NOAA Technical Memorandum NMFS-NE-186

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:

Silver Hake, Merluccius bilinearis,

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-186

Meredith C. Lock and David B. Packer

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

Essential Fish Habitat Source Document:

Silver Hake, Merluccius bilinearis,

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.
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 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

have begun to be 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 silver hake EFH source

document is based on the original by Wallace W.

Morse, Donna L. Johnson, Peter L. Berrien, and Stuart 

J. Wilk, with a foreword by Jeffrey N. Cross (Morse 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...................................................................................................................................................................6

Habitat Characteristics......................................................................................................................................................................8

Status of the Stocks.........................................................................................................................................................................10

Research Needs..............................................................................................................................................................................11

Acknowledgments...........................................................................................................................................................................11

References Cited ............................................................................................................................................................................11

Tables

Table 1. Mean length at age in silver hake, Merluccius bilinearis....................................................................................................15

Table 2. Observations of silver hake, Merluccius bilinearis, age and length at maturity ....................................................................16

Table 3. Published reports of nearshore and estuarine occurrences of silver hake eggs and larvae from south of Cape Cod..................17

Table 4. Average number of silver hake, Merluccius bilinearis, in Narragansett Bay, per tow by season. .........................................18

Table 5. Distribution and abundance of silver hake, Merluccius bilinearis, in North Atlantic and Mid-Atlantic estuaries......................19

Table 6. Published observations about silver hake: bottom water temperature, depth distributions, and preferences...............................20

Figures

Figure 1. The silver hake, Merluccius bilinearis (Mitchell) (from Goode 1884) ...............................................................................21

Figure 2. Percent of diet by weight of the major prey items in the diet of silver hake .........................................................................22

Figure 3. Overall distribution of silver hake in the northwest Atlantic Ocean during 1975-1994...........................................................23

Figure 4. Distribution and abundance of silver hake eggs collected during NEFSC MARMAP surveys ..............................................24

Figure 5. Distribution and abundance of silver hake larvae collected during NEFSC MARMAP surveys............................................28

Figure 6. Distribution and abundance of juvenile silver hake collected during NEFSC bottom trawl surveys ........................................32

Figure 7. Distribution and abundance of juvenile silver hake in Massachusetts coastal waters............................................................36

Figure 8. Distribution, abundance, and length frequencies of juvenile and adults collected during Narragansett Bay surveys.................38

Figure 9. Distribution and abundance of juvenile and adult silver hake collected in Long Island Sound.................................................41

Figure 10. Monthly log10 length frequencies of juvenile and adult silver hake collected in Long Island Sound..........................................42

Figure 11. Relative abundance catch/tow and percent occurrence for juvenile and adult silver hake in Long Island Sound.....................43

Figure 12. Distribution and abundance of juvenile silver hake collected in the Hudson-Raritan estuary..................................................44

Figure 13. Catch per unit effort for total catch of juveniles/adults in Chesapeake Bay from the VIMS trawl surveys.............................45

Figure 14. Seasonal distribution and abundance of silver hake in Chesapeake Bay from the VIMS trawl surveys..................................46

Figure 15. Distribution and abundance of adult silver hake collected during NEFSC bottom trawl surveys ............................................47

Figure 16. Distribution and abundance of adult silver hake in Massachusetts coastal waters................................................................51

Figure 17. Abundance of silver hake eggs relative to bottom temperature and depth from NEFSC MARMAP surveys.........................53

Figure 18. Abundance of silver hake larvae relative to bottom temperature and depth from NEFSC MARMAP surveys.......................54

Figure 19. Distributions of juveniles relative to bottom temperature, depth, and salinity based on NEFSC trawl surveys.........................55

Figure 20. Distributions of juveniles relative to bottom temperature and depth based on Massachusetts inshore surveys ........................57

Figure 21. Seasonal distributions of juveniles relative to bottom temperature and depth from Narragansett Bay surveys ........................59

Figure 22. Distributions of juveniles relative to bottom temperature, DO, depth, and salinity from Hudson-Raritan trawl surveys............60

Figure 23. Hydrographic preferences for juveniles/adults in Chesapeake Bay from the VIMS trawl surveys ........................................61

Figure 24. Distributions of adults relative to bottom temperature, depth, and salinity based on NEFSC trawl surveys.............................62

Figure 25. Distributions of adults relative to bottom temperature and depth based on Massachusetts inshore surveys ............................64

Figure 26. Seasonal distributions of silver hake adults relative to bottom temperature and depth from Narragansett Bay surveys............66

Figure 27. Trends in NEFSC fall survey data and landings for northern and southern stocks of silver hake ...........................................67

Figure 28. Distribution and abundance of juveniles and adults during low and high abundance periods from NEFSC surveys..................68

Page 1

INTRODUCTION

Silver hake, Merluccius bilinearis (Figure 1), are 

distributed on the continental shelf of the northwest

Atlantic Ocean from the Gulf of St. Lawrence and the 

southern edge of the Grand Banks, Newfoundland,

Canada (Leim and Scott 1966; Brodziak 2001) to Cape 

Fear, North Carolina (Karnella 1973) and perhaps as far 

south as South Carolina (Bolles and Begg 2000). Their 

presence in the deep waters off the Bahamas reported by 

Norman (1939) was probably a misidentification of

Merluccius albidus, the offshore hake. In general, silver 

hake are abundant from Nova Scotia to New Jersey.

Silver hake are slender, fast swimming gadids with 

well-developed gill rakers and eyes, strong teeth, and

pike-like jaws (Garrison and Link 2000). These

demersal fish are often found in dense schools

associated with specific hydrographic conditions, prey 

concentrations, and spawning requirements.

Silver hake are distributed from shallow waters to 

depths greater than 400 m (Dery 1988; Bolles and Begg 

2000). Scotian Shelf silver hake prefer warm bottom 

water, which extends to depths > 120m on the shelf 

(Rikhter et al. 2001).

STOCK STRUCTURE

In U.S. waters, two stocks of silver hake have been 

tentatively identified based on morphometric differences. They are managed separately due to differences in 

exploitation patterns (Garrison and Link 2000). One 

stock ranges from the Gulf of Maine to northern

Georges Bank, while the other stock ranges from

southern Georges Bank to Cape Hatteras. Both can be 

found on Georges Bank during summer months

(Brodziak 2001). 

Numerous studies using a variety of methods,

including morphometrics (Conover et al. 1961; Almeida 

1987), growth patterns on otoliths (Nichy 1969),

serological analyses (Konstantinov and Noskov 1969;

Schenk 1981), seasonal distribution patterns (Anderson 

1974; Almeida 1987), and growth (Helser 1996),

indicate that fish in the Middle Atlantic Bight are distinct 

from fish in the Gulf of Maine. The line dividing these 

two stocks occurs somewhere between Nantucket Shoals 

and the northern edge of Georges Bank. A reevaluation 

of how the stocks are defined has arisen due to the need 

for an efficient means of determining levels of stock 

mixing for fishery assessment and management.

Distributions of the two stocks vary seasonally and

spatially, most likely in response to temperature and

depth (Bolles and Begg 2000). Helser (1996) found that 

silver hake growth rates differed both between and within 

the two stocks, a finding that is inconsistent with the 

stock boundaries currently defined and confounds the 

delineation of the stocks and the degree to which they 

mix. Bolles and Begg (2000) report that some level of 

mixing does occur and is probably due to the wide

migratory patterns of silver hake. The degree to which

morphological differences between silver hake stocks 

are caused by environmental or genetic influences is not 

known.

Although there is uncertainty as to the how the

stocks are defined, it has been proven that there are two 

stocks. Bolles and Begg (2000) confirmed in their study 

that two stocks exist by using whole otolith morphometrics and growth rates. Their study found the northern 

stock grew at a slower rate and had larger otoliths than 

the southern stock. Also, otoliths of the northern stock 

tended to be longer, wider, and greater in area and

perimeter than similar-sized fish from the southern

stock. This was probably due to the fact that the northern 

fish were older and had more time to accumulate otolith 

material. Although no statistical analyses were used to 

test her observations, Dery (1988) observed that silver 

hake otoliths from the northern stock were narrower and 

thicker in cross-section than those of the southern stock. 

Calculating linear discriminate functions of otolith 

morphometric characteristics for 1-year old silver hake 

on a yearly basis, differentiated by sex, should provide a 

level of discrimination not yet seen for silver hake

stocks in U.S. waters of the northwest Atlantic and may 

assist in estimating levels of stock mixing. Whole

otolith morphometrics in combination with image

processing and discriminant function analysis can

provide successful identification of stocks that is

essential for assessment and management purposes

(Bolles and Begg 2000).

LIFE HISTORY

EGGS

The eggs are pelagic, 0.88-0.95 mm in diameter, 

drift with the prevailing currents, and hatch in about two 

days at 20°C.

LARVAE

Newly hatched larvae are pelagic and are about 2.6-

3.5 mm long (Fahay 1974, Steves and Cowen 2000).

Steves and Cowen (2000) estimate larval duration in the 

New York Bight at 34.5 days; the larvae are an important 

constituent of the summer ichthyoplankton. Jeffrey and 

Taggart (2000) estimate a pelagic existence at 3-5

months for the Scotian Shelf. Their study also provides 

evidence for larvae inhabiting the upper mixed layer of 

the Scotian Shelf. When hake reach 17-20 mm long, the 

larvae descend to the bottom as juveniles. Steves and 
Page 2

Cowen (2000) found larval growth to be slower prior to 

settlement, indicating that growth potential might be

increased by settlement.

JUVENILES AND ADULTS

Steves et al. (2000) found that age-0 silver hake 

(average length 28 mm SL) settled on the outer shelf of 

the New York Bight mostly during summer and fall,

where inferred growth rates were about 15 mm per 

month; Steves and Cowen (2000) suggest that silver hake 

experience higher abundance and growth rates when

settlement on the shelf occurs in September rather than 

in October. Steves and Cowen (2000) also found a

minimum size of 12.9 mm in samples collected by a 

beam trawl with a 4 mm mesh size, suggesting that silver 

hake settle to the bottom at smaller sizes and sooner than 

originally thought by Fahay (1974), who reported a

minimum size of 17-20 mm in otter trawl collections 

that used a 6.4 mm mesh.

Juvenile and adult silver hake migrate to deeper

waters of the continental shelf as water temperatures 

decline in the autumn and return to shallow waters in 

spring and summer to spawn. Major spawning areas 

include the coastal Gulf of Maine, southern and

southeastern Georges Bank, and the southern New

England area south of Martha’s Vineyard. Vinnichenko 

et al. (2001) found that on the Scotian Shelf silver hake 

were distributed to depths of 150-250 m during spring, 

moving to depths of 100-150 m during the spawning 

season. In July, they migrated along the slope to 250 m.

According to Rikhter et al. (2001), long term studies 

have shown that such life-cycle stages as over wintering 

and feeding occur in near bottom slope water. Older 

hake prefer the warmer waters of the shelf slope and 

deep-water shelf area.

Silver hake are relatively fast growing, reaching

sexual maturity at 2-3 years (20-35 cm), and live a

maximum of 14 years, although in recent years fish older 

than 6 years are rare (Brodziak 2001).

REPRODUCTION

Silver hake eggs and larvae have been collected in all 

months on the continental shelf in U.S. waters, although 

the onset of spawning varies regionally (Bigelow and

Schroeder 1953; Marak and Colton 1961; Sauskan and 

Serebryakov 1968; Fahey 1974; Morse et al. 1987;

Waldron 1988; Berrien and Sibunka 1999). Silver hake 

spawn over a wide range of temperatures and depths.

Rikhter et al. (2001) found Scotian Shelf silver hake 

preferred warm, shallow waters (> 10oC) at depths of 30-

40 m for mass spawning.

Spawning begins in January along the shelf and slope 

in the Middle Atlantic Bight. During May, spawning

proceeds north and east to Georges Bank. By June

spawning spreads into the Gulf of Maine and continues to 

be centered on Georges Bank through summer. In

October, spawning is centered in southern New England 

and by December is observed again along the shelf and 

slope in the Middle Atlantic Bight. Peak spawning

occurs May to June in the southern stock and July to 

August in the northern stock (Brodziak 2001). Over the 

U.S. continental shelf, significant numbers of eggs are 

produced beginning in May. Numbers increase through 

August and decline rapidly during September and October 

(Berrien and Sibunka 1999).

According to Koeller et al. (1989), spawning on the 

Scotian Shelf occurs from July to October. Rikhter et

al. (2001) found similar results; spawning begins by the 

end of June, approaches a peak in July-August, and

finishes in September. They also found summer current 

patterns define spawning conditions for silver hake of the 

Scotian Shelf.

Female silver hake are asynchronous spawners that 

produce and release several batches of eggs during the 

spawning season (Sauskan and Serebryakov 1968). Up to 

3 spawning events may occur within one season (Steves 

and Cowen 2000).

The primary spawning grounds most likely coincide 

with concentrations of ripe adults and newly spawned

eggs. These grounds occur between Cape Cod,

Massachusetts, and Montauk Point, New York (Fahay

1974), on the southern and southeastern slope of

Georges Bank (Sauskan 1964) and the area north of Cape 

cod to Cape Ann, Massachusetts (Bigelow and Schroeder 

1953).

AGE AND GROWTH

Studies of age and growth of silver hake in U.S.

waters began with Schaefer (1960). Nichy (1969) aged

juvenile fish and conducted an age validation study. In an 

investigation of the effect of stock size on growth of 

various age classes in the northern Georges Bank-Gulf of 

Maine stock, Ross and Almeida (1986) and Penntila et

al. (1989) used von Bertalanffy growth functions to 

describe growth of the northern and southern stocks.

Although Almeida (1978) found faster growth and

greater size in the northern stock compared to the

southern stock, Bolles and Begg (2000) reported slower 

growth for the northern stock. The authors also found 

northern fish to be older. 

Helser (1996) made a detailed analysis of the growth 

of silver hake in four areas of the U.S. continental shelf 

during 1975-1980, 1982-1987, and 1988-1992. He 

found significant differences in growth between the

Middle Atlantic and southern Georges Bank in all three 

periods, between northern Georges Bank and the Gulf of 
Page 3

Maine during 1975-1980 and 1982-1987 and between 

northern and southern Georges Bank during 1982-1987.

Growth in the Gulf of Maine was slow on average, but the 

fish attained the large asymptotic length (k = 0.33, L∞ = 

47 cm) compared to the Middle Atlantic Bight (k = 0.51, 

L∞ = 43 cm). Growth on Georges Bank was intermediate.

Growth analyses on silver hake were conducted

based on National Marine Fisheries Service (NMFS)

Northeast Fisheries Science Center (NEFSC) survey

size-at-age data for the spring and fall surveys. (Brodziak

et al. 2001). Growth curves were computed for the early 

1970s and 1990s to investigate time periods not covered

in Helser’s (1996) study. Results showed a substantial 

change in growth between the early 1970s and the 1990s 

for the northern and southern stock areas and combined 

stock area. During the early 1970s the average silver 

hake growth pattern conformed to a von Bertalanffy

model, while during the 1990s the average growth pattern 

was nearly linear with age (Brodziak et al. 2001).

Females grow faster and live longer than males.

According to Waldron (1992), the majority of the silver 

hake population after age 5 consists of females,

suggesting that mortality on males was high due to

cannibalism, predation, or other natural influences.

Reported maximum lengths and ages are 34 cm and 6 

years for males, and 60-64 cm and 12 years for females 

(Bigelow and Schroeder 1953; Nichy 1969). Dery

(1988) reported maximum lengths and ages of 42 cm and 

10 years for males, and 67 cm and 12 years for females.

Interestingly, maximum lengths of silver hake collected 

during the NEFSC bottom trawl survey are 78 cm in

spring and 76 cm in autumn. Table 1 lists mean lengths at 

age to indicate relative size-at-age for 1988-1992 for 

Gulf of Maine, Middle Atlantic, northern and southern 

Georges Bank. 

Silver hake median length at maturity (i.e., 50%

mature) has declined in recent years. Rikhter et al.

(2001) report Scotian Shelf males reaching 50%

maturity at 24 cm and females at 27 cm. Table 2 lists 

observations of silver hake age and length at maturity.

FOOD HABITS

Silver hake are an important predator species on the 

continental shelf of the Northwest Atlantic [Garrison and 

Link (2000); see also Tsou and Collie (2001a, b) for 

Georges Bank]. Their dominant biomass and high prey 

consumption affect population dynamics and contribute 

heavily to the regulation of this ecosystem (Bowman

1984; Garrison and Link 2000). These semi-pelagic

predators are nocturnal feeders (Koeller et al. 1989) 

with a predictable diet consisting of fish (80.0%),

crustaceans (10.2%), and squid (9.2%) (Bowman 1983).

The diet of young silver hake consists of euphausiids,

shrimp, amphipods, and decapods (Bowman 1984;

Waldron 1992; Sigaev 1995; Steves and Cowen 2000).

All silver hake are ravenous piscivores that feed on

smaller hake and other schooling fishes such as young 

herring, mackerel, menhaden, alewives, sand lance, or 

silversides (Sigaev 1995; Link and Garrison 2002a) as 

well as crustaceans and squids (Schaefer 1960;

Domanevsky and Nozdrin 1963; Dexter 1969; Edwards 

and Bowman 1979; Bowman 1984; Helser et al. 1995; 

Sigaev 1995; Garrison and Link 2000).

Variations in diet are dependent upon size, sex,

season, migration, spawning, and age (Schaefer 1960;

Domanevsky and Nozdrin 1963; Dexter 1969; Edwards 

and Bowman 1979; Bowman 1984; Helser et al.; 1995; 

Sigaev 1995; Garrison and Link 2000; Vinogradov 2000;

Link and Garrison 2002a, b). Garrison and Link (2000) 

concluded that size has the most influence on diet. Silver 

hake larvae feed on planktonic organisms such as

copepod larvae and younger copepodites. Scotian Shelf 

fish that are 10-40 cm feed mainly on euphausiids, which 

are an essential part of the hake diet and, according to 

Vinogradov (2000), important in determining the success 

of the individual life stages.

Migration results in seasonal and yearly variations in 

silver hake diet (Garrison and Link 2000). According to 

Waldron (1992), silver hake diet changes from fish in the 

spring and autumn to fish, crustaceans, and mollusks

during the summer. Small fish 26-55 mm in length were 

observed to consume more food in October and

November, while larger fish 86-115 mm experience

increased food consumption by January (Vinogradov

2000). Vinnichenko et al. (2001) found feeding was 

most active during the summer on the Scotian Shelf, with 

euphausiids and Themisto being the dominant prey.

Other prey items include shrimp, fishes, crabs, and

squids. There is, however, no rapid shift in the diet of 

juveniles that can be associated with ontogenetic vertical 

migration or the critical life history change (Koeller et

al. 1989).

Rikhter et al. (2001) observed increases in pelagic 

silver hake catches during zooplankton ascent at night and 

descent in the morning. This leads to the conclusion that 

diurnal vertical migrations of silver hake are related to 

diurnal vertical migrations of plankton.

Spawning also influences feeding behavior. Bowman

(1984) found that silver hake stomachs contained a

greater amount of food before and after spawning.

During spawning, about nine times less food was present 

in hake stomachs compared to the stomachs of other 

fish. Furthermore, this study determined that depth

affects the type and quantity of food consumed by silver 

hake. (i.e.; fish sampled at deeper depths have less food 

in their stomachs). 

Bowman (1984) determined that male diets have the 

largest percentage of crustaceans, while female diets 

have the largest percentage of fish and squid. According 

to Waldron (1992), crustaceans constitute 48% of the 
Page 4

total weight of all prey in the diet of male silver hake.

Fish consumption was half that of crustaceans and

consisted of mainly myctophids and other silver hake.

Crustaceans ranked highest in frequency of occurrence in 

the diet of female silver hake; however, weight

contribution was less for males. Fish prey represented 

53% of the female silver hake diet. Females generally 

consumed twice the amount by weight of fish prey as 

males. Waldron believes the differences noted between 

the sexes in prey selection are associated with size.

Because females are larger, hence faster, they are able to 

consume larger, highly mobile prey such as fish and

squid. Males on the other hand tend to be smaller at age 

and therefore concentrate much of their feeding activity 

on crustaceans, which are abundant and easily obtained.

After the age of 5, females constitute over 70% of the 

silver hake population, so it is expected that the diet of 

older silver hake will consist of larger prey.

Age-zero silver hake may compete with or prey upon 

the early life history stages of other commercially

important species (Koeller et al. 1989; Waldron 1992).

The availability of suitable foods is more critical during 

the juvenile stage than the larval stage and may affect

yearclass strength (Koeller et al. 1989). Early juvenile 

stage survival is related to feeding conditions and water 

temperature, especially during the thermal minimum

(Koeller et al. 1989; Sigaev 1995; Vinogradov 2000).

Sigaev (1995) found silver hake migrated along the warm 

side of the “shelf/slope” in search of food and were 

observed to avoid colder areas. 

Diet also differs between the northern and southern 

stocks. The northern stock primarily consumes

euphausiids, Atlantic herring, silver hake, and other fish, 

while the southern stock consumes crangonid shrimp,

squids, cephalopods, and sand lance (Garrison and Link 

2000). Illex sp. and Loligo sp. of squid are found in the 

diet of silver hake that live in southern habitats (Garrison 

and Link 2000).

Cannibalism is common among silver hake (Koeller 

et al. 1989; Garrison and Link 2000; Tsou and Collie 

2001a, b; Link and Garrison 2002a). Conspecific

juveniles contribute more than 10% to the adult diet and 

more than 20% to the total diet (Garrison and Link

2000). According to Tsou and Collie (2001a),

cannibalism accounted for more than 50% of predation 

rates on Georges Bank. Cannibalism is most common in

adult silver hake (Garrison and Link 2002a), although it 

can occur at the early juvenile stage (Koeller et al. 1989, 

Vinogradov 2000). This interaction can be extremely

intense, with the potential to limit production (Koeller et

al. 1989) and regulate the species (Waldron 1992).

According to Vinogradov (2000), cannibalism of pelagic 

young hake seems to increase in years with unfavorable 

food conditions. For example, when euphausiids are 

scarce from October to January, cannibalism is

significant, contributing 100% to some individual’s

diets.

Bowman (1984) studied samples collected from 8 

NEFSC Marine Resources Monitoring, Assessment, and 

Prediction (MARMAP) bottom trawl surveys conducted 

by NMFS between March 1973 and November 1976.

These surveys were concentrated in the Middle Atlantic, 

Southern New England, and Georges Bank. It was found 

that 80% of the diet by weight was fish, 10.2%

crustaceans, and 9.2% squid. Euphausiids consisted

mainly of Meganyctiphanes norvegica and Euphausia.

Decapod groups included Crangonidae (Crangon

septemspinosa and Sclerocrangon boreas), Pandalidae 

(Dichelopandalus leptocerus and Pandulus borealis),

and Pasiphaedae (Pasiphaea multidentata), as well as 

other unidentifiable decapods which were mostly shrimp.

Amphipods present in the stomachs of silver hake were 

mainly from the Ampeliscidae (Ampelisca agaxxize, A. 

spinipes, A. vadorum, and Byblis serrata), Oedicerotidae (Manoculodes edwardsi and M. intermedius), and 

Hyperiidea families. Other crustacean groups included 

the Mysidacea, Cumacea, and Copepoda. Additional

stomach contents that were identified include

cephalopods (Loligo pealei and Rossia), Polychaeta, and 

miscellaneous organisms such as Echinodermata, and

Chaetognatha. The study also found that silver hake

measuring less than 20 cm fork length (FL) ate mostly 

crustaceans, while those that were greater than 20 cm FL 

ate mostly fish and squid. Silver hake 3-5 cm FL

contained the largest percentage of smaller crustacean 

forms, such as amphipods and copepods. Fish 6-20 cm 

FL ate decapods, euphausiids, and mysids.

Bowman (1984) found Cephalopoda to be another 

important prey group of silver hake. Fish in Southern 

New England ate the largest quantities of squid, 13.7% by

weight. Squid comprised 6.7% of the silver hake diet of 

Georges Bank and 4.3% of the diet for Middle Atlantic. 

The percentage of euphausiids and squid in the diet tends 

to increase at deeper bottom depths, while the percent 

weight of fish in the diet shows a corresponding

decrease. The trend is that fish sampled at deeper depths 

will have less food on average in their stomachs.

Availability of prey is probably one of the most

important factors in determining what type and how much 

food silver hake eat.

Waldron (1992) conducted food studies on silver 

hake age groups 1-9 on the Scotian shelf between 1981-

1986. The author found silver hake ages 1-3 primarily 

fed on invertebrates, while fish older than 3 were

piscivorous. Fish comprise more than 50% of the adult 

silver hake diet. It is believed that this large fish

consumption influences population dynamics and may be 

a limiting factor to the recovery of overexploited stocks 

(Garrison and Link 2000). 

The most frequently occurring prey items were

crustaceans, especially the euphausiid Meganyctiphanes

norvegica. By weight, fish constituted 48% of the diet.

Cannibalism was a significant constituent, accounting for 

25%, while unidentifiable fish accounted for 15% of the 
Page 5

diet

There was a greater consumption of fish and mollusks and a decrease in the presence of crustaceans in the 

diet of age group 3. Sea cucumbers (Holothuroidea) 

were present in the diet of this age group, indicating

vertical migration. The diet of silver hake less than four 

years of age primarily consisted of invertebrates, with 

fish and larger prey entering the diet after age 4. Age 

group 4 also showed a decrease in crustaceans in the diet 

and an increase in fish and mollusk consumption.

Cannibalism was observed in this age group. For age 

group 6, fish (especially silver hake) was the single 

major prey species of total prey consumed. Illex

illecebrosus was the major invertebrate prey item. Fish 

dominated age groups 7-9, with crustaceans not as

prevalent in the diet of age group 7 and rarely seen in 

ages 8 and up. It was determined that crustaceans,

particularly M. norvegica, were an important component 

in the diet for all ages. Their relative contribution by 

weight was far greater in ages 1-3. Generally, silver hake 

ages 4 and older preferred fish and mollusks as prey. 

Koeller et al. (1989) also conducted diet studies on 

the Scotian Shelf. In October 1980, studies found that 

calanoids were the dominant prey items in fish up to 40 

mm. The diet of fish larger than 40 mm consisted of 

larger prey such as amphipods, mysids, euphausiids, and 

calanoids. Cannibalism was evident in fish as small as 

22-25 mm, and comprised 25% of the diet by weight of 

fish greater than 46 mm. The authors also found

evidence for changes in feeding associated with depth. In 

October of 1980, Metridia lucens and Candacia armata

increased in importance as food items for fish caught in 

shallow depth zones. This indicated that silver hake were 

feeding near the bottom, thus they must be distributed 

near the bottom.

The NEFSC has conducted quantitative food-habits

sampling in seasonal surveys from 1973 to the present.

The 1973-2001 NEFSC food habits database for silver 

hake [Figure 2; see Link and Almeida (2000) for details] 

generally confirms previous studies. Several other

studies, such as Garrison and Link (2000) and Tsou and 

Collie (2001a, b) use the same database, although the

years differ. Garrison and Link (2000) found that small 

(< 20 cm) silver hake consumed large amounts of

euphausiids, pandalids, and other shrimp species. The 

diet of medium sized (20-50 cm) silver hake consisted 

of fishes, squids, and shrimp taxa. The diet of large (> 50 

cm) silver hake consisted of over 50% fish, including 

Atlantic herring, clupeids, Atlantic mackerel, and other 

scombrids. A higher proportion of cephalopods, sand 

lance, and amphipods are present in the diets of silver 

hake that occupy southern habitats (Southern Atlantic 

Bight, Mid- Atlantic Bight, Southern New England).

Silver hake of northern regions (Gulf of Maine, Georges 

Bank, Scotian Shelf) prey more heavily on pelagic fishes, 

euphausiids, and pandalid shrimps. For example,

euphausiids make up 25% of the diet for silver hake of 

the Gulf of Maine and 7.2% for the Middle Atlantic 

Bight. Atlantic herring comprise 0.2% of the Middle 

Atlantic Bight diet and 12.9% of the Georges Bank diet.

Squids (Loligo sp. and cephalopods), sand lance, and

butterfish accounted for 5-10% of silver hake diets in the 

Middle Atlantic Bight and Southern New England

compared to less than 1% in the Gulf of Maine and

Southwestern Nova Scotian Shelf regions. Sissenwine et

al. (1984) and Link and Garrison (2002a) also confirm 

that silver hake is a major piscivore on Georges Bank, 

with an ontogenetic shift in diet towards increased

piscivory (Link and Garrison 2002a).

Tsou and Collie (2001a) used the NMFS food-habits

database to identify trophic relationships for silver hake 

on Georges Bank for years 1978-1992. Based on the 

NEFSC survey database, silver hake ate the largest prey 

and had the widest range of prey preference relative to its 

body weight. It was discovered that more fish were 

consumed in the autumn with herring being the major 

prey item during that season. Cannibalism was observed 

to be especially important to silver hake in the spring.

[See also Tsou and Collie (2001b)]. This may be related 

to the smaller preferred habitat range during this season, 

as the distribution of the adults and juveniles overlap

more during this time, providing a greater opportunity for 

cannibalism (J. Brodziak, NOAA/NMFS/NEFSC, Woods 

Hole Laboratory, Woods Hole, MA, pers. comm.).

PREDATORS AND SPECIES 

ASSOCIATIONS

Silver hake are an important prey for offshore,

silver, white, red, and spotted hakes (e.g., Tsou and Collie 

2001b). Demersal gadids, pelagic species, and squids 

also feed upon small hakes (Garrison and Link 2000;

Link and Garrison 2002a, b). They are an important food 

item for fish 76-90 mm, but do not contribute to the diet 

of fish less than 57 mm (Koeller et al. 1989). Larger

cod (> 30 cm) consume more silver hake than smaller

cod, and silver hake are a large component of cod diet in 

northern areas (Link and Garrison 2002a, b). Tsou and 

Collie (2001a) showed that silver hake was the most 

important prey species in the Georges Bank fish

community and was preyed upon by all predators, but

especially by cod and other silver hake, which accounted 

for 20-50% and 30-80% of predation, respectively [see 

also Tsou and Collie (2001b)]. Silver hake is a

significant prey item for elasmobranchs, in particular 

spiny dogfish, but also skates such as winter skate (Tsou 

and Collie 2001a; Link et al. 2002). Gannon et al.

(1998) examined stomach contents of harbor porpoises 

and found that silver hake was a common prey item.
Page 6

GEOGRAPHICAL DISTRIBUTION

The overall distribution of silver hake is from the 

Gulf of St. Lawrence to Cape Hatteras (Figure 3). The 

areas of highest abundance are the southern edge of the 

Grand Bank, the Scotian Shelf, the Gulf of Maine,

Georges Bank, and the Middle Atlantic Bight off Long 

Island.

EGGS

Silver hake eggs were found throughout the area

surveyed during the NEFSC MARMAP ichthyoplankton 

surveys (Figure 4). They were most abundant in the 

deeper parts of Georges Bank (> 60 m) and the shelf off 

southern New England. Eggs were captured in all months 

of the year. From January to March, eggs occurred in 

small numbers in the deep waters of the Middle Atlantic 

Bight. By April, the occurrence of eggs extended

eastward along the southern edge of Georges Bank and 

the total number of eggs increased slightly. During May

and June the catches of eggs extended into the shelf and 

into nearshore waters of the Middle Atlantic Bight and 

southern New England areas. Some eggs were captured 

in the western part of the Gulf of Maine. By July and 

August the center of abundance had shifted east onto 

Georges Bank with southern New England and the Gulf 

of Maine continuing to show some catches of eggs. In 

September and October the occurrences of eggs began to 

decline with centers of abundance still on Georges Bank 

and extending into southern New England. Few eggs 

were captured in November or December, but those that 

were occurred in deeper waters of the Middle Atlantic 

Bight.

LARVAE

The individual survey distributions of silver hake

larvae from Cape Hatteras, North Carolina to Nova

Scotia based on 50 ichthyoplankton surveys in the

NEFSC MARMAP series (1977-1984), reveal

considerable year-to-year differences in the temporal 

and spatial patterns of abundance. Centers of abundance 

in July-September occurred on Georges Bank and in

southern New England in 1977, 1978, 1982, and 1983.

In 1981 few larvae were found anywhere in the survey 

area. Only in 1979 and 1980 were significant numbers 

of larvae encountered in the Gulf of Maine (Morse et al.

1987).

The cumulative distribution and abundance of silver 

hake larvae from all NEFSC MARMAP surveys is shown 

in Figure 5. The overall pattern of distribution is similar 

to the distribution of eggs, wherein the center of

abundance is on Georges Bank and a secondary center is 

in the southern New England area. Few larvae were 

captured from January through March and none in April, 

but those that were captured occurred in the Middle 

Atlantic Bight (Figure 5). The low catches reflect the 

relatively low egg production of silver hake during the 

early months of the year. During May and June, larvae 

were abundant in depths from 60-130 m from off

Virginia to the southwestern part of Georges Bank. The 

peak months of larval abundance were July-September

and the centers of abundance were in southern New

England and on Georges Bank. Distribution of larvae 

during October to December had shifted to the west from 

Georges Bank to southern New England and the Middle 

Atlantic Bight, and abundance had dropped following the 

decrease in egg production during the late autumn and 

early winter. Table 3 lists the published reports of the 

nearshore and estuarine occurrences of silver hake eggs 

and larvae south of Cape Cod.

JUVENILES

NEFSC bottom trawl surveys [see Reid et al. (1999) 

for details] captured juvenile (< 22 cm TL) silver hake 

year-round and show some of the seasonal onshore/offshore movements mentioned above. (Figure 6;

note that winter and summer distributions are presented 

as presence/absence data, precluding a discussion of

abundances.) In winter, juveniles were found across the 

shelf in the Middle Atlantic Bight and southern New

England areas, along the southern and northern edges of 

Georges Bank, and scattered throughout the Gulf of

Maine. In spring, they were found throughout the survey 

area, but tended to avoid the shallowest part of Georges 

Bank. Concentrations occurred in relatively shallow

waters in southern New England and in most of the

southern and western parts of the Gulf of Maine. In

summer, juveniles were found across the shelf in the

Middle Atlantic Bight and southern New England areas 

and along the southern and northern edges of Georges 

Bank, with concentrations in the Gulf of Maine. By

autumn, the distribution of juveniles again covered the 

shelf. Concentrations occurred in nearshore waters off 

New Jersey and Long Island, south of Rhode Island, on 

Georges Bank, and along the coast of Massachusetts and 

Maine.

Silver hake juveniles ( 22 cm TL) were caught 

throughout the Massachusetts trawl survey area [see Reid 

et al. (1999) for details] in spring and autumn, with

concentrations off Cape Ann, in Cape Cod Bay, and south 

of Martha’s Vineyard. Light catches were made in

Vineyard Sound and Buzzards Bay (Figure 7).

Juvenile silver hake were captured throughout

Narragansett Bay in all seasons with the highest average 

catches of juveniles (~3 hake/tow) occurring in summer 

(Table 4; Figure 8). In general, low numbers of hake 
Page 7

occurred throughout the Bay, with the highest average 

catches occurring at the ocean station 1. Seasonal length 

frequencies indicate that juveniles and adults occurred in 

similar proportions during all seasons except summer, 

when juveniles dominated the catches.

The distributions and abundances of both juveniles 

and adults in Long Island Sound (Figures 9-11) as

described by Gottschall et al. (2000) will be discussed in 

the Habitat Characteristics section. Silver hake sampled 

in the survey ranged from 8-38 cm (Figure 10) and were 

commonly observed in all months, ranging from 27.6% 

occurrence in September to 72.2% in June (Figure 11D).

Abundance peaked in June, dropped in August and

September, and increased again in October and

November (Figure 11A).

Surveys of the Hudson-Raritan estuary show that 

juvenile silver hake were found throughout most of the 

area but were concentrated near the ocean (Figure 12).

The highest catches occurred in autumn (Oct.-Dec.). No 

juveniles were captured in summer (July-Aug.).

The 1988-1999 Virginia Institute of Marine Science 

(VIMS) trawl surveys of Chesapeake Bay shows that 

silver hake abundance increases as spring progress,

peaking in April and May (Figure 13 [both juveniles and 

adults]; Geer [2002]). Catches were concentrated in the 

Bay proper in the deeper waters of the channels (Figure 

14; Geer [2002]).

ADULTS

NEFSC bottom trawl surveys [Figure 15;see Reid et

al. (1999) for details] captured adult (> 22 cm TL) silver

hake year round and show some of the seasonal

onshore/offshore movements above. (Note that winter 

and summer distributions are presented as presence/absence data, precluding a discussion of

abundances.) In winter, adults were distributed across the 

shelf in the northern Middle Atlantic Bight and southern 

New England areas, along the southern and northern

edges of Georges Bank, and scattered throughout the 

Gulf of Maine. In spring they were found throughout the 

survey area, but tended to avoid the shallowest parts of 

the Middle Atlantic Bight and Georges Bank.

Concentrations occurred in relatively deep waters of the 

Middle Atlantic, southern New England, along the

southern and northern edges of Georges Bank, and in the 

western part of the Gulf of Maine. In summer, adults 

were found across the shelf in the Middle Atlantic Bight 

and southern New England areas and along the southern 

and northern edges of Georges Bank. By autumn, the 

distribution of adults again covered the shelf except for 

the southwestern part of the Middle Atlantic Bight and in 

the center of Georges Bank. Concentrations occurred

south of Rhode Island, on the northern edge of Georges 

Bank, and most of the Gulf of Maine.

Silver hake adults (> 22 cm TL) were caught

throughout the Massachusetts trawl survey area [Figure

16; see Reid et al. (1999) for details] in spring and 

autumn, with concentrations off Cape Ann and in Cape 

Cod Bay. In spring, there were concentrations south of 

Martha’s Vineyard and light catches made in Vineyard 

Sound and Buzzards Bay. In autumn, light catches were 

made south of Martha’s Vineyard.

Results of the Rhode Island trawl survey showed

that, in general, low numbers of hake occurred

throughout Narragansett Bay and the highest average

catches were at the ocean station 1 (Figure 8). Adult 

hakes occurred throughout the bay in small numbers in 

all seasons. Seasonal length frequencies indicate that 

juveniles and adults occurred in similar proportions

during all seasons except summer, when juveniles

dominated the catches.

The distribution and abundance of both adults and 

juveniles in Long Island Sound were discussed previously 

(Figures 9-11; Gottschall et al. [2000]).

The Hudson-Raritan estuary trawl survey caught a

total of just one adult silver hake in January 1995.

The seasonal distribution and abundance of both

adults and juveniles in Chesapeake Bay were discussed 

previously (Figures 13 and 14).

Jury et al. (1994) compiled summaries of the

occurrence and relative abundance of eggs, larvae,

juveniles and adults in estuaries north of Cape Cod.

Stone et al. (1994) compiled similar data for Cape Cod 

to Cape Hatteras (Table 5).

MIGRATION

Silver hake migration is triggered by seasonal

changes in water temperature. In the spring they begin to 

move towards shallow and warmer water, where spawning 

occurs during late spring and early summer (Brodziak 

2001; Northeast Fisheries Science Center 2002). They

return to deeper water in autumn. During winter, fish in 

the northern stock move to deep basins of the Gulf of 

Maine, while fish in the southern stock move to outer 

continental shelf and slope waters (Brodziak 2001).

During the spring and summer, silver hake move into 

nearshore waters in the Gulf of Maine, to the northern 

edge of Georges Bank, and northward in the Middle

Atlantic Bight. By autumn, they return again to the

deeper basins in the Gulf and along the continental slope.

Juveniles follow distribution and movement patterns

similar to adult silver hake; however centers of

abundance for juveniles occur in shallower waters such 

as inshore along the Middle Atlantic and on the shoals of 

Georges Bank.

Older or larger fish were found to migrate into

broader areas of the shelf, suggesting that nursery

habitats are less restrictive than settlement areas. This 
Page 8

may be explained by two non-exclusive mechanisms:

inshore migration of juveniles, and increased mortality 

offshore (Steves and Cowen 2000). However, also note 

that there is some suggestion that there have been

changes in the spatial distribution of silver hake by stock 

area, as is discussed in Brodziak et al. (2001).

The Koeller et al. (1989) study supports earlier 

trawl data that discovered the existence of diel and

ontogenetic migratory behavior of larvae and juveniles.

This study also found that shortly after metamorphosis, 

silver hake begin a strong diel vertical migration during 

which they are near or on the bottom by day and

throughout the water column at night. Bowman and

Bowman (1980) also found this to be true in adults. As

stated in the diet section, Sigaev (1995) observed

aggregations of silver hake migrated along the warm side 

of the “shelf/slope” hydrological front in search of food 

and Rikhter et al. (2001) found that diurnal vertical 

migrations of silver hake are related to diurnal vertical 

migrations of plankton.

HABITAT CHARACTERISTICS

EGGS

Data from the NEFSC MARMAP ichthyoplankton 

survey was used to determine the relationships between 

bottom depth and water temperature in the upper 15 m 

and silver hake egg abundance (Figure 17). Eggs

occurred in relatively deeper water than the stations

sampled. The bottom depths where eggs were captured 

ranged from 10-1250 m, however most eggs were

collected between 50-150 m. A shift to shallower shelf 

waters during late spring is evident (Figure 17); the 

average depth of egg occurrences declined from about 

100 m in spring to about 60 m in summer.

The percent frequencies of stations sampled show an 

expected annual cycle in water temperatures (Figure 17).

The occurrences of eggs show a similar cycle. During 

March and April when temperatures are coldest, silver 

hake eggs were found at 5-12°C, the coldest temperatures of the year. As the water warmed in the spring, the 

occurrences of eggs shifted to warmer waters until

summer, when eggs were found mostly between 13 and 

20°C. During autumn the waters began to cool and egg 

occurrences shifted to cooler temperatures of 10-15°C.

Peak abundance of eggs occurred from June to

September when temperatures were 11-17°C. The large 

bar in June at 21°C reflects an unusually large catch of 

eggs (18,908 eggs/10m2

).

The results from the NEFSC MARMAP survey

support published observations of depth and temperature 

occurrences of silver hake eggs (Bigelow and Schroeder 

1953; Fahay 1974; Waldron 1988).

In the Middle Atlantic Bight, newly spawned eggs 

were collected at surface water temperatures between 

13°C and 22°C (Fahey 1974). In the Gulf of Maine, 

Bigelow and Schroeder (1953) reported that spawning 

temperatures ranged from 5°C to 13°C.

LARVAE

The relationships of bottom depth and water

temperature to the abundance of silver hake larvae from 

the NEFSC MARMAP survey are shown in Figure 18.

Larvae occurred in shallower water than eggs and in

relatively deeper water than the overall depths of stations 

sampled. The bottom depths where larvae were captured 

ranged from 10-1250 m, however most occurred

between 50-130 m. The depths of larvae occurrence 

remained stable throughout most of the year, but a shift 

to slightly deeper waters occurred during May and June.

The occurrences of larvae in relation to water

temperature showed that temperature preference varied 

in response to the annual warming and cooling cycle 

(Figure 18). During the months of February and March 

when temperatures are coldest, larvae were found in the 

coldest water of the year, with temperatures ranging from 

5-12°C. As the water warmed in the spring, the

occurrences of larvae shifted to warmer waters until

summer when they were found mostly between 10-16°C.

During autumn, the waters began to cool, but larvae

remained in warmer waters 10-16°C. Peak abundance of

larvae occurred from July to October. During these 

months most larvae were found in temperatures of 11-

16°C.

JUVENILES

Silver hake juveniles and adults are found over wide 

temperature and depth ranges in U.S. continental shelf 

waters (Table 6). The spring and fall distributions of 

juvenile silver hake relative to bottom water temperature,

depth, and salinity based on 1963-2002 NEFSC bottom 

trawl surveys from the Gulf of Maine to Cape Hatteras 

are shown in Figure 19. In spring, they were found in

waters between 2-16oC, with the majority at about 4-8oC.

During that season they were found over a depth range of 

1-400 m. Juveniles were found at salinities between 30-

36 ppt, with most between 33-34 ppt. During autumn, 

juvenile silver hake were found over a temperature range 

of 4-21°C, with most caught roughly between 6-13°C.

During this time, they were found over depths ranging

from 1-400 m. They were found at salinities ranging 

from about 32-36 ppt, with the majority between 33-34

ppt.

The spring and autumn distributions of juvenile silver 

hake in Massachusetts coastal waters relative to bottom 

water temperature and depth based on 1978-2002
Page 9

Massachusetts inshore trawl surveys are shown in Figure 

20. During the spring, juveniles were found in waters

ranging from 1-13°C with the majority spread between 4-

6oC. Their depth range was from 11-85 m, with the 

majority between 41-60 m. In the autumn they were 

found in temperatures ranging from 4-18oC, with most 

spread between 6-10oC. Juveniles were found over a 

depth range of 11-85 m, with the highest percentages 

found between 41-60 m.

The seasonal distributions of juvenile silver hake 

relative to bottom water temperature and depth based on 

1990-1996 Rhode Island Narragansett Bay trawl surveys 

are shown in Figure 21. In the winter they were found at 

temperatures ranging from 3-8oC, with most at about 

7oC. In the spring they were found in waters ranging 

from approximately 2-14oC, with the majority spread

between 6-12oC. During the summer, juveniles where

found at temperatures ranging from 10-18oC, with most 

at about 10oC. In the autumn they were found in waters 

ranging from 7-21oC, with a large percentage at 17oC.

Juvenile silver hake were found at depths ranging from 

approximately 20-120 ft in winter, spring, and summer,

with the majority found at about 100 ft. During the 

autumn they were found at depths ranging between 30-80

ft, with most found at 30 ft.

The distributions and abundances of both juvenile

and adult silver hake in Long Island Sound from April to 

November 1984-1994, based on the Connecticut

Fisheries Division bottom trawl surveys, are shown in 

Figures 9-11. The following description of their

distributions relative to depth and bottom type is taken 

verbatim from Gottschall et al. (2000).

Silver hake were primarily distributed in the Central 

and Western Basins (Figure 9). Generally, silver hake 

abundance was highest over mud bottom with abundance 

over transitional and sand bottoms ranking second and 

third respectively (Figure 11B), and abundance tended to 

increase with depth (Figure 11C). This pattern became 

more evident through spring as abundance increased, and 

was very pronounced in summer. During July, a month of 

high abundance, they were concentrated in depths > 27 m 

over mud bottom in the two basins. Eight of the nine 

largest samples observed in July occurred over mud

bottom, and seven occurred in depths > 27 m (the other 

two were between 18-27 m). Although abundance was 

low in autumn, the distribution of silver hake was similar 

to summer. In November, when abundance increased

again, silver hake were distributed in all depths, although 

primarily in the northern half of the Central Basin

(Gottschall et al. 2000).

The distributions of juvenile silver hake relative to 

bottom water temperature, dissolved oxygen, depth, and 

salinity based on 1992-1997 NEFSC Hudson-Raritan

estuary trawl surveys are shown in Figure 22. Juveniles 

were found in waters ranging from 1-23oC, with the 

majority found at 5oC and between 20-21oC. They were 

found in dissolved oxygen levels of 4-12 mg/L, with 

most spread between 10-11 mg/L. They were found over

a depth range of 15-75 ft, with the highest percentages

found between 40-45 ft. Juveniles were found in

salinities ranging from 15-33 ppt, with the majority

found at 28 ppt.

The hydrographic preferences of both juvenile and 

adult silver hake in Chesapeake Bay from the 1988-1999

VIMS trawl surveys are shown in Figure 23 (all years and 

months combined). Geer (2002) states that catches are 

concentrated in the Bay proper in the deeper waters of 

the channels at depths > 10 m, and prefer high salinity 

with nearly 95% of the catch in waters > 24 ppt.

Temperature observations indicate a preference for

waters < 14oC.

Auster et al. (1997) found that silver hake (1.5-5

cm) in the Middle Atlantic Bight were more abundant on 

silt-sand bottoms containing amphipod tubes at depths of 

55 m. Steves and Cowen (2000) found amphipod tube 

mats to be associated with 0-group silver hake within the 

New York Bight. Steves and Cowen (2000) also suggest 

that early settlement patterns of silver hake are cued to a 

narrow interaction of temperature and depth, with a

subsequent broadening of habitat preference as juveniles 

grow and local physical regimes shift. Steves et al.

(2000) found that age-0 silver hake showed some

movement in depth between their settlement and nursery 

areas within the outer shelf of the New York Bight; also,

settlement did not peak until bottom temperature was > 

9oC.

Auster et al. (2003) studied the small scale spatial

distributions of both juvenile and adult silver hake within 

sand wave habitats and the diel patterns of habitat use on 

the southern side of Georges Bank and on Stellwagon 

Bank. Silver hake were not randomly distributed within 

sand wave habitats; there was a positive relationship

between fish length and sand wave period. However,

other factors, such as currents and available prey, may 

also influence their distribution in these habitats. Fish

were in direct contact with these sand wave habitats with 

greater frequency during the day, and fish were observed 

in social or co-operative foraging (polarized groups of 

fish swimming in linear formation) during the day and at 

dusk. At one site in the Mid-Atlantic Bight, silver hake 

(12.6-27.6 cm) were found on flat sand, sand-wave

crests, shell and biogenic depressions, but most often on 

flat sand (Auster et al. 1991). Silver hake were

associated with particular microhabitats (e.g., sand-wave

crests, biogenic depressions) at the 55 m site during the 

day but were randomly distributed during the night; this 

may be attributed to diel differences in feeding behavior 

(Auster et al. 1995). At the larger, regional scale within 

the New York Bight, juveniles showed high variability in 

abundance between stations in a study by Sullivan et al.

(2000).
Page 10

ADULTS

The spring and fall distributions of adult silver hake 

relative to bottom water temperature, depth, and salinity 

based on 1963-2002 NEFSC bottom trawl surveys from 

the Gulf of Maine to Cape Hatteras are shown in Figure 

24. In the spring, adult silver hake were found over a 

temperature range of 2-15°C, with the majority found

between 6-12°C. They were found in depths ranging

from 11-500 m. Adults were found in salinities ranging 

from 32-36 ppt with most spread between 33-35 ppt.

During the autumn, adults were found over a temperature 

range of 4-17°C, with greatest percentages between

about 7-10°C. In this season, they were found over a 

depth range of 21-400 m. They were found at a salinity

range of between 32-36 ppt, with most between 33-35

ppt.

The spring and autumn distributions of adults in

Massachusetts coastal waters relative to bottom water 

temperature and depth are shown in Figure 25. In the

spring, adults were found over a temperature range of 1-

13 °C, with a large percentage spread between 4-6oC.

They were found in depths ranging from 11-85 m, the 

majority found between 31-60 m. During the autumn, 

adults were found in waters ranging from 4-14oC, with 

most found between 6-10oC. They were found over a 

depth range of 21-85 m, with a large percentage between 

41-60 m.

Overall, it was found that silver hake tend toward 

warmer water in the spring. In both spring and autumn,

temperatures lie will within the preferred temperature 

range published for this species (Northeast Fisheries 

Science Center 2002).

The seasonal distributions of adult silver hake

relative to bottom water temperature and depth based on 

1990-1996 Rhode Island Narragansett Bay trawl surveys 

are shown in Figure 26. In the winter they were found in 

waters ranging from 5-10oC, with a large percentage 

found at 7oC. In the spring adults were found in

temperatures ranging from 7-14oC, with the majority

found at 14oC. In the summer they were found at

temperatures ranging from 11-16oC, with about 80%

found at 16oC. In the autumn they were found in waters 

ranging from 11-20oC, with the majority spread between 

11-15oC. Adult silver hake were found at depths ranging 

from approximately 30-120 ft in the winter, spring and 

autumn, with the largest percentages found between 80-

100 ft. In the summer, they were found at depths ranging 

from 70-100 ft, with about 70% found at 100 ft.

The distributions and abundances of both juvenile 

and adult silver hake in Long Island Sound relative to 

depth and bottom type were discussed previously

(Figures 9-11; Gottschall et al. [2000]).

The hydrographic preferences of both juvenile and 

adult silver hake in Chesapeake Bay from the 1988-1999

VIMS trawl surveys were discussed previously (Figure 

23).

Scott (1982) reported that silver hake on the Scotian 

Shelf were mostly found at salinities between 33 and 34 

ppt, but were captured in salinities ranging from 31-34

ppt. In a large-scale analysis of research bottom trawl 

surveys on the Scotian Shelf, Scott (1982) found silver 

hake occurred on all bottom types from gravel to fine silt 

and clay, but were mainly associated with silts and clays.

The areal trends in bottom type on the Scotian Shelf 

shows coarse sand and gravel is associated with shallow 

water and finer grain deposits are associated with deeper 

water. It was also found that the proportion of gravel 

increases from east to west. Thus, the areal trends in 

grains size and bottom water temperatures, as well as 

prey distributions, confound our ability to determine

which factors contribute to distribution pattern of silver 

hake on the Scotian Shelf.

For small scale spatial distributions of both juvenile

and adult silver hake within sand wave habitats and the 

diel patterns of habitat use on Georges Bank, Stellwagon 

Bank, and the Mid-Atlantic Bight, see the discussion of 

the Auster et al. (1991, 1995, 2003) studies in the 

juvenile Habitat Characteristics section, above.

Helser and Almeida (1997) performed a detailed

analysis of the possible effects of stock abundance,

growth, spring water temperatures, and depths on the 

proportion of silver hake that are mature at age 2 and 3.

Population abundance accounted for most of the

variation in sexual maturity. Growth in the southern

stock accounted for some additional variation. Both

catch-weighted water temperature and catch-weighted

bottom depth had no statistically significant effect on the 

proportion mature at age 2 or 3 for the northern stock, or 

at age 2 for the southern stock. A slight effect was found 

for the proportion mature at age 3 for the southern stock. 

Steves and Cowen (2000) found through age-atlength studies that silver hake growth and abundance is 

higher in cooler waters of the outer shelf of the New 

York Bight, possibly due to an interaction between

temperature and food availability.

As stated in the food habits section, Bowman (1984) 

determined that depth affects the type and quantity of 

food consumed by silver hake (i.e., fish sampled at

deeper depths have less food in their stomachs.)

STATUS OF THE STOCKS

Long-term trends in NEFSC fall survey data indicate 

that the northern stock of silver hake is at a relatively 

high biomass level, while the southern stock is currently 

at a relatively low biomass level (New England Fishery

Management Council 2003). Figure 27 illustrates trends 

in the autumn survey biomass index for both stocks. Over 

time, the biomass index for southern silver hake

gradually decreased to levels indicating that the stock 
Page 11

was in an overfished condition in the 1990s. The trend 

has recently reversed, and the 1999-2001 survey average 

increased above the biomass threshold. The 2001 autumn 

survey point for southern silver hake was the highest 

since the mid-1980s, although during 2002, the stock 

was below its biomass target (-22%), but above its

threshold level (+55%) (New England Fishery

Management Council 2002, 2003). Both northern and 

southern stocks of silver hake are not considered to be 

overfished; however, while the northern stock is

considered to be rebuilt, the southern stock has not yet 

completely rebuilt to its target level after being in an 

overfished condition during 1998-2000 (New England 

Fishery Management Council 2003). According to

Garrison and Link (2000), silver hake have sustained

considerable exploitation in directed fisheries and as 

incidental catch in otter-trawl fisheries for other

groundfish over the last four decades. Foreign

exploitation of the southern stock as bycatch in the squid 

fishery continued until 1987 (Brodziak 2001).

Periods of high (1989-1993) and low abundance 

(1967-1971) were analyzed for the distribution and

relative abundance of juveniles and adults in autumn

(Figure 28). The overall distribution of juveniles and 

adults appears about the same regardless of stock size.

The relative abundance is quite different between the two 

time periods. Much higher catches of juveniles and

adults occurred on Georges Bank and particularly in the 

Gulf of Maine during the period of high abundance.

RESEARCH NEEDS

• Questions remain about the definition of silver hake 

stocks. Research is needed to define the biological 

basis of the two (or more) stocks. Seasonal distributions indicate considerable movement of fish across 

the current stock boundary line on Georges Bank, 

which raises the question of the degree of intermixing between the stocks. What is currently known is 

based on results from the late 1970s and early

1980s.

• There is evidence of temporal changes in growth for 

both stocks (Brodziak et al. 2001). The observed 

temporal differences in growth warrant further

investigation.

• The habitat parameters used in this report are

location, depth, temperature, and, for Long Island

Sound, salinity. A critical parameter is bottom type, 

which needs to be included in future habitat considerations.

• Little is known about the effects of prey on the 

distribution of silver hake. Additional food habits 

analysis is needed to determine the possible relationships between predators and prey and distribution abundance for predicting and managing stock

recovery. Analyses of stomach content[s] should be 

performed on board at each trawling station during 

surveys. These analyses should include lengthfrequency measurements and a stomach content

index to determine the prevalence of small zooplankton, large zooplankton, and other prey species 

such as fish.

• There are indications that fine scale (less than shelf 

wide) habitat characteristics may be important at

various times in the life of silver hake. Examples are 

food and predator abundance during the larval stage,

fine-scale bottom structure for small juveniles, and 

the contribution of estuaries to the success of year 

classes.

• The settlement needs of silver hake need to be better 

defined. A change from a completely pelagic

existence to one partially demersal may be considered settlement.

• Silver hake fecundity has not been sufficiently

researched. The data presently available only allows 

for a general observation that a high fecundity is 

typical of this species, similar to other gadoids.

ACKNOWLEDGEMENTS

The authors wish to thank Jason Link of the NEFSC

Woods Hole for providing the NEFSC food habits

graphs. Barry Shafer and John McCarthy created the

NEFSC maps and bar charts. Jon Brodziak of the NEFSC 

Woods Hole provided reviews and comments.

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NMFS 113. 66 p.

Penttila, J.A., G.A. Nelson and J.M. Burnett, III. 1989. 

Guidelines for estimating lengths at age for 18

northwest Atlantic finfish and shellfish species.

NOAA Tech. Mem. NMFS-F/NEC-66. 39 p.

Perlmutter, A. 1939. A biological survey of the salt

waters of Long Island, 1938. An ecological survey of 

young fish and eggs identified from tow net
Page 14

collections. 28th Ann. Rep. N.Y. State Cons. Dep., 

Suppl., Pt. II: 11-71.

Reid, R., F. Almeida, and C. Zetlin. 1999. Essential fish 

habitat source document: Fishery independent

surveys, data sources, and methods. NOAA Tech.

Mem. NMFS-NE-122. 39 p.

Richards, S.W. 1959. Pelagic fish eggs and larvae of

Long Island Sound. In G.A. Riley et al. eds.

Oceanography of Long Island Sound 1954-1955. p. 

95-124. Bull. Bingham Oceanogr. Collect. 17 (1).

Rikhter, V.A., I.K. Sigaev, V.A. Vinogradov, and V.I.

Isakov. 2001. Silver Hake of Scotian Shelf: fishery, 

environmental conditions, distribution, and biology 

and abundance dynamics. J. Northwest Atl. Fish. Sci. 

29: 51-92.

Ross, M.R. and F.P. Almeida. 1986. Density-dependent

growth of silver hakes. Trans. Am. Fish. Soc. 115:

548-554.

Sarnits, A.A. and V.I. Sauskan. 1967. Hydrographic

conditions and distribution of silver hake,

Merluccius bilinearis Mitchill, on Georges Bank

and off Nova Scotia in 1962-1964. Int. Comm.

Northwest Atl. Fish. (ICNAF) Res. Bull. 4: 76-86.

Sauskan, V.A. 1964. Results of Soviet observations on 

the distribution of silver hake in the areas of

Georges Bank (5Z) and Nova Scotia (4W) in 1962-

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

Doc. No. 61. 8 p.

Sauskan, V.I. and V.P. Serebryakov. 1968. Reproduction 

and development of the silver hake, (Merluccius

bilinearis Mitchell). Vopr. Ikhtiol. 8(3): 398-414.

Schaefer, R.H. 1960. Growth and feeding habits of the 

whiting or silver hake in the New York Bight. N.Y. 

Fish Game J. 7: 85-98.

Schenk. R. 1981. Population identification of silver hake 

(Merluccius bilinearis) using isoelectric focusing. 

U.S. Natl. Mar. Fish. Serv., Northeast Fish. Cent., 

Woods Hole Lab. Ref. Doc. 81-44. 31 p.

Scott, J.S. 1982. Depth, temperature and salinity

preferences of common fishes of the Scotian Shelf. 

J. Northwest Atl. Fish. Sci. 3: 29-39.

Sigaev, I.K. 1995. Distribution of silver hake, water

temperatures and zooplankton on the Scotian Shelf 

in May-July 1990. NAFO Scientific Council studies. 

23: 1-7.

Sissenwine, M.P., E.B. Cohen, and M.D. Grosslein.

1984. Structure of the Georges Bank ecosystem.

Rapp. P-v. Reun. Cons. Int. Explor. Mer. 183: 243-

254.

Steves, B.P. and R.K. Cowen. 2000. Settlement, growth, 

and movement of silver hake Merluccius bilinearis

in nursery habitat on the New York Bight continental 

shelf. Mar. Ecol. Prog. Ser. 196: 279-290.

Steves, B.P., R.K. Cowen, and M.H. Malchoff. 2000.

Settlement and nursery habitats for demersal fishes 

on the continental shelf of the New York Bight. Fish. 

Bull. (U.S.) 98: 167-188.

Stone, S.L., T.A. Lowery, J.D. Field, C.D. Williams, D.M. 

Nelson, S.H. Jury, M.E. Monaco, and L. Anderson. 

1994. Distribution and abundance of fishes and

invertebrates in Mid-Atlantic estuaries. ELMR Rep. 

No. 12. NOAA/NOS Strategic Environmental

Assessments Division, Silver Spring, MD. 280 p.

Sullivan, M.C., R.K. Cowan, K.W. Able, and M.P. Fahay. 

2000. Spatial scaling of recruitment in four

continental fishes. Mar. Ecol. Prog. Ser. 207: 141-

154.

Tsou, T.S. and J.S. Collie. 2001a. Estimating predation 

mortality in the Georges Bank fish community. Can. 

J. Fish. Aquat. Sci. 58: 908-922.

Tsou, T.S. and J.S. Collie. 2001b. Predation-mediated

recruitment in the Georges Bank fish community. 

ICES. J. Mar. Sci. 58: 994-1001.

Vinnichenko, V.I., K.V. Gorchinsky, and N.V. Gnilitsky.

2001. The Results of Russian Research and Fishery 

on Silver Hake (Merluccius bilinearis) on the Nova 

Scotian Shelf in 2000. NAFO Sci. Coun. Res. Doc. 

01/12. 6 p. 

Vinogradov, V.I. 2000. Feeding of 0-group Silver Hake 

(Merluccius bilinearis) in Scotian Shelf Area.

NAFO Sci. Coun. Res. Doc. 00/3 14 p.

Virginia Institute of Marine Science Fisheries

Laboratory. 1961. Fishes and fish larvae collected 

from Atlantic plankton cruises of R/V Pathfinder 

December 1959-December 1960. Virginia Inst. Mar. 

Sci. Fish. Lab. Spec. Sci. Rep. No. 26. 15 p.

Waldron, D.E. 1988. Trophic biology of the silver hake 

(Merluccius bilinearis) population on the Scotian 

Shelf. Ph.D dissertation, Dalhousie Univ., Halifax, 

Nova Scotia. 363 p.

Waldron, D.E. 1992. Diet of silver hake (Merluccius

bilinearis) on the Scotian Shelf. J. Northwest Atl. 

Fish. Sci. 14: 87-101.

Wheatland, S.B. 1956. Pelagic fish eggs and larvae. In: G. 

A. Riley et al. eds. Oceanography of Long Island 

Sound, 1952-1954. p. 234-314. Bull. Bingham

Oceanogr. Collect. 15.
Page 15

Table 1. Mean length (cm) at age (years) in silver hake, Merluccius bilinearis, for Gulf of Maine (GM), Middle 

Atlantic (MA), northern Georges Bank (NGB), and southern Georges Bank (SGB) from samples collected during 

1988-1992; based on Helser (1996).

Area

Age GM MA NGB SGB

1 12.3 9.1 12.1 11.7

2 22.0 21.2 22.1 21.4

3 28.8 28.7 28.8 27.8

4 33.6 33.5 33.3 31.9

5 37.0 36.4 36.3 34.6

6 39.3 38.2 38.3 36.4

7 41.0 39.4 39.7 37.5

8 42.1 40.1 40.6 38.3

9 43.0 40.5 41.2 38.8

10 43.5 40.8 41.6 39.1

11 43.9 41.0 41.9 39.3

12 44.2 41.1 42.1 39.4
Page 16

Table 2. Observations of silver hake, Merluccius bilinearis, age and length at maturity.

Author Years Area Age (years) Length (cm)

Bigelow and Schroeder 

(1953)

1950s Gulf of Maine ~ 2

Sauskan (1964) 1962-

1964

Georges Bank 2-3 29-33

Morse (1979) 1977 US Shelf 24-26

Beacham (1983) 1960s1970sScotian Shelf 1-2 31 females 1960s;

26 females 1970s 

O’Brien et al. (1993) 1985-

1989

US Shelf 1.6-1.7 22.3-22.7 males

23.1-23.2 females

Helser and Almeida 

(1997)

1973-

1990

US Shelf 2 - 20% mature in 1973

2 - 80% mature in 1990 

Bolles and Begg (2000) 1990 Gulf of 

MaineNorthern

Georges Bank

2 16-24 males

17-28 females

Southern

Georges

Bank-Middle

Atlantic Bight

2 17-26 males

18-22 females

Brodziak (2001) 1999 Gulf of 

MaineNorthern

Georges Bank

1.7 - A50 22.3 males - L50

23.1 females - L50

Southern

Georges

Bank-Middle

Atlantic Bight

1.6 - A50 22.7 males - L50

23.2 females - L50

Rikhter et al. (2001) 1960s1997Scotian Shelf ~ 2 - A50 24 males - L50

27 females - L50
Page 17

Table 3. Published reports of the nearshore and estuarine occurrences of silver hake, Merluccius bilinearis, eggs and 

larvae from the area south of Cape Cod.

Study Area and Dates Eggs Larvae

Herman (1963) Narragansett Bay 

March 1957 - March 

1958, weekly sampling

6 eggs July - October.

Temperatures 14.8–

21.4o

C

33 larvae July - October 

Temperatures 12.0-22.4o

C

Bourne and 

Govoni (1988)

Narragansett Bay, RI 

June 1972 - August 

1973

Listed as present in low 

numbers

Listed as present in low 

numbers

Perlmutter

(1939)

Salt waters of Long 

Island, NY 1938

Small numbers off 

Montauk Point in June & 

July

37 Larvae (2.6-6.0 mm) 

from June to September, 

most in June in Block Island 

Sound

Merriman and 

Sclar (1952)

Block Island Sound, RI 

1943 – 1946

None 16 larvae (4.0-9.0 mm) July

and November

Wheatland

(1956)

Long Island Sound 

March 1952 - March 

1954

None None

Richards (1959) Long Island Sound 

1954 – 1955

None None

Monteleone

(1992)

Great South Bay, NY 

April 1985 - December 

1986

None None

Dovel (1981) Hudson River March -

December 1972

None None

Virginia Institute 

of Marine 

Science Fisheries 

Laboratory

(1961)

Lower Chesapeake Bay 

and nearshore ocean 

December 1959 -

December 1960

None 31 larvae (4-21 mm) caught 

only in the ocean.

December - April, June
Page 18

Table 4. Average number of silver hake, Merluccius bilinearis, in Narragansett Bay, per tow by season. From the 

Rhode Island Division of Fish and Wildlife bottom trawl surveys of Narragansett Bay, 1990 - 1996.

Species Juveniles Adults

Winter Spring Summer Autumn Winter Spring Summer Autumn

Silver Hake 2.353 0.286 3.031 1.425 1.495 0.449 0.179 0.187
Page 19

Table 5. Summary of the distribution and abundance of silver hake, Merluccius bilinearis, in North Atlantic and MidAtlantic estuaries based on Jury et al. (1994) and Stone et al. (1994).

Adults Sp Adults Juveniles Larvae Eggs

Estuary T M S T M S T M S T M S T M S

 Passamaquoddy Bay c a r c a * * r * * r

 Englishman/Machias Bays c a r c a * * r * * r

 Narragaugus Bay c a r c a * * r * * r

 Blue Hill Bay c a r c a * * r * * r

 Penobscot Bay c a r c a * * r * * r

 Muscongus Bay c c r c c * * r * * r

 Damariscotta Bay c c r c c * * r * * r

 Sheepscot Bay c a r c c * * r * * r

 Kennebec/Androscoggin Rivers c c n c c * * n * * n

 Casco Bay c c r c c * r c r c

 Saco Bay c c r c c r r r r

 Wells Harbor nz r nz * nz r nz r nz r

 Great Bay R r r r

 Merrimack River r nz nz r nz r nz R nz

 Massachusetts Bay nz nz c nz nz c nz nz c nz nz c nz nz c

 Boston Harbor nz c c nz nz c c nz r c nz r c

 Cape Cod Bay nz c c nz c nz c c nz r c nz r c

 Waquoit Bay n n n n n n n n n n n n n n n

 Buzzards Bay n n n n n n n n n n n n n n n

 Narragansett Bay n n n n n n n n n n n n n n n

 Connecticut River n n n n n n n n n n n n n n n

 Gardiners Bay n n n n n n n n n n n n n n n

 Long Island Sound n n n n n n n n n n n n n n n

 Great South Bay n n n n n n n n n n n n n n n

 Hudson River/Raritan Bay n n n n n n n n n n n n n n n

 Barnegat Bay n n n n n n n n n n n n n n n

 New Jersey Inland Bays n n n n n n n n n n n n n n n

 Delaware Bay n n n n n n n n n n n n n n n

 Delaware Inland Bays n n n n n n n n n n n n n n n

 Chincoteague Bay n n n n n n n n n n n n n n n

 Chesapeake Bay mainstream n n n n n n n n n n n n n n n

 Chester River n n n n n n n n n n n n n n n

 Choptank River n n n n n n n n n n n n n n n

 Patuxent River n n n n n n n n n n n n n n n

 Potomac River n n n n n n n n n n n n n n n

 Tangier/Pocomoke Sounds n n n n n n n n n n n n n n n

 Rappahannock River n n n n n n n n n n n n n n n

 York River n n n n n n n n n n n n n n n

 James River n n n n n n n n n n n n n n n

Relative Abundance

h = Highly abundant, a = abundant,

c = common, r = rare, blank = not present, 

n = no data presented, * = no data available, 

nz = particular zone not present

Data Reliability for Life Stages

Highly Certain = Bold and Underlined Text

Moderately Certain = Bold Text

Reasonable Inference = Normal Text

Tidal Zones

T = Tidal Fresh 0.0-0.5 ppt

M= Mixing Zone 0.5-25 ppt

S = Seawater Zone > 25 ppt
Page 20

Table 6. Published observations about silver hake, Merluccius bilinearis: bottom water temperature, depth

distributions, and preferences.

Author Area Temperature (°C) Depth (m)

Range Preference Range Preference

Bigelow and 

Schroeder

(1953)

Gulf of Maine 4-18 > 6 tide line -

> 700

Domanevsky

and Nozdrin 

(1963)

Southeast

Georges Bank

9-11 90-110

Sauskan

(1964)

Georges Bank;

1962-1963

6-12 10-12: ripe 

adults, 6-10:

post spawn

85-200 spring

40-110 summer

Fritz (1965) Continental

Shelf, NJ to 

Nova Scotia; 

Autumn,

1955-1961

3.9-19.4 6-12 30-410 70-210

Sarnits and 

Sauskan

(1967)

Georges Bank 

1964

7-8 140-230

Edwards

(1965)

Southern New 

England

> 9

Scott (1982) Eastern Gulf 

of Maine

1-13 7-10 15 - > 200 

fathoms

80-89 fathoms

Bowman

(1984)

Northwest

Atlantic

1973-1976

38-110

Almeida

(1987)

U.S

Continental

Shelf

Adults:

inshore - 400

Murawski and 

Finn (1988)

Georges Bank Winter: 5.97

Spring: 8.45

Summer: 8.95

Autumn: 8.42

Winter: 208

Spring: 186

Summer: 97

Autumn: 163

Murawski

(1993)

U.S.

Continental

Shelf

Spring: 6.76

Summer: 8.03

Autumn: 10.00

Spring: 186

Summer: 97

Autumn: 163

Sigaev (1995) Scotian Shelf

1990

< 1-10.5 7-10.5 200

Helser and 

Almeida

(1997)

U.S.

Continental

Shelf

5.5-10.5 most > 8.0 southern 

Stock

50-150 most > 80 southern 

Stock

Gottschall et

al. (2000)

Long Island 

Sound

> 27 most

Steves and 

Cowen (2000)

New York 

Bight

Continental

Shelf

1996-1997

0-25 8-10 0-200 60-100
Page 21

Figure 1. The silver hake, Merluccius bilinearis (Mitchell) (from Goode 1884).
Page 22

Figure 2. Percent of diet by weight of the major prey items in the diet of three size categories of silver hake collected 

during NEFSC bottom trawl surveys from 1973-2001 (all seasons). Size categories of silver hake are small: < 20 cm; 

medium: > 20 cm and < 40 cm; and large: > 40 cm. The category “WDP” refers to well-digested prey. For details on 

NEFSC diet analysis, see Link and Almeida (2000).

Small Silver Hake

0

20

40

60

Amphipods

WDP

Clupeids

Misc. Crustaceans

Decapods

Euphasiids

Gadids

Mysids

Other Fish

% Diet Composition (g)

Medium Silver Hake

0

10

20

30

Ammodytes sp.

Amphipods

WDP

Squids

Clupeids

Misc. Crustaceans

Decapods

Euphasiids

Gadids

Other FishScombrids

Butterfish

% Diet Composition (g)

Large Silver Hake

0

10

20

30

40

Ammodytes sp.

Squids

Clupeids

Euphasiids

Gadids

Other FishScombrids

Butterfish

% Diet Composition (g)
Page 23

Figure 3. Overall distribution of silver hake in the northwest Atlantic Ocean during 1975-1994. Data are from the U.S. 

NOAA/Canada DFO East Coast of North America Strategic Assessment Project (http://www-rca.nos.noaa.gov/projects/

ecnasap/ecnasap_table1.html). Note that data for these plots came from trawl surveys, and the surveys did not use the 

same sampling gear. The Canadian and U.S. trawl surveys have catchabilities on the same order of magnitude, but they 

do differ enough to warrant cautious interpretation.
Page 24

Figure 4. Distribution and abundance of silver hake eggs collected during NEFSC MARMAP ichthyoplankton surveys, 

January to December, 1978-1987 [see Reid et al. (1999) for details].

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

35

36

37

38

39

40

41

42

43

44

45

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

January to December; 1978 to 1987

Number of tows = 9478, with eggs = 1897

Silver Hake

Eggs / 10m 2

1 to <10

10 to <100

100 to <1000

1000 to <10000

10000 to 24264

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

35

36

37

38

39

40

41

42

43

44

45

January, 1978 to 1987

Number of tows = 433, with eggs = 19

None

1 to < 10

10 to < 100

100 to 132

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

February, 1978 to 1987

Number of tows = 459, with eggs = 6

None

1 to < 10

10 to < 100

100 to 111

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

March, 1978 to 1987

Number of tows = 853, with eggs = 29

None

1 to < 10

10 to < 100

100 to 133

Eggs / 10m2
Page 25

Figure 4. cont’d.

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

35

36

37

38

39

40

41

42

43

44

45

April, 1978 to 1987

Number of tows = 1020, with eggs = 63

None

1 to < 10

10 to < 100

100 to 835

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

May, 1978 to 1987

Number of tows = 1085, with eggs = 276

None

1 to < 10

10 to < 100

100 to < 1000

1000 to 7073

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

June, 1978 to 1987

Number of tows = 709, with eggs = 216

None

1 to < 10

10 to < 100

100 to < 1000

1000 to < 10000

Eggs / 10m2

10000 to 18908

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

35

36

37

38

39

40

41

42

43

44

45

July, 1978 to 1987

Number of tows = 781, with eggs = 294

None

1 to < 10

10 to < 100

100 to < 1000

1000 to < 10000

Eggs / 10m 2

10000 to 10168
Page 26

Figure 4. cont’d.

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

35

36

37

38

39

40

41

42

43

44

45

August, 1978 to 1987

Number of tows = 863, with eggs = 329

None

1 to < 10

10 to < 100

100 to < 1000

1000 to < 10000

Eggs / 10m2

10000 to 24264

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

35

36

37

38

39

40

41

42

43

44

45

September, 1978 to 1987

Number of tows = 747, with eggs = 212

None

1 to < 10

10 to < 100

100 to < 1000

1000 to 6416

Eggs / 10m 2

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

35

36

37

38

39

40

41

42

43

44

45

October, 1978 to 1987

Number of tows = 1044, with eggs = 320

None

1 to < 10

10 to < 100

100 to < 1000

1000 to 2735

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

November, 1978 to 1987

Number of tows = 915, with eggs = 117

None

1 to < 10

10 to < 100

100 to 303

Eggs / 10m 2
Page 27

Figure 4. cont’d.

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

35

36

37

38

39

40

41

42

43

44

45

December, 1978 to 1987

Number of tows = 569, with eggs = 16

None

1 to < 10

10 to 37

Eggs / 10m 2
Page 28

Figure 5. Distribution and abundance of silver hake larvae collected during NEFSC MARMAP ichthyoplankton 

surveys, 1977-1987 [see Reid et al. (1999) for details].

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

Jan. to March / May to Dec.; 1977 to 1987

Silver Hake

Number of Tows = 10157, with larvae = 1544

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

35

36

37

38

39

40

41

42

43

44

45

1 to < 10

10 to < 100

100 to < 1000

1000 to 9396

Number of Larvae / 10m2

January, 1977 to 1987

Number of Tows = 434, with larvae = 12

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

35

36

37

38

39

40

41

42

43

44

45

Number of Larvae / 10m2

None

1 to < 10

10 to 34

February, 1977 to 1987

Number of Tows = 686, with larvae = 6

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

35

36

37

38

39

40

41

42

43

44

45

Number of Larvae / 10m 2

None

1 to 7

March, 1977 to 1987

Number of Tows = 1031, with larvae = 1

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

35

36

37

38

39

40

41

42

43

44

45

Number of Larvae / 10m 2

None

1 to 6
Page 29

Figure 5. cont’d.

May, 1977 to 1987

Number of Tows = 1472, with larvae = 58

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

35

36

37

38

39

40

41

42

43

44

45

Number of Larvae / 10m2

None

1 to < 10

10 to < 100

100 to 403

June, 1977 to 1987

Number of Tows = 893, with larvae = 87

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

35

36

37

38

39

40

41

42

43

44

45

None

1 to < 50

50 to < 250

250 to < 1000

1000 to 2388

Number of Larvae / 10m2

July, 1977 to 1987

Number of Tows = 938, with larvae = 269

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

35

36

37

38

39

40

41

42

43

44

45

None

1 to < 50

50 to < 250

250 to < 1000

1000 to 2853

Number of Larvae / 10m 2

April, 1977 to 1987

Number of Tows = 1281, with larvae = 2

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

35

36

37

38

39

40

41

42

43

44

45

Number of Larvae / 10m 2

None

1 to 4
Page 30

Figure 5. cont’d.

September, 1977 to 1987

Number of Tows = 774, with larvae = 168

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

35

36

37

38

39

40

41

42

43

44

45

None

1 to < 50

50 to < 300

300 to < 1000

1000 to 3807

Number of Larvae / 10m2

August, 1977 to 1987

Number of Tows =1148, with larvae = 377

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

35

36

37

38

39

40

41

42

43

44

45

None

1 to < 50

50 to < 250

250 to < 5000

5000 to 9396

Number of Larvae / 10m 2

October, 1977 to 1987

Number of Tows = 1147, with larvae = 340

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

35

36

37

38

39

40

41

42

43

44

45

Number of Larvae / 10m2

None

1 to < 50

50 to < 300

300 to 689

November, 1977 to 1987

Number of Tows = 1031, with larvae = 196

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

35

36

37

38

39

40

41

42

43

44

45

Number of Larvae / 10m2

None

1 to < 50

50 to < 250

250 to 487
Page 31

Figure 5. cont’d.

December, 1977 to 1987

Number of Tows = 603, with larvae = 63

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

35

36

37

38

39

40

41

42

43

44

45

Number of Larvae / 10m2

None

1 to < 50

50 to < 100

100 to 148
Page 32

Silver Hake

NEFSC Bottom Trawl Surveys

(1964 - 2002)

Number per tow

Winter/juveniles

(<= 22 cm)

Present

Figure 6. Seasonal distribution and abundance of juvenile silver hake collected during NEFSC bottom trawl surveys 

[1963-2002, all years combined; see Reid et al. (1999) for details]. Winter and summer distributions are presented as 

presence/absence data; survey stations where juveniles were not found are not shown.
Page 33

Silver Hake

NEFSC Bottom Trawl Surveys

(1968 - 2002)

Spring/juveniles

(<= 22 cm)

NPTOW

1 - 10

11 - 100

101 - 1000

> 1000

Number per tow

Figure 6. cont’d.
Page 34

Silver Hake

NEFSC Bottom Trawl Surveys

(1963 - 1995)

Number per tow

Summer/juveniles

 (<= 22 cm)

Present

Figure 6. cont’d. 
Page 35

Silver Hake

NEFSC Bottom Trawl Surveys

(1963 - 2001)

Fall/juveniles

(<= 22 cm)

NPTOW

1 - 10

11 - 100

101 - 1000

> 1000

Number per tow

Figure 6. cont’d.
Page 36

New Hampshire

Cape Ann

Massachusetts

Cape Cod

Martha's

Vineyard

Nantucket

Spring/juveniles

NPTOW

1 - 10

11 - 100

101 - 500

> 500

Silver Hake

Massachusetts Inshore

Trawl Survey

(1978 - 2002)

Spring/juveniles

(<= 22 cm)

 Number per tow

Figure 7. Distribution and abundance of juvenile silver hake in Massachusetts coastal waters collected during the spring 

and autumn Massachusetts inshore trawl surveys [1978-2002, all years combined; see Reid et al. (1999) for details].
Page 37

New Hampshire

Cape Ann

Massachusetts

Cape Cod

Martha's

Vineyard

Nantucket

Spring/juveniles

NPTOW

1 - 10

11 - 100

101 - 500

> 500

Silver Hake

Massachusetts Inshore

Trawl Survey

(1978 - 2001)

Fall/juveniles

(<= 22 cm)

 Number per tow

Figure 7. cont’d.
Page 38

Figure 8. Distribution, abundance, and length frequencies of juvenile and adult silver hake collected during each season 

in Narragansett Bay during 1990-1996 Rhode Island bottom trawl surveys. The numbers shown at each station are the 

average catch per tow rounded to one decimal place [see Reid et al. (1999) for details].

4.9

0.2

0.1

0.0

0.1

0.0

0.0

0.0

0.0

0.1

2.6

0.6 0.1

1.1

0.1

0.1

0.0

0.2

0.0

0.0

0.1

0.1

0.4

0.5

0.4 0.0

12.6

0.0

0.0

0.0

0.2

0.1

0.0

0.2

0.0

0.5

1.8

0.0 0.0

3.2

0.3

0.1

0.0

1.4

0.1

0.3

0.5

0.3

1.3

2.9

0.4 0.5

Spring

Summer Autumn

Winter

Silver Hake Juveniles (<23cm)
Page 39

Figure 8. cont’d.

3.2

0.0

0.0

0.0

0.1

0.0

0.0

0.0

0.0

0.0

5.3

0.3 0.0

0.5

0.0

0.0

0.0

0.4

0.0

0.0

0.0

0.2

1.1

1.1

0.7 0.0

0.8

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

1.2

0.0 0.0

1.6

0.0

0.0

0.0

0.1

0.0

0.0

0.0

0.0

0.0

0.6

0.0 0.1

Spring

Summer Autumn

Winter

Silver Hake Adults (>=23cm)
Page 40

Figure 8. cont’d.

5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

0

20

40

60

80

100

5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

0

3

6

9

12

5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

0

50

100

150

200

250

5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

0

20

40

60

80

100

Total Length (cm)

Winter

Spring

Summer

Autumn
Page 41

Figure 9. Distribution and abundance of juvenile and adult silver hake (8-38 cm TL) collected in Long Island Sound, 

based on the finfish surveys of the Connecticut Fisheries Division, 1984-1994 [from Gottschall et al. (2000)]. Circle 

diameter is proportional to the number of fish caught, and is scaled to the maximum catch (indicated by “max=” or 

“max>”). Collections were made with a 14 m otter trawl at about 40 stations chosen by stratified random design.
Page 42

Figure 10. Monthly log10 length frequencies (cm) of juvenile and adult silver hake collected in Long Island Sound, 

based on 2,863 fish taken in 101 tows between 1989-1990. From Gottschall et al. (2000).
Page 43

Figure 11. Relative abundance (geometric mean catch/tow) catch/tow and percent occurrence (proportion of samples 

in which at least one individual was observed) for juvenile and adult silver hake in Long Island Sound by month, month 

and bottom type, and month and depth interval. From Gottschall et al. (2000).
Page 44

Figure 12. Distribution and abundance of juvenile silver hake collected in the Hudson-Raritan estuary from January 

1992 - June 1997, based on Hudson-Raritan trawl surveys [see Reid et al. (1999) for details].

Staten

Island

NEW

YORK

NEW

JERSEY

No/Tow

 1 - 4

5 - 9

10 - 19

20 - 39

40 - 60

Silver Hake

Hudson-Raritan Estuary

January 1992 - June 1997

All Juveniles (<23 cm)

Staten

Island

NEW

YORK

NEW

JERSEY

No/Tow

 1 - 4

5 - 9

10 - 19

20 - 39

40 - 60

Silver Hake

Hudson-Raritan Estuary

Winter 1992 - 1997

Juveniles (<23 cm)

Staten

Island

NEW

YORK

NEW

JERSEY

No/Tow

 1 - 4

5 - 9

10 - 19

20 - 39

40 - 60

Hudson-Raritan Estuary

Spring 1992 - 1997

Juveniles (<23 cm)

Silver Hake

Staten

Island

NEW

YORK

NEW

JERSEY

No/Tow

 1 - 4

5 - 9

10 - 19

20 - 39

40 - 60

Silver Hake

Hudson-Raritan Estuary

Fall 1992 - 1996

Juveniles (<23 cm)
Page 45

Figure 13. Catch per unit effort for total catch of juvenile and adult silver hake in Chesapeake Bay, from the Virginia 

Institute of Marine Science’s (VIMS) trawl surveys, 1988-1999 (all years combined). Monthly surveys were conducted 

using a random stratified design of the main stem of the Bay using a 9.1 m semi-balloon otter trawl with 38 mm mesh 

and 6.4 mm cod end with a tow duration of five minutes. Adapted from Geer (2002).

Month

Juveniles Adults

J F AMJ M J A S O N D

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Catch per Trawl

Month

Juveniles Adults

J F AMJ M J A S O N D

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Catch per Trawl
Page 46

Figure 14. Seasonal distribution and abundance of silver hake in Chesapeake Bay, from the VIMS trawl surveys, 1988-

1999 (all years combined). Adapted from Geer (2002).

Catch Key:

1 - 5

6 - 10

26 - 50

11 - 25

> 50

N
Page 47

Silver Hake

NEFSC Bottom Trawl Surveys

(1964 - 2002)

Number per tow

Winter/adults

 (> 22 cm)

Present

Figure 15. Seasonal distribution and abundance of adult silver hake collected during NEFSC bottom trawl surveys 

[1963-2002, all years combined; see Reid et al. (1999) for details]. Winter and summer distributions are presented as 

presence/absence data; survey stations where juveniles were not found are not shown.
Page 48

Silver Hake

NEFSC Bottom Trawl Surveys

(1968 - 2002)

Spring/adults

(> 22 cm)

NPTOW

1 - 10

11 - 100

101 - 1000

> 1000

Number per tow

Figure 15. cont’d.
Page 49

Silver Hake

NEFSC Bottom Trawl Surveys

(1963 - 1995)

Number per tow

Summer/adults

 (> 22 cm)

Present

Figure 15. cont’d. 
Page 50

Fall/adults

(> 22 cm)

NPTOW

1 - 10

11 - 100

101 - 1000

> 1000

Silver Hake

NEFSC Bottom Trawl Surveys

(1963 - 2001)

Number per tow

Figure 15. cont’d.
Page 51

New Hampshire

Cape Ann

Massachusetts

Cape Cod

Martha's

Vineyard

Nantucket

Spring/juveniles

NPTOW

1 - 10

11 - 100

101 - 500

> 500

Silver Hake

Massachusetts Inshore

Trawl Survey

(1978 - 2002)

Spring/adults

(> 22 cm)

 Number per tow

Figure 16. Distribution and abundance of adult silver hake in Massachusetts coastal waters collected during the spring 

and autumn Massachusetts inshore trawl surveys [1978-2002, all years combined; see Reid et al. (1999) for details].
Page 52

New Hampshire

Cape Ann

Massachusetts

Cape Cod

Martha's

Vineyard

Nantucket

Spring/juveniles

NPTOW

1 - 10

11 - 100

101 - 500

> 500

Silver Hake

Massachusetts Inshore

Trawl Survey

(1978 - 2001)

Fall/adults

(> 22 cm)

 Number per tow

Figure 16. cont’d.
Page 53

Figure 17. Abundance of silver hake eggs relative to water column temperature and bottom depth from NEFSC 

MARMAP ichthyoplankton surveys (1978-1987) by month for all years combined. Open bars represent the proportion 

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

m2

).

January

0

10

20

30

40

Stations

Egg Catch

April

0

10

20

30

May

0

10

20

30

June

Percent

0

10

20

30

July

0

10

20

August

0

10

20

October

0

10

20

30

Silver Hake Eggs

September

0

10

20

February

0

10

20

60

80

March

0

10

20

30

November

0

10

20

30

December

Water Temperature (0 to 15m, C)

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

0

10

20

30

January

0

10

20

30

40

Stations

Egg Catch

April

0

10

20

30

40

October

0

10

20

30

Silver Hake Eggs

September

0

10

20

30

May

0

10

20

30

June

Percent

0

10

20

30

40

July

0

10

20

30

40

August

0

20

40

60

December

Bottom Depth (m), Interval Midpoint

1030507090

110130150170190

210230250270290325375450750

12501750

>2000

0

10

20

30

November

0

10

20

30

March

0

10

20

30

February

0

10

20

6070
Page 54

Figure 18. Abundance of silver hake larvae relative to water column temperature and bottom depth from NEFSC 

MARMAP ichthyoplankton surveys (1977-1987) by month for all years combined. Open bars represent the proportion 

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

m2

).

January

0

10

20

30

60

70

Stations

Larva Catch

December

Bottom Depth (m), Interval Midpoint

1030507090

110130150170190210230250270290325375450750

12501750

>2000

0

10

20

30

40

Silver Hake Larvae (<20mm length)

September

0

10

20

30

40

June

Percent

0

10

20

30

40

July

0

10

20

30

40

50

August

0

10

20

30

40

October

0

10

20

30

40

March

0

10

20

30

90

100

February

0

10

20

40

50

November

0

10

20

40

60

May

0

10

20

30

January

0

10

20

30

Stations

Larva Catch

May

0

10

20

30

June

Percent

0

10

20

30

40

July

0

10

20

30

40

August

0

10

20

30

November

0

10

20

30

Silver Hake Larvae (<20mm length)

September

0

10

20

30

March

0

10

20

90

100

October

0

10

20

30

February

0

10

20

30

40

December

Water-Column Temperature (C)

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

0

10

20

30

40
Page 55

0

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Bottom Temperature (°C)

Percent

Trawls N=10537

Occurrence N=1063

Catch N=48856

0

10

20

30

40

1-10

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

91-100

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

Bottom Depth (m)

Percent

Trawls N=12193

Occurrence N=1192

Catch N=53916

0

20

40

60

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

Salinity (PPT)

Percent

Trawls N=1959

Occurrence N=233

Catch N=19214

Silver Hake

NEFSC Bottom Trawl Survey

Spring/Juveniles

Figure 19. Spring and fall distributions of juvenile silver hake and trawls relative to bottom water temperature, depth, 

and salinity based on NEFSC bottom trawl surveys (1963-2002; all years combined). White bars give the distribution 

of all the trawls, black bars give the distribution of all trawls in which silver hake occurred, and gray bars represent, 

within each interval, the percentage of the total number of silver hake caught. Note that the bottom depth intervals 

change with depth (from 10 to 20 to 100 m) in the bottom depth bar chart.
Page 56

0

5

10

15

20

25

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

Bottom Temperature (°C)

Percent

Trawls N=12159

Occurrence N=1706

Catch N=96420

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=13863

Occurrence N=1910

Catch N=102840

0

20

40

60

27 29 30 31 32 33 34 35 36 37

Salinity (PPT)

Percent

Trawls N=2271

Occurrence N=444

Catch N=31318

Silver Hake

NEFSC Bottom Trawl Survey

Fall/Juveniles

Figure 19. cont’d.
Page 57

0

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Bottom Temperature (°C)

Percent

Trawls N=2312

Occurrence N=153

Catch N=3353

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=2385

Occurrence N=157

Catch N=3568

Silver Hake

Massachusetts Inshore Trawl Survey

Spring/Juveniles

Figure 20. Spring and fall distributions of juvenile silver hake and trawls relative to bottom water temperature and 

depth based on Massachusetts inshore trawl surveys (1978-2002, all years combined). White bars give the distribution 

of all the trawls, black bars give the distribution of all trawls in which silver hake occurred, and gray bars represent, 

within each interval, the percentage of the total number of silver hake caught.
Page 58

0

5

10

15

20

25

30

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Bottom Temperature (°C)

Percent

Trawls N=2152

Occurrence N=183

Catch N=11992

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=2245

Occurrence N=190

Catch N=12173

Silver Hake

Massachusetts Inshore Trawl Survey

Fall/Juveniles

Figure 20. cont’d.
Page 59

Figure 21. Seasonal distributions of juvenile silver hake and trawls relative to bottom water temperature and depth 

based on Rhode Island Narragansett Bay trawl surveys (1990-1996; all years combined). White bars give the 

distribution of all the trawls and black bars represent, within each interval, the percentage of the total number of silver

hake caught.

-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27

0

10

20

30

40

50

-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27

0

20

40

60

80

-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27

0

4

8

12

16

20

-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27

0

20

40

60

80

Bottom Temperature (C)

Winter

Spring

Summer

Autumn

Stations

Catches

10 20 30 40 50 60 70 80 90 100 110 120 0

10

20

30

40

50

10 20 30 40 50 60 70 80 90 100 110 120

0

10

20

30

40

10 20 30 40 50 60 70 80 90 100 110 120

0

20

40

60

10 20 30 40 50 60 70 80 90 100 110 120 0

20

40

60

80

Winter

Autumn

Summer

Spring

Stations

Catches

Bottom Depth (ft)
Page 60

Figure 22. Distributions of juvenile silver hake and trawls relative to bottom water temperature, depth, salinity, and 

dissolved oxygen based on NEFSC Hudson-Raritan estuary trawl surveys (1992-1997; all years combined). White bars 

give the distribution of all the trawls and black bars represent, within each interval, the percentage of the total number 

of silver hake caught.

Temperature (C)

Depth (ft)

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

0

2

4

6

8

10

12

14

Stations

Catches

10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85

0

5

10

15

20

25

30

35

Dissolved Oxygen (mg/l)

Salinity (ppt)

0 1 2 3 4 5 6 7 8 9 10 11 12 13

0

5

10

15

20

25

30

35

15 17 19 21 23 25 27 29 31 33 35

0

5

10

15

20

25

30
Page 61

Figure 23. Hydrographic preferences for juvenile and adult silver hake in Chesapeake Bay, from the VIMS trawl 

surveys, 1988-1999 (all years combined). Adapted from Geer (2002). Percent Percent Percent Percent

Stations

Catches

Salinity (ppt) Depth (m)

Bottom Temperature ( Dissolved Oxygen (mg/l) OC) Percent Percent

Percent Percent

Stations

Catches

Salinity (ppt) Depth (m)

Bottom Temperature ( Dissolved Oxygen (mg/l) OC)
Page 62

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Bottom Temperature (°C)

Percent

Trawls N=10537

Occurrence N=1546

Catch N=54808

0

10

20

30

40

50

1-10

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

91-100

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

Bottom Depth (m)

Percent

Trawls N=12193

Occurrence N=1773

Catch N=64695

0

10

20

30

40

50

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

Salinity (PPT)

Percent

Trawls N=1959

Occurrence N=286

Catch N=8525

Silver Hake

NEFSC Bottom Trawl Survey

Spring/Adults

Figure 24. Spring and fall distributions of adult silver hake and trawls relative to bottom water temperature, depth, and 

salinity based on NEFSC bottom trawl surveys (1963-2002; all years combined). White bars give the distribution of all 

the trawls, black bars give the distribution of all trawls in which silver hake occurred, and gray bars represent, within 

each interval, the percentage of the total number of silver hake caught. Note that the bottom depth intervals change with 

depth (from 10 to 20 to 100 m) in the bottom depth bar chart.
Page 63

0

10

20

30

40

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

Bottom Temperature (°C)

Percent

Trawls N=12159

Occurrence N=1958

Catch N=55328

0

5

10

15

20

25

30

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=13863

Occurrence N=2211

Catch N=62522

0

10

20

30

40

50

27 29 30 31 32 33 34 35 36 37

Salinity (PPT)

Percent

Trawls N=2271

Occurrence N=473

Catch N=21740

Silver Hake

NEFSC Bottom Trawl Survey

Fall/Adults

Figure 24. cont’d.
Page 64

0

10

20

30

40

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Bottom Temperature (°C)

Percent

Trawls N=2312

Occurrence N=144

Catch N=1495

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=2385

Occurrence N=148

Catch N=1522

Silver Hake

Massachusetts Inshore Trawl Survey

Spring/Adults

Figure 25. Spring and fall distributions of adult silver hake and trawls relative to bottom water temperature and depth 

based on Massachusetts inshore trawl surveys (1978-2002, all years combined). White bars give the distribution of all 

the trawls, black bars give the distribution of all trawls in which silver hake occurred, and gray bars represent, within 

each interval, the percentage of the total number of silver hake caught.
Page 65

0

5

10

15

20

25

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Bottom Temperature (°C)

Percent

Trawls N=2152

Occurrence N=164

Catch N=8156

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=2245

Occurrence N=170

Catch N=8282

Silver Hake

Massachusetts Inshore Trawl Survey

Fall/Adults

Figure 25. cont’d. 
Page 66

Figure 26. Seasonal distributions of adult silver hake and trawls relative to bottom water temperature and depth based 

on Rhode Island Narragansett Bay trawl surveys (1990-1996; all years combined). White bars give the distribution of 

all the trawls and black bars represent, within each interval, the percentage of the total number of silver hake caught.

10 20 30 40 50 60 70 80 90 100 110 120

0

10

20

30

40

50

10 20 30 40 50 60 70 80 90 100 110 120

0

10

20

30

40

50

10 20 30 40 50 60 70 80 90 100 110 120

0

20

40

60

80

10 20 30 40 50 60 70 80 90 100 110 120

0

20

40

60

Autumn

Summer

Spring

Stations

Catches

Bottom Depth (ft)

-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27

0

10

20

30

40

50

-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27 0

20

40

60

80

-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27

0

20

40

60

80

-1 1 3 5 7 9 11 13 15 17 19 21 23 25 27

0

20

40

60

80

Bottom Temperature (C)

Winter

Spring

Summer

Autumn

Stations

Catches

Winter
Page 67

Figure 27. Trends in NEFSC fall survey data and landings for northern (top) and southern (bottom) stocks of silver 

hake, from New England Fishery Management Council (2003).
Page 68

Figure 28. Distribution and abundance of juvenile and adult silver hake from NEFSC autumn bottom trawl surveys 

during a period of relatively low abundance (autumn 1967-1971) and a period of relatively high abundance (autumn 

1989-1993).

Number/Tow

 1 to < 50

 50 to < 100

 100 to < 500

 500 to < 1000

 1000 to < 3611

NMFS Trawl Surveys

Autumn 1967 - 71

Juveniles (<23cm)

Low Abundance

Silver Hake

Number/Tow

 1 to < 50

 50 to < 100

 100 to < 500

 500 to < 1000

 1000 to < 3611

NMFS Trawl Surveys

Autumn 1967 - 71

Adults (>=23cm)

Low Abundance

Silver Hake

Number/Tow

 1 to < 50

 50 to < 100

 100 to < 500

 500 to < 1000

 1000 to < 3611

NMFS Trawl Surveys

Autumn 1989 - 93

Adults (>=23cm)

High Abundance

Silver Hake

Number/Tow

1 to < 50

50 to < 100

100 to < 500

500 to < 1000

1000 to < 3611

NMFS Trawl Surveys

Autumn 1989 - 93

Juveniles (<23cm)

High Abundance

Silver Hake
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

 MAIL