QL

155

.S63

no.82-

11.112

Library

National Wetlands Research C&H

U. S. Fbh and Wildlife Scrvicc

700 Cafundomc Boulevard

Lafayc ttc, La. 70508

Biological Report 82 (11.112)

August 1989

TR EL-82-4

Species Profiles: Life Histories and

Environmental Requirements of Coastal Fishes

and Invertebrates (Mid-Atlantic)

SUMMER AND WINTER FLOUNDER

Fish and Wildlife Service

U.S. Department of the Interior

Coastal Ecology Group

Waterways Experiment Station

U.S. Army Corps of Engineers

Biological Report 82t11.112)

TR EL-82-4

August 1989

Species Profiles: Life Histories and Environmental Requirements

of Coastal Fishes and Invertebrates (biid-Atlanticj

SUMMER AND WINTER FLOUNDER

Barbara H. Grimes, ?lelvin T. Huish, and J. Howard Derby

1J.j. Fish and Wildlife Service

North Carolina Cooperative Fishery Research Unit

Department of Zoology

North Carolina State University

Raleigh, NC 27695

and

David Moran

U.S. Fish and Wilalife Service

National Wetlands Research Center

1010 Gause Boulevard

Slidell, LA 70458

Project Manager

Edward Pendleton

U.S. Fish and Wildlife Service

National Wetlands Research Center

1010 Gause Boulevard

Slidell, LA 70458

Performed for

Coastal Ecology Group

Waterways Experiment Station

U.S. Army Corps of Engineers

Vicksburg, MS 39180

and

U.S.Department of the Interior _

Fish and Wildlife Service

Research and Development

National Wetlands Researcn Center

Washington, DC 20240
This series should be referenced as follows:

U.S. Fish ano Wildlife Service. 1983-i9!38. Species profiles: life histories and

environmental requirements of coastal fishes and invertebrates. 1J.S. Fish

WildI. Serv. Biol. Rep. 82(11). U.S. Army Corps of Engineers, TR EL-82-4.

This profile should be cited as follows:

Grimes, B.H., M.T. Huish, J.H. Derby, and D. plot-an. 1989. Species profiles:

life histories and environmental requirements of coastal fishes and

invertebrates (Mid-Atlantic)--summer and winter flounder. U.S. Fish Wildl.

Serv. Biol. Rep. 82(11.112). U.S. Army Corps of Engineers, TR EL-82-4. 18PP.
PREFACE

This species profile is one of a series on coastal aquatic organisms,

principally fish, of sport, commercial, or ecological importance. The profiles

are designed to provide coastal managers, engineers, and biologists with a brief

comprehensive sketch of the biological characteristics and environmental

requirements of the species and to describe how populations of the species may be

expected to react to environmental changes caused by coastal development. Each

profile has sections on taxonomy, life history! ecological role, environmental

requirements, and economic importance, if applicable. A three-ring binder is

used for this series so that new profiles can be added as they are prepared.

This project is jointly planned and financed by the U.S. Army Corps of Engineers

and the U.S. Fish and Wildlife Service.

Suggestions or questions regarding this report should be directed to one of

the following addresses.

Information Transfer Specialist

National Wetlands Research Center

U.S. Fish and Wildlife Service

NASA-Slide11 Computer Complex

1010 Gause Boulevard

Slidell, LA 70458

or

U.S. Army Engineer Waterways Experiment Station

Attention: WESER-C

Post Office Box 631

Vicksburg, MS 39180

iii
CONVERSION TABLE

Multiply !!Y To Obtain

millimeters (mm) 0.03937 inches

centimeters (cm) 0.3937 inches

meters (m) 3.281 feet

meters (m) 0.5468 fathoms

kilometers (km) 0.6214 statute miles

kilometers (km) 0.5396 nautical miles

square meters (m*) 10.76

square kilometers (km*) 0.3861

hectares (ha) 2.471

square feet

square miles

acres

liters (1) 0.2642

cubic meters (m3> 35.31

cubic meters (m3) 0.0008110

milligrams (mg) 0.00003527

grams (9) 0.03527

kilograms (kg) 2.205

metric tons (t) 2205.0

metric tons (t) 1.102

gallons

cubic feet

acre-feet

ounces

ounces

pounds

pounds

short tons

kilocalories (kcal)

Celsius degrees ("C)

3.968 British thermal units

1.8('C) + 32 Fahrenheit degrees

U.S. Customary to Metric

inches

inches

feet (ft.)

fathoms

statute miles (mi)

nautical miles (nmi)

25.40 millimeters

2.54 centimeters

0.3048 meters

1.829 meters

1.609 kilometers

1.852 kilometers

square feet (ft*)

square miles (mi*)

acres

0.0929 square meters

2.590 square kilometers

0.4047 hectares

gallons (gal)

cubic feet (ft3)

acre-feet

3.785 liters

0.02831 cubic meters

1233.0 cubic meters

ounces (oz)

ounces (02)

pounds (lb)

pounds (lb)

short tons (ton)

28350.0 milligrams

28.35 grams

0.4536 kilograms

0.00045 metric tons

0.9072 metric tons

British thermal units (Btu)

Fahrenheit degrees (OF)

0.2520

0.5556 (OF

iv

32)

kilocalories

Celsius degrees

Metric to U.S. Customary
CONTENTS

Page

PREFACE ...................................

CONVERSION FACTORS .............................

ACKNOWLEDGMENTS. ..............................

NOMENCLATURE/TAXONOMY/RANGE. ........................

Summer Flounder. .............................

Winter Flounder.

MORPHOLOGY/IDENTIFICAi!ON'AiDS : : : : : : : : : : : : : : : : : : : : : : :

Summer Flounder. .............................

Winter Flounder. .............................

REASON FOR IKLUSION IN SERIES .......................

LIFEHISTORY ................................

Reproductive Physiology/Strategy .....................

Spawning .................................

Eggs ...................................

Larvae ..................................

Juveniles .................................

Adults ..................................

GROWTH CHARACTERISTICS ...........................

Growth Rates and Length-Weight Relationships ...............

THE FISHERY. ................................

Commercial Fisheries ...........................

Recreational Fisheries ..........................

Population Dynamics. ...........................

ECOLOGICAL ROLE. ..............................

FoodHabits ................................

Feeding Behavior .............................

Parasites .................................

ENVIRONMENTAL REQUIREMENTS .........................

Temperature and Salinity .........................

Pollution .................................

iii

iv

vi

1

1

z

;

2

4

4

4

5

5

6

6

z

::

::

11

::

11

12

12

12

LITERATURE CITED ..............................15

V
ACKNOWLEDGMENTS

We would like to express our sincere thanks to Dorothy Wright for typing

this manuscript. Also, we would like to thank Dr. Larry Ray Grimes for technical

assistance and advice. We also thank John Musick of the Virginia Institute of

Marine Science and Paul Scarlett of the New Jersey Division of Fish and Game for

reviewing the report.

vi
Figure 1. A. Summer flounder (Powell 1974), B. Winter flounder

(Martin and Drewry 1978).

SUMMER AND WiNTER FLOUNDER

NOMENCLATi_iRE/TAXGNOMY/RANGE

Summer Flounder

Scientific name... . . . . . . ..Paralichthys

dentatus

Preferred common nmTle...........Summer

flounaer (Figure LA)

Other common names...........Flounder,

fluke, plaice fish, plaice, plaise,

splaice, chicken halibut, flounder

of New York, common flounder, brail,

turbot, flatfish, longtoothed flounder

Class.... . . . . . . . . . . . . . . . ..Osteichthyes

Order........ . . . . . . ..Pleuronectiformes

Family........................Bothidae

Geographic range: The summer flounder

prefxs estuarine and shelf waters

of the Atlantic Ocean. It is found

between Nova Scotia and the

southeastern coast of Florida but is

most abundant from Cape Cod,

Massachusetts, to Cape Hatteras,

North Carolina (Hildehrand and

Schroeder 1928). Distribution in

1
the mid-Atlantic region is shown in

Figure 2.

Winter Flounder

Scientific name.... .Pseudooleuronectes

americanus

Preferred common name...........kinter

flounder (Figure la)

Other common names.......:...Flatfish,

blackback, Georges Bank flounder,

lemon sole, flounder, sole, rough

flounuer, plie rouge, carrelet,

halibut, holibut, dab.

Class.....................Osteichthyes

Order................Pleuronectiformes

Family..................Pleuronectidae

Geographic range: The winter flounder

has a broad range, occurrinq from

Buttle Harbor and Windy Tickle,

Labrador, to Beaufort, North

Carolina, but is most common in

estuaries between the Gulf of St.

Lawrence and Chesapeake Bay.

Distribution in the Mid-Atlantic

Region is shown in Figure 2.

MORPHOLOGY/IDEtiTIFICATIG~ AIDS

Summer Flounder

The body of the summer floljnder

is laterally flattenea; a margin of

the preopercle is free; and the eyes

are on the left side. The bases cf

both pelvic fins are short. The

ocular side of the fish ranges from

tan to dark brown and has numerous

ocellated spots. Five prominent spots

are arranged in two triangles with a

common apex on the lateral 1in.e;

however, this configuration is

generally lacking in larger specimens.

The fish are able to blend into their

background by adapting to the texture

and color of the substrate on which

they live.

Meristic characteristics: Dorsal

rays, 80-98; anal rays, 63-78;

pectoral rays, 10-13; vertebrae 40-43

(Smith and Daiber 1977); gill rakers

on lower limb of first arch 14-19.

Average head length and average upper

jaw length are contained 3.96 and 2.05

times, respectively, in standard

length (SL) (Hildebrand and Schroeder

1928). The scales are ctenoid. Late

postlarvae of summer flounder have a

well-defined band of black pigment

along the anterior two-thirds of the

anal fin and a similar band along the

anterior four-fifths of the dorsal fin

(Figure 3d) which are lacking in the

southern flounder (Paralichthvs

lethostiqma) and the gulf flounder (p.

albioutta). Summer flounder

postlarvae typically have 40-42 total

vertebrae while southern flounder

postlarvae have 37 or 38 and gulf

flounder postlarvae have 36-38.

Summer flounder postlarvae have 81-94

dorsal rays and 61-74 anal rays, while

gulf flounder postlarvae have 72-82

dorsal rays and 53-63 anal rays

(Deubler 1958).

Winter Flounder

The winter flounder's body is

ovate and laterally compressed. The

eyes are on the right side, separated

by a narrow scaled ridge; the upper

eye is near the edge of the head. The

mouth is of moderate size and the

length of the maxillary on the blind

side is less than one-third that of

the head. Winter flounder are olive

green to reddish-brown in color and

sometimes have a few rusty spots. The

lateral line is nearly straight. The

dorsal fin originates opposite the

forward edge of the eye and is of

nearly equal height throughout its

length.

Meristic characteristics: Dorsal

rays 56-81; anal rays 47-54; pectoral

rays 10-11; gill rakers on lower limb

of first arch, 7-8; vertebrae, 36.

Average head length is 4.0 cm

(Hildebrand and Schroeder 1928; Pierce

and Howe 1977). The scales are

ctenoid.

REASON FOR INCLUSION IN SERIES

The summer flounder is an

important commercial and recreational

2
NEW YORK

1 -

--------‘-

F----- \

\

\

-._

‘ASHINGTON, D.C., <

NORTH CAROLINA- “

ATLANTIC OCEAN

MILES

KILOMETERS

tsl Summer flounder

Winter flounder

CAPE HATTERAS

Figure 2. Distribution of the Summer and Winter flounder in the mid-Atlantic

region.

3
species along the Atlantic seaboard of

the United States and is the major

recreationally caught flounder of the

mid-Atlantic inshore waters. There

are three major commercial fisheries:

the inshore summer fishery; the

offshore winter fishery; and a fall

and winter trawl fishery inside the

20-fathom (36-m) contour that

developed on the Virginia and North

Carolina coast in the 1960's

(Hildebrand and Schroeder 1928;

Scarlett 1981).

LIFE HISTORY

Reproductive

Adult female summer flounder, on

the average, are 60 mm longer (in

total length, TL) than males at first

attainment of sexual maturity in the

Mid-Atlantic Bight (Morse 1981). The

summer flounder appears to become

sexually mature by the age of II

(Morse 1981). Gonads of summer

flounder ripened from mid-August

through November in the Delaware Bay;

the fish moved offshore to spawn in

the winter (Smith and Daiber 1977).

Morse (1981) reported that summer

flounder have a protracted spawning

season of variable duration with early

maturation, high fecundity, serial

spawning, and extensive migrations

across the continental shelf. Life

history parameters are determined by

local genetic and environmental

factors.

The number of maturing ova in

summer flounder is highly correlated

with weight and length. Fish in the

Mid-Atlantic Region between 366 and

680 mm TL have an estimated 0.46 to

4.19 million ova (Morse 1981).

Total egg count of winter

flounder ranged from 0.435 million for

an age-III fish to 3.329 million eggs

for an age-V fish captured off

Massachusetts (Topp 1968). The

regression equation for the

relationship of fecundity to fish

weight for winter flounder

follows: I

In F = 0.1605 t 1.0659 In W

where W is weight in grams.

was as

(N = 30)

South Atlantic Bight (Smith 1973).

Adult summer flounder move back

inshore to estuaries or coastal waters

in the winter and spring (Wilk et al.

1980).

Soawning ---

In

spawning

flounder

the South Atlantic Bight,

times and habitats of summer

are poorly documented. Based

on collections of newly hatched

larvae, commercial catch rates, and

generalized coastal and shelf trawling

surveys, seasonal migration patterns

of adult fish have been deduced. It

is known that summer flounder migrate

offshore during cooler months. In

late fall, winter, or early spring

they spawn near the bottom of shelf

waters 30-200 m deep. The genetically

distinct populations north and south

of Cape Hatteras may behave

differently.

Between Cape Cod, Piassachusetts,

and Cape Lookout, North Carolina,

spawning of summer flounder began in

September (Smith 1973). In the survey

by Smith (1973), spawning continued

through December in the northern part,

and through February to the south.

Spawning in the Mid-Atlantic Region

continues into February and March in

some years and probably begins north

of Chesapeake Bay and progresses

southward in a cycle that ends in the

South Atlantic Bight (Smith 1973).

Adult summer flounder move back

inshore to estuaries or coastal waters

in the winter and spring (Wilk et al.

1980).

Spawning times of the winter

flounder are variable, like those of

the summer flounder; spawning occurs

first in the southern part of the

4
range and progressively later towards

the north in keeping with water

temperatures. Spawning occurs inshore

from November through June from

Newfoundland to Delaware. Male winter

flounder in northern (Canadian) waters

showed spermatogenesis and gonad

development 6 months before the

spawning season (which was in May to

June). Oocytes may take three years

to mature. Nonreproductive

individuals occur in the spawning

season, but condition factors are less

in these fish. They may be conserving

resources to spawn after a later

feeding season with abundant food

where their condition factor is higher

(Burton and Idler 1984).

Saila (1961) showed with tagging

studies that winter flounoer returned

to the tagging locality with high

frequency over one year of recovery

data. Fish dispersed from the

breeding grounds in summer and

returned in winter. The same breeding

area was not always successfully

located (Saila 1961).

Winter flounder spawn 'in shallow

inshore waters (Jeffries and Johnson

1974). Spawning occurs at night

(Breder 1922). In observations by

Breder (1922) in the laboratory,

spawning is preceded by extensive

swimming in spirals. The females

extrude eggs in wide counterclockwise

spirals due to the centrifugal force

(Breder 1922).

Eggs of the summer flounder are

pelagic. Incubation time in the

laboratory was 9 days at 5 'C and 2-3

days at 21 'C. Mean diameter of

mature unfertilized eggs is 0.98 mm.

Yolk occupies about 95% of the egg

volume (Johns et al. 1981).

Winter flounder eggs are minute,

demersal, and adhesive, sinking to the

bottom (Breder 1924). The adhesive

eggs averaged 0.81 mm (Breder 1924) or

0.61 mm (Topp 1968) in modal diameter.

They clump together after fertilization, thus often becoming distorted

and ovoid in shape (Breder 1924).

Larvae

Notochord length of summer

flounder was about 3.0 mm at hatching

in the laboratory and was about 3.6 mm

when yolk-sac absorption was complete

(Johns et al. 1981). Growth until the

absorption of the yolk sac is complete

is not temperature dependent. Larvae

that hatch at both 11 oC and 21 OC

grow to about 3.6 mm notochord length

within 6 days after hatching (Johns et

al. 1981). No data on larval feeding

habits is available.

Larvae of summer flounder are

transported to estuarine nursery areas

by currents. Greater densities of

young fish were found in or near

inlets, and greater numbers were

captured during periods of the full

moon (Williams and Deubler 1968).

In larval winter flounder (7 mm

TL), the digestive tract is completely

developed; the eyes are pigmented; and

the mouth is fully functional

(Sullivan 1914).

Sullivan (1914), who described

the winter flounder larva from

hatching to the end of the second

month in the laboratory, divided its

larval history into four stages which

he selected to show diagnostic

characteristics for identification.

Stage I - A group of dark piqment

spots on the posterior half of

the body is the most important

character for identification.

The notochord is present as a

straight tube. Yolk absorption

is gradual and varies with

temperature.

Stage II - Yolk absorbed, age 12 days,

length 5 ~11.

5
Stage III - Metamorphosing larva 5-7

weeks old and 5.8 mm long.

Stage IV - Postlarva about 8 weeks

old and 6.5 mm long; average body

depth 2.75 mm.

Juveniles

Young summer flounder are >6 mm

long when they first move into

estuaries (Weinstein et al. 1980). In

the Cape Fear River Estuary, North

Carolina, postlarvae first entered

the marshes in March and April

(Weinstein 1979). Prior to late

summer, juvenile summer flounder were

randomly distributed in an estuary,

but in late summer and early fall,

they were more abundant in an

estuarine sea grass bed than in an

adjacent tidal marsh creek (Weinstein

and Brooks 1983).

No postlarval summer flounder

have been collected at salinities

below 12 ppt in the Neuse River

basin, North Carolina (Keup and

8ayless 1964). However, juveniles

were prevalent higher

salinities (Powell and :cthwartz 1979).

Pamlico Sound and adjacent estuaries

are important nursery areas

for summer flounder (Powell and

Schwartz 1977). Yearling; move to the

ocean in summer, but underyearlings

remain in the estuaries (Powell and

Schwartz 1977).

For the first summer,

young-of-year winter flounder remain

in shallow waters of bays and

estuaries where they were spawned.

Sandy coves appear to be preferred

habitats of these fish (Hildebrand and

Schroeder 1928).

The juveniles are preyed upon by

summer flounder, striped bass,

bluefish, and other species of fish of

larger size; cormorants and harbor

seals are also predators. The young

are found from June through November

from Mystic River, Connecticut, to

Long Island Sound. In the Upper

Mystic Estuary and Long Island Sound,

between July and February, the average

length of the young was 23 mm TL

(Pearcy 1962). Juveniles have been

observed year-round in Long Island

Sound and are abundant from June to

October in Shinnecock and Peconic Bay,

Long Island. March through November

is a peak period in the Delaware River

Estuary. Off Massachusetts, only

about 73% of the juveniles moved

offshore in the spring and summer

seaward migration (Howe et al. 1976).

In Narragansett Bay, Rhode Island,

smaller fish (lo-20 cm long) do not

migrate beyond the headlands in spring

(Jeffries and Johnson 1974).

See Figures 3 and 4 for general

development of both species.

Adults

Saila et al. (1965) prepared

age-weight tables for winter flounder

caught in Charlestown Pond and harragansett Bay, Rhode Island. The

average weight of 12-year-old specimens was calculated to be 874 g.

The largest recorded adult was 570 mm

(TL) and was probably considerably

older than 12 years (Bigelow and

Schroeder 1953).

Off southern Massachusetts,

winter flounder moved seaward to

deeper water in the spring and summer

months, but usually remained within

the 55-m depth contour (Howe and

Coates 1975). This seaward movement

may have been an avoidance of the

temperature rise in the nearshore

waters.

Annual natural mortality rate for

winter flounder in the Mid-Atlantic

Region was estimated at 27% (Howe and

Coates 1975). Winter flounder

dominated the catch of a research

trawl and represented 50%-90% of all

individuals in Narragansett Bay

(Jeffries and Johnson 1974).

6
A

mm NL

.

C

9.47 mm NL

d

SL

Figure 3. The general development for the summer flounder from hatching to

adult. (Martin and Drewry 1978).

7
A

B

C

5mm

D

Figure 4. The general developent for winter flounder from hatching to adult:

A. newly hatched; 8. 19 day larva; C. larva; D. juvenile (krtin and Drewry

1978).

8
Table 1. Weight-length regressions for summer flounder, where log

(g) = a + b log10 length (mm) and r = correlation coefficient 5O

weight

(Roger and Van

Den Avyle 1983).

Location and source a b r

Pamlico Sound, North Carolina

(Powell 1974) -5.254 3.099 0.99

Mid Atlantic Bight

(Wilk et al. 1978)

Males -5.289 3.126 0.96

Females -5.578 3.226 0.98

GROWTH CHARACTERISTICS

Growth Rates and Length-Weight Relationships

In the Mid-Atlantic Region,

growth rate of age I+ summer flounder

decreases from north to south. A

substantial shift in size at age I

from 26 mm in New Jersey to 16 mm in

South Carolina may result from

differences in growth rates and

spawning times; peak spawning in New

Jersey is in November while it may

occur as late as March in South

Carolina (Smith et al. 1981). Growth

of young-of-the-year ceased toward the

end of their first year in fall and

did not resume again until spring when

the fish were yearlings (Powell and

Schwartz 1977). Table 1 shows the

length-weight relationships of summer

flounder for Pamlico Sound, North

Carolina, and the Mid-Atlantic Bight

(Rogers and Van Den Avyle 1983).

Pearcy (1962) published comprehensive data on growth rates of

young-of-the-year winter flounder from

the Mystic River Estuary and noted

seasonal changes in growth. Because

metamorphosis was not completed until

June, growth during the first 2 months

was underestimated and was excluded

from analysis. Growth of otoliths

after deposition of the opaque center

r/as variable; consequently the age of

the young-of-the-year cannot be

determined on the basis of otolith

characteristics. Mean daily growth

rates of winter flounder (in dry

weight) were greater at 8 oC (10.1%)

than at 5 OC (5.8%) or at 2 oC (2.6%),

as shown by Laurence (1975).

Growth in weight for winter

flounder was estimated by Pearcy

(1962) who took average length of

flounder in millimeters at the

beginning of each month and converted

it to weight in grams by the formula:

W=O.O00017xL3 (Figure 5). Females are

generally larger than males of the

AVERAGE WEIGHT -2 5

2

4D- 3

I

6

5

-4 $

3

I

GROWTH RATE

_. \ / - F

\ I

z

Figure 5. Average monthly weight gain

for winter flounder in the Mystic

River estuary (Pearcy 1962).

9
Table 2. Estimated length (mm TL) at

age for winter flounder south of Cape

Cod off Massachusetts (Howe and Coates

1975).

Age

Length (mm TL)

Males Females

III 252 294

IV 301 350

V 340 390

VI 370 418

VII 393 438

VIII 411 452

IX 425 462

X 436 469

XI 445 474

XII 452 478

same age (Table 2) and grow

significantly faster (Howe and Coates

1975).

THE FISHERY

Commercial Fisheries

In the late 1920's, as trawlers

from northern ports moved south to

exploit flounders and other species,

the Cape Hatteras winter trawl fishery

was initiated (Pearson 1932).

The average total annual landings

for 1974 through 1978 in North

Carolina were about 8.4 million kg,

valued at $9.7 million (tiational

!qarine Fisheries Service 1980).

Edwards (1968) computed biomass

of winter flounder on the Continental

Shelf of New England by calculating

the average catch in pounds per tow

made by the 1963-66 groundfish survey

using a "36 Yankee" trawl (0.5 inch

cod end liner). Biomass was

calculated by multiplying catch per

tow by a correction factor which was

the number of square miles for each

zone divided by the area swept by the

net in each tow. After the use of a

second correction factor that eliminated remaining biases, standing crop

for inshore waters of New England was

estimated at 90 million pounds. Off

southeastern Massachusetts, the winter

flounder supports a coastal ground

fishery in spring and autumn and an

offshore fishery in summer (Howe et

al. 1976). In a nearby area, fishing

pressure was not correlated with

depression in abundance of the inshore

spawning stock (Jeffries and Johnson

1974).

Smolowitz (1983) demonstrated

that, when used to catch winter

founder, trawl nets with an average

mesh size of 133 mm in the cod end

(large mesh) decreased weight of

discarded fish by 73% compared to nets

averaging 103 mm in the cod end (small

mesh).

Recreational Fisheries

Compared to catches in the MidAtlantic Bight, the recreational catch

of summer flounder in the South

Atlantic Bight is minor. In the South

Atlantic Bight, North Carolina

fishermen take 72% of the total catch.

Fish less than five years old make up

most of recreational catch in the MidAtlantic Bight.

Briggs (1965), who calculated

catch rate of winter flounder per unit

of effort (16-20 fish/angler/trip) by

sportsmen fishing from five types of

boats in four locations arouna Long

Island for each month in 1961-63,

showed that catch was highest in

spring and lowest in summer.

Population Dynamics

Identification of the summer and

winter flounder stocks and stockspecific biological traits is

necessary for proper management, since

genetically distinct stocks can have

different rates of recruitment,

growth, and mortality. The existence

of three spawning populations was

lil
proposed by Smith (1973) (one each

from: Cape Cod to Delaware Bay;

Virginia to Cape Hatteras, North

Carolina; Cape Hatteras to Cape

Lookout, North Carolina). Wilk et al.

(1980) used discriminant analysis of

morphometric characters to conclude

that summer flounder from the MidAtlantic and South Atlantic Bights

constitute two separate stocks divided

by Cape Hatteras. The distribution of

juveniles in Pamlico Sound is

ubiquitous, and the estuary is

accessible to both stocks. Juveniles

in Pamlico Sound may exit to join the

stock offshore to which they belong.

Pierce and Howe (1977) suggest;

on the basis of fin ray counts, that

winter flounder south of Cape Cod

(including Martha's Vineyard but not

Buzzards Bay) be managed as a unit

stock. Saila (1962a, b), who compared

sex ratios of winter flounder in

Narragansett Bay, Rhode Island, with

those from Charlestown Pond, Rhode

Island, concluded that the higher

proportion of females than males in

the catch was due to catch selectivity

for larger fish: females are

considerably larger than males and the

market preference is for larger fish.

ECOLOGICAL ROLE

Food Habits

It has been suggested that

zooplankton and small crustaceans are

eaten by larval and postlarval summer

flounder, but supporting data is

lacking. Mysid shrimp and small fish

are the diet of juveniles, and adults

feed on fish and nysid and decapod

crustaceans (Hildebrand and Schroeder

1928; Smith and Daiber 1977; Powell

and Schwartz 1979).

Sullivan (1914) stated that

winter flounaer larvae did not eat

until after yolk absorption. Pearcy

(1962) presents a detailea account of

larval ana young juvenile feeding

habits, Throughout their range,

adults maintained a varied diet from

polychaetes to fish eggs. Their diet

is related to size: the larger the

individual, the greater the size of

the food item to be consumed. The

inajor food types of winter flounder

were polychaetes and amphipods for

fish 11-26 cm long from April to

October (Worobec 19841. Predominant

sizes of invertebrates eaten were

similar to predominant sizes in the

habitat for winter flounder 25-29 cm

long, but fish 30-35 cm long

selectively chose larger prey (Levings

1974). Winter flounder in Canada did

not feed until after spawning at the

start of the seaward migration, when

they began feeding on polychaetes and

large amphipods (Jeffries and Johnson

1974).

Feeding Behavior

Adult summer flounder feed in

estuaries and shelf waters and are

more active during daylight hours

(Olla et al. 1972; Smith and Daiber

1977). Summer flounder can feed

equally well in the water column or on

the bottom. Bottom feeding is always

preceded by an active search, and

benthic prey is usually stalked.

Searching, stalking, active eye

motion, and visual fixation on prey

during the day indicate that summer

flounder are primarily visual feeders

then (Olla et al. 1972).

Winter flounder feed partly by

sight. They lie still on the bottom

just before lunging at prey. They are

inactive from within 30 minutes after

evening twilight until the beginning

of morning twilight. Fish feed

throughout the day (Olla et al. 1969).

Parasites

The microsporidean protozoan

Glugea stephani infected 8% of winter

flounder sampled from the Mid-Atlantic

Region; the infection is present yearround (Takvorian and Cali 1984).

11

flounder exposed to oiled sediments.

Feeding rates were significantly less

in fish exposed to fresh oil in

sediments, but little or no response

to oiled sediments aged for 1 year was

observed. Reduced feeding in response

to oil contamination could deplete

reserves that winter flounder need for

sustenance and reproduction in winter

(Fletcher et al 1981). No feeding or

mortality occurred in winter.

Summer flounder larvae survived

exposure to high concentrations of sea

water sediment extract from Charleston

Harbor, South Carolina, better than

did pinfish larvae; survival was 100%

(Hess et al. 1974). The sediment

extract probably contained any

contaminants that would be in the

outfall (runoff) from a dyked disposal

area for dredged material taken from

the harbor (Hoss et al. 1974). Fin

rot disease in summer flounder was

slightly more common in the inshore

waters of the New York and New Jersey

coasts than in more offshore waters

(Ziskowski et al. 1987). In a model

of the effects of pollution on a

multispecies group of coastal fishes,

summer flounder showed moderate

effects (depression of abundance) but

took lo-12 years to recover (Schaaf et

al. 1987).

.3

LITERATURE CITED

Bigelow, H.B., and W.C. Schroeder.

1953. Fishes of the Gulf of Vaine.

U.S. Fish kildl. Serv. Fish. Bull.

53. 577 QQ.

Breder, C.M., Jr. 1922. Description

of the spawning habits of

Pseudopleuronectes americanus in

captivity. Copeia 102:3-4.

Breder, C.M., Jr. 1924. Some

embryonic and larval stages of the

winter flounaer. Bull. U.S. Bur.

Fish. 38:311-315.

Briggs, P.T. 1365. The sport

fisheries fcr winter flounder in

several bays of Long Island, N.Y.

Fish Game J. 12:48-70.

Burton, M. P., and D.R. Idler. 1984.

The reproductive cvcle in winter

flounder, Pleuronecies americanus.

Can. J. Zool. 62:2563-2567.

Casterlin, M.E., and W.W. Reynolds.

1982. Thermoregulatory behavior and

die1 activity of yearling winter

flounder, PSeUdOQleUrOneCteS

americanus. Environ. Biol. Fishes

7:177-180.

Deacutis, C.F. 1978. Effect of

thermal shock on predator avoidance

by larvae of two fish species.

Trans. Am. Fish. Sot. 107:632-635.

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.

Deubler, E.E., Jr. 1958. A

comparative study of the postlarvae

of three flounders (Paralichthvs) in

North Carolina. Copeia 1958:112-

116.

Edwards, R.L. 1968. Fishery

resources of the North Atlantic

area. Pages 52-60 in D. Gilbert,

ed. The future ofthe fishing

industry of United States. Univ.

Wash. Publ. Fish. New Ser. 4.

Fletcher, G.L., J.W. Kiceniuk, and V.P.

Williams. 1981. Effects of oiled

sediments on mortality, feeding, and

growth of winter flounder

(Pseudooleuronectes americanus).

Mar. Ecol. Prog. Ser. 4:91-96.

Hildebrand, S.F., and W.C. Schroeder.

1928. Fishes of the Chesapeake Bay.

U.S. Bureau of Fisheries 1024:366

PP.

Hoff, J.G., and J.R. Westman. 1966.

The temperature tolerances of three

species of marine fishes. J. Mar.

Res. 24:131-140.

Hoss, D.E., L.C. Coston, and W.E.

Schaaf. 1974. Effects of seawater

extracts of sediments from

Charleston Harbor, S.C., on larval

estuarine fishes. Estuarine Coastal

Mar. Sci. 2:323-328.

Howe, A.B., and P.G. Coates. 1975.

Winter flounder movements, growth,

and mortality off Massachusetts.

Trans. Am. Fish. Sot. 104:13-29.

Howe, A.B., P.G. Coates, and D.E.

Pierce. 1976. Winter flounder

15
estuarine year-class abundance,

mortality, and recruitment. Trans.

Am. Fish. Sot. 105:647-657.

Itzkowitz, N., and J.R. Schubel.

1983. Tolerance of five-day-old

winter flounder, Pseudopleuronectes

americanus, larvae to thermal shock.

U.S. Natl. Mar. Fish. Serv. Fish.

Bull. 81:913-916.

Itzkowitz, N., J.R. Schubel, and

P.M.J. Woodhead. 1983. Responses

of summer flounder, Paralichthys

dentatus, embryos to thermal shock:

Environ. Biol. Fishes 8:125-135.

Jeffries, H.P., and W.C. Johnson.

1974. Seasonal distributions of

bottom fishes in the Narragansett

9ay area: seven-year variations ?n

the aoundance of winter flounder

(Pseudopleuronectes americanus). J.

Fish. Res. Board Can. 31:1057-i066.

Johns, D.M., W.H. Howell, and G.

Klein-MacPhee. 1981. Yolk

utilization and growth to yolk sac

absorotion in summer flounder

(Paraiichthys aentatus) larvae at

constant and cyclic temperatures.

Mar. Biol. (Berl.) 63:301-330.

Kennedy, V.S., and D.H. Steele. 1971.

The winter flounder

(Pseudopleuronectes americanus) in

Long Pond, Conception Bay,

Newfoundland. J. Fish. Res. Board

Can. 2831153-1165.

Keup, L., and J. Bayless. 1964. Fish

distribution at varying salinities

in Neuse River basin, North

Carolina. Chesapeake Sci. 5:119-

123.

Laurence, G.C. 1975. Laboratory

growth and metabolism of the winter

americanus from hatching through

metamorohosis at three temoeratures.

Mar. Bibl. (Berl.) 32:223-229.

Levings, C.D. 1974. Seasonal changes

in feeding and particle selection by

winter flounder (Pseudopleuronectes

americanus). Trans. Am. Fish. Sot.

103:828-832.

Martin, F.D., and G.E. Drewry. 1978.

Development of fishes of the MidAtlantic Bight, an atlas of egg,

larval, and juvenile stages. Vol.

VI, Stromateidae through

Ogocephalidae. U.S. Fish. Wildl.

Serv. Biol. Serv. Program FWS/OBS78112. 416 pp.

McCracken, F.D. 1963. Seasonal

movements of the winter flounder,

PseudoDleuronectes americanus

(Walbaum), on the Atlantic coast.

J. Fish. Res. Board Can. 20:551-586.

Morse, W.W. 1981. Reproduction of

the summer flounder, Paralichth s

i9:ia9-203.

dentatus (L.). J. d

;lational Yarine Fisheries Service.

1980. Fishery Statistics of the

United States, 1979. U.S. Natl.

Mar. Fish. Serv. Curr. Fish. Stat.

No. 8000.

National Marine Fisheries Service.

1987a. Fisheries of the United

States, 1586. IUS. Natl. Mar. Fish.

Serv. Curr. Fish. Stat. 8385.

National Marine Fisheries Service.

1987b. Marine recreational fishery

statistics survey, Atlantic and gulf

coasts, 1986. U.S. Natl. Mar. Fish.

Serv. Curr. Fish. Stat. 8392.

Olla, B.L., R. Wicklund, and S. Wilk.

1969. Behavior of winter flounder

in a natural habitat. Trans. Am.

Fish. Sot. 98:717-720.

Olla, B.L., C.E. Samet, and A.L.

Studholme. 3972. Activity and

feeding behavior of the summer

flounder (Paralichthvs dentatus)

under controlled laboratory

conditions. Fish. Bull. 70:1127-

1136.

16
Pearcy, W.G. 1962. Ecology of an

estuarine population of winter

flounder 'Pseudopleuronectes

americanus (walbaum). Bull. 5ingham

dceanogr. Collect., Yale Univ.

18(l). 78 pp.

Pearson, J.C. 1932. Winter trawl

fishery off the Virginia and North

Carolina coasts. U.S. Bur. Fish.

Invest. Rep. 10. 31 pp.

Peters, D.S.,and J.W. Angelovic.

1971. Effect of temperature

salinity, and food availability on

growth and energy utilization of

juvenile summer flounder,

Paralichthys dentatus. Pages 545-

554 in D.J. INelson, ed.

Radionuclides in ecosvstems.

National Symposium on Radioecology,

Oak Ridge, Tenn.

Pierce, D.E., and A.B. Howe. 1977.

A further study on winter flounder

group identification off

Massachusetts. Trans. Am. Fish.

Sot. 106:131-139.

Powell. A.B. 1974. Bioloqy of the

summer flounder, Para-lichthys

dentatus, in Pamlico Sound and

adjacent waters, with comments on P.

lethostigma and P. albigutta. il . 7.

Thesis. University of North

Carolina, Chapel Hill. ~145 pp.

Powell, A.B., and F.J. Schwartz.

1977. Distribution of paralichthid

flounders [Bothidae: Paralichthys)

in North Carolina estuaries.

Chesapeake Sci. 18:534-339.

i-qwell. A.;;., and F.J. Schwartz.

estuaries. Estuaries 2:276-279.

Richards, C.E., and M.' Castagna.

1970. Marine fishes of Virginia's

Eastern Shore (inlet and marsh,

seaside ,.:aters). Chesapeake Sci.

!1:235-248.

Rogers, C.A. 1976. Effects of

temperature and salinity on the

survival of winter flounder embryos.

U.S. Natl. Mar. Fish. Serv. Fish.

Bull. 74:52-58.

Rogers, S.G., and M.J. Van Den Avyle.

1983. Species profiles: Life

histories and environmental

requirements of coastal fishes and

invertebrates (South Atlantic)--

summer flounder. U.S. Fish. Wildl.

Serv. FWS/OBS-82/11.15. U.S. Army

Corps of Engineers, TR EL-82-4. i4

PP.

Saila, S.B. 1961. A study of winter

flounder movements. Limnol.

Dceanogr. 0:292-298.

Saila, S.B. 1962a. The ccntribution

of estuaries to the offshore winter

flounder fishery in Rhode Island.

Proc. Gulf Caribb. Fish. Inst.

14:95-109.

Saila, S.B. i962b. Proposed hurricane barriers related to winter

flounder movements in Narrangansett

Bay. Trans. Am. Fish. Sot.

91:189-195.

Saila, S.B., D.B. Horton, and R.J.

Berry. 1965. Estimates of the

theoretical biomass of juvenile

winter flounder, Pseudopleuronectes

americanus (Walbaum), required for a

fishery in Rhode Island. J. Fish.

Res. Board Can. 22:945-995.

Scarlett, P.G. 1981. Fishery

management plan for the summer

flounder fishery. Atlantic States

Marine Fisheries Commission

Management Report 81-1. Washington,

D.C. 80 pp.

Schaaf, W.E., D.S. Peters, D.S.

Vaughan, L. Coston-Clements, and

C.W. Krouse. 1987. Fish population

responses to chronic and acute

pollution: the influence of life

history strategies. Estuaries

10:267-275.

17
Smith, R.W., and F.C. Daiber. 1977.

Biology of the summer flounder,

Paralichthys dentatus, in Delaware

Bay. U.S. Natl. Mar. Fish. Serv.

Fish. Bull. 75:823-830.

Smith, R.W., L.M. Dery, P.J. Scarlett,

and A. Jearld, Jr. 1981.

Proceedings of the summer flounder

(Paralichthvs dentatus) age and

growth workshop 20-21 May 1980,

Northeast Fishery Center, Woods

Hole, Massachusetts. NOAA Tech.

Memo. NMFS-F/NEC-11. 31 pp.

Smith, W.G. 1973. The distribution

of summer flounder, Paralichthys

dentatus, eggs and larvae on the

Continental Shelf between Cape Cod

and Cape Lookout, 1965-1966. U.S.

Natl. Mar. Fish. Serv. Fish. Bull.

71~527-548.

Smolowitz, R.J. 1983. Mesh size and

the New England ground fishery--

applications and implications. NOAA

Tech. Rep. NMFS-SSRF-771. 60 pp.

Sullivan, W.E. 1914. A description

of the younq staqes of the winter

flounder {P seudopleuronectes

Fish. 

americanus 

Sot. 44:125-136.

Wm

Takvorian, P.M., and A. Cali. 1984.

Seasonal prevalence of the

microsporidkan, Glugea stephani

(Hagenmuller), in winter flounder,

Pseudopleuronectes ameriCanUS

(Walbaum), from the New York-New

Jersey Lower Bay Complex. J. Fish

Biol. 24:655-663.

Topp, R.W. 1968. An estimate of

fecundity of the winter flounder

Fish. ies. Loard Can. 2\:1299-1302.

(Pseud pleu onectespme icams). J.

Weinstein, M.P. 1979. Shallow marsh

habitats as primary nurseries for

fishes and shellfishes, Cape Fear

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Mar. Fish. Serv. Fish. Bull.

77:339-357.

Weinstein, M.P., and H.A. Brooks.

1983. Comparative ecology of nekton

residing in a tidal creek and

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Hodson, and L.R. Gerry. 1980.

Retention of three taxa of post

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flushed tidal estuary, Cape Fear

.River, North Carolina. U.S. Natl.

Mar. Fish. Serv. Fish. Bull.

78:419-436.

Wilk, S.J., W.W. Morse, and D.E.

Ralph. 1978. Length-weight

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Acad. Sci. 23:58-64.

Wilk, S.W., W.G. Smith, D.E. Ralph,

and J. Sibunka. 1980. Population

structure of summer flounder between

New York and Florida based on linear

discriminant analysis. Trans. Am.

Fish. Sot. 109:265-271.

Williams, A.B., and E.E. Deubler.

1968. A ten-year study of

meroplankton in North Carolina

estuaries: assessment of environmental factors and sampling success

among bothid flounders and penaeid

shrimps. Chesapeake Sci. 9:27-41.

Worobec, M.N. 1984. Field estimates

of the daily ration of winter

flounder, Pseudopleuronectes

americanus (Walbaum), in a southern

New England salt pond. J. Exp. Mar.

Biol. Ecol. 77:183-196.

Ziskowski, J., and R. Murchelano.

1975. Fin erosion in winter

flounder. Mar. Pollut. Bull. 6:26-

29.

Ziskowski, J.J., L. Despres-Patanjo,

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18
G

0171_101

REPORT DOCUMENTATION 1. REPORT NO- 2.

PAGE I

Bioloqical Report 82(11.112)* I

!. Title and Subtitle

Species Profiles: Life Histories and Environmental Requirements of

Coastal Fishes and Invertebrates (Mid-Atlantic&Summer and Winter

Flounder

‘. Author(s)

Barbara H.Grimes, Melvin T.Huish, and J. Howard Kerbya; David i%ranb

a. North Carolina Cooperative

Fishery Research Unit bNationa1 Wetlands Research Center

U.S. Fish and Wildlife Service Department of Zoology, Box 7617 IOIO Gause Boulevard

North Carolina State University Slidellj, LA 70458

--_Raleighi, NC 27695______ -___--

.2. Sponsoring Organization Name and Address

U.S. Department of the Interior U.S. Army Corps of Engineers

Fish and Wildlife Service Waterways Experiment Station

National Wetlands Research Center P.O. Box 631

Washington, DC 20240 Vicksburg, MS 39180

3. Recipient’s Accession No.

6. Rwort oat*

August 1989

6.

8. Pwforming Organization Rept. MI

IO. PmiwtlTalklWork Unit NO.

11. Contract(C) or Grant(G) NO.

(C)

(G)

14.

U.S. Army Corps of Engineers Report No. TR EL-82-4

16. Abstract (Limit: 200 words)

Species profiles are literature summaries of the taxonomy, morphology, range, life

history, and environmental requirements of coastal species. They are designed to

assist in environmental impact assessments. The summer flounder supports an

important commercial and recreational fishery in the Mid-Atlantic and are important

constituent of estuarine and continental shelf systems throughout the region.

Summer flounder spawning begins in Septetier and winter flounder spawning begins in

June. Summer flounder eggs are pelagic whereas winter flounder eggs are demersal.

Summer flounder larvae are more abundant in inlets, and juveniles are found in

estuarine seagrass beds in salinities 112 ppt. Winter flounder juveniles are

abundant in shallow bays and estuaries, moving seaward in spring and summer.

Growth of winter flounder and summer flounder is seasonal. There are probably

three spawning populations of both species which produce a complex stock pattern.

Summer flounder are tolerant of a wide range of chemical and physical factors, but

prefer 710 ppt salinities. Winter flounder optimal temperature is 18.5 "C.

Diseases of winter flounder are more prevalent in polluted waters. Summer flounder

are tolerant of sediments laden with contaminants.

II. Document Analysis a. Descriptors

a) Flounder Fisheries

Growth Feeding habits

Life cycles

Salinity

Temperature

b. IdentltienlOpen-Ended Terms

b) Paralichthys dentatus Summer flounder

Pseudopleuronectes americanus Winter flounder

c. COSATI Field/Group

6. AvarIability Statement

Unlimited Distribution

19. Sccurlty Class (This Report) 21. No. of Pa6er

Unclassified 18 - -

20. Security Class (This Pa& 22. price

Unclassified

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the Interior has responsibility for most of our nationally owned

public lands and natural resources. This includes fostering the

wisest use of our land and water resources, protecting our fish

and wildlife, preserving the environmental and cultural values of our

national parks and historical places, and providing for the enjoyment of life through outdoor recreation. The Department assesses

our energy and mineral resources and works to assure that their

development is in the best interests of all our people. The Department also has a major responsibility for American Indian reservation

communities and for people who live in island territories under U.S.

administration.

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