female flounder died in water temperatures of 10°C, and 
their ova were stunted and misshapen. Male flounders 
held under the same conditions suffered no ill effects. 



ACKNOWLEDGMENTS 

I thank Annette Doherty, John MacPhee, and Ralph 
Boragine for their artwork; John Cardin, Marion 
McHugh, and James Brennan for the photography; 
Ronald Eisler and Allan Beck for reviewing the manu- 
script and making editorial comments; Rose Ann 
Gamache, Bruce Lancaster, and Mary Worobec for 
library and technical assistance; and Jennie K. Dunning- 
ton for typing the manuscript. 



LITERATURE CITED 

ACKMAN, R. G., and P. J. KE. 

1968. Commercial redfish and flatfish (flounder) oils; comparative 
features of fatty acid composition. J. Fish. Res. Board Can. 25: 
1061-1065. 

ANONYMOUS. 

1964. Blackback flounder studies aided by discovery of distinctive 
group on Georges Bank. Commer. Fish. Rev. 26(10):30. 

BAKER. J. T. P. 

1969. Histological and electron microscopical observations on cop- 
per poisoning in the winter flounder (Pseudopleuronectes ameri- 
canus). J. Fish. Res. Board Can. 26:2785-2793. 

BATTLE, H. I. 

1926. Effects of extreme temperatures on muscle and nerve tissue 
in marine fishes. Trans. R. Soc. Can. 20(sect. V):127-143. 
BEAMISH, F. W. H. 

1966. Swimming endurance of some Northwest Atlantic fishes. J. 
Fish. Res. Board Can. 23:341-347. 
BERE, R. 

1930. The parasitic copepods of the fish of the Passamaquoddy re- 
gion. Contrib. Can. Biol., New Ser. 5:423-430. 
BERRY, R. J. 

1959. Critical growth studies of winter flounder, (Pseudopleuro- 
nectes americanus) (Walbaum), in Rhode Island waters. M.S. 
Thesis, Univ. Rhode Island, Kingston, 52 p. 
BERRY, R. J., S. B. SAILA, and D. B. HORTON. 

1965. Growth studies of winter flounder, Pseudopleuronectes 
americanus (Walbaum), in Rhode Island. Trans. Am. Fish. Soc. 
94:259-264. 

BIGELOW, H. B., and W. C. SCHROEDER. 

1953. Fishes of the Gulf of Maine. U.S. Fish Wild]. Serv., Fish. 
Bull. 53, 577 p. 
BISHOP, S. C. 

1946. Reversal in the winter flounder. Science (Wash., D.C.) 103: 
174-175. 
BOGDANOV, A. S., and K. G. KONSTANTINOV. 

1973. Fishery regulations in the ICNAF area. J. Fish. Res. Board 
Can. 30:2436-2443. 
BREDER, C. M., Jr. 

1922. Description of the spawning habits of Pseudopleuronectes 

americanus in captivity. Copeia 102:3-4. 
1924. Some embryonic and larval stages of the winter flounder. 
Bull. U.S. Bur. Fish. 38:311-315. 



1938. An unusual aberrently colored pleuronectid. Zoologies 
(N.Y.) 23:393-395. 
BRICE, J. J. 

1898. The flatfish or winter flounder. In A manual of fish cul- 
ture, based on the methods of the United States Commission of 
Fish and Fisheries, p. 215-218. Rep. U.S. Comm. Fish, for 1897, 
part 23. 
BRIGGS, P. T. 

1965. The sport fisheries for winter flounder in several bays of Long 
Island. N.Y. Fish. Game J. 12:48-70. 
BROOKE, R. 0„ E. M. RAVESI, and M. A. STEINBERG. 

1962. The composition of commercially important fish taken from 
New England waters. II. Proximate analyses of butterfish, floun- 
der, pollock and hake and their seasonal variation. J. Food Sci. 
27:73-76. 
COOPER, A. R. 

1915. Trematodes from marine and fresh-water fishes, including 
one species of ectoparasitic turbellarian. Trans. R. Soc. Can., 
Ser. 3 9(sect. 4):181-205. 
1918. North American pseudophyllidean cestodes from fishes, m. 
Biol. Monogr. 4(4), 243 p. 
DAVIS, R. E., and J. E. BARDACH. 

1965. Time-co-ordinated prefeeding activity in fish. Anim. Be- 
hav. 13:154-162. 
DAWSON, C. E. 

1962. Notes on anomalous American Heterosomata with descrip- 
tions of five new records. Copeia 1962:138-146. 

1967. Three new records of partial albinism in American Heteroso- 
mata. Trans. Am. Fish. Soc. 96:400-404. 

DERICKSON, W. K„ and K. S. PRICE, Jr. 

1973. The fishes of the shore zone of Rehoboth and Indian River 
Bays, Delaware. Trans. Am. Fish. Soc. 102:552-562. 
DEUEL, D. G. 

1973. 1970 salt-water angling survey. U.S. Dep. Commer., NOAA, 
Natl. Mar. Fish. Serv., Curr. Fish. Stat. 6200, 54 p. 

DEUEL, D. G., and J. R. CLARK. 

1968. The 1965 salt-water angling survey. U.S. Bur. Sport Fish. 
Wildl. Resour. Publ. 67, 51 p. 

DEXTER, R. W. 

1944. The bottom community of Ipswich Bay, Massachusetts. 
Ecology 25:352-359. 
DICKIE, L. M„ and F. D. McCRACKEN. 

1955. Isopleth diagrams to predict equilibrium yields of a small 
flounder fishery. J. Fish. Res. Board Can. 12:187-209. 
DONAHUE, J. K. 

1941. Occurrence of estrogens in the ovaries of the winter flounder. 
Endocrinology 28:519-520. 
DUMAN, J. G., and A. L. de VRIES. 

1974. Freezing resistance in winter flounder Pseudopleuronectes 
americanus. Nature (Lond.) 247:247-248. 

DUNN, R. S. 

1970. Further evidence for a three-year oocyte maturation time in 

the winter flounder (Pseudopleuronectes americanus). J. Fish. 

Res. Board Can. 27:957-960. 
DUNN, R. S., and A. V. TYLER. 

1969. Aspects of the anatomy of the winter flounder ovary with 
hypotheses on oocyte maturation time. J. Fish. Res. Board Can. 
26:1943-1947. 

EDWARDS, R. L. 

1968. Fishery resources of the North Atlantic area. In D. Gilbert 

(editor). The future of the fishing industry of the United States, 

p. 52-60. Univ. Wash. Publ. Fish., New Ser. 4. 
EISLER, R. 

1963. Partial albinism and ambicoloration in winter flounder, 

Pseudopleuronectes americanus. Copeia 1963:275-277. 
1965a. Erythrocyte counts and hemoglobin content in nine species 

of marine teleosts. Chesapeake Sci. 6:119-120. 
1965b. Some effects of a synthetic detergent on estuarine fishes. 

Trans. Am. Fish. Soc. 94:26-31. 

1970. Acute toxicities of organochlorine and organophosphorus in- 
secticides to estuarine fishes. U.S. Bur. Sport Fish. Wildl. Tech. 
Pap. 46, 12 p. 



40 



ELLIS, M. F. 

1928. Ichthyophonus hoferi, Plehn and Mulsow, a flounder parasite 

new to North American waters. Proc. Trans. Nova Scotian Inst. 

Sci. 17:185-192. 
FAIRBANKS, R. B., W. S. COLLINGS, and W. T. SIDES. 

1971. An assessment of the effects of electrical power generation on 
marine resources in the Cape Cod Canal. Mass. Dep. Nat. Re- 
sour., Div. Mar. Fish., 48 p. 

FISH, F. F. 

1934. A fungus disease in fishes of the Gulf of Maine. Parasitology 
26:1-16. 
FRAME, D. W. 

1972. Biology of young winter flounder Pseudopleuronectes ameri- 
canus (Walbaum): Feeding habits, metabolism and food utiliza- 
tion. Ph.D. Thesis, Univ. Mass., Amherst, 109 p. 

1973a. Biology of young winter flounder Pseudopleuronectes ameri- 
canus (Walbaum); metabolism under simulated estuarine condi- 
tions. Trans. Am. Fish. Soc. 102:423-430. 
1973b. Conversion efficiency and survival of young winter flounder 
(Pseudopleuronectes americanus) under experimental conditions. 
Trans. Am. Fish. Soc. 102:614-616. 
FREEMAN, H. C, D. A. HORNE, B. McTAGUE, and M. McMENEMY. 
1974. Mercury in some Canadian Atlantic coast fish and shellfish. 
J. Fish. Res. Board Can. 31:369-372. 
GOLDSTEIN, L., and R. P. FORSTER. 

1965. The role of uricolysis in the production of urea by fishes and 
other aquatic vertebrates. Comp. Biochem. Physiol. 14:567-576. 
GRAFFLIN, A. L. 

1935. Renal function in marine teleosts. I. Urine flow and urinary 
chloride. Biol. Bull. (Woods Hole) 69:391-402. 

GRAFFLIN, A. L„ and R. G. GOULD, Jr. 

1936. Renal function in marine teleosts. II. The nitrogenous con- 
stituents of the urine of sculpin and flounder, with particular 
reference to trimethylamine oxide. Biol. Bull. (Woods Hole) 70: 
16-27. 

GUDGER, E. W. 

1934. Ambicoloration in the winter flounder, Pseudopleuronectes 
americanus. Am. Mus. Novit. 717, 8 p. 

1935. Abnormalities in flatfishes (Heterosomata) I. Reversal of 
sides. A comparative study of the known data. J. Morphol. 58: 
1-39. 

1945. Reversal in the winter flounder, Pseudo-pleuronectes ameri- 
canus: The three known cases. Science (Wash., D.C.) 102:672- 
673. 
HAEDRICH, R. L„ and S. O. HAEDRICH. 

1974. A seasonal survey of the fishes in the Mystic River, a polluted 
estuary in downtown Boston, Massachusetts. Estuarine Coastal 
Mar. Sci. 2:59-73. 

HERMAN, S. S. 

1963. Planktonic fish eggs and larvae of Narragansett Bay. Lim- 
nol. Oceanogr. 8:103-109. 
HESS, K. W., M. P. SISSENWINE, and S. B. SAILA. 

1975. Simulating the impact of the entrainment of winter flounder 
larvae. In S. B. Saila (editor), Fisheries and energy production: 
A symposium, p. 1-29. D. C. Heath and Co., Lexington, Mass. 

HILDEBRAND, S. F„ and W. C. SCHROEDER. 

1928. Fishes of Chesapeake Bay. Bull. U.S. Bur. Fish., 43 (Part I 
for 1927), 388 p. 
HO, J.-S. 

1962. On a new species of Lepeophtheirus (Copepoda parasitica) 
from Pseudopleuronectes americanus Walbaum. Pac. Sci. 16: 
359-362. 
HOFF, J. G., and J. R. WESTMAN. 

1966. The temperature tolerance of three species of marine fishes. 
J. Mar. Res. 24:131-140. 
HOWE, A. B., and P. G. COATES. 

1975. Winter flounder movements, growth, and mortality off 
Massachusetts. Trans. Am. Fish. Soc. 104:13-29. 
HUNTSMAN, A. G., and M. I. SPARKS. 

1924. Limiting factors for marine animals. 3. Relative resistance to 
high temperatures. Contrib. Can. Biol., New Ser. 2:97-114. 
JANICKI, R. H., and W. B. KINTER. 

1971. DDT inhibits Na+, K+, Mg 2+ -ATPase in the intestinal mu- 



cosae and gills of marine teleosts. Nat. New Biol. 233:148-149. 
JANICKI, R., and J. LINGIS. 

1970. Mechanism of ammonia production from aspartate in teleost 
liver. Comp. Biochem. Physiol. 37:101-105. 

JEFFRIES, H. P., and W. C. JOHNSON. 

1974. Seasonal distributions of bottom fishes in the Narragansett 
Bay area: Seven-year variations in the abundance of winter floun- 
der (Pseudopleuronectes americanus). J. Fish. Res. Board Can. 
31:1057-1066. 

JOINT GROUP OF EXPERTS ON THE SCIENTIFIC ASPECTS OF 
MARINE POLLUTION. 

1969. Joint IMCO/FAO/UNESCO/WMO group of experts on the 
scientific aspects of marine pollution. Abstract of the report of the 
first session. Water Res. 3:995-1005. 
JORDAN, D. S., B. W. EVERMANN, and H. W. CLARK. 

1930. Check list of the fishes and fishlike vertebrates of North and 
Middle America north of the northern boundary of Venezuela and 
Colombia. Rep. U.S. Fish Comm. 1928(part 2), 670 p. 
KENNEDY, V. S., and D. H. STEELE. 

1971. The winter flounder (Pseudopleuronectes americanus) in 
Long Pond, Conception Bay, Newfoundland. J. Fish. Res. Board 
Can. 28:1153-1165. 

KENDALL, W. C. 

1909. The fishes of Labrador. Proc. Portland Soc. Nat. Hist. 2: 

207-243. 
1912. Notes on a new species of flatfish from off the coast of New 
England. Bull. U.S. Bur. Fish. 30(1910):391-394. 
KLEINZELLER. A., and E. M. McAVOY. 

1973. Sugar transport across the peritubular face of renal cells of 
the flounder. J. Gen. Physiol. 62:169-184. 
LANDERS, W. S. 

1941. Age determination of the winter flounder of Narragansett 
Bay by otolith analysis. M.S. Thesis, Rhode Island State College, 
Kingston, 44 p. 

LAURENCE, G. C. 

1975. Laboratory growth and metabolism of the winter flounder 
Pseudopleuronectes americanus from hatching through metamor- 
phosis at three temperatures. Mar. Biol. (Berl.) 32:223-229. 

LEIDY, J. 

1855. Notices of some tape worms. Proc. Acad. Nat. Sci. Phila. 

7:443-444. 
1904. Researches in helminthology and parasitology. Smithson 
Misc. Collect. 46(1477), 281 p. 
LEIM, A. H., and W. B. SCOTT. 

1966. Fishes of the Atlantic Coast of Canada. Fish. Res. Board 
Can., Bull. 155, 485 p. 
LEVIN, M. A., R. E. WOLKE, and V. J. CABELLI. 

1972. Vibrio anguillarum as a cause of disease in winter flounder 
(Pseudopleuronectes americanus). Can. J. Microbiol. 18:1585- 
1592. 

LINTON, E. 

1901. Parasites of fishes of the Woods Hole Region. Bull. U.S. 

Fish. Comm. 19:405-492. 
1914. On the seasonal distribution of fish parasites. Trans. Am. 

Fish. Soc. 44:48-56. 
1921. Food of young winter flounders. Rep. U.S. Fish. Comm. 

1921 (app. IV), 14 p. 
1924. Notes on cestode parasites of sharks and skates. Proc. U.S. 

Natl. Mus. 64(2511), 114 p. 

1933. On the occurrence of Echinorhynchus gadi in fishes of the 
Woods Hole region. Trans. Am. Microsc. Soc. 52:32-34. 

1934. Some observations on the distribution of helminth Entozoa of 
fishes of the Woods Hole region (Massachusetts U.S.A.). James 
Johnstone Memorial Volume, Liverpool, p. 121-131. 

1941. Cestode parasites of teleost fishes of the Woods Hole region, 
Massachusetts. Proc. U.S. Natl. Mus. 90:417-442. 
LOBELL, M. J. 

1939. A biological survey of the salt waters of Long Island, 1938. 
Report on certain fishes. Winter flounder (Pseudopleuronectes 
americanus). 28th Annu. Rep. N.Y. Con. Dep., Part I, Suppl. 
14:63-96. 
LOM, J., and M. LAIRD. 

1969. Parasitic protozoa from marine and euryhaline fish of New- 



41 



foundland and New Brunswick. I. Peritrichous ciliates. Can. J. 
Zool. 47:1367-1380. 
LUX. ! I 

1969. Length-weight relationships of six New England flatfishes. 
Trans. Am. Fish. Soc. 98:617-621. 

1973. Age and growth of the winter flounder, Pseudop'.euronectes 
americanus, on Georges Bank. Fish. Bull., U.S. 71:505-512. 
LUX. F. E., A. E. PETERSON. Jr., and R. F. HUTTON. 

1970. Geographical variation in fin ray number in winter flounder, 
Pseudopleuronectes americanus (Walbaum), off Massachusetts. 
Trans. Am. Fish. Soc. 99:483-488. 

MAACK. T.. and W. B. KINTER. 

1969. Transport of protein by flounder kidney tubules during long- 
term incubation. Am. J. Physiol. 216:1034-1043. 
MacPHEE. G. K. 

1969. Feeding habits of the winter flounder. Pseudopleuronectes 
americanus (Walbaum). as shown by stomach content analysis. 
M.A. Thesis. Boston Univ.. Boston. 66 p. 
McCRACKEN, F. D. 

1963. Seasonal movements of the winter flounder, Pseudopleuro- 
nectes americanus (Walbaum), on the Atlantic coast. J. Fish. 
Res. Board Can. 20:551-586. 
McERLEAN, A. J.. S. G. O'CONNOR, J. A. MIHURSKY, and C. I. 
GIBSON. 

1973. Abundance, diversity and seasonal patterns of estuarine fish 
populations. Estuarine Coastal Mar. Sci. 1:19-36. 
MAHONEY. J. B.. F. H. MIDLIGE, and D. G. DEUEL. 

1973. A fin rot disease of marine and euryhaline fishes in the New 
York Bight. Trans. Am. Fish. Soc. 102:596-605. 
MEAD. AD. 

1909. A method of fish culture and of transporting live fishes. 
39th Annu. Rep. Comm. Inland Fish. Rhode Island, p. 79-106. 
MEDCOF. J. C. 

1946. More reversed winter flounders. Science (Wash., D.C.) 
103:488. 

MERRIMAN, D., and H. E. WARFEL. 

1948. Studies on the marine resources of southern New England. 
VII. Analysis of a fish population. Bull. Bingham Oceanogr. Col- 
lect., Yale Univ. 11(41:131-164. 
MONTREUIL, P. L. J. 

1955. Acanthocephala of seals at the Magdalen Islands. M.S. 
Thesis, McGill Univ., Montreal, Canada, 179 p. 
MORROW. J. E„ Jr. 

1944. A size record for the winter flounder, Pseudopleuronectes 
americanus. Copeia 1944:186. 
MULKANA, M. S. 

1966. The growth and feeding habits of juvenile fishes in two Rhode 
Island estuaries. Gulf Res. Rep. 2:97-167. 
NICHOLS, J. T. 

1918. An abnormal winter flounder and others. Copeia 55:37-39. 
NORMAN. J. R. 

1934. A systematic monograph of the flatfishes (Heterosomata). 
Br. Mus. (Nat. Hist.), 459 p. 
OLLA. B. L.. R. WICKLUND, and S. WILK. 

1969. Behavior of winter flounder in a natural habitat. Trans. 
Am. Fish. Soc. 98:717-720. 
OVIATT, C. A., and S. W. NIXON. 

1973. The demersal fish of Narragansett Bay: An analysis of com- 
munity structure, distribution and abundance. Estuarine Coastal 
Mar. Sci. 1:361-378. 
PEARCY, W. G. 

1961. Seasonal changes in osmotic pressure of flounder sera. 

Science (Wash., D.C.) 134:193-194. 
1962a. Ecology of an estuarine population of winter flounder 
Pseudopleuronectes americanus (Walbaum). Bull. Bingham 
Oceanogr. Collect., Yale Univ. 18(1), 78 p. 
1962b. Distribution and origin of demersal eggs within the order 

Pleuronectiformes. J. Cons. 27:232-235. 
1962c. A tail-less flounder. Trans. Am. Fish. Soc. 91:233-234. 
PERLM UTTER, A. 

1947. The blackback flounder and its fishery in New England and 
New York. Bull. Bingham Oceanogr. Collect., Yale Univ. 11(2), 
92 p. 



PESCH, G. 

1970. Plasma protein variation in a winter flounder {Pseudopleuro- 
nectes americanus) population. J. Fish. Res. Board Can. 27:951- 
954. 

PHILLIPS. J. G., and P. J. MULROW. 

1959. Failure of corpuscles of Stannius from winter flounder 
(Pseudopleuronectes americanus) to synthesize adrenocortico- 
steroids in vitro. Nature (Lond.) 184:558. 
POOLE, J. C. 

1966a. Growth and age of winter flounder in four bays of Long Is- 
land. N.Y. Fish Game J. 13:206-220. 
1966b. The use of salt-water coves as winter flounder nursery 
grounds. N.Y. Fish Game J. 13:221-225. 

1969. A study of winter flounder mortality rates in Great South 
Bay, New York. Trans. Am. Fish. Soc. 98:611-616. 

PRITCHARD, J. B., A. GAURINO, and W. KINTER. 

1973. Distribution metabolism and excretion of DDT and Mirex by 

a marine teleost, the winter flounder. Environ. Health Perspect. 

2:45-54. 
RADLE, E. W. 

1971. A partial life history of the winter flounder {Pseudopleuro- 
nectes americanus) exposed to thermal addition in an estuary, In- 
dian River Bay, Delaware. M.S. Thesis, Univ. Delaware, Lewes, 
74 p. 

RATHBUN, R. 

1885. Annotated list of the described species of parasitic Copepoda 
(Siphonostoma) from American waters contained in the United 
States National Museum. Proc. U.S. Natl. Mus. 7:483-492. 
1893. Report upon the inquiry respecting food-fishes and the fish- 
ing grounds. Rep. U.S. Comm. Fish. 17:97-171. 
RICHARDS, C. E., and M. CASTAGNA. 

1970. Marine fishes of Virginia's Eastern Shore (inlet and marsh, 
seaside waters). Chesapeake Sci. 11:235-248. 

RICHARDS, S. W. 

1963. The demersal fish population of Long Island Sound. Bull. 
Bingham Oceanogr. Collect., Yale Univ. 18(2), 101 p. 
ROGERS. C. A. 

1976. Effects of temperature and salinity on the survival of winter 
flounder embryos. Fish. Bull., U.S. 74:52-58. 
RONALD, K. 

1957. The metazoan parasites of the Heterosomata of the Gulf of 
St. Lawrence. I. Echinorhynchus laurentianus sp. nov. (Acantho- 
cephala: Echinorhynchidae). Can. J. Zool. 35:437-439. 
1958a. The metazoan parasites of the Heterosomata of the Gulf of 

St. Lawrence. III. Copepoda Parasitica. Can. J. Zool. 36:1-6. 
1958b. The metazoan parasites of the Heterosomata of the Gulf of 
St. Lawrence. IV. Cestoda. Can. J. Zool. 36:429-434. 

1959. A check list of the metazoan parasites of the Heterosomata. 
Dep. Fish., Quebec, Contrib. 67, 152 p. 

1960. The metazoan parasites of the Heterosomata of the Gulf of 
St. Lawrence. VI. Digenea. Can. J. Zool. 38:923-937. 

1963. The metazoan parasites of the Heterosomata of the Gulf of 
St. Lawrence. VII. Nematoda and Acanthocephala. Can. J. Zool. 
41:15-21. 
SAILA, S. B. 

1961. A study of winter flounder movements. Limnol. Oceanogr. 
6:292-298. 

1962a. The contribution of estuaries to the offshore winter flounder 
fishery in Rhode Island. Proc. Gulf Caribb. Fish. Inst. 14th Annu. 
Sess. 1961:95-109. 
1962b. Proposed hurricane barriers related to winter flounder 
movements in Narragansett Bay. Trans. Am. Fish. Soc. 91:189- 
195. 
SAILA, S. B., D. B. HORTON, and R. J. BERRY. 

1965. Estimates of the theoretical biomass of juvenile winter floun- 
der, Pseudopleuronectes americanus (Walbaum), required for a 
fishery in Rhode Island. J. Fish. Res. Board Can. 22:945-954. 
SCOTT, W. C. M. 

1929. A note on the effect of temperature and salinity on the hatch- 
ing of the eggs of the winter flounder {Pseudopleuronectes 
americanus Walbaum). Contrib. Can. Biol., New Ser. 4:139-141. 
SHERWOOD, G. H., and V. N. EDWARDS. 

1901. Notes on the migration, spawning, abundance, etc., of certain 



42 



fishes in 1900. Biological notes No. 2, Bull. U.S. Fish Comm. 21: 
27-31. 
SMIGIELSKI, A. S. 

1975. Hormonal-induced ovulation of the winter flounder, Pseudo- 
pleuronectes americanus. Fish. Bull., U.S. 73:431-438. 
SMIGIELSKI, A. S., and C. R. ARNOLD 

1972. Separating and incubating winter flounder eggs. Prog. Fish- 
Cult. 34:113. 
SMITH, G. M. 

1935. A hyperplastic epidermal disease in the winter flounder in- 
fected with Oryptocotyle lingua (Oreplin). Am. J. Cancer 25: 
108-112. 
SMITH, R. M., and C. F. COLE. 

1970. Chlorinated hydrocarbon insecticide residues in winter floun- 
der, Pseudopleuronectes americanus, from the Weweantic River 
estuary, Massachusetts. .J. Fish. Res. Board Can. 27:2374-2380. 

STAFFORD, J. 

1904. Trematodes from Canadian fishes. Zool. Anz. 27:481-495. 
STILES, C. W., and A. HASSALL. 

1894. A preliminary catalogue of the parasites in the collections 
of the llnited States Bureau of Animal Industry, United States 
Medical Museum, Biological Department of the University of 
Pennsylvania (Coll. Leidy) and in Coll. Stiles and Coll. Hassall. 
Vet. Mag. 1:245-253; 331-354. 
STOCK, V. 

1915. On some of the parasitic copepods of the Bay of Fundy fish. 
Contrib. Can. Biol. Fasc. 1:68-71. 
STUNKARD, H. W., and F. E. LUX. 

1965. A microsporidian infection of the digestive tract of the winter 
flounder, Pseudopleuronectes americanus. Biol. Bull. (Woods 
Hole) 129:371-387. 
SULLIVAN, W. E. 

1915. A description of the young stages of the winter flounder 
(Pseudopleuronectes americanus Walbaum). Trans. Am. Fish. 
Soc. 44.125-136. 
SUTTERLIN, A. M. 

1975. Chemical attraction of some marine fish in their natural 
habitat. J. Fish. Res. Board Can. 32:729-738. 
TOPP, R. W. 

1968. An estimate of fecundity of the winter flounder, Pseudo- 
pleuronectes americanus. J. Fish. Res. Board Can. 25:1299-1302. 
TYLER, A. V. 

1971. Periodic and resident components in communities of Atlantic 
fishes. J. Fish. Res. Board Can. 28:935-946. 

1972a. Surges of winter flounder, Pseudopleuronectes americanus, 
into the intertidal zone. J. Fish. Res. Board Can. 28:1727-1732. 



1972b. Food resource division among northern, marine, demersal 
fishes. J. Fish. Res. Board Can. 29:997-1003. 
TYLER, A. V., and R, S. DUNN. 

1976. Ration, growth, and measures of somatic and organ condition 
in relation to meal frequency in winter flounder, Pseudopleuro- 
nectes americanus, with hypotheses regarding population homeo- 
stasis. J, Fish. Res. Board Can. 33:62-75. 
UMMINGER, B. L.. and J. B. MAHONEY. 

1972. Seasonal changes in the serum chemistry of the winter floun- 
der. Pseudopleuronectes americanus. Trans. Am. Fish. Soc. 101: 
746-748. 
VOYER, R. A., and G. E. MORRISON. 

1972. Factors affecting respiration rate of winter flounder (Pseudo- 
pleuronectes americanus). J. Fish. Res. Board Can. 28:1907- 
1911. 

WALLACE, N. A. 

1919. The Isnpoda of the Bay of Fundy. Univ. Toronto Stud., 
Biol. Ser. 18. Studies Biol. Stn„ Biol. Board Can. 1:1-42. 
WELLS. B„ D. H. STEELE, and A. V. TYLER. 

1973. Intertidal feeding of winter flounders (Pseudopleuronectes 
americanus) in the Bay of Fundy. J. Fish. Res. Board Can. 30: 
1374-1378. 

WHEATLAND, S. B. 

1956. Oceanography of Long Island Sound, 1952-1954. VII. Pelagic 
fish eggs and larvae. Bull. Bingham Oceanogr. Collect., Yale 
Univ. 15:234-314. 
WILLIAMS, G. C. 

1975. Viable embryogenesis of the winter flounder Pseudopleuro- 
nectes americanus from -1.8° to 15°C. Mar. Biol. (Berl.) 33:71- 
74. 

WILSON, C. B. 

1905. North American parasitic copepods belonging to the family 

Caligidae. Part I.— The Caliginae. Proc. U.S. Natl. Mus. 28:479- 

672. 
1932. The copepods of the Woods Hole region Massachusetts. 

Bull. U.S. Natl. Mus. 158, 635 p. 

WOLFGANG, R. W. 

1954a. Studies of the trematode Stephanostomum baccatum 
(Nicoll, 1907): I. The distribution of the metacercaria in eastern 
Canadian flounders. J. Fish. Res. Board Can. 11:954-962. 
1954b. Studies of the trematode Stephanostomum baccatum 
(Nicoll, 1907): II. Biology, with special reference to the stages af- 
fecting the winter flounder. J. Fish. Res. Board Can. 11:963-987. 
ZISKOWSKI, J., and R. MURCHELANO. 

1975. Fin erosion in winter flounder. Mar. Pollut. Bull. 6:26-29. 



43 



<r U.S. GOVERNMENT PRINTING OFFICE: 1978-797-967/22 REGION 10 



FISHERIES SYNOPSES 

This series of documents, issued by FAO, CSIRO, INP, and NMFS, contains comprehensive reviews of present knowledge 
on species and stocks of aquatic organisms of present or potential economic interest. The Fishery Resources and Environ- 
ment Division of FAO Is responsible for the overall coordination of the series. The primary purpose of this series is to make 
existing information readily available to fishery scientists according to a standard pattern, and by so doing also to draw atten- 
tion to gaps in knowledge. It is hoped that synopses in this series will be useful to other scientists initiating investigations of the 
species concerned or of related ones, as a means of exchange of knowledge among those already working on the species, 
and as the basis for comparative study of fisheries resources. They will be brought up to date from time to time as further in- 
formation becomes available. 



The documents of this Series are issued under the following titles: 



FAO 
CSIRO 
INP 
NMFS 



Fisheries Synopsis No. 
Fisheries Synopsis No. 
Sinopsis sobre la Pesca No. 
Fisheries Synopsis No. 



Symbol 

FIR/S 

DFO/S 

INP/S 

NMFS/S 



Synopses in these series are compiled according to a standard outline described in Flb/S1 Rev. 1 (1965). FAO, CSIRO, 
INP,and NMFS are working to secure the cooperation of other organizations and of individual scientists in drafting synopses 
on species about which they have knowledge, and welcome offers of help in this task. Additions and corrections to synopses 
already issued will also be most welcome. Comments on individual synopses and requests for information should be ad- 
dressed to the coordinators and editors of the issuing organizations, and suggestions regarding the expansion or modifica- 
tion of the outline, to FAO: 



FAO: 

Fishery Resources and Environment Division 
Aquatic Resources Survey and Evaluation Service 
Food and Agriculture Organization of the United Nations 
Via delle Terme di Caracalla 
00100 Rome, Italy 



CSIRO: 

CSIRO Division of Fisheries and Oceanography 

Box 21 

Cronulla, N.S.W. 2230 

Australia 



INP: 

Instituto Nacional de Pesca 
Subsecretaria de Pesca 
Secretaria de Pesca 
Secretaria de Industria y Comercio 
Carmona y Valle 101-403 
Mexico 7, D.F. 



NMFS: 

Scientific Editor 

National Marine Fisheries Service, NOAA 

Auke Bay Fisheries Laboratory 

P.O. Box 155 

Auke Bay, AK 99821 

U.S.A. 



Consolidated lists of species or groups covered by synopses issued to date or in preparation will -be issued from time to 
time. Requests for copies of synopses should be addressed to the issuing organization. 



The following synopses in this series have been issued since January 1975: 



FIRS/S111 

FIRS/S112 

INP/S2 

FIR/S115 

FIR/S114 

FIR/S113 
NMFS/S116 



Synopsis of biological data on rohu, Labeo rohita 

Synopsis of biological data on the Norway lobster. Nephrops norvegicus 

Synopsis de datos bioldgicos sobre la tortuga golfina, Lepidochelys olivacea 

Synopsis of biological data on the largemouth bass, Micropterus salmoides 

Synopsis of biological data on scallops, Chlamys (Aequipecten) opercularis, Argopecten 

irradians and Argopecten gibbus 
Synopsis of biological data on the perch, Perca fluviatilis and flavescens 
Synopsis of biological data on the red progy, Pagrus pagrus (Linnaeus) 



June 1975 

September 1975 

Febrero 1976 

November 1976 

December 1976 

December 1977 

May 1978 



UNITED STATES 
DEPARTMENT OF COMMERCE 

NATIONAL OCEANIC AND AIMOSPHf »ic ADMINISTRATION 

s-AKlNE FISHERIES SERVICE 

SClfNTlFlC PUBLICATIONS STAFF 

ROOM 4 SO 

1107 N e 45TM ST 

SEATTLE WA9810S 



OFFICIAL SUSINESS 







NOAA SCIENTIFIC AND TECHNICAL PUBLICATIONS 

NOA A, the National Oceanic and A tmospherk Administration, was established as part of the Department of 
Commerce on October 3, 1970. The mission responsibilities of NOAA are to monitor and predict the state of the 
solid Earth, the oceans and their living resources, the atmosphere, and the space environment of the Earth, and to 
assess the socioeconomic impact of natural and technological changes in the environment. 

The six Major Line Components of NOAA regularly produce various types of scientific and technical infor- 
mation in the following kinds of publications: 



PROFESSIONAL PAPERS— Important definitive 
research results, major techniques, and special in- 
vestigations. 

TECHNICAL REPORTS— Journal quality with 
extensive details, mathematical developments, or 
data listings. 

TECHNICAL MEMORANDUMS— Reports of 
preliminary, partial, or negative research or tech- 
nology results, interim instructions, and the like. 

CONTRACT AND GRANT REPORTS— Reports 
prepared by contractors or grantees under NOAA 
sponsorship. 



TECHNICAL SERVICE PUBLICATIONS— 

These are publications containing data, observations, 
instructions, etc. A partial listing: Data serials: Pre- 
diction and outlook periodicals; Technical manuals, 
training papers, planning reports, and information 
serials; and Miscellaneous technical publications. 



ATLAS— Analysed data generally presented in the 
form of maps showing distribution of rainfall, 
chemical and physical conditions of oceans and at- 
mosphere, distribution of fishes and marine mam- 
mals, ionospheric conditions, etc. 







Information on availability ol NOAA publication* can ba obtained from: 

ENVIRONMENTAL SCIENCE INFORMATION CENTER 

ENVIRONMENTAL DATA SERVICE 

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION 

U.S. DEPARTMENT OF COMMERCE 

3300 Whitehaven Street, N.W. 
Washington, D.C. 20235