NOAA Technical Memorandum NMFS-NE-187

U. S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Northeast Fisheries Science Center

Woods Hole, Massachusetts

August 2004

Essential Fish Habitat Source Document:

American Plaice, Hippoglossoides platessoides,

Life History and Habitat Characteristics

Second Edition
166. Report on the Third Northwest Atlantic Herring Acoustic Workshop, University of Maine Darling Marine Center,

Walpole, Maine, March 13-14, 2001. By William L. Michaels, ed. & co-conven., and Philip Yund, co-conven. December 2001. iv +

18 p., 14 figs., 2 app. NTIS Access. No. PB2003-101556.

167. Assessment and Characterization of Salt Marshes in the Arthur Kill (New York and New Jersey) Replanted after a Severe

Oil Spill. By David B. Packer, ed. December 2001. x + 228 p., 54 figs., 58 tables, 6 app. NTIS Access. No. PB2004-106067.

168. U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments – 2001. By Gordon T. Waring, Janeen M. Quintal, and

Steven L. Swartz, eds., Phillip J. Clapham, Timothy V.N. Cole, Carol P. Fairfield, Aleta Hohn, Debra L. Palka, Marjorie C. Rossman, U.S.

Fish and Wildlife Service, and Cynthia Yeung, contribs. December 2001. vii + 310 p., 43 figs., 54 tables, 2 app. NTIS Access. No. PB2002-

104350.

169. U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments – 2002. By Gordon T. Waring, Janeen M. Quintal, and

Carol P. Fairfield, eds., Phillip J. Clapham, Timothy V.N. Cole, Lance P. Garrison, Georgia Department of Natural Resources, Aleta A. Hohn,

Blair G. Maise, Wayne E. McFee, Debra L. Palka, Patricia E. Rosel, Marjorie C. Rossman, U.S. Fish and Wildlife Service, Frederick W. Wenzel,

and Cynthia Yeung, contribs. September 2002. vii + 318 p., 42 figs., 56 tables, 4 app. NTIS Access. No. PB2003-104167.

170. In press.

171. Length-Weight Relationships for 74 Fish Species Collected during NEFSC Research Vessel Bottom Trawl Surveys. By

Susan E. Wigley, Holly M. McBride, and Nancy J. McHugh. March 2003. vi + 26 p., 1 fig., 3 tables. NTIS Access. No. PB2003-106486.

172. Variability of Temperature and Salinity in the Middle Atlantic Bight and Gulf of Maine Based on Data Collected as

Part of the MARMAP Ships of Opportunity Program, 1978-2001. By Jack W. Jossi and Robert L. Benway. March 2003. vi + 92

p., 74 figs., 5 tables. NTIS Access. No. PB2004-100835.

173. Essential Fish Habitat Source Document: Barndoor Skate, Dipturus laevis, Life History and Habitat Characteristics. By

David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 23 p., 14 figs., 1 table. NTIS Access. No. PB2003-104257.

174. Essential Fish Habitat Source Document: Clearnose Skate, Raja eglanteria, Life History and Habitat Characteristics.

By David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 50 p., 25 figs., 2 tables. NTIS Access. No. PB2003-

104260.

175. Essential Fish Habitat Source Document: Little Skate, Leucoraja erinacea, Life History and Habitat Characteristics. By

David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 66 p., 27 figs., 2 tables. NTIS Access. No. PB2003-104259.

176. Essential Fish Habitat Source Document: Rosette Skate, Leucoraja garmani virginica, Life History and Habitat

Characteristics. By David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 17 p., 11 figs., 1 table. NTIS Access.

No. PB2003-104258.

177. Essential Fish Habitat Source Document: Smooth Skate, Malacoraja senta, Life History and Habitat Characteristics. By

David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 26 p., 15 figs., 1 table. NTIS Access. No. PB2003-104256.

178. Essential Fish Habitat Source Document: Thorny Skate, Amblyraja radiata, Life History and Habitat Characteristics. By

David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 39 p., 18 figs., 2 tables. NTIS Access. No. PB2003-104255.

179. Essential Fish Habitat Source Document: Winter Skate, Leucoraja ocellata, Life History and Habitat Characteristics.

By David B. Packer, Christine A. Zetlin, and Joseph J. Vitaliano. March 2003. v + 57 p., 25 figs., 2 tables. NTIS Access. No. PB2003-

104254.

180. Variability in Blood Chemistry of Yellowtail Flounder, Limanda ferruginea, with Regard to Sex, Season, and Geographic

Location. By Renee Mercaldo-Allen, Margaret A. Dawson, Catherine A. Kuropat, and Diane Kapareiko. September 2003. vi + 20 p., 1

fig., 10 tables.

181. In press.

182. U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments – 2003. By Gordon T. Waring, Richard M. Pace, Janeen

M. Quintal, Carol P. Fairfield, and Katherine Maze-Foley, eds., Nicole Cabana, Phillip J. Clapham, Timothy V.N. Cole, Gregory L. Fulling,

Lance P. Garrison, Aleta A. Hohn, Blair G. Maise, Wayne E. McFee, Keith D. Mullin, Debra L. Palka, Patricia E. Rosel, Marjorie C. Rossman,

Frederick W. Wenzel, and Amy L. Whitingham, contribs. May 2004. vii + 287 p., 47 figs., 58 tables, 4 app., index

Recent Issues in This Series:
U. S. DEPARTMENT OF COMMERCE

Donald L. Evans, Secretary

National Oceanic and Atmospheric Administration

Vice Admiral Conrad C. Lautenbacher, Jr., USN (ret.), Administrator

National Marine Fisheries Service

William T. Hogarth, Assistant Administrator for Fisheries

Northeast Fisheries Science Center

Woods Hole, Massachusetts

August 2004

This series represents a secondary level of scientific publishing. All issues employ

thorough internal scientific review; some issues employ external scientific review.

Reviews are -- by design -- transparent collegial reviews, not anonymous peer

reviews. All issues may be cited in formal scientific communications.

NOAA Technical Memorandum NMFS-NE-187

Donna L. Johnson

National Marine Fisheries Serv., 74 Magruder Rd., Highlands, NJ 07732

Essential Fish Habitat Source Document:

American Plaice, Hippoglossoides platessoides,

Life History and Habitat Characteristics

Second Edition
Editorial Notes on "Essential Fish Habitat Source Documents"

Issued in the NOAA Technical Memorandum NMFS-NE Series

Editorial Production

For "Essential Fish Habitat Source Documents" issued in the NOAA Technical Memorandum NMFS-NE series, staff

of the Northeast Fisheries Science Center's (NEFSC's) Ecosystems Processes Division largely assume the role of staff of

the NEFSC's Editorial Office for technical and copy editing, type composition, and page layout. Other than the four covers

(inside and outside, front and back) and first two preliminary pages, all preprinting editorial production is performed by,

and all credit for such production rightfully belongs to, the staff of the Ecosystems Processes Division.

Internet Availability and Information Updating

Each original issue of an "Essential Fish Habitat Source Document" is published both as a paper copy and as a Web

posting. The Web posting, which is in "PDF" format, is available at: http://www.nefsc.noaa.gov/nefsc/habitat/efh.

Each issue is updated at least every five years. The updated edition will be published as a Web posting only; the

replaced edition(s) will be maintained in an online archive for reference purposes.

Species Names

The NMFS Northeast Region's policy on the use of species names in all technical communications is generally to

follow the American Fisheries Society's lists of scientific and common names for fishes (i.e., Robins et al. 1991aa

, bb),

mollusks (i.e., Turgeon et al. 1998c), and decapod crustaceans (i.e., Williams et al. 1989d), and to follow the Society for

Marine Mammalogy's guidance on scientific and common names for marine mammals (i.e., Rice 1998e). Exceptions to this

policy occur when there are subsequent compelling revisions in the classifications of species, resulting in changes in the

names of species (e.g., Cooper and Chapleau 1998f

; McEachran and Dunn 1998g).

a

Robins, C.R. (chair); Bailey, R.M.; Bond, C.E.; Brooker, J.R.; Lachner, E.A.; Lea, R.N.; Scott, W.B. 1991a. Common and scientific names

of fishes from the United States and Canada. 5th ed. Amer. Fish. Soc. Spec. Publ. 20; 183 p. b

Robins, C.R. (chair); Bailey, R.M.; Bond, C.E.; Brooker, J.R.; Lachner, E.A.; Lea, R.N.; Scott, W.B. 1991b. World fishes important to

North Americans. Amer. Fish. Soc. Spec. Publ. 21; 243 p. c

Turgeon, D.D. (chair); Quinn, J.F., Jr.; Bogan, A.E.; Coan, E.V.; Hochberg, F.G.; Lyons, W.G.; Mikkelsen, P.M.; Neves, R.J.; Roper, C.F.E.;

Rosenberg, G.; Roth, B.; Scheltema, A.; Thompson, F.G.; Vecchione, M.; Williams, J.D. 1998. Common and scientific names of aquatic

invertebrates from the United States and Canada: mollusks. 2nd ed. Amer. Fish. Soc. Spec. Publ. 26; 526 p. d

Williams, A.B. (chair); Abele, L.G.; Felder, D.L.; Hobbs, H.H., Jr.; Manning, R.B.; McLaughlin, P.A.; Pérez Farfante, I. 1989. Common

and scientific names of aquatic invertebrates from the United States and Canada: decapod crustaceans. Amer. Fish. Soc. Spec. Publ. 17;

77 p.

e

Rice, D.W. 1998. Marine mammals of the world: systematics and distribution. Soc. Mar. Mammal. Spec. Publ. 4; 231 p. f

Cooper, J.A.; Chapleau, F. 1998. Monophyly and interrelationships of the family Pleuronectidae (Pleuronectiformes), with a revised

classification. Fish. Bull. (Washington, DC) 96:686-726. g

McEachran, J.D.; Dunn, K.A. 1998. Phylogenetic analysis of skates, a morphologically conservative clade of elasmobranchs

(Chondrichthyes: Rajidae). Copeia 1998(2):271-290.
NOAA Technical Memorandum NMFS-NE-187 

Essential Fish Habitat Source Document: American Plaice, Hippoglossoides

platessoides, Life History and Habitat Characteristics (Second Edition) 

ERRATA

Page 23

In Table 5. Con't., footnote 2, change:

2

 Bigelow and Schroeder (1953); Howell and Caldwell (1984); Scherer (1984); Neilson et 

al. (1988); DFO (1989); Berrien and Sibunka (1999); Hebert and Wearing-Wilde 2002. 

to:

2

 Bigelow and Schroeder (1953); Bowman and Michaels (1984); Howell and Caldwell 

(1984); Scherer (1984); Neilson et al. (1988); DFO (1989); Berrien and Sibunka (1999); 

Hebert and Wearing-Wilde (2002); Link and Almeida (2000); Link et al. (2002); Packer 

and Langton (unpubl. manuscript). 

In Table 5. Con't., eliminate footnote 4:

4

 Bigelow and Schroeder (1953); Bowman and Michaels (1984); Link and Almeida 

(2000); Link et al. (2002); Packer and Langton (unpubl. manuscript). 

In Table 5. Con't., line 1 of footnote 5, change:

5

 Huntsman (1918); Bigelow and Schroeder (1953); Backus (1957); Powles (1965); 

Colton (1972); Pitt (1973); Dow

to:

4

 Huntsman (1918); Bigelow and Schroeder (1953); Backus (1957); Powles (1965); 

Colton (1972); Pitt (1973); Dow

Page 25

In Table 5. Con't., footnote 2, change:

2

 Powles (1965); Bowman and Michaels (1984); Ross and Hokenson (1997).

to:

2

 Powles (1965); Bowman and Michaels (1984) 
Page iii

PREFACE TO SECOND EDITION 

One of the greatest long-term threats to the viability of 

commercial and recreational fisheries is the continuing 

loss of marine, estuarine, and other aquatic habitats. 

Magnuson-Stevens Fishery Conservation and 

Management Act (October 11, 1996) 

The long-term viability of living marine resources 

depends on protection of their habitat. 

NMFS Strategic Plan for Fisheries Research 

(February 1998) 

The Magnuson-Stevens Fishery Conservation and 

Management Act (MSFCMA), which was reauthorized 

and amended by the Sustainable Fisheries Act (1996), 

requires the eight regional fishery management councils 

to describe and identify essential fish habitat (EFH) in 

their respective regions, to specify actions to conserve 

and enhance that EFH, and to minimize the adverse 

effects of fishing on EFH. Congress defined EFH as 

“those waters and substrate necessary to fish for 

spawning, breeding, feeding or growth to maturity.” 

The MSFCMA requires NOAA Fisheries to assist the 

regional fishery management councils in the 

implementation of EFH in their respective fishery 

management plans. 

NOAA Fisheries has taken a broad view of habitat 

as the area used by fish throughout their life cycle. Fish 

use habitat for spawning, feeding, nursery, migration, 

and shelter, but most habitats provide only a subset of 

these functions. Fish may change habitats with changes 

in life history stage, seasonal and geographic 

distributions, abundance, and interactions with other 

species. The type of habitat, as well as its attributes and 

functions, are important for sustaining the production of 

managed species. 

The Northeast Fisheries Science Center compiled 

the available information on the distribution, 

abundance, and habitat requirements for each of the 

species managed by the New England and Mid-Atlantic 

Fishery Management Councils. That information is 

presented in a series of EFH species reports (plus one 

consolidated methods report). The EFH species reports 

are a survey of the important literature as well as 

original analyses of fishery-independent data sets from 

NOAA Fisheries and several coastal states. The species 

reports are also the source for the current EFH 

designations by the New England and Mid-Atlantic 

Fishery Management Councils, and understandably are 

referred to as the “EFH source documents.” 

NOAA Fisheries provided guidance to the regional 

fishery management councils for identifying and 

describing EFH of their managed species. Consistent 

with this guidance, the species reports present 

information on current and historic stock sizes, 

geographic range, and the period and location of major 

life history stages. The habitats of managed species are 

described by the physical, chemical, and biological 

components of the ecosystem where the species occur. 

Information on the habitat requirements is provided for 

each life history stage, and it includes, where available, 

habitat and environmental variables that control or limit 

distribution, abundance, growth, reproduction, 

mortality, and productivity. 

The initial series of EFH species source documents 

were published in 1999 in the NOAA Technical 

Memorandum NMFS-NE series. Updating and review 

of the EFH components of the councils’ Fishery 

Management Plans is required at least every 5 years by 

the NOAA Fisheries Guidelines for meeting the 

Sustainable Fisheries Act/EFH Final Rule. The second 

editions of these species source documents were written 

to provide the updated information needed to meet 

these requirements. The second editions provide new 

information on life history, geographic distribution, and 

habitat requirements via recent literature, research, and 

fishery surveys, and incorporate updated and revised 

maps and graphs. This second edition of the American 

plaice EFH source document is based on the original by 

Donna L. Johnson, Peter L. Berrien, Wallace W. Morse, 

and Joseph J. Vitaliano, with a foreword by Jeffrey N. 

Cross (Johnson et al. 1999). 

Identifying and describing EFH are the first steps 

in the process of protecting, conserving, and enhancing 

essential habitats of the managed species. Ultimately, 

NOAA Fisheries, the regional fishery management 

councils, fishing participants, Federal and state 

agencies, and other organizations will have to cooperate 

to achieve the habitat goals established by the 

MSFCMA.
Page iv 
Page v

Contents

INTRODUCTION................................................................................................................................................................1

LIFE HISTORY ...................................................................................................................................................................1

GEOGRAPHICAL DISTRIBUTION ..................................................................................................................................4

HABITAT CHARACTERISTICS .......................................................................................................................................6

RESEARCH NEEDS ...........................................................................................................................................................8

REFERENCES CITED ........................................................................................................................................................9

ADDITIONAL REFERENCES .........................................................................................................................................13

Tables

Table 1. The age and length at maturity of female American plaice in the northwest Atlantic. ....................................16

Table 2. Diet composition of American plaice by fish length category. ........................................................................17

Table 3. Diet composition of American plaice by geographical area. ...........................................................................18

Table 4. Distribution and relative abundance of American plaice in North Atlantic estuaries and rivers by life history 

stage. ................................................................................................................................................................19

Table 5. Summary of habitat parameters for American plaice, based on the pertinent literature. .................................21

Table 6. Summary of habitat parameters for American plaice, based on available surveys. .........................................26

Figures

Figure 1. The American plaice, Hippoglossoides platessoides (Fabricius 1780) (from Goode 1884). ...........................27

Figure 2. Percent by weight of the major prey items in the diet of three size categories of American plaice.................28

Figure 3. Distributions and abundances of American plaice eggs collected during NEFSC MARMAP 

ichthyoplankton surveys. .................................................................................................................................29

Figure 4. Distributions and abundances of American plaice eggs collected during GLOBEC Georges Bank 

ichthyoplankton surveys. .................................................................................................................................33

Figure 5. Distributions and abundances of American plaice larvae collected during NEFSC MARMAP 

ichthyoplankton surveys. .................................................................................................................................37

Figure 6. Distributions and abundances of American plaice larvae collected during GLOBEC Georges Bank 

ichthyoplankton surveys. .................................................................................................................................40

Figure 7. Seasonal distributions and abundances of juvenile American plaice collected during NEFSC bottom trawl 

surveys. ............................................................................................................................................................44

Figure 8. Distribution and abundance of American plaice along the coasts of Maine and New Hampshire...................48

Figure 9. Regional catch-per-unit-effort of American plaice caught along the Maine and New Hampshire coasts, by 

season/year.......................................................................................................................................................49

Figure 10. Length frequency plots for American plaice caught along the Maine and New Hampshire coasts, by season 

and year............................................................................................................................................................50

Figure 11. Seasonal distributions and abundances of juvenile American plaice in Massachusetts coastal waters............51

Figure 12. Seasonal distributions and abundances of adult American plaice collected during NEFSC bottom trawl 

surveys. ............................................................................................................................................................53

Figure 13. Seasonal distributions and abundances of adult American plaice in Massachusetts coastal waters.................57

Figure 14. Monthly distributions of American plaice eggs collected during NEFSC MARMAP ichthyoplankton 

surveys relative to water column temperature and bottom depth.....................................................................59

Figure 15. Distributions of American plaice eggs collected during GLOBEC ichthyoplankton surveys relative to water 

column temperature..........................................................................................................................................60

Figure 16. Distributions of American plaice eggs collected during GLOBEC ichthyoplankton surveys relative to 

bottom depth. ...................................................................................................................................................61
Page vi 

Figure 17. Monthly distributions of American plaice larvae collected during NEFSC MARMAP ichthyoplankton 

surveys relative to water column temperature and bottom depth.....................................................................62

Figure 18. Distributions of American plaice larvae collected during GLOBEC ichthyoplankton surveys relative to 

water column temperature................................................................................................................................63

Figure 19. Distributions of American plaice larvae collected during GLOBEC ichthyoplankton surveys relative to 

bottom depth. ...................................................................................................................................................64

Figure 20. Distributions of juvenile American plaice and trawls from NEFSC bottom trawl surveys relative to bottom 

water temperature, depth, and salinity..............................................................................................................65

Figure 21. Distributions of juvenile American plaice and trawls in Massachusetts coastal waters relative to bottom 

water temperature and depth. ...........................................................................................................................67

Figure 22. Distributions of adult American plaice and trawls from NEFSC bottom trawl surveys relative to bottom 

water temperature, depth, and salinity..............................................................................................................69

Figure 23. Distributions of adult American plaice and trawls in Massachusetts coastal waters relative to bottom water 

temperature and depth. .....................................................................................................................................71
Page 1

INTRODUCTION

The American plaice, Hippoglossoides platessoides 

(Figure 1), is an arctic-boreal to temperate-marine 

pleuronectid (righteye) flounder that inhabits both sides 

of the North Atlantic on the continental shelves of 

northeastern North America and northern Europe (Scott 

and Scott 1988; Sparholt 1990; Langton and Bowman 

1981). In Europe, it is known as the long rough dab 

and occurs from Iceland and Spitzbergen south to the 

North Sea, the western Baltic, and as far south as the 

English Channel. In the western Atlantic, it is common 

from the outer coast of Labrador, south from Hamilton 

Inlet, Newfoundland, on the Grand Banks, in the Gulf 

of St. Lawrence, west and south to Cape Cod, Bigelow 

and Schroeder 1953; Smith et al. 1975). It occurs as far 

south as Montauk Point, NY. The spawning seasons 

are geographically connected with latitude, where 

spawning occurs in the southern limits first, followed 

by the northern region (Howell and Caldwell 1984). 

It is considered to be the most abundant flatfish 

species in the western Atlantic Ocean (Bowering and 

Brodie 1991; Nagler et al. 1999) and to have historic 

importance in the offshore fishery of North America 

(Walsh 1994). In the early 1980s through 1990s, 

American plaice populations in the western Atlantic 

declined dramatically for undetermined causes 

(Beacham 1983; Bowering et al. 1997; Nagler et al.

1999), environmental changes, such as temperature 

(Morgan 1992) and pollution (Nagler and Cyr 1997), 

may be responsible. An overwhelming contributing 

factor to the decline in some stocks is believed to be 

overfishing (Nagler et al. 1999). Northeast stock 

assessment reports through 2001 classify American 

plaice as ‘overfished’ and that overfishing is occurring 

in the Gulf of Maine-Georges Bank region (O’Brien et 

al. 2002). 

In Canadian waters, American plaice have been 

exploited since the start of the otter trawl fishery in 

1947. It is one of four major species contributing to the 

Newfoundland and Labrador fisheries (Bowering and 

Brodie 1991). Notable increases in abundance of plaice 

were found inside the closed fishing grounds of 

Emerald Bank/Western Bank (Frank et al. 2000). In 

U.S. waters, the fishery for American plaice started to 

develop around 1975 in the Gulf of Maine as the 

abundance of other commercially desirable flatfish, 

such as yellowtail flounder, winter flounder, and 

summer flounder, began to decrease (Sullivan 1981). 

Prior to 1973, the primary use of American plaice 

caught on Georges Bank was for bait (Lange and Lux 

1978). 

LIFE HISTORY 

EGGS

American plaice spawn buoyant eggs, which lack 

oil globules. The eggs have a characteristically large, 

transparent perivitelline space, which is formed from 

water entering between the egg and its membrane 

(Bigelow and Schroeder 1953). The perivitelline width 

is approximately 37% of the reference diameter 

(Russell 1976); this large sac allows the egg to float 

near the surface for about 2 weeks, and thus can be 

transported far from where it was shed (Hebert and 

Wearing-Wilde 2002). The eggs are smooth, nonsticky, and spherical in shape. The average diameter of 

an egg is 2.5 mm (range 1.38-3.2 mm). The yolk is 

unsegmented and unpigmented. During development, 

the embryo is covered with a scattered pigment and 

there are no pigments on the primordial fin (Russell 

1976). 

LARVAE 

American plaice larvae hatch at 2.4 mm SL (Fahay 

1983) and development of five clusters or groups of 

pigment begins at 4-6 mm (Klein-MacPhee 2002). 

Yolk absorption is complete about 5 days after hatching 

when the larva is 6.2-7.5 mm long. Transformation of 

the larva and migration of the left eye begins when the 

larva is approximately 20 mm. Although the duration 

of the transformation process varies with temperature, it 

is usually complete when the larva is 30-40 mm (Colton 

and Marak 1969). 

JUVENILES

Dramatic physiological transformations occur 

during the juvenile stage. The body shape continues to 

change, flattening and increasing in depth from side to 

side. As the migration of the left eye across the top of 

the head to the right side reaches completion, descent 

towards the bottom begins (Huntsman 1918). Pigment 

patterns become more abundant and develop on the 

right side of the body while the left side remains 

unpigmented. Growth during the first year is greater in 

warmer, southern climates. Juveniles can reach a 

length of 7.6 cm by winter. 
Page 2 

ADULTS 

The adult plaice has a slender, broad body, rough 

scales, a small head with a sharp nose, a wide gaping 

mouth, and a slightly protruding lower jaw. The upper 

and lower jaws are lined with many small conicalshaped teeth (Hebert and Wearing-Wilde 2002). Both 

the anal and dorsal fins are soft rayed and extend the 

length of the body. The pelvic fins are smaller than the 

rounded pectoral fins. The dorsal fin starts above the 

left eye (Muus and Nielsen 1999). On the dorsal side, 

where both eyes reside, it is reddish brown, while the 

ventral side is blind and white. Adults obtain average 

lengths from 27-66 cm TL. As with most flatfish 

species, the sexes differ in size at age, with females 

reaching larger sizes than males (Bowering and Brodie 

1991; Swain and Morgan 2001). It is the only Gulf of 

Maine flounder that is right-handed with a large mouth, 

round tail, and straight lateral line with a slight arch 

over the pectoral fin (Bigelow and Schroeder 1953). In 

many locations it is characterized as a sedentary, slow 

growing flatfish (Bigelow and Schroeder 1953). 

REPRODUCTION

Identification of egg quality and reproduction 

capabilities are important for predicting fecundity and 

recruitment variability in marine populations of 

American plaice (Nagler et al. 1999). Measurements of 

fecundity have been used for determining recruitment 

in marine fish populations as have the counting of 

viable egg numbers and larval production 

measurements. Nagler et al. (1999) studied patterns of 

egg production, fecundity, egg quality, and hatch 

success of spawning female American plaice under 

laboratory conditions. They found no direct correlation 

between absolute fecundity and size of American plaice 

females; therefore size could not be used to predict their 

actual fecundity. This differs from previous studies by 

Pitt (1964) who showed a positive correlation between 

absolute fecundity and body size. 

American plaice have been categorized as batch 

spawners. Eggs are released in batches every few days 

over the spawning period (Nagler et al. 1999). Adults 

spawn and fertilize their eggs at or near the bottom. 

Eggs drift into the upper water column after they are 

released (Colton and Temple 1961). Plaice produce 

large quantities of eggs. For example, a 40 cm plaice is 

capable of producing between 250,000 and 300,000 

eggs, and a 65 - 70 cm plaice can produce 

approximately 1,500,000 eggs. Eggs float and hatch at 

the surface (DFO 1989; Hebert and Wearing-Wilde 

2002) and the amount of time between fertilization and 

hatching varies with water temperature. A large 

amount of time could pass before young fish finally 

settle to the bottom (DFO 1989). 

In the northern part of its range, plaice spawn in the 

summer (Hebert and Wearing-Wilde 2002). In the 

southern part of its range in the Gulf of Maine, the 

spawning season extends from March through the 

middle of June, with peak spawning activity in April 

and May (Bigelow and Schroeder 1953; Colton et al.

1979; Smith et al. 1975). Nursery areas are found in 

coastal waters of the Gulf of Maine (Bigelow and 

Schroeder 1953). Spawning occurs at depths < 90 m 

and spawning adults migrate from deeper depths into 

shallower grounds before spawning (Bigelow and 

Schroeder 1953). 

MATURITY 

American plaice exhibit dimorphic growth and 

maturation rates. Males tend to mature at an earlier age 

and at a smaller size (O’Brien et al. 1993). In northern 

regions there is much variation in maturity of American 

plaice at age and size (Pitt 1975; Bowering and Brodie 

1991; Morgan and Colbourne 1999). Results from a 

back-calculated growth study by Fossen et al. (1999) 

indicated that sexually mature American plaice tended 

to be larger than immature individuals at the same age. 

Their study revealed a correlation between slow 

growth, delayed maturation, and expected maximum 

age. Their findings suggest that rapid growth leads to 

early maturation and that maturity may lead to sizeselected mortality, for example, mature individuals are 

exposed to higher mortality rates. 

In Canadian waters, maturation was determined to 

be density dependent. American plaice stocks would 

mature earlier when population levels were lower than 

the average population size. In addition, cohorts 

settling at warm temperatures with higher growth rates 

over their juvenile period tended to mature earlier and 

at a smaller size range (Morgan and Colbourne 1999). 

Species in the Gulf of Maine and Georges Bank 

area can reach lengths of 70 cm and can attain ages > 

20 years. At age 3, they are approximately 22 to 28 cm 

in length, between 90-190 g in weight and most are 

sexually mature by age 4 (O’Brien 1998). On Georges 

Bank, maturity studies from 1992-1996 revealed that 

males matured at 21.3 cm TL, and females at 29.8 cm 

TL and during the years 1987-1991, females matured at 

28.2 cm TL (Wigley et al. 1998) (Table 1). In the Gulf 

of Maine during 1986-1990, males matured in 3 years 

at 22.1 cm TL and females in 3.6 years at 26.8 cm TL 

(O’Brien et al. 1993). Growth rates are higher and 

maturity is reached earlier in the southern areas 

(Scotian Shelf, Gulf of Maine) than in the north. The 

lowest growth rates occurred in St. Mary’s Bay while 

the fastest growth rates occurred in the Gulf of Maine 

(Table 1). Powles (1965) noted that slower growth 
Page 3

rates were observed in deeper waters. Differences also 

occurred between genders and after four years of age, 

females grew faster than males (Sullivan 1981). 

Huntsman (1918) noted that the age at maturity of 

plaice varied as much as 11 years and depended on 

water temperatures. In areas of highest temperature; 

e.g., 10°C, in Passamaquoddy Bay and the Cape Cod 

region, plaice had the shortest development time to 

maturity (3-5 years). The lowest temperature recorded 

was 0°C for Newfoundland (Bay of Islands) and there, 

plaice had the longest development time (10-13 years) 

(Huntsman 1918; Bigelow and Schroeder 1953). 

In Canadian waters, temperature controls spawning 

of American plaice, resulting in spatial and temporal 

variations in spawning (Bowering and Brodie 1991). 

Normally, American plaice are captured within wide 

ranges of temperatures from -1.5 to 13°C, and are most 

numerous within -0.5 to 2.5°C. However, during peak 

spawning periods bottom temperature preferences vary 

(Pitt 1966), ranging from 3.5°C on the Flemish Cap to -

1.3°C on the northern part of the Grand Bank 

(Bowering and Brodie 1991). 

Areas of maximum spawning occur in the western 

Gulf of Maine and over southeastern Georges Bank; 

optimum spawning temperatures range between 3-6°C. 

These bottom water temperatures exist throughout 

much of the spawning period within the 100 m isobath 

from Cape Cod to New Jersey (Colton 1972). Outside 

this southern boundary, temperatures are too high for 

survival rather than too high for reproduction (Colton 

1972). 

FOOD HABITS 

American plaice larvae show a gradual shift in 

size-selective preference when maxilla length ranges 

change from 100-200 m to 200 - 500 m (Pepin and 

Penney 1997). Larvae feed on plankton, diatoms, and 

copepods found in the upper water layers. Prior to 

settling, juveniles feed on small crustaceans, 

polychaetes, and cumaceans (Bigelow and Schroeder 

1953). When they do settle on the ocean floor, their 

diet gradually changes as fish grow and the size of their 

mouth gape increases to accept wider sized prey (DFO 

1989). Feeding competition exists between young 

plaice and cod (Powles 1965). 

Adult plaice are opportunistic feeders, flexible in 

their dietary habits, and will take whatever is most 

abundant or accessible (Langton and Bowman 1981; 

Macdonald and Green 1986; Langton and Watling 

1990; Keats 1991; Zamarro 1992; Klemetsen 1993; 

Ntiba and Harding 1993; Martell and McClelland 1994; 

Packer et al. 1994; Berestovskiy 1995). Although their 

normal habitat is at or near the ocean floor, and they are 

considered benthic feeders, they frequently migrate off 

the bottom at night in pursuit of prey (DFO 1989). 

They are categorized as a predator whose diet 

composition consists of a combination of small benthic 

crustaceans, echinoderms, cnidarians, and polychaetes 

(Bowman et al. 2000; Table 2 and Table 3). Diets of 

adults are primarily echinoderms, chiefly sand dollars, 

sea urchins, and brittle stars (Huntsman 1918; Pitt 

1973; Sullivan 1981; Keats 1991). The brittle star, 

Ophiura sarsi, makes up 65% of the plaice diet at some 

locations in the Gulf of Maine (Klein-MacPhee 2002). 

The diets of plaice collected during 1973-2001 

Northeast Fisheries Science Center (NEFSC) bottom 

trawl surveys were also dominated by echinoderms; 

arthropods, annelids, and mollusks were also eaten 

(Figure 2). The stomach contents of plaice from 

western Nova Scotia, Gulf of Maine, Georges Bank, 

and Southern New England are generally similar 

(Powles 1965; Minet 1973; Pitt 1973; Langton and 

Bowman 1981) although the specific prey consumed 

can vary geographically. 

Off the coastal bank of Norway, American plaice 

feeding habits are distinctly different from other flatfish 

species. They feed more on benthic and epibenthic 

organisms such as ophiuroids and crustaceans. In the 

North Sea they feed on more fish (particularly 

sandlance), as well as polychaetes, crustaceans and 

ophiuroids (Ntiba and Harding 1993; Høines and 

Bergstad 2002). In Passamaquoddy Bay, Canada, 

amphipods, mysids, euphausiids, polychaetes, bivalve 

mollusks and Atlantic herring are the major prey of 

plaice (Tyler 1971, 1972; Macdonald and Green 1986; 

Macdonald and Waiwood, 1987). In Sheepscot Bay, 

Maine, polychaetes, mysids, amphipods, sand shrimp 

(Crangon septemspinosa), and Atlantic herring are 

important prey (Langton and Watling 1990; Packer and 

Langton, unpublished manuscript.). Offshore in the 

Gulf of Maine, the brittle star Ophiura sarsi is one of 

the dominant epifaunal taxa (Watling et al. 1988) and is 

the primary prey of plaice; crustaceans (euphausiids 

and pandalid shrimp), bivalve mollusks (Yoldia spp., 

Chlamys islandica, Cerastoderma pinnulatum), and 

tube-dwelling polychaetes are of secondary importance 

(Langton and Bowman 1981; Bowman and Michaels 

1984; Packer et al. 1994). Using NEFSC data from 

1977-1980, Bowman et al. (2000) found that on 

Georges Bank, they ate almost exclusively 

echinoderms, making up 92% of the total stomach 

content by weight. In the Gulf of Maine they consumed 

mostly echinoderms (47% by weight) and bivalve 

mollusks (26% by weight). Mollusks accounted for 

over 60% of the diet (by weight) on the Scotian Shelf. 

Inshore north of Cape Hatteras the preferred prey 

consisted of echinoderms (47% by weight) and 

crustaceans (18% by weight) (Table 3). In southern 

New England, plaice consume large quantities of 

amphipods, shrimp (Crangon), polychaetes, and 

bivalves (Klein-MacPhee 2002). 

The 1973-2001 NEFSC food habits database for 

American plaice (Figure 2) shows that diet composition 

did not change significantly over time, with 
Page 4 

echinoderms and ophiuroids remaining the dominant 

prey types (Link et al. 2002). Previous studies suggest 

there are ontogenetic shifts in diet, with American 

plaice consuming fewer polychaetes as their body size 

increased. Smaller (< 16-30 cm) individuals fed 

predominately on polychaetes, crustaceans, and small 

brittle stars. As they grew larger (> 30 cm) they fed 

primarily on bivalve mollusks, brittle stars and other 

echinoderms, decapods, and fish (Huntsman 1918; 

Powles 1965; Pitt 1973; Langton and Bowman 1981; 

Bowman and Michaels 1984; Martell and McClelland 

1994). A detailed listing of prey-type (by percent 

weight) by size-class of plaice, from Bowman et al. 

(2000), is shown in Table 2. Bowman and Michaels 

(1984) reported that polychaetes were especially 

important prey of plaice < 20 cm and noted that the 

largest fish fed mostly on echinoderms. In Sheepscot 

Bay, Maine, mysids generally decreased in importance 

with increasing predator size while polychaetes 

appeared to increase (Packer and Langton, unpublished 

manuscript). 

Seasonal shifts occurred as well. Echinoderms and 

other invertebrates were heavily consumed in the 

spring, then bivalves, pandalids and polychaetes in 

summer, followed by ophiuroids and fish eggs in 

autumn (Link et al. 2002). There is little or no feeding 

during January and February. This is followed by a 

rapid increase in feeding in May, which continues 

through September (Powles 1965). The highest feeding 

rates occur during the summer, enabling high-energy 

production for metabolic use and gonad maturation 

(MacKinnon 1972). 

PREDATION AND MORTALITY 

American plaice larvae are commonly consumed 

by redfish (Klein-MacPhee 2002). Larger plaice 35 

cm are frequently preyed on by cod and other bottom 

feeding species (Powles 1965; Bowman and Michaels 

1984). Adults are consumed by Greenland sharks, cod, 

halibut, goosefish, and spiny dogfish (Bigelow and 

Schroeder 1953; Hebert and Wearing-Wilde 2002). 

Along the Scotian Shelf and in the Gulf of St. 

Lawrence, grey seals are the primary predators of plaice 

(Benoit and Bowen 1990). Harbour seals in Sable 

Island, Nova Scotia exhaust minimal foraging energy 

and secure high capture rates while preying upon 

American plaice and other flounders (Bowen et al.

2002). 

In the Newfoundland-Labrador fishery it was 

determined that fishing contributed more to mortality at 

a much greater rate than predation, discarding, disease, 

starvation, temperature or environmental changes 

(Bundy 2001). The northern shrimp trawl fishery 

operates December through May from the Stellwagen 

Bank area off Massachusetts to the central Maine coast 

(McInnes 1986; Ross and Hokenson 1997). 

Worldwide, this industry accounts for 35% of the 

discarded bycatch (Alverson et al. 1994; Ross and 

Hokenson 1997). In New England, mortalities of 

American plaice were positively correlated with ondeck sorting time. Also seabird (e.g., great blackbacked gulls and herring gulls) predation was relatively 

high for American plaice. Consumption by seabirds 

was found to be directly proportional to the amount of 

time the fish were on deck (Ross and Hokenson 1997). 

MIGRATION

In U.S. and Canadian waters, American plaice is 

regarded as a sedentary species migrating only for 

spawning and feeding (Pitt 1969; Colton 1972; 

Bowering and Brodie 1991). Results from tagging 

studies have indicated only minor distances in 

migration. Most recaptured plaice were less than 30 

miles from the tagging site and approximately 7-8 years 

after tagging (DFO 1989). 

In Canadian waters, American plaice tend to 

occupy a wide depth range, often migrating to deeper 

offshore locations in the winter and returning to 

shallower water by spring (Hebert and Wearing-Wilde 

2002). They have been captured at depths of 700 m; 

typically, the largest commercial catches occur between 

100 - 200 meters at a temperature < 1.0°C (Hebert and 

Wearing-Wilde 2002). 

GEOGRAPHICAL DISTRIBUTION 

American plaice occur on both sides of the North 

Atlantic. On the western side of the Atlantic, it is 

common from the outer coast of Labrador, 

Newfoundland, the Grand Banks, and the Gulf of St. 

Lawrence west and south to Cape Cod; its southern 

limit is Montauk Point, NY (Bigelow and Schroeder 

1953; Smith et al. 1975). It also occurs in North 

Atlantic estuaries and rivers where it ranges from 

highly abundant to rare (Jury et al. 1994; Table 4). 

Plaice are also found in inshore areas north of Cape 

Hatteras, NC (Bowman et al. 2000). 

EGGS

Ichthyoplankton collections made in Cape Cod Bay 

revealed that plaice eggs were present from January 

through July, and larvae were present from January 

through August (Scherer 1984). Early stage eggs were 

collected on the northern perimeter of the Bay 
Page 5

suggesting that it was a spawning site. The southern 

distribution of late-stage eggs suggested displacement 

by counter-clockwise drift patterns in the Bay. It is 

believed that the American plaice eggs may have been 

spawned outside of Cape Cod Bay and carried into the 

Bay by prevailing currents. The eggs could have 

drifted as much as 49.0 km from their original 

spawning location (Scherer 1984). Smith et al. (1975) 

determined from the low larval occurrence and the 

prevailing circulation patterns off southern New 

England that spawning had occurred along the southern 

edge of Georges Bank and that currents flowing into the 

Middle Atlantic Bight subsequently transported the 

larvae. 

The NEFSC Marine Resources Monitoring, 

Assessment and Prediction (MARMAP) 

ichthyoplankton surveys (1978-1987; see Reid et al.

[1999] for details) captured eggs throughout the year 

(Figure 3). During February and March, eggs were 

collected on Stellwagen Bank, off Cape Ann, on 

Jeffreys Ledge, along coastal Maine, and on Georges 

Bank. During April and May, the highest egg 

concentrations occurred along the eastern edge of 

Georges Bank and along the coastal areas off eastern 

Massachusetts, the Gulf of Maine, southwest Nova 

Scotia, and Browns Bank. From June through 

December, eggs were collected almost exclusively 

along the coastal areas in the Gulf of Maine; some eggs 

were collected on Georges Bank and the Scotian Shelf. 

The cumulative distribution and abundance of 

American plaice eggs for all Georges Bank U.S. Global 

Ocean Ecosystems Dynamics (GLOBEC) 

ichthyoplankton surveys during 1995-1999 are shown 

in Figure 4. American plaice eggs were generally 

restricted to locations within depth zones > 56 m. They 

were most abundant at greater depths on Georges Bank 

(56-110 m); along the Great South Channel, the central 

and eastern part of the southern flank and the northern 

part of the Northeast Channel where depths are > 185 

m. Very few eggs were captured during January. 

Catches increased tenfold by February along the eastern 

part of the Northeast Peak reaching peak numbers by 

March. The occurrence of eggs extended eastward 

along the southern flank of Georges Bank and into the 

eastern section of Georges Basin. By April, the high 

concentrations shifted toward the western part of the 

southern flank. In May and June catches of eggs 

declined dramatically, with centers of abundance still 

along the southern flank of Georges Bank. 

LARVAE 

Sullivan (1981) found that larval plaice were 

transported by currents southwest along the coast; some 

were retained in the Gulf of Maine while others were 

transported to Georges Bank. Changes in circulation 

patterns also lead to large numbers of pelagic larvae 

being transported off Georges Bank (Colton and 

Temple 1961; Sullivan 1981). Larval plaice that drift 

into the slope water zone along the southern edge of 

Georges Bank are susceptible to transport in a 

northeasterly direction away from Georges Bank and 

the continental shelf. Differences in temperature 

between the coastal and slope water zones could affect 

the transported larvae by subjecting them to thermal 

stress. Plaice larvae were found in relatively shallow 

waters on Georges Bank, in Massachusetts Bay, and 

along coastal Maine (Smith et al. 1975). 

Larvae were first captured in the NEFSC 

MARMAP ichthyoplankton surveys (1977-1987) in 

small numbers during March on the southeastern flank 

of Georges Bank (Figure 5). By April, numbers 

increased throughout Georges Bank and larval 

distributions spread towards the Great South Channel 

and onto Nantucket Shoals. Peak abundance occurred 

during May from Georges Bank as far south as 

Delaware. The highest May abundance occurred 

around Cape Cod Bay and along the 60 m contour on 

Georges Bank. Larval abundance decreased 

dramatically in June and continued to decline in 

August. 

The cumulative distribution and abundance of 

American plaice larvae for all GLOBEC Georges Bank 

surveys is shown in Figure 6. As with the distribution 

of eggs, the overall pattern was retained within the 

deeper water zones. Centers of abundance were also 

located in areas of the Great South Channel and along 

the southern flank. Few larvae were collected during 

February. During March and April, larvae were 

abundant from the central part of the southern flank 

westward to the Great South Channel at depths ranging 

between 56-110 m. In May, areas of higher abundance 

appeared along the northern part of the Great South 

Channel. By June, abundance levels dropped at all 

areas across Georges Bank. 

JUVENILES

NEFSC bottom trawl surveys [see Reid et al. 

(1999) for details] captured juvenile (< 26 cm TL) 

American plaice year-round, mostly in the Gulf of 

Maine and Georges Bank (Figure 7; note that winter 

and summer distributions are presented as presence data 

only, precluding a discussion of abundances). In winter, 

they were mostly scattered throughout the Gulf of 

Maine and the Great South Channel; some occurred on 

Georges Bank, especially along the northern edge, and 

in southern New England. In spring, plaice were found 

in the same areas, but the highest densities were in the 

western Gulf of Maine, especially near the coast and off 

Cape Cod, including Massachusetts and Cape Cod 

Bays. They also appear to be concentrated in the 
Page 6 

western Gulf of Maine in the summer. Fall distributions 

are similar to those in the spring, with many also in the 

Great South Channel and on the northern edge of 

Georges Bank. 

The distributions and abundances of both juvenile 

and adult American plaice along the coasts of Maine 

and New Hampshire, based on spring and fall 2000-

2004 Maine-New Hampshire inshore groundfish 

surveys (Sherman et al. 2005), are shown in Figure 8. 

They were most abundant in the southwestern Gulf of 

Maine in the spring (Figure 8 and Figure 9). Spring 

catches showed a larger size range (Figure 10), while 

fall catches were made up of more juveniles (Sherman 

et al. 2005). 

Both the spring and fall 1978-2003 Massachusetts 

inshore trawl surveys [Figure 11; see Reid et al. (1999) 

for details] show that juvenile American plaice were 

abundant around Cape Ann, Massachusetts Bay, and in 

Cape Cod Bay. 

ADULTS 

NEFSC bottom trawl surveys [see Reid et al. 

(1999) for details] captured adult American plaice (> 26 

cm TL) in the same areas as the juveniles, but generally 

in lower numbers in spring and fall (Figure 12; again, 

winter and summer distributions are presented as 

presence data only, precluding a discussion of 

abundances). In winter, they were scattered throughout 

the Gulf of Maine and Georges Bank, with a few in 

southern New England. In spring, they were found in 

the same areas, with the highest densities in the western 

Gulf of Maine, especially near the coast, off Cape Cod, 

and near the Great South Channel, as well as on the 

northern edge of Georges Bank and central Georges 

Bank. Adults also appear to be heavily concentrated in 

the western Gulf of Maine in the summer. Fall 

distributions are somewhat similar to those in the 

spring, but the adults are even more abundant in the 

western Gulf of Maine and near the Great South 

Channel, with lower numbers throughout Georges 

Bank. 

The distributions and abundances of both juvenile 

and adult American plaice along the coasts of Maine 

and New Hampshire, based on spring and fall 2000-

2004 Maine-New Hampshire inshore groundfish 

surveys, was discussed previously (Sherman et al. 

2005). 

The distributions of the adults in both the spring 

and fall 1978-2003 Massachusetts inshore trawl surveys 

(Figure 13) are similar to those of the juveniles, but in 

lower overall numbers. Again, they were abundant 

around Cape Ann, Massachusetts Bay, and in Cape Cod 

Bay. 

HABITAT CHARACTERISTICS 

Information on the habitat requirements and 

preferences of American plaice (based on both the 

pertinent literature and the most recent NEFSC and 

state surveys) are presented here and summarized in 

Table 5 and Table 6. 

EGGS

In the northwest Atlantic, plaice eggs have been 

collected during all months of the year (Berrien and 

Sibunka 1999). In the Gulf of Maine and on the 

Scotian Shelf, egg abundance peaked in early April and 

May (Smith et al. 1975; Neilson et al. 1988). 

Data from the NEFSC MARMAP ichthyoplankton 

surveys (Figure 14) and the GLOBEC Georges Bank 

survey (Figure 15 and Figure 16) were used to 

determine the relationships between bottom depth and 

water column temperature and American plaice egg 

abundances. Eggs from the MARMAP survey were 

found over depths ranging from 10 m to approximately 

325 m, with the majority occurring between about 50-

90 m. Eggs from the GLOBEC Georges Bank survey 

occurred as deep as 501-1000 m; however, the majority 

were found between 41-100 m. 

Plaice eggs were collected at temperatures ranging 

from about 1-12°C during the MARMAP survey. 

During February through April, most eggs were 

collected between 3-6°C. During May to July the 

majority of eggs were found at 5-8°C. From August to 

December, eggs were found at higher temperatures, 

with most eggs found at approximately 9-11°C. During 

the seven-month period of the GLOBEC Georges Bank 

survey, eggs remained within a narrow range of about 

4-8°C. 

Bigelow and Schroeder (1953) reported that eggs 

incubate from 11 to 14 days at 3.9°C. Howell and 

Caldwell (1984) reared embryos and yolk-sac larvae at 

temperature regimes of 2, 6, 10, and 14°C. For all 

temperatures < 10°C, a positive correlation resulted 

between temperature and the development rate; growth 

of those reared at 10°C was the fastest. Mortality 

resulted for all embryos reared at the upper thermal 

limit of 14°C. The laboratory controlled embryos and 

larvae were smaller in size at yolk-sac absorption than 

their wild reared counterparts and would be more 

susceptible to predation and starvation. However, those 

reared between 2-6°C were larger and developed a 

greater probability of surviving and first feeding. 
Page 7

LARVAE 

Shepherd et al. (2000) reared yolk-sac larvae at 

two controlled temperatures of 5 and 10C during the 

developmental period to test swimming capabilities and 

escape responses. They found a significant relationship 

between temperature and development of finfold area 

and yolk-sac size at age. Larvae reared at 10C had 

larger fin fold area and used up their yolk-sac reserves 

earlier. Therefore in many cases the development rate 

was altered by the temperature and affected swimming 

performance, but there was no effect on escape 

response. American plaice larvae with low development 

rates do appear to have an advantage when food is 

scarce. 

Larvae from the NEFSC MARMAP 

ichthyoplankton surveys (Figure 17) were found over 

depths ranging from 30-210 m, with most occurring at 

50-90 m except for August, where about 45% also 

occurred at 130 m. Larvae occurred from February 

through June during the GLOBEC Georges Bank 

surveys (Figure 18 and Figure 19). The bottom depths 

where larvae were captured ranged from 41 m to 

between 301-350 m, with the majority between 41-120 

m. The depth at which larvae occurred remained 

constant from February to May, changing to deeper 

waters in June. 

Plaice larvae were captured at temperatures 

ranging from 4-14°C during the NEFSC MARMAP 

surveys. Larvae were most abundant at 5-8°C from 

March through June and 10-12°C during July and 

August. During the GLOBEC Georges Bank survey, 

larvae were found in the coldest temperatures (4-6°C) 

from February to April. In May and June the larvae 

were found from 6-11°C. 

JUVENILES

The spring and fall distributions of juvenile 

American plaice (< 26 cm TL) relative to bottom water 

temperature, depth, and salinity based on 1963-2003 

NEFSC bottom trawl surveys from the Gulf of Maine to 

Cape Hatteras are shown in Figure 20. In the spring, 

juveniles were found between 2-10°C, with most 

between 4-6°C. During autumn, they were found 

between 4-16°C, with the majority between about 5-

11°C. They occurred at depths ranging from 11-400 m 

in both the spring and autumn. They were caught in a 

salinity range of 31-35 ppt, with the majority found at 

33 ppt during both seasons. 

The spring and autumn distributions of juvenile 

American plaice in Massachusetts coastal waters 

relative to bottom water temperature and depth based 

on 1978-2003 Massachusetts inshore trawl surveys are 

shown in Figure 21. Juvenile plaice were collected at 

temperatures ranging from 1-12°C during the spring, 

and 4°C to about 17°C during the autumn. They were 

most abundant at 4-6°C in the spring and 7-10°C in the 

autumn. In the spring, they were found over depths 

ranging from 6-85 m, with the majority occurring 

between about 46-65 m. During autumn they were also 

found from 6-85 m, with the majority again occurring 

between approximately 46-65 m. 

ADULTS 

The geographic boundaries of American plaice 

distribution appear to be defined by warm summer and 

fall temperatures. Since the early 1940s, coastal 

warming and cooling trends have been observed in 

waters between Cape Sable and Long Island (Colton 

1972). These trends are related to changes of 

subsurface water. Cold years are defined as years when 

coastal water from Labrador displaces slope water. 

Warm years occur when there is a low ratio of coastal 

to central Atlantic water and slope water borders the 

200 m isobath. 

The spring and fall distributions of adult American 

plaice in the Gulf of Maine and on Georges Bank 

relative to bottom water temperature, depth, and salinity 

based on NEFSC bottom trawl surveys are shown in 

Figure 22. Adults in the spring appeared to have similar 

temperature preferences to juveniles with most found at 

temperatures from 4-6°C with an overall range of 1-

12°C. In autumn, plaice were found in a temperature 

range of 3-15°C, with most at about 6-9°C. Their depth 

range in spring was from 11-400 m and in fall the range 

was from 21-400 m. They were caught in a salinity 

range of 31-35 ppt, with the majority found at 33 ppt in 

the spring and 33-34 ppt in the autumn. 

The spring and autumn distributions of adult 

American plaice in Massachusetts coastal waters 

relative to bottom water temperature and depth are 

shown in Figure 23. Adults had similar temperature 

preferences to the juveniles. Adult plaice were 

collected at temperatures from 1-12°C during the spring 

and 4-14°C during the autumn. The majority was 

found between 4-6°C in the spring and 7-9°C in the 

autumn. Adults were found at depths ranging from 6-

85 m in the spring and 16-85 m during the autumn. 

American plaice display great contrasts in seasonal 

habitat association in different geographic regions. 

Generally, American plaice from southern Labrador to 

Rhode Island are found in deep water from 90-180 m 

and do not normally occur in water less than 25-35 m 

(O’Brien 2000; Dery 1998). In Canadian waters they 

occur in temperatures ranging from approximately –

1.5°C to temperatures above 5°C and from depth 

locations inshore down to 700 m. Preferences in 

temperature are 0-1.5°C and depths 90-250 m (DFO 

1989). Generally, plaice encountered in the deeper 
Page 8 

depth ranges are at higher temperatures (DFO 1989). 

Scott (1982a) reported that on the Scotian Shelf, 

American plaice ranged between depths of 27-366 m, 

with preferences between 55-128 m, while their 

temperature range was between 0-13°C, with 

preferences between 1-4°C. However, in other locations 

such as on the Grand Bank’s Division 3L, they have 

been captured at depths > 800 m (Iglesias et al. 1996). 

Other surveys in the U.S. and commercial catch 

statistics generally confirm similar movement and depth 

preferences in the Gulf of Maine (Colton 1972). Gulf 

of Maine plaice normally occur in waters 25-180 m 

deep, but are also found in shoal waters when 

temperatures are severely cold (Bigelow and Schroeder 

1953). With the exception of witch flounder, plaice is 

considered the most abundant of all flatfish in the Gulf 

of Maine at depths between 54-90 m (Klein-MacPhee 

2002). They are also widespread on Georges Bank 

along the 90-180 m zone of its northern edge (Bigelow 

and Schroeder 1953). 

Dow (1977) found that water temperatures 

influence the abundance of American plaice in a study 

of climatic effects on relative abundance and 

availability. There were significant positive correlations 

between the annual catch of fish off the Maine coast 

and mean annual surface temperatures. These results 

imply that temperature is a limiting factor in the 

abundance of American plaice. 

Temperature is a chief determinant of habitat 

quality for fish (Fry 1971; Reynolds and Casterlin 

1979; Swain and Morgan 2001). The relationship 

between the amount of food available and temperature 

ultimately affect growth rates in fish, because prey are 

often more readily abundant at certain depth ranges. 

For plaice, this is more pronounced in some areas than 

others, such as in the southern Gulf of St. Lawrence and 

off Newfoundland. It has been observed that female 

plaice seek warmer temperatures during feeding (Swain 

et al. 1998). It is believed that these warmer locations 

also provide optimal conditions for growth during the 

summer. Temperature-mediated differences in 

metabolic rate have been used to explain relationships 

in different latitudinal locations and maximum body 

length as well as other features of American plaice 

(Walsh 1994; Walsh 1996). Stratoudakis et al. (1997) 

found differences in life history features by comparing 

length frequency and age of plaice from two 

geographically different areas. Behavior, such as 

swimming mobility, can also be effected by extreme 

temperatures. Laboratory studies of swimming speeds 

of American plaice when herded by trawl gear also 

revealed swimming efficiency to be temperature and 

size dependent (Winger et al. 1999). 

Swain et al. (1998) found significant differences in 

habitat selection by plaice for both the winter (January) 

and summer (September) seasons. Both genders were 

found to occupy deeper, warmer water during the 

winter time period. Females were found to occupy 

significantly warmer water in September during the 

feeding season in the southern Gulf of St. Lawrence and 

exhibited a faster growing rate than males. In this 

location, plaice were found at depths of 58-67 m and 

temperatures of –0.1 to 0.3°C in September, and at 

depths of 374-426 m and temperatures of 5.2-5.4°C in 

January. Minimal feeding occurs during the 

overwintering period in some northwest Atlantic 

groundfish populations (Powles 1965; Swain et al.

1998). 

Murawski (1993) used data from NEFSC bottom 

trawl surveys and principal component analyses to 

classify American plaice as a deep-cold water sedentary 

species. In comparison to the entire shelf, the Gulf of 

Maine has a narrow temperature range with increasing 

depth (Holzwarth and Mountain 1990; Murawski 

1993). Thus, in the deep waters of the Gulf, American 

plaice are not subjected to the as much temperature 

variability as shallow water inhabitants. 

American plaice occur at mean salinities of 20-22 

ppt in Hamilton Inlet, Labrador (Backus 1957), 30 ppt 

or lower in Baltic areas, 32.8 ppt in the Gulf of Maine, 

and 34 ppt in offshore Atlantic waters (Bigelow and 

Schroeder 1953). 

During a study of fishes of the Scotian Shelf, Scott 

(1982a) found American plaice had salinity preferences 

between 31-34 ppt; highest abundance occurred at 33 

ppt. Of the 31 species studied by Scott (1982a), 

American plaice displayed the widest salinity, depth, 

and temperature ranges. 

American plaice prefer a soft bottom substrate 

(Sparholt 1990; Langton and Bowman 1981) and they 

are frequently found on fine sand or gravel bottoms 

(Scott and Scott 1988; Bowering and Brodie 1991). 

Under laboratory conditions, Morgan (2000) found that 

American plaice demonstrated a clear preference for 

finer gravelly sand particles over courser gravel 

substrate. When temperature and substrate were tested 

together, plaice would continue to prefer sand even if 

the temperature fell below zero degrees. On the Scotian 

Shelf, plaice were most abundant on sand and gravel 

substrates (Scott 1982b). They were found in lesser 

numbers on sand, silt, and clay and were rare on 

Scotian Shelf drift (a mixed substrate). In eastern 

Newfoundland, plaice were frequently collected where 

sandy substrates bordered areas of bedrock. It is 

believed that they occur near bedrock because bedrock 

is the preferred habitat of an important prey species, 

green sea urchins (Strongylocentrotus droebachiensis) 

(Keats 1991). In some areas, their distribution has been 

correlated with mud substrates (Walsh 1996; Packer 

and Langton, unpublished manuscript). 

RESEARCH NEEDS 

 Determination of how depth, temperature, and 

bottom type control the spatial and temporal 
Page 9

distribution of plaice; this is especially important 

for U.S. populations where little research has been 

conducted. 

 Confirmation of vertical migration and seasonal 

distribution patterns of early life stages. 

 Age and growth determination based on otolith 

microstructure for early life stages. 

 The strength of habitat dependency and/or 

interaction for juveniles and adults. 

 Determination of adult migration patterns (i.e., 

tagging studies). 

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Page 13

ADDITIONAL REFERENCES 

References (with abstracts) that may be useful, many pertaining to U.S. and Canadian groundfish stock assessments, 

which were not covered in this document. 

Colton, J.B. and J.M. St. Onge. 1974. Distribution of 

fish eggs and larvae in continental shelf waters, 

Nova Scotia to Long Island. Amer. Geographical 

Soc. Ser. Atlas Mar. Environ. Folio 23. 

Gonzalez, C., E. Roman, and X. Paz. 2003. Food and 

feeding chronology of American plaice 

(Hippoglossoides platessoides) in the North 

Atlantic. Sci. Counc. Res. Doc. NAFO. 03/23. 21 

p. 

“Food and feeding of 5,592 individuals of 

American plaice (Hippogolossoides platessoides, 

Fabricius) was examined from Grand Bank (NAFO 

Divisions 3NO), Flemish Cap (NAFO Div. 3M) and 

Svalbard Area (ICES Div. IIb). Differences in diet 

composition were observed by areas. Feeding intensity 

was higher on Flemish Cap (77.6%) and lower in the 

Svalbard (4.7%). There was significant seasonal 

feeding variation in the Svalbard, with higher feeding 

intensity in summer. The main groups of prey were 

Pisces (46%), Echinodermata (20%), Crustacea (16%) 

and Mollusca (10%). The prey spectrum was larger in 

the south of the Grand Bank, the main prey being 

Pisces (64%), while both on Flemish Cap and in 

Svalbard the main prey was Ophiuroidea (39%). 

Feeding pattern indicated that American plaice is a 

daytime feeder, and no marked differences were noted 

over a 24 hour period. Low cannibalism intensity was 

observed on Grand Bank. A greater similitude was 

present between the diets on Flemish Cap and in 

Svalbard. Composition and overlapping diet, by length 

classes, were also analyzed.” 

Lux, F.E. 1970. Note on growth of American plaice, 

Hippoglossoides platessoides (Fabr.), in ICNAF 

Subarea 5. Int. Comm. Northwest Atl. Fish. 

(ICNAF) Res. Bull. 7: 5-7. 

“American plaice from off New England (ICNAF 

Subarea 5) grow faster than in western north Atlantic 

waters farther to the north. Von Bertalanffy growth 

equations were   0.27( 0.41) 450 1     t

t l e for males 

and   0.15( 0.10) 675 1     t

t l e for females.” 

Morgan, M.J. 2001. Time and location of spawning of 

American plaice in NAFO divisions 3LNO. J. 

Northwest Atl. Fish. Sci. 29: 41-49. 

“Spawning times and spawning locations of 

American plaice (Hipploglossoides platessoides) on the 

Grand Bank (NAFO Divisions 3LNO) were examined 

from 1971 to 1999. No specific spawning locations 

were identified; rather, spawning was widespread 

throughout the Grand Bank. Spawning occurred over a 

broad seasonal period; spawning females were found in 

all months from February through August, with the 

highest proportion of spawners occurring in April 

through June. Significant annual variability occurred in 

the time of spawning, with a trend towards later 

spawning in the early-1990s. Spawning time was 

positively correlated with temperature and depth, and 

negatively correlated with the weighted mean age of the 

spawning stock biomass.” 

Morgan, M.J. 2003. A preliminary examination of 

variability in condition of American plaice in 

NAFO divisions 3LNO. Sci. Counc. Res. Doc. 

NAFO. 03/11. 14 p. 

“Spatial and temporal changes in condition were 

examined for American plaice (Hippoglossoides 

platessoides) in NAFO Div. 3L, 3N and 3O. Data were 

available from spring and fall Canadian research vessel 

surveys from 1993 to 2002 (2001 for fall). Data were 

available for males and females for both total body and 

liver weight. There was a clear seasonal difference in 

condition of American plaice with condition being 

higher in the fall. Relative body condition tended to be 

highest in Div. 3N in both spring and fall. Relative liver 

condition was highest in Div. 3L and lowest in Div. 3O 

in both seasons. There were no significant correlations 

between condition and abundance in a NAFO Division. 

There was significant annual variability in condition but 

no consistent pattern over time.” 

Morgan, M.J. 2003. Variation with age in the timing 

and duration of spawning in American plaice. J. 

Fish. Biol. 62: 464-473. 

“Spawning time of female American plaice 

Hippoglossoides platessoides varied significantly with 

age. This effect, however, was not consistent across 

years. Generally, younger fish spawned earlier than 

older fish, but in the 1990s they spawned later than 

older fish. Spawning duration also varied with age, with 

younger fish generally having a longer spawning period 

than older fish. Changes in depth distribution were 
Page 14

related to changes in both spawning time and duration. 

As depth increased, spawning time became later and 

duration became shorter. Fish < 11 years old showed 

the largest change in both spawning time and depth 

distribution.” 

Morgan, M.J., W.B. Brodie, and D.W. Kulka. 2002. 

Was over-exploitation the cause of the decline of 

the American plaice stock off Labrador and 

northeast Newfloundland? Fish. Res. 57: 39-49. 

“The population of American plaice in the waters 

off Labrador and on the northeast Newfoundland shelf 

declined substantially during the mid to late 1980s, 

early 1990s at a time when reported catches were very 

low. An earlier study examined the overlap in 

distribution between American plaice and cod in 

research vessel survey data and concluded that 

unreported bycatch in the cod fishery could explain the 

decline of the Div. 2J portion of the Subarea 2+ Div. 

3K stock of American plaice. We evaluate the method 

proposed in that study and use reported and observer 

estimates of catch to investigate potential catch levels 

relative to survey estimates of population biomass. 

This method does not appear to be a good predictor of 

American plaice bycatch in the cod fishery as most of 

the regressions were not significant and it requires 

extrapolation well beyond the range of the data used to 

build the regressions. Furthermore, there was a little 

overlap between the extent of the commercial cod 

fishing grounds and the distribution of American plaice 

in the autumn surveys. For this stock, catch to survey 

biomass ratios were low regardless of the source of 

information used to estimate catch and suggest an 

exploitation rate that should be well below sustainable 

levels. These analyses support the conclusion that 

fishing was not the cause of the decline in this 

population of American plaice.” 

Nevinsky, M.M. and V.P. Serebryakov. 1973. 

American plaice, Hippoglossoides platessoides

Fabr., spawning in the Northwest Atlantic area. 

Int. Comm. Northwest Atl. Fish. (ICNAF) Res. 

Bull. 10: 23-26. 

“The temporal and spatial distribution of American 

plaice spawning in Subareas 2, 3, and 4 are based on 

ichthyoplankton collections at 3,127 stations during 

1959-70 and the maturity condition of the gonads of 

9,000 adult specimens taken from commercial catches 

during 1954-70. American plaice seem to spawn in 

most parts of the area in depths of 50 to 250 m. The 

main spawning areas are on the northern shallows of 

the Grand Bank, off southern Newfoundland, on St. 

Pierre and Green Banks, off Cape Breton and on 

Banquereau Bank. The temperatures of the nearbottom and the surface water layers over the spawning 

grounds were from 0° to 6°C and 6° to 18°C 

respectively. The most intensive spawning was 

observed in April, May, and June with near-bottom 

temperatures from 0° to 2.5°C. The spawning grounds 

are situated in the areas of action of branches of the 

Labrador Current or in those of cold water from the 

Gulf of St. Lawrence. Larvae at different stages of 

development were found in the same general areas as 

the eggs, i.e. mostly over the spawning grounds. The 

low current velocities over the spawning areas and the 

peculiarities of larvae distribution indicate that the 

passive migration period of the American plaice is not 

long during their early stage of development.” 

Ollerhead, L.M.N., M.J. Morgan, D.A. Scruton, and B. 

Marrie. 2004. Mapping spawning times and 

locations for 10 commercially important fish 

species found on the Grand Banks of 

Newfloundland. Can. Tech. Rep. Fish. Aquat. Sci. 

2522. 49 p. 

“Using data collected on Department of Fisheries 

and Oceans (DFO) research vessel surveys, a 

Geographic Information System (GIS) was used to 

create maps that illustrated locations and timing of 

higher intensity spawning for ten commercially 

important fish species found on the Grand Banks. The 

maps showed that within the coverage of the Grand 

Banks surveys, peak spawning occurred for many 

species in spring and early summer with the location of 

the spawning peak often varying from month to month. 

Marked areas of higher intensity spawning were found 

for most species, with other, lesser amounts occurring 

simultaneously in other regions of the survey. During 

peak season in the spring and early summer, 

considerable spawning activity was observed on much 

of the Grand Banks. Historical versus recent spawning 

trends were also mapped to illustrate how the locations 

of the higher intensity spawning areas behaved over a 

longer time frame. These maps showed, for some 

species, that the spawning areas were static while others 

were dynamic. This project studied American plaice 

(Hippoglossoides platessoides), Atlantic cod (Gadus 

morhua), haddock (Melanogrammus aeglefinus), 

redfish (Sebastes spp.), witch flounder (Glyptocephalus 

cynoglossus), yellowtail flounder (Limanda ferruginea), 

northern shrimp (Pandalus borealis), Iceland scallop 

(Chlamys islandica), sea scallop (Placopectin 

magellanicus) and surf clam (Spisula solidissima).” 

Walsh, S.J., M. Simpson, M.J. Morgan, K.S. Dwyer, 

and D. Stansbury. 2001. Distribution of juvenile 

yellowtail flounder, American plaice and Atlantic 

cod on the southern Grand Bank: A discussion of 

nursery areas and marine protected areas. Sci. 

Counc. Res. Doc. NAFO. 01/78. 49 p. 
Page 15

“The annual Canadian fall bottom trawl survey 

data from the southern Grand Bank, NAFO Div. 3NO 

were examined for the period 1985-1999 for the 

location of possible nursery areas for yellowtail 

flounder, American plaice and cod. Only the juvenile 

yellowtail flounder nursery area remained 

geographically localized throughout the time series with 

minimum temporal and spatial shifts. There was a large 

shift in the temporal and spatial pattern of juvenile 

plaice nursery areas in the southern Grand Bank, which 

may be related to a reduced overall stock size. This 

was also evident in the northern nursery area of Div. 

3L. The temporal and spatial pattern of juvenile cod 

was also quite variable which may be related to changes 

in population size and bottom temperatures. The main 

nursery area for yellowtail flounder occupied the area 

of the southern portion of the Southeast Shoal together 

with area immediately to the west, i.e. in the NAFO 

Regulatory Area outside Canada’s 360 km economic 

zone. This nursery is the only area for which a physical 

boundary can be defined in the context of establishing a 

Marine Protected Area. Two areas, a small and large 

box, were suggested that encompass, on average, 62% 

(small box) and 83% (large box) of all the juvenile 

yellowtail flounder on the southern Grand Bank. On 

average, 14% and 32% of all juvenile American plaice, 

respectively, and 13% and 44% of all juvenile cod, 

respectively, on the southern Grand Bank were found in 

these two boxes.” 

Wigley, S.E. and W.L. Gabriel. 1991. Distribution of 

sexually immature components of 10 northwest 

Atlantic groundfish species based on Northeast 

Fisheries Center bottom trawl surveys, 1968-86. 

NOAA Tech. Mem. NMFS-F/NEC-80. 17 p. 

“Analyses of data obtained from research vessel 

survey cruises over a 19-year period reveal distinctive 

patterns in the geographic occurrence of immature fish. 

These occurrences provide qualitative evidence for 

potentially significant fishing mortality of the sexually 

immature components of 10 species in the Gulf of 

Maine-Georges Bank-Southern New England region, 

where substantial overlap exists between unregulated 

mesh/exempted fishing areas and the distributions of 

these immature fish.” 
Page 16

Table 1. The age and length at maturity of female American plaice in the northwest Atlantic. 

Area A50

(yrs) 

L50

(cm) 

Year Source 

 

Labrador 8.11 45.84 1978-1988 Bowering and Brodie (1991) 

Northern Grand Bank 13.98 42.14 1961-1965 Pitt (1975) 

Northern Grand Bank 10.57 40.36 1969-1972 Pitt (1975) 

St. Mary’s Bay, Newfoundland 15.20 54.00 1964 Pitt (1966) 

Flemish Cap 7.80 40.00 1964 Pitt (1966) 

Southeastern Grand Bank 8.79 41.45 1971 Pitt (1975) 

St. Pierre Bank 9.48 48.26 1978-1988 Bowering and Brodie (1991) 

Scotian Shelf 6.00 31.00 1970-1974 Beacham (1983) 

Scotian Shelf 4.70 30.80 1975-1979 Beacham (1983) 

Nova Scotia to Cape Hatteras - - 33.60 1979 Morse (1979) 

Atl. Coast of N. Am. (77’ - 42’) 8.00 30.00 1991 Miller et al. (1991) 

Gulf of Maine 3.80 29.70 1980 Sullivan (1981) 

Gulf of Maine 3.60 26.80 1986-1990 O’Brien et al. (1993) 

Georges Bank - - 28.20 1987-1991 Wigley et al. (1998) 

Georges Bank - - 29.80 1992-1996 Wigley et al. (1998) 

(A50) Age at which 50% of females are mature 

(L50) Length at which 50% of females are mature 
Page 17

Table 2. Diet composition of American plaice by fish length category. 

Values are the percent of stomach content by weight, from Bowman et al. (2000). 

Length Category (cm)

Stomach Contents <16 16-20 21-25 26-30 31-35 36-40 41-45 46-50 >50 Total 

Anthozoa - - - 1.8 4.3 - - - - 0.7 

Nematoda 1.8 2.5 11.1 <0.1 <0.1 <0.1 - - - 0.5 

Mollusca - - 0.2 <0.1 34.6 24.3 12.2 29.8 16.8 20.3 

Bivalvia - - 0.2 <0.1 34.6 24.3 12.2 24.4 11.9 17.7 

Chlamys islandica - - - - - - - - 7.6 2.5 

Arctica islandica - - - - 0.4 - - - 4.3 1.4 

Cyclocardia borealis - - - - - - 11.2 - - 1.3 

Bivalvia unid. - - 0.2 <0.1 34.2 24.3 1.0 24.4 <0.1 12.5 

Mollusca unid. - - - - - - - 5.4 4.9 2.6 

Polychaeta 5.2 8.1 2.5 5.0 1.4 4.3 3.3 - 5.8 2.2 

Lumbrineridae <0.1 0.9 - <0.1 - - - - - <0.1 

Nephtys sp. - - - 0.7 0.4 - - - - 0.1 

Nephtyidae 3.4 - 2.4 - - - - - - 0.2 

Spionidae 0.4 0.8 <0.1 1.7 <0.1 0.9 0.4 - 0.3 0.4 

Terebellidae - - - - - 0.4 - - - <0.1 

Polychaeta unid. 1.4 6.4 0.1 2.6 1.0 3.0 2.9 - 5.5 1.5 

Crustacea 0.4 2.1 14.7 8.3 17.1 13.0 3.0 0.7 0.2 5.2 

Isopoda - - - 0.1 - - - - - <0.1 

Chiridotea sp. - - - 0.1 - - - - - <0.1 

Amphipoda 0.2 0.2 - 1.8 0.9 0.5 - 0.7 - 0.5 

Unicola irrorata 0.2 - - - - - - - - <0.1 

Monoculodes intermedius - 0.2 - - - - - - - <0.1 

Leptocheirus pinguis - - - 1.8 0.9 - - 0.7 - 0.4 

Gammaridea <0.1 - - - <0.1 0.5 - <0.1 - 0.1 

Euphausiacea - - - - - 7.9 - - - 0.7 

Decapoda 0.2 - 14.7 6.4 16.2 4.6 3.0 - 0.2 4.0 

Dichelopandalus leptocerus - - - 2.8 - - 3.0 - - 0.6 

Pandalidae - - - - 16.2 4.6 - - - 2.5 

Crangon septemspinosa - - 13.6 3.6 - - - - - 0.8 

Crangonidae 0.2 - - - - - - - - <0.1 

Decapoda unid. - - 1.1 - - - - - 0.2 0.1 

Crustacea unid. - 1.9 - - <0.1 - <0.1 - - <0.1 

Echinodermata 4.1 3.2 0.7 26.4 26.3 41.8 64.9 68.3 62.0 49.8 

Echinoidea - - - 1.8 3.2 1.1 0.5 17.2 1.6 4.5 

Echinarachnius parma - - - - - - - 16.5 - 3.1 

Echinoidea unid. - - - 1.8 3.2 1.1 0.5 0.7 1.6 1.4 

Opiuroidea 4.1 2.4 0.7 24.6 23.1 40.7 64.4 20.3 60.4 39.5 

Ophiura robusta - - - - 3.8 - - - - 0.5 

Ophiura sarsi - 1.9 - 18.3 3.4 8.7 56.7 17.4 6.4 14.5 

Ophiuroidea unid. 4.1 0.5 0.7 6.3 15.9 32.0 7.7 2.9 54.0 24.5 

Echinodermata unid. - 0.8 - - - - - 30.8 - 5.8 

Animal Remains and Misc. 88.5 25.6 64.1 34.7 16.3 16.3 16.6 1.2 7.3 15.9 

Sand and Rock - 58.5 6.7 23.8 - 0.3 - - 7.9 5.4 

 

Number Sampled 30 22 35 51 53 34 33 19 23 300 

Number Empty 12 9 19 27 24 18 21 10 7 147 

Mean Stomach Content (g) 0.153 0.077 0.157 0.250 0.366 0.418 0.530 1.546 2.187 0.518 

Mean Fish Length (cm) 12 18 23 28 32 37 42 47 55 32 
Page 18

Table 3. Diet composition of American plaice by geographical area. 

Values are the percent of stomach content by weight, from Bowman et al. (2000). 

 Geographical area 

Stomach Contents Georges 

Bank 

Gulf of 

Maine 

Scotian 

Shelf 

Inshore 

North of Cape 

Hatteras 

Anthozoa 0.8 - - 2.9 

Nematoda - 0.1 - 2.3 

Mollusca 0.4 26.4 61.2 <0.1 

Bivalvia 0.4 24.6 37.3 <0.1 

Chlamys islandica - - 37.3 - 

Arctica islandica 0.3 2.5 - - 

Cyclocardia borealis - 2.2 - - 

Bivalvia unid. 0.1 19.9 - <0.1 

Mollusca unid. - 1.8 23.9 - 

Polychaeta 0.5 1.0 - 7.9 

Lumbrineridae - <0.1 - <0.1 

Nephtys sp. - <0.1 - 0.3 

Nephtyidae - - - 1.0 

Spionidae - <0.1 - 1.9 

Terebellidae - - - 0.2 

Polychaeta unid. 0.5 1.0 - 4.5 

Crustacea 2.3 2.3 - 17.6 

Isopoda <0.1 - - - 

Chiridotea sp. <0.1 - - - 

Amphipoda 2.2 <0.1 - 0.2 

Unicola irrorata <0.1 - - - 

Monoculodes intermedius - - - <0.1 

Leptocheirus pinguis 2.2 - - - 

Gammaridea <0.1 <0.1 - 0.2 

Euphausiacea - 1.3 - - 

Decapoda 0.1 1.0 - 17.4 

Dichelopandalus 

leptocerus 

- 1.0 - - 

Pandalidae - - - 13.2 

Crangon septemspinosa 0.1 - - 4.0 

Decapoda unid. - <0.1 - 0.2 

Crustacea unid. - <0.1 - - 

Echinodermata 92.3 42.4 - 47.5 

Echinoidea 16.9 2.4 - - 

Echinarachnius parma 16.9 - - - 

Echinoidea unid. - 2.4 - - 

Opiuroidea 75.4 40.0 - 16.0 

Ophiura robusta - - - 2.5 

Ophiura sarsi - 24.2 - 4.6 

Ophiuroidea unid. 75.4 15.8 - 8.9 

Echinodermata unid. - <0.1 - 31.5 

Animal Remains and Misc. 3.6 25.3 - 14.3 

Sand and Rock 0.1 2.5 38.8 7.5 

 

Number Sampled 17 186 6 91 

Number Empty 4 92 5 46 

Mean Stomach Content (g) 1.689 0.471 1.717 0.315 

Mean Fish Length (cm) 27 33 40 30 
Page 19

Table 4. Distribution and relative abundance of American plaice in North Atlantic estuaries and rivers by life history 

stage. 

Source: Jury et al. (1994). 

Distribution and Relative Abundance 

Estuaries and Rivers Life Stage Mixing Seawater 

Months of 

Occurrence 

Data

Reliability

Passamaquoddy Bay Adults (A) Common March - Nov ** 

 Spawning adults (S) Common March - May ** 

 Juveniles (J) Common Common March - Nov * 

 Larvae (L) Common April - June ** 

 Eggs (E) Common March - May ** 

Englishman / Machias Bay A Common March - Nov * 

 S Common March - May * 

 J Common Common March - Nov * 

 L Common April - June * 

 E Common March - May * 

Narraguagus Bay A Common March - Nov * 

 S Common March - May * 

 J Common Common March - Nov * 

 L Common April - June * 

 E Common March - May * 

Blue Hill Bay A Common March - Nov * 

 S Common March - May * 

 J Common Common March - Nov * 

 L Common April - June * 

 E Common March - May * 

Penobscot Bay A Common March - Nov ** 

 S Common March - May ** 

 J Common Common March - Nov ** 

 L Common April - June ** 

 E Common March - May ** 

Muscongus Bay A Abundant March - Nov ** 

 S Common March - May * 

 J Common Highly Abundant March - Nov * 

 L Rare Common April - June * 

 E Common March - May * 

Damariscotta River A Abundant March - Nov ** 

 S Common March - May ** 

 J Common Highly Abundant March - Nov * 

 L Rare Common April - June * 

 E Common March - May ** 

Sheepscot River A Abundant March - Nov *** 

 S Common March - May *** 

 J Common Highly Abundant March - Nov *** 

 L Rare Common April - June *** 

 E Common March - May ** 

Kennebec / Androscoggin Rivers A Abundant March - Nov ** 

 S Common March - May * 

 J Common Highly Abundant March - Nov * 

 L Rare Common April - June * 

 E Common March - May * 

Casco Bay A Abundant March - Nov * 

 S Common March - May * 

 J Common Highly Abundant March - Nov * 

 L Rare Common April - June * 

 E Common March - May * 

(*** = Highly Certain; ** = Moderately Certain; * = Reasonable Inference) 
Page 20

Table 4. Cont’d. 

Distribution and Relative Abundance 

Estuaries and Rivers Life Stage Mixing Seawater 

Months of 

Occurrence 

Data

Reliability

Saco Bay A Abundant March. - Nov. * 

 S Common March - May * 

 J Common Highly Abundant March. - Nov. * 

 L Rare Common April - June * 

 E Common March - May * 

Wells Harbor A * 

 S ** 

 J Rare June - Oct. * 

 L Rare April - June * 

 E Rare March - May * 

Great Bay A Rare March - Nov. * 

 S ** 

 J Rare March - Nov. * 

 L Rare April - July * 

 E Rare March - June * 

Merrimack River A * 

 S ** 

 J Rare March - Sept. * 

 L Rare April - July * 

 E Rare March - June * 

Massachusetts Bay A Highly Abundant Jan. - Dec. *** 

 S Highly Abundant Feb. - June ** 

 J Highly Abundant Jan. - Dec. *** 

 L Abundant March - July * 

 E Abundant Feb. - June * 

Boston Harbor A Abundant Jan. - Dec. ** 

 S Common Feb. - June * 

 J Abundant Jan. - Dec. * 

 L Rare Common March - July * 

 E Rare Common Feb. - June * 

Cape Cod Bay A Abundant Jan. - Dec. ** 

 S Highly Abundant Feb. - May ** 

 J Highly Abundant Jan. - Dec. ** 

 L Rare Highly Abundant March - July ** 

 E Rare Highly Abundant Feb. - July ** 

(*** = Highly Certain; ** = Moderately Certain; * = Reasonable Inference) 
Page 21

Table 5. Summary of habitat parameters for American plaice, based on the pertinent literature. 

Life Stage Depth Substrate Salinity Temperature/Season 

Spawning

Adults 1

Adults spawn and fertilize 

their eggs at or near the 

bottom, eggs drift into the 

upper water column after 

they are released. 

Coastal waters of the Gulf 

of Maine are nursery areas. 

Spawning occurs at depths < 

90 m and spawning adults 

migrate from deeper depths 

into shoaler grounds before 

spawning. 

 In the Gulf of Maine the spawning 

season extends from March 

through the middle of June, with 

peak spawning activity in April 

and May. 

Water temperatures control 

spawning of American plaice 

resulting in varied times and 

locations of spawning in the 

northwest Atlantic. Normally, 

American plaice are captured 

within wide ranges of 

temperatures from -1.5 to 13°C, 

and are most numerous within -

0.5° to 2.5°C. However, during 

peak spawning periods, bottom 

temperature preferences vary. 

Areas of maximum spawning 

occur in the western Gulf of 

Maine and over southeastern 

Georges Bank; optimum spawning 

temperatures range between 3-

6o

C. These bottom water 

temperatures exist throughout 

much of the spawning period 

within the 100 m isobath from 

Cape Cod to New Jersey. Outside 

this southern boundary, 

temperatures are too high for 

survival. 

Eggs 2 Eggs float and hatch at the 

surface and the amount time 

between fertilization and 

hatching of eggs varies 

depending on water 

temperature. 

 Eggs incubate from 11 to 14 days 

at 3.9oC. 

In the Gulf of Maine and on the 

Scotian Shelf, egg abundance 

peaks in early April and May. In 

Cape Cod Bay plaice eggs were 

present from January through July

Lab reared eggs between 2-6°C 

were larger and developed a 

greater probability of surviving 

and first feeding, growth of those 

reared as 10°C was the fastest. 
Page 22

Table 5. Cont’d. 

Life Stage Depth Substrate Salinity Temperature/Season 

Larvae 3 Plaice larvae were found in 

relatively shallow waters on 

Georges Bank, in 

Massachusetts Bay, and 

along coastal Maine. 

Larval plaice that drift into 

the slope water zone along 

the southern edge of 

Georges Bank are 

susceptible to transport in a 

northeasterly direction away 

from Georges Bank and the 

continental shelf. 

Larval plaice found in the 

upper water levels can be 

transported by currents 

southwest along the coast; 

some were retained in the 

Gulf of Maine while others 

can be transported to 

Georges Bank. 

 In Cape Cod Bay larvae were 

present from January through 

August. 

Larval transformation process 

varies with temperature, it is 

usually complete when the larva is 

30-40 mm 

Larvae reared at 10C had larger 

fin fold area and used up their 

yolk-sac reserves earlier. 

Therefore in many cases the 

development rate was altered by 

the temperature and affected 

swimming performance, but no 

affect on escape response. 

Juveniles 4 
Page 23

Table 5. Cont’d. 

Life Stage Depth Substrate Salinity Temperature/Season 

Adults 5 Their normal habitat is at or 

near the ocean floor; 

however, they frequently 

migrate off the bottom at 

night in pursuit of prey. 

Plaice are found in shoal 

waters when temperatures 

are severely cold, they 

normally occur in waters 25-

180 m deep. 

In southern Labrador to 

Rhode Island are generally 

found in deep water from 

90-180 m and are not 

normally found in water < 

25-35m. 

In Canadian waters it occurs 

at preferred depths of 90-

250 m. 

On the Scotian Shelf 

American plaice range 

between 27-366 m, with 

preferences between 55-128 

m. 

Gulf of Maine plaice 

normally occur in waters 25-

180 m deep, but are also 

found in shoal waters when 

temperatures are severely 

cold. With the exception of 

witch flounder, plaice is 

considered most abundant of 

all flatfish in Gulf of Maine 

at depths between 54-90 m. 

Widespread on Georges 

Bank along the 90-180 m 

zone of its northern edge. 

They prefer a soft 

bottom substrate. 

Laboratory experiments 

show a preference for 

the finer gravelly sand. 

On the Scotian Shelf, 

plaice were most 

abundant on sand and 

gravel substrates. 

In eastern 

Newfoundland, plaice 

were frequently 

collected where sandy 

substrates bordered 

areas of bedrock. 

In some areas, their 

distribution has been 

correlated with mud 

substrates. 

American plaice 

occur at mean 

salinities of 20-

22 ppt in 

Hamilton Inlet, 

Labrador 

30 ppt or lower 

in Baltic areas, 

32.8 ppt in the 

Gulf of Maine, 

34 ppt in 

offshore Atlantic 

waters. 

On Scotian 

Shelf, had 

salinity 

preferences 

between 31-34 

ppt; highest 

abundances 

occurred at 33 

ppt. 

They can thrive in temperatures 

ranging from -0.5 to 13.0o

C. 

In Canadian waters it occurs in 

temperatures ranging from 

approximately -1.5°C to 

temperatures above 5°C, with a 

preferred temperature range of 0-

1.5°C. 

The warmer temperature sought 

by females during feeding also 

provide optimal conditions for 

growth during the summer. 

The maturity of plaice varied as 

much as 11 years and depended on 

water temperatures. 

The highest temperature, 10o

C, for 

Passamaquoddy Bay and the Cape 

Cod region had the shortest time 

of development to maturity (3-5 

years). 

The lowest temperature recorded 

was 0o

C for Newfoundland (Bay 

of Islands) and plaice had the 

longest development time (10-13 

years) 

On the Scotian Shelf, American 

plaice ranged between 0-13o

C 

with preferences between 1-4o

C 

Significant positive correlations 

exist between the annual catch of 

fish off the Maine coast and mean 

annual surface temperatures, 

meaning that temperature is a 

limiting factor in the abundance of 

plaice.

1 Bigelow and Schroeder (1953); Colton and Temple (1961); Colton (1972); Smith et al. (1975); Colton et al. (1979); 

Bowering and Brodie (1991). 

2 Bigelow and Schroeder (1953); Howell and Caldwell (1984); Scherer (1984); Neilson et al. (1988); DFO (1989); 

Berrien and Sibunka (1999); Hebert and Wearing-Wilde 2002. 

3 Colton and Marak (1969); Smith et al. (1975); Sullivan (1981); Scherer (1984); Shepherd et al. (2000). 4 Bigelow and Schroeder (1953); Bowman and Michaels (1984); Link and Almeida (2000); Link et al. (2002); Packer 

and Langton (unpubl. manuscript). 

5 Huntsman (1918); Bigelow and Schroeder (1953); Backus (1957); Powles (1965); Colton (1972); Pitt (1973); Dow 

(1977); Langton and Bowman (1981); Scott (1982a); Scott(1982b); Bowman and Michaels (1984); Scott and Scott 

(1988); Holzwarth and Mountain (1990); Langton and Watling (1990); Sparholt (1990); Bowering and Brodie (1991); 

Murawski (1993); Iglesias et al. (1996); Walsh (1996); Dery (1998); Morgan (2000); Klein-MacPhee (2002); Packer and 

Langton (unpubl. manuscript). 
Page 24

Table 5. Cont’d. 

Life Stage Prey Predators / Species Associations

Eggs N/A 

Larvae1 American plaice larvae show a gradual size-selectivity preference 

when maxilla length ranges change from 100-200 m to 200 - 500 

m. 

Larvae feed on plankton, diatoms, and copepods that exist in the upper 

water layers. 

 

Redfish consumes larvae. 

Juveniles2 Prior to settling, juveniles feed on small crustaceans, polychaetes, and 

cumaceans. 

When they settle their diet gradually changes as they grow and the 

size of their mouth gape increases to accept wider-sized prey. 

They consume mostly ophiuroids. 

Smaller (< 25-30 cm) individuals feed predominately on mysids, 

amphipods, polychaetes, small brittle stars, and some mollusks. 

In Sheepscot Bay, Maine, mysids generally decreased in importance 

with increasing predator size and polychaetes appeared to increase. 

Feeding competition exists 

between young plaice and cod. 

Cod and other bottom feeding 

species prey upon them. 
Page 25

Table 5. Cont’d. 

Life Stage Prey Predators / Species Associations

Adults3 Consumed ophiuroids, echinoderms, chiefly sand dollars, sea urchins, 

and brittle stars. 

Larger individuals (> 30 cm) feed primarily on fish, brittle stars and 

other echinoderms, and bivalve mollusks. 

The brittle star, Ophiura sarsi, makes up 65% of the plaice diet at 

some locations in the Gulf of Maine. 

Diets of plaice collected during 1973-2001 NEFSC bottom trawl 

surveys were also dominated by echinoderms; arthropods, annelids, 

and mollusks were also eaten. 

Off the coastal bank of Norway, American plaice feeding habits are 

distinctly different from other flatfish species, they feed more on 

benthic and epibenthic organisms such as ophiuroids and crustaceans. 

In the North Sea they feed on more fish (particularly sandlance), as 

well as polychaetes, crustaceans and ophiuroids. 

In Passamaquoddy Bay, Canada, they feed on amphipods, mysids, 

euphausiids, polychaetes, bivalve mollusks, and Atlantic herring. 

In Sheepscot Bay, Maine, they eat polychaetes, mysids, amphipods, 

sand shrimp. 

Offshore in the Gulf of Maine, the brittle star Ophiura sarsi is the 

primary prey; crustaceans (euphausiids and pandalid shrimp), bivalve 

mollusks (Yoldia spp., Chlamys islandica, Cerastoderma pinnulatum), 

and tube-dwelling polychaetes are of secondary importance. 

On Georges Bank, they ate almost exclusively echinoderms. 

In Southern New England, plaice consume large quantities of 

amphipods, shrimp (Crangon), polychaetes, and bivalves. 

In the spring echinoderms and other invertebrates were heavily 

consumed. 

In summer (highest feeding rates): bivalves, pandalids and 

polychaetes. 

In autumn: ophiuroids and fish eggs. 

There is little or no feeding in January and February and a rapid 

increase of feeding in May through September. 

Eaten by Greenland sharks, cod, 

halibut, goosefish, and spiny 

dogfish. 

Along the Scotian Shelf and in the 

Gulf of St. Lawrence, grey seals 

are the primary predators 

Seabird consumption on landed 

fish aboard boats; consumption 

was found to be directly 

proportional to the amount of time 

the fish was on deck.

1

 Pepin and Penney (2000); Klein-MacPhee (2002). 

2 Powles (1965); Bowman and Michaels (1984); Ross and Hokenson (1997). 

3

 Huntsman (1918); Bigelow and Schroeder (1953); Powles (1965); Tyler (1971); Tyler (1972); Pitt (1973); Langton and 

Bowman (1981); Sullivan (1981); Bowman and Michaels (1984); Macdonald and Green (1986); Macdonald and 

Waiwood (1987); Watling et al. (1988); DFO (1989); Benoit and Bowen (1990); Langton and Watling (1990); Keats 

(1991); Zamarro (1992); Klemetsen (1993); Ntiba and Harding (1993); Alverson et al. (1994); Martell and McClelland 

(1994); Packer et al. (1994); Ross and Hokenson (1997); Link and Almeida (2000); Bowen et al. (2002); Hebert and 

Wearing-Wilde 2002; Klein-MacPhee (2002); Link et al. (2002); Packer and Langton (unpubl. manuscript). 
Page 26

Table 6. Summary of habitat parameters for American plaice, based on available surveys. 

Life Stage Survey Temperature Depth Salinity 

1978-1987 MARMAP 

ichthyoplankton surveys 

from Nova Scotia to Cape 

Hatteras. 

Range: 1-12°C, overall 

range 4-8°C; Feb.-Apr. 3-

6°C, May-July 5-8°C, 

Aug.-Dec. 9-11°C. 

Range: approximately 10-

325 m, majority occurring 

between 50-90 m. 

Eggs n/a 

1995-1999 GLOBEC 

surveys on Georges Bank. 

Range: from Jan.-June 

remained in a narrow 

range of about 4-8°C. 

Range: most occurred 

between 41-100 m. 

n/a 

1977-1987 MARMAP 

ichthyoplankton surveys 

from Nova Scotia to Cape 

Hatteras. 

Range: 4-14°C. During 

Mar.-Jun. most occurred 

between 5-8°C, during 

July-Aug. between 10-

12°C. 

Range: 30-210 m. Most 

occurred at 50-90 m, 

except Aug. where the 

majority were found at 

130 m. 

Larvae n/a 

1995-1999 GLOBEC 

surveys on Georges Bank. 

Range: 4-6°C from Feb.-

Apr., 6-11°C from MayJune.

Range: 41 m to between 

301-350 m, majority 

between 41-120 m. Depth 

at which larvae occurred 

remained constant from 

Feb.-May, changing to 

deeper waters in June. 

n/a 

1963-2003 Spring and Fall 

NEFSC trawl surveys 

from Gulf of Maine to 

Cape Hatteras. 

Spring: range of 2-10°C, 

most between 4-6°C. 

Fall: range of 4-16°C, 

majority between 5-11°C. 

Spring: range of 11-400 

m. 

Fall: range of 11-400 m. 

Spring: range of 31-

35 ppt, majority 

found at 33 ppt. 

Fall: range of 31-35 

ppt, majority found at 

33 ppt. 

Juveniles

1978-2003 Massachusetts 

inshore trawl surveys. 

Spring: range of 1-12°C, 

with most between 4-6°C. 

Fall: range of 4-17°C, 

majority between 7-10°C.

Spring: range of 6-85 m, 

majority between 46-65 m. 

Fall: range of 6-85 m, 

majority between 46-65 m.

n/a

1963-2003 Spring and Fall 

NEFSC trawl surveys 

from Gulf of Maine to 

Cape Hatteras. 

Spring: range of 1-12°C, 

most between 4-6°C. 

Fall: range of 3-15°C, 

peaks between about 6-

9°C.

Spring: range between 11-

400 m. 

Fall: range of 21-400 m.

Spring: range of 31-

35 ppt, majority at 33 

ppt. 

Fall: range of 31-35 

ppt, majority at 33-34 

ppt. 

Adults 

1978-2003 Massachusetts 

inshore trawl surveys. 

Spring: range of 1-12°C, 

majority between 4-6°C. 

Fall: range of 4-14°C, 

most between 7-9°C.

Spring: range of 6-85 m. 

Fall: range of 16-85 m.

n/a 
Page 27

Figure 1. The American plaice, Hippoglossoides platessoides (Fabricius 1780) (from Goode 1884). 
Page 28

Diet Composition of Major Prey Items 

<=20 cm

0

10

20

30

40

50

Amphipods

Asteroids

Bivalves

Decapods

Echinoids

Euphasiids

Misc.

Crustaceans

Ophiuroids

Other

Echinoderms

Polychaetes

Well

Digested

Prey

Percent

20-40 cm

0

10

20

30

40

50

60

Amphipods

Asteroids

Bivalves

Decapods

Echinoids

Euphasiids

Misc.

Crustaceans

Ophiuroids

Other

Echinoderms

Polychaetes

Well

Digested

Prey

Percent

41-70 cm

0

10

20

30

40

50

60

Amphipods

Asteroids

Bivalves

Decapods

Echinoids

Euphasiids

Misc.

Crustaceans

Ophiuroids

Other

Echinoderms

Polychaetes

Well

Digested

Prey

Percent

Figure 2. Percent by weight of the major prey items in the diet of three size categories of American plaice. 

From specimens collected during NEFSC bottom trawl surveys from 1973-2001 (all seasons). For details on NEFSC diet 

analysis, see Link and Almeida (2000). 
Page 29

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

January to December; 1978 to 1987

Number of Tows = 9478; with Eggs = 416

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

Eggs / 10m2

1 to <10

10 to <100

100 to <1000

1000 to 1703

Figure 3. Distributions and abundances of American plaice eggs collected during NEFSC MARMAP ichthyoplankton 

surveys. 

For all available months and years from 1978-1987 combined. 
Page 30

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

January; 1978 to 1987

Number of Tows = 433; with Eggs = 2

None

1 to 6

Eggs / 10m2

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

February; 1978 to 1987

Number of Tows = 459; with Eggs = 31

None

1 to <10

10 to <100

100 to 137

Eggs / 10m2

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

March; 1978 to 1987

Number of Tows = 853; with Eggs = 39

None

1 to <10

10 to <100

100 to 254

Eggs / 10m2

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

April; 1978 to 1987

Number of Tows = 1020; with Eggs = 187

None

1 to <10

10 to <100

100 to <1000

Eggs / 10m2

1000 to 1703

Figure 3. Cont’d. 

From MARMAP ichthyoplankton surveys, January through April, 1978-1987. 
Page 31

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

May; 1978 to 1987

Number of Tows = 1085; with Eggs = 77

None

1 to <10

10 to <100

100 to <1000

Eggs / 10m2

1000 to 1074

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

June; 1978 to 1987

Number of Tows = 709; with Eggs = 52

None

1 to <10

10 to <100

100 to 539

Eggs / 10m2

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

July; 1978 to 1987

Number of Tows = 781; with Eggs = 8

None

1 to <10

10 to <100

100 to 238

Eggs / 10m2

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

August; 1978 to 1987

Number of Tows = 863; with Eggs = 11

None

1 to <10

10 to <100

100 to 116

Eggs / 10m2

Figure 3. Cont’d. 

From MARMAP ichthyoplankton surveys, May through August, 1978-1987. 
Page 32

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

September; 1978 to 1987

Number of Tows = 747; with Eggs = 3

None

1 to 6

Eggs / 10m2

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

October; 1978 to 1987

Number of Tows = 1044; with Eggs = 2

None

1 to <10

10 to 42

Eggs / 10m2

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

November; 1978 to 1987

Number of Tows = 915; with Eggs = 3

None

1 to 10

Eggs / 10m2

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

American Plaice

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

December; 1978 to 1987

Number of Tows = 569; with Eggs = 1

None

1 to 7

Eggs / 10m2

Figure 3. Cont’d. 

From MARMAP ichthyoplankton surveys, September through December, 1978-1987. 
Page 33

Figure 4. Distributions and abundances of American plaice eggs collected during GLOBEC Georges Bank 

ichthyoplankton surveys. 

For all available years (February-July, 1995; January-June, 1996-1999) combined. 
Page 34

Figure 4. Cont’d. 

From GLOBEC ichthyoplankton surveys, January and February, for all available years combined. 
Page 35

Figure 4. Cont’d. 

From GLOBEC ichthyoplankton surveys, March and April, for all available years combined. 
Page 36

Figure 4. Cont’d. 

From GLOBEC ichthyoplankton surveys, May and June, for all available years combined. 
Page 37

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

March to August (1977 to 1987)

American Plaice

Number of Tows = 6763, with larvae = 210

1 to < 10

10 to < 100

100 to 509

Number of Larvae / 10m2

Figure 5. Distributions and abundances of American plaice larvae collected during NEFSC MARMAP 

ichthyoplankton surveys. 

For all available months and years from 1977-1987 combined. 
Page 38

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

March (1977 to 1987)

Number of Tows = 1031, with larvae = 6

Number of Larvae / 10m2

None

1 to < 10

10 to 60

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

April (1977 to 1987)

Number of Tows = 1281, with larvae = 50

Number of Larvae / 10m2

None

1 to < 10

10 to < 100

100 to 364

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

May (1977 to 1987)

Number of Tows = 1472, with larvae = 96

Number of Larvae / 10m2

None

1 to < 10

10 to < 100

100 to 509

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

June (1977 to 1987)

Number of Tows = 893, with larvae = 40

Number of Larvae / 10m2

None

1 to < 10

10 to 72

Figure 5. Cont’d. 

From MARMAP ichthyoplankton surveys, March through June, 1977-1987. 
Page 39

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

July (1977 to 1987)

Number of Tows = 938, with larvae = 13

Number of Larvae / 10m2

None

1 to < 10

10 to 27

76 75 74 73 72 71 70 69 68 67 66 65

35

36

37

38

39

40

41

42

43

44

45

August (1977 to 1987)

Number of Tows = 1148, with larvae = 5

Number of Larvae / 10m2

None

1 to < 10

10 to 46

Figure 5. Cont’d. 

From MARMAP ichthyoplankton surveys, July and August, 1977-1987. 
Page 40

Figure 6. Distributions and abundances of American plaice larvae collected during GLOBEC Georges Bank 

ichthyoplankton surveys. 

For all available years (February-July, 1995; January-June, 1996-1999) combined. 
Page 41

Figure 5. Cont’d. 

From GLOBEC ichthyoplankton surveys, February and March, for all available years combined. 
Page 42

Figure 5. Cont’d. 

From GLOBEC ichthyoplankton surveys, April and May, for all available years combined. 
Page 43

Figure 5. Cont’d. 

From GLOBEC ichthyoplankton surveys, June, for all available years combined. 
Page 44

Figure 7. Seasonal distributions and abundances of juvenile American plaice collected during NEFSC bottom trawl 

surveys. 

Based on NEFSC winter bottom trawl surveys (1964-2003, all years combined). Distributions are displayed as presence 

only. 
Page 45

Figure 7. Cont’d. 

Based on NEFSC spring bottom trawl surveys (1968-2003, all years combined). Survey stations where juveniles were 

not found are not shown. 
Page 46

Figure 7. Cont’d. 

Based on NEFSC summer bottom trawl surveys (1963-1995, all years combined). Distributions are displayed as 

presence only. 
Page 47

Figure 7. Cont’d. 

Based on NEFSC fall bottom trawl surveys (1963-2003, all years combined). Survey stations where juveniles were not 

found are not shown. 
Page 48

Figure 8. Distribution and abundance of American plaice along the coasts of Maine and New Hampshire. 

Based on the Maine – New Hampshire spring 2001-2004 and fall 2000-2003 inshore groundfish trawl surveys. 

For details on the survey, see Sherman et al. (2005). 
Page 49

Figure 9. Regional catch-per-unit-effort of American plaice caught along the Maine and New Hampshire coasts, by 

season/year. 

Based on the Maine – New Hampshire inshore groundfish trawl survey for spring 2001-2004 and fall 2000-2003. 

Region 1 = NH–Southern ME; Region 2 = Casco Bay–Midcoast ME; Region 3 = Penobscot Bay, ME; Region 4 = 

Jerico–Frenchmens Bay, ME; Region 5 = Downeast ME. Source: Sherman et al. (2005). 
Page 50

Figure 10. Length frequency plots for American plaice caught along the Maine and New Hampshire coasts, by season 

and year. 

Based on the Maine – New Hampshire inshore groundfish trawl survey for spring 2001-2004 and fall 2000-2003. 

Source: Sherman et al. (2005). 
Page 51

Figure 11. Seasonal distributions and abundances of juvenile American plaice in Massachusetts coastal waters. 

Based on spring Massachusetts inshore bottom trawl surveys (1978-2003, all years combined). Survey stations where 

juveniles were not found are not shown. 
Page 52

Figure 11. Cont’d. 

Based on fall Massachusetts inshore bottom trawl surveys (1978-2003, all years combined). Survey stations where 

juveniles were not found are not shown. 
Page 53

Figure 12. Seasonal distributions and abundances of adult American plaice collected during NEFSC bottom trawl 

surveys. 

Based on NEFSC winter bottom trawl surveys (1964-2003, all years combined). Distributions are displayed as presence 

only. 
Page 54

Figure 12. Cont’d. 

Based on NEFSC spring bottom trawl surveys (1968-2003, all years combined). Survey stations where adults were not 

found are not shown. 
Page 55

Figure 12. Cont’d. 

Based on NEFSC summer bottom trawl surveys (1963-1995, all years combined). Distributions are displayed as 

presence only. 
Page 56

Figure 12. Cont’d. 

Based on NEFSC fall bottom trawl surveys (1963-2003, all years combined). Survey stations where adults were not 

found are not shown. 
Page 57

Figure 13. Seasonal distributions and abundances of adult American plaiceError! Reference source not found. in 

Massachusetts coastal waters. 

Based on spring Massachusetts inshore bottom trawl surveys (1978-2003, all years combined). Survey stations where 

adults were not found are not shown. 
Page 58

Figure 13. Cont’d. 

Based on fall Massachusetts inshore bottom trawl surveys (1978-2003, all years combined). Survey stations where adults 

were not found are not shown. 
Page 59

Figure 14. Monthly distributions of American plaice eggs collected during NEFSC MARMAP ichthyoplankton surveys 

relative to water column temperature and bottom depth. 

For all available months and years from 1978-1987, combined. Open bars represent the proportion of all stations which 

were surveyed, while solid bars represent the proportion of the sum of all standardized catches (number/10 m2

). Note that 

the bottom depth interval changes with increasing depth. 

January

0

10

20

30

90

100

Stations

Egg Catch

April

0

10

20

30

40

May

0

10

20

40

50

June

Percent

0

10

20

30

40

50

July

0

10

20

30

40

50

August

0

20

40

60

October

0

10

90

100

American Plaice Eggs

September

0

10

20

30

40

February

0

10

20

30

40

50

March

0

20

40

60

November

0

10

20

70

80

December

Water Temperature (0 to 200m, C)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

0

10

20

30

90

100

January

0

10

20

30

40

50

Stations

Egg Catch

April

0

10

20

30

October

0

10

20

80

American Plaice Eggs

September

0

10

20

30

May

0

10

20

30

40

50

June

Percent

0

10

20

30

40

50

July

0

10

20

30

40

August

0

20

40

60

December

Bottom Depth (m), Interval Midpoint

1030507090

110130150170190210230250270290325375450750

12501750

>2000

0

10

20

80

100

November

0

10

20

50

60

March

0

10

20

30

40

50

February

0

10

20

30

40

50
Page 60

January

0

20

40

60

80

Percent

Stations

Egg Catch

February

0

20

40

60

80

Percent

March

0

20

40

60

80

Percent

April

0

20

40

60

80

Percent

May

0

20

40

60

80

Percent

June

0

20

40

60

80

Percent

July

0

20

40

60

80

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Water Column Temperature (0-200m, °C)

Percent

Figure 15. Distributions of American plaiceError! Reference source not found. eggs collected during GLOBEC 

ichthyoplankton surveys relative to water column temperature. 

Based on GLOBEC Georges Bank surveys (February-July, 1995; January-June, 1996-1999) by month for all available 

years combined. Light bars represent the proportion of all stations surveyed, while dark bars represent the proportion of 

the sum of all standardized catches (number/10 m2

). 
Page 61

January

0

20

40

60

80

Percent

Stations

Egg Catch

February

0

20

40

60

80

Percent

March

0

20

40

60

80

Percent

April

0

20

40

60

80

Percent

May

0

20

40

60

80

Percent

June

0

20

40

60

80

Percent

July

0

20

40

60

80

1-20

21-4041-6061-80

81-100

101-120121-140141-160161-180181-200201-220221-240241-260261-280281-300301-350351-400401-500

501-1000

1001-15001501-2000

>2001

Bottom Depth (m)

Percent

Figure 16. Distributions of American plaice eggs collected during GLOBEC ichthyoplankton surveys relative to bottom 

depth. 

Based on GLOBEC Georges Bank surveys (February-July, 1995; January-June, 1996-1999) by month for all available 

years combined. Light bars represent the proportion of all stations surveyed, while dark bars represent the proportion of 

the sum of all standardized catches (number/10 m2

). Note that the bottom depth intervals change with depth. 
Page 62

Figure 17. Monthly distributions of American plaice larvae collected during NEFSC MARMAP ichthyoplankton 

surveys relative to water column temperature and bottom depth. 

For all available months and years from 1977-1987, combined. Open bars represent the proportion of all stations which 

were surveyed, while solid bars represent the proportion of the sum of all standardized catches (number/10 m2

). Note that 

the bottom depth interval changes with increasing depth. 

April

0

10

20

30

60

70

80

May

0

10

20

30

40

June

Percent

0

10

20

30

July

0

10

20

30

August

Water-Column Temperature (0-200m, C)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

0

5

10

35

40

45

American Plaice Larvae

March

0

10

20

30

40

50

Stations

Larva Catch

April

0

10

20

30

40

50

American Plaice Larvae

May

0

10

20

30

40

50

June

Percent

0

10

20

30

July

0

10

20

30

40

August

Bottom Depth (m), Interval Midpoint

1030507090

110130

150

170190210

230250270

290325375450750

12501750

>2000

0

10

20

30

40

50

March

0

10

20

30

40

50

Stations

Larva Catch
Page 63

January

0

20

40

60

80

Percent

Stations

Larvae Catch

February

0

20

40

60

80

Percent

March

0

20

40

60

80

Percent

April

0

20

40

60

80

Percent

May

0

20

40

60

80

Percent

June

0

20

40

60

80

Percent

July

0

20

40

60

80

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28

Water Column Temperature (0-200m, °C)

Percent

Figure 18. Distributions of American plaice larvae collected during GLOBEC ichthyoplankton surveys relative to water 

column temperature. 

Based on GLOBEC Georges Bank surveys (February-July, 1995; January-June, 1996-1999) by month for all available 

years combined. Light bars represent the proportion of all stations surveyed, while dark bars represent the proportion of 

the sum of all standardized catches (number/10 m2

). 
Page 64

January

0

20

40

60

80

Percent

Stations

Larvae Catch

February

0

20

40

60

80

Percent

March

0

20

40

60

80

Percent

April

0

20

40

60

80

Percent

May

0

20

40

60

80

Percent

June

0

20

40

60

80

Percent

July

0

20

40

60

80

1-20

21-4041-6061-80

81-100

101-120121-140141-160161-180181-200201-220221-240241-260261-280281-300301-350351-400401-500

501-1000

1001-15001501-2000

>2001

Bottom Depth (m)

Percent

Figure 19. Distributions of American plaice larvae collected during GLOBEC ichthyoplankton surveys relative to 

bottom depth. 

Based on GLOBEC Georges Bank surveys (February-July, 1995; January-June, 1996-1999) by month for all available 

years combined. Light bars represent the proportion of all stations surveyed, while dark bars represent the proportion of 

the sum of all standardized catches (number/10 m2

). Note that the bottom depth intervals change with depth. 
Page 65

American Plaice

NEFSC Bottom Trawl Survey

Spring 1968 - 2003

Juveniles (<27 cm)

0

2

4

6

8

10

12

14

16

1-10

11-2021-3031-4041-5051-6061-7071-8081-90

91-100

101-120121-140141-160161-180181-200201-300301-400401-500

>500

Bottom Depth (m)

Percent

Trawls N=12514

Occurrence N=2109

Catch N=27838

0

10

20

30

40

50

60

24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Salinity (PPT)

Percent

Trawls N=2270

Occurrence N=328

Catch N=4294

0

10

20

30

40

50

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Bottom Temperature (°C)

Percent

Trawls N=10879

Occurrence N=1832

Catch N=24161

Figure 20. Distributions of juvenile American plaice and trawls from NEFSC bottom trawl surveys relative to bottom 

water temperature, depth, and salinity. 

Based on NEFSC spring bottom trawl surveys (temperature and depth: 1968-2003, all years combined; salinity: 1991-

2003, all years combined). Light bars show the distribution of all the trawls, dark bars show the distribution of all trawls 

in which American plaice occurred and medium bars show, within each interval, the percentage of the total number of 

American plaice caught. Note that the bottom depth interval changes with increasing depth. 
Page 66

American Plaice

NEFSC Bottom Trawl Survey

Fall 1963 - 2003

Juveniles (<27 cm)

0

5

10

15

20

1-10

11-2021-3031-4041-5051-6061-7071-8081-90

91-100

101-120121-140141-160161-180181-200201-300301-400401-500

>500

Bottom Depth (m)

Percent

Trawls N=14186

Occurrence N=2575

Catch N=37217

0

10

20

30

40

50

60

70

24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Salinity (PPT)

Percent

Trawls N=2272

Occurrence N=357

Catch N=5250

0

5

10

15

20

25

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Bottom Temperature (°C)

Percent

Trawls N=12207

Occurrence N=2274

Catch N=31663

Figure 20. Cont’d. 

Based on NEFSC fall bottom trawl surveys (temperature and depth: 1963-2003, all years combined; salinity: 1991-2003, 

all years combined). Light bars show the distribution of all the trawls, dark bars show the distribution of all trawls in 

which American plaice occurred and medium bars show, within each interval, the percentage of the total number of 

American plaice caught. Note that the bottom depth interval changes with increasing depth. 
Page 67

American Plaice

Massachusetts Inshore Trawl Survey

Spring 1978 - 2003

Juveniles (<27 cm)

0

5

10

15

20

25

30

1-5

6-10

11-1516-2021-2526-3031-3536-4041-4546-5051-5556-6061-6566-7071-7576-8081-85

Bottom Depth (m)

Percent

Trawls N=2482

Occurrence N=548

Catch N=89100

0

10

20

30

40

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Bottom Temperature (°C)

Percent

Trawls N=2407

Occurrence N=530

Catch N=85864

Figure 21. Distributions of juvenile American plaice and trawls in Massachusetts coastal waters relative to bottom water 

temperature and depth. 

Based on spring Massachusetts inshore bottom trawl surveys (1978-2003, all years combined). Light bars show the 

distribution of all the trawls, dark bars show the distribution of all trawls in which American plaice occurred and medium 

bars show, within each interval, the percentage of the total number of American plaice caught. 
Page 68

American Plaice

Massachusetts Inshore Trawl Survey

Fall 1978 - 2003

Juveniles (<27 cm)

0

5

10

15

20

25

30

1-5

6-10

11-1516-2021-2526-3031-3536-4041-4546-5051-5556-6061-6566-7071-7576-8081-85

Bottom Depth (m)

Percent

Trawls N=2338

Occurrence N=483

Catch N=82333

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Bottom Temperature (°C)

Percent

Trawls N=2244

Occurrence N=470

Catch N=78545

Figure 21. Cont’d. 

Based on fall Massachusetts inshore bottom trawl surveys (1978-2003, all years combined). Light bars show the 

distribution of all the trawls, dark bars show the distribution of all trawls in which American plaice occurred and medium 

bars show, within each interval, the percentage of the total number of American plaice caught. 
Page 69

American Plaice

NEFSC Bottom Trawl Survey

Spring 1968 - 2003

Adults (>=27 cm)

0

2

4

6

8

10

12

14

16

1-10

11-2021-3031-4041-5051-6061-7071-8081-90

91-100

101-120121-140141-160161-180181-200201-300301-400401-500

>500

Bottom Depth (m)

Percent

Trawls N=12514

Occurrence N=3002

Catch N=27176

0

10

20

30

40

50

60

24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Salinity (PPT)

Percent

Trawls N=2270

Occurrence N=511

Catch N=4412

0

5

10

15

20

25

30

35

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Bottom Temperature (°C)

Percent

Trawls N=10879

Occurrence N=2658

Catch N=24744

Figure 22. Distributions of adult American plaice and trawls from NEFSC bottom trawl surveys relative to bottom water 

temperature, depth, and salinity. 

Based on NEFSC spring bottom trawl surveys (temperature and depth: 1968-2003, all years combined; salinity: 1991-

2003, all years combined). Light bars show the distribution of all the trawls, dark bars show the distribution of all trawls 

in which American plaice occurred and medium bars show, within each interval, the percentage of the total number of 

American plaice caught. Note that the bottom depth interval changes with increasing depth. 
Page 70

American Plaice

NEFSC Bottom Trawl Survey

Fall 1963 - 2003

Adults (>=27 cm)

0

5

10

15

20

1-10

11-2021-3031-4041-5051-6061-7071-8081-90

91-100

101-120121-140141-160161-180181-200201-300301-400401-500

>500

Bottom Depth (m)

Percent

Trawls N=14186

Occurrence N=3062

Catch N=35655

0

10

20

30

40

50

24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Salinity (PPT)

Percent

Trawls N=2272

Occurrence N=431

Catch N=5500

0

5

10

15

20

25

30

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Bottom Temperature (°C)

Percent

Trawls N=12207

Occurrence N=2690

Catch N=31492

Figure 22. Cont’d. 

Based on NEFSC fall bottom trawl surveys (temperature and depth: 1963-2003, all years combined; salinity: 1991-2003, 

all years combined). Light bars show the distribution of all the trawls, dark bars show the distribution of all trawls in 

which American plaice occurred and medium bars show, within each interval, the percentage of the total number of 

American plaice caught. Note that the bottom depth interval changes with increasing depth. 
Page 71

American Plaice

Massachusetts Inshore Trawl Survey

Spring 1978 - 2003

Adults (>=27 cm)

0

5

10

15

20

25

30

1-5

6-10

11-1516-2021-2526-3031-3536-4041-4546-5051-5556-6061-6566-7071-7576-8081-85

Bottom Depth (m)

Percent

Trawls N=2482

Occurrence N=504

Catch N=16834

0

10

20

30

40

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Bottom Temperature (°C)

Percent

Trawls N=2407

Occurrence N=488

Catch N=16099

Figure 23. Distributions of adult American plaice and trawls in Massachusetts coastal waters relative to bottom water 

temperature and depth. 

Based on spring Massachusetts inshore bottom trawl surveys (1978-2003, all years combined). Light bars show the 

distribution of all the trawls, dark bars show the distribution of all trawls in which American plaice occurred and medium 

bars show, within each interval, the percentage of the total number of American plaice caught. 
Page 72

American Plaice

Massachusetts Inshore Trawl Survey

Fall 1978 - 2003

Adults (>=27 cm)

0

5

10

15

20

25

30

1-5

6-10

11-1516-2021-2526-3031-3536-4041-4546-5051-5556-6061-6566-7071-7576-8081-85

Bottom Depth (m)

Percent

Trawls N=2338

Occurrence N=365

Catch N=12371

0

5

10

15

20

25

30

35

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30

Bottom Temperature (°C)

Percent

Trawls N=2244

Occurrence N=353

Catch N=11883

Figure 23. Cont’d. 

Based on fall Massachusetts inshore bottom trawl surveys (1978-2003, all years combined). Light bars show the 

distribution of all the trawls, dark bars show the distribution of all trawls in which American plaice occurred and medium 

bars show, within each interval, the percentage of the total number of American plaice caught. 
Publishing in NOAA Technical Memorandum NMFS-NE

Manuscript Qualification

This series represents a secondary level of scientific

publishing in the National Marine Fisheries Service (NMFS).

For all issues, the series employs thorough internal scientific

review, but not necessarily external scientific review. For most

issues, the series employs rigorous technical and copy editing.

Manuscripts that may warrant a primary level of scientific

publishing should be initially submitted to one of NMFS's

primary series (i.e., Fishery Bulletin, NOAA Technical Report

NMFS, or Marine Fisheries Review).

Identical, or fundamentally identical, manuscripts should

not be concurrently submitted to this and any other publication

series. Manuscripts which have been rejected by any primary

series strictly because of geographic or temporal limitations

may be submitted to this series.

Manuscripts by Northeast Fisheries Science Center

(NEFSC) authors will be published in this series upon approval

by the NEFSC's Deputy Science & Research Director. Manuscripts by non-NEFSC authors may be published in this series

if: 1) the manuscript serves the NEFSC's mission; 2) the

manuscript meets the Deputy Science & Research Director's

approval; and 3) the author arranges for the printing and binding

funds to be transferred to the NEFSC's Research Communications Unit account from another federal account. For all

manuscripts submitted by non-NEFSC authors and published

in this series, the NEFSC will disavow all responsibility for the

manuscripts' contents; authors must accept such responsibility.

The ethics of scientific research and scientific publishing

are a serious matter. All manuscripts submitted to this series

are expected to adhere -- at a minimum -- to the ethical guidelines

contained in Chapter 1 ("Ethical Conduct in Authorship and

Publication") of the CBE Style Manual, fifth edition (Chicago,

IL: Council of Biology Editors). Copies of the manual are

available at virtually all scientific libraries.

edition of the United States Government Printing Office Style

Manual. That style manual is silent on many aspects of scientific

manuscripts. NEFSC publication and report series rely more on the

CBE Style Manual, fifth edition.

For in-text citations, use the name-date system. A special

effort should be made to ensure that the list of cited works contains

all necessary bibliographic information. For abbreviating serial

titles in such lists, use the guidance of the International Standards

Organization; such guidance is easily accessed through the various

Cambridge Scientific Abstracts’ serials source lists (see http://

www.public.iastate.edu/~CYBERSTACKS/JAS.htm). Personal communications must include date of contact and full name and mailing

address of source.

For spelling of scientific and common names of fishes, mollusks, and decapod crustaceans from the United States and Canada,

use Special Publications No. 20 (fishes), 26 (mollusks), and 17

(decapod crustaceans) of the American Fisheries Society (Bethesda,

MD). For spelling of scientific and common names of marine

mammals, use Special Publication No. 4 of the Society for Marine

Mammalogy (Lawrence, KS). For spelling in general, use the most

recent edition of Webster’s Third New International Dictionary of

the English Language Unabridged (Springfield, MA: G.&C.

Merriam).

Typing text, tables, and figure captions: Text, tables, and

figure captions should be converted to WordPerfect. In general,

keep text simple (e.g., don't switch fonts and type sizes, don't use

hard returns within paragraphs, don't indent except to begin

paragraphs). Also, don't use an automatic footnoting function; all

notes should be indicated in the text by simple numerical superscripts, and listed together in an "Endnotes" section prior to the

"References Cited" section. Especially, don't use a graphics

function for embedding tables and figures in text.

Tables should be prepared with a table formatting function.

Each figure should be supplied both on paper and on disk, unless

there is no digital file of a given figure. Except under extraordinary

circumstances, color will not be used in illustrations.

Manuscript Preparation

Organization: Manuscripts must have an abstract, table

of contents, and -- if applicable -- lists of tables, figures, and

acronyms. As much as possible, use traditional scientific

manuscript organization for sections: "Introduction," "Study

Area," "Methods & Materials," "Results," "Discussion" and/

or "Conclusions," "Acknowledgments," and "References Cited."

Style: All NEFSC publication and report series are

obligated to conform to the style contained in the most recent

Northeast Fisheries Science Center

Operations, Management & Information Services Staff

Research Communications Unit

Editorial Office

Manuscript Submission

Authors must submit one paper copy of the double-spaced

manuscript, one disk copy, and original figures (if applicable).

NEFSC authors must include a completely signed-off "NEFSC

Manuscript/Abstract/Webpage Review Form." Non-NEFSC authors who are not federal employees will be required to sign a

"Release of Copyright" form.

Send all materials and address all correspondence to: Jon A.

Gibson (Biological Sciences Editor), NMFS Northeast Fisheries

Science Center, 166 Water Street, Woods Hole, MA 02543-1026.
Research Communications Unit

Northeast Fisheries Science Center

National Marine Fisheries Service, NOAA

166 Water St.

Woods Hole, MA 02543-1026

Publications and Reports

of the

Northeast Fisheries Science Center

The mission of NOAA's National Marine Fisheries Service (NMFS) is "stewardship of living marine resources

for the benefit of the nation through their science-based conservation and management and promotion of the health

of their environment." As the research arm of the NMFS's Northeast Region, the Northeast Fisheries Science

Center (NEFSC) supports the NMFS mission by "conducting ecosystem-based research and assessments of living

marine resources, with a focus on the Northeast Shelf, to promote the recovery and long-term sustainability of these

resources and to generate social and economic opportunities and benefits from their use." Results of NEFSC

research are largely reported in primary scientific media (e.g., anonymously-peer-reviewed scientific journals).

However, to assist itself in providing data, information, and advice to its constituents, the NEFSC occasionally

releases its results in its own media. Currently, there are three such media:

NOAA Technical Memorandum NMFS-NE -- This series is issued irregularly. The series typically includes: data reports of longterm field or lab studies of important species or habitats; synthesis reports for important species or habitats; annual reports of overall

assessment or monitoring programs; manuals describing program-wide surveying or experimental techniques; literature surveys of

important species or habitat topics; proceedings and collected papers of scientific meetings; and indexed and/or annotated bibliographies.

All issues receive internal scientific review and most issues receive technical and copy editing.

Northeast Fisheries Science Center Reference Document -- This series is issued irregularly. The series typically includes: data reports

on field and lab studies; progress reports on experiments, monitoring, and assessments; background papers for, collected abstracts of,

and/or summary reports of scientific meetings; and simple bibliographies. Issues receive internal scientific review, but no technical

or copy editing.

Resource Survey Report (formerly Fishermen's Report) -- This information report is a quick-turnaround report on the distribution

and relative abundance of selected living marine resources as derived from each of the NEFSC's periodic research vessel surveys of the

Northeast's continental shelf. There is no scientific review, nor any technical or copy editing, of this report.

OBTAINING A COPY: To obtain a copy of a NOAA Technical Memorandum NMFS-NE or a Northeast Fisheries Science Center

Reference Document, or to subscribe to the Resource Survey Report, either contact the NEFSC Editorial Office (166 Water St., Woods

Hole, MA 02543-1026; 508-495-2228) or consult the NEFSC webpage on "Reports and Publications" (http://www.nefsc.noaa.gov/

nefsc/publications/).

ANY USE OF TRADE OR BRAND NAMES IN ANY NEFSC PUBLICATION OR REPORT DOES NOT IMPLY ENDORSEMENT.

MEDIA

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