NOAA Technical Memorandum NMFS-NE-141

Essential Fish Habitat Source Document:

Atlantic Mackerel, Scomber scombrus,

Life History and Habitat Characteristics

U. S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Northeast Region

Northeast Fisheries Science Center

Woods Hole, Massachusetts

September 1999
Recent Issues

105. Review of American Lobster (Homarus americanus) Habitat Requirements and Responses to Contaminant Exposures.

By Renee Mercaldo-Allen and Catherine A. Kuropat. July 1994. v + 52 p., 29 tables. NTIS Access. No. PB96-115555.

106. Selected Living Resources, Habitat Conditions, and Human Perturbations of the Gulf of Maine: Environmental and

Ecological Considerations for Fishery Management. By Richard W. Langton, John B. Pearce, and Jon A. Gibson, eds.

August 1994. iv + 70 p., 2 figs., 6 tables. NTIS Access. No. PB95-270906.

107. Invertebrate Neoplasia: Initiation and Promotion Mechanisms -- Proceedings of an International Workshop, 23 June

1992, Washington, D.C. By A. Rosenfield, F.G. Kern, and B.J. Keller, comps. & eds. September 1994. v + 31 p., 8 figs.,

3 tables. NTIS Access. No. PB96-164801.

108. Status of Fishery Resources off the Northeastern United States for 1994. By Conservation and Utilization Division,

Northeast Fisheries Science Center. January 1995. iv + 140 p., 71 figs., 75 tables. NTIS Access. No. PB95-263414.

109. Proceedings of the Symposium on the Potential for Development of Aquaculture in Massachusetts: 15-17 February 1995,

Chatham/Edgartown/Dartmouth, Massachusetts. By Carlos A. Castro and Scott J. Soares, comps. & eds. January 1996.

v + 26 p., 1 fig., 2 tables. NTIS Access. No. PB97-103782.

110. Length-Length and Length-Weight Relationships for 13 Shark Species from the Western North Atlantic. By Nancy E.

Kohler, John G. Casey, Patricia A. Turner. May 1996. iv + 22 p., 4 figs., 15 tables. NTIS Access. No. PB97-135032.

111. Review and Evaluation of the 1994 Experimental Fishery in Closed Area II on Georges Bank. By Patricia A. Gerrior,

Fredric M. Serchuk, Kathleen C. Mays, John F. Kenney, and Peter D. Colosi. October 1996. v + 52 p., 24 figs., 20 tables. NTIS

Access. No. PB98-119159.

112. Data Description and Statistical Summary of the 1983-92 Cost-Earnings Data Base for Northeast U.S. Commercial

Fishing Vessels: A Guide to Understanding and Use of the Data Base. By Amy B. Gautam and Andrew W. Kitts. December

1996. v + 21 p., 11 figs., 14 tables. NTIS Access. No. PB97-169320.

113. Individual Vessel Behavior in the Northeast Otter Trawl Fleet during 1982-92. By Barbara Pollard Rountree. August 1997.

v + 50 p., 1 fig., 40 tables. NTIS Access. No. PB99-169997.

114. U.S. Atlantic and Gulf of Mexico Marine Mammal Stock Assessments -- 1996. By Gordon T. Waring, Debra L. Palka, Keith

D. Mullin, James H.W. Hain, Larry J. Hansen, and Kathryn D. Bisack. October 1997. viii + 250 p., 42 figs., 47 tables. NTIS

Access. No. PB98-112345.

115. Status of Fishery Resources off the Northeastern United States for 1998. By Stephen H. Clark, ed. September 1998. vi

+ 149 p., 70 figs., 80 tables. NTIS Access. No. PB99-129694.

116. U.S. Atlantic Marine Mammal Stock Assessments -- 1998. By Gordon T. Waring, Debra L. Palka, Phillip J. Clapham, Steven

Swartz, Marjorie C. Rossman, Timothy V.N. Cole, Kathryn D. Bisack, and Larry J. Hansen. February 1999. vii + 182 p., 16

figs., 56 tables. NTIS Access. No. PB99-134140.

117. Review of Distribution of the Long-finned Pilot Whale (Globicephala melas) in the North Atlantic and Mediterranean.

By Alan A. Abend and Tim D. Smith. April 1999. vi + 22 p., 14 figs., 3 tables. NTIS Access. No. PB99-165029.

118. Tautog (Tautoga onitis) Life History and Habitat Requirements. By Frank W. Steimle and Patricia A. Shaheen. May 1999.

vi + 23 p., 1 fig., 1 table. NTIS Access. No. PB99-165011.

119. Data Needs for Economic Analysis of Fishery Management Regulations. By Andrew W. Kitts and Scott R. Steinback.

August 1999. iv + 48 p., 10 figs., 22 tables. NTIS Access. No. PB99-171456.

120. Marine Mammal Research Program of the Northeast Fisheries Science Center during 1990-95. By Janeen M. Quintal and

Tim D. Smith. September 1999. v + 28 p., 4 tables, 4 app. NTIS Access. No. PB2000-100809.
U. S. DEPARTMENT OF COMMERCE

William Daley, Secretary

National Oceanic and Atmospheric Administration

D. James Baker, Administrator

National Marine Fisheries Service

Penelope D. Dalton, Assistant Administrator for Fisheries

Northeast Region

Northeast Fisheries Science Center

Woods Hole, Massachusetts

September 1999

Essential Fish Habitat Source Document:

Atlantic Mackerel, Scomber scombrus,

Life History and Habitat Characteristics

Anne L. Studholme, David B. Packer, Peter L. Berrien,

Donna L. Johnson, Christine A. Zetlin, and Wallace W. Morse

National Marine Fisheries Serv., James J. Howard Marine Sciences Lab., 74 Magruder Rd., Highlands, NJ 07732

This series represents a secondary level of scientifiic 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-141
Editorial Notes on Issues 122-152

in the

NOAA Technical Memorandum NMFS-NE Series

Editorial Production

For Issues 122-152, staff of the Northeast Fisheries Science Center's (NEFSC's) Ecosystems Processes Division have

largely assumed 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 has been performed by, and all credit for such production rightfully belongs to, the authors and

acknowledgees of each issue, as well as those noted below in "Special Acknowledgments."

Special Acknowledgments

David B. Packer, Sara J. Griesbach, and Luca M. Cargnelli coordinated virtually all aspects of the preprinting editorial

production, as well as performed virtually all technical and copy editing, type composition, and page layout, of Issues

122-152. Rande R. Cross, Claire L. Steimle, and Judy D. Berrien conducted the literature searching, citation checking,

and bibliographic styling for Issues 122-152. Joseph J. Vitaliano produced all of the food habits figures in Issues 122-

152.

Internet Availability

Issues 122-152 are being copublished, i.e., both as paper copies and as web postings. All web postings are, or will soon

be, available at: www.nefsc.nmfs.gov/nefsc/habitat/efh. Also, all web postings will be in "PDF" format.

Information Updating

By federal regulation, all information specific to Issues 122-152 must be updated at least every five years. All official

updates will appear in the web postings. Paper copies will be reissued only when and if new information associated with

Issues 122-152 is significant enough to warrant a reprinting of a given issue. All updated and/or reprinted issues will retain

the original issue number, but bear a "Revised (Month Year)" label.

Species Names

The NMFS Northeast Regions policy on the use of species names in all technical communications is generally to follow

the American Fisheries Societys lists of scientific and common names for fishes (i.e., Robins et al. 1991a), mollusks (i.e.,

Turgeon et al. 1998b

), and decapod crustaceans (i.e., Williams et al. 1989c), and to follow the Society for Marine

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

).

a

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

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

b

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.

c

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.

d

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

e

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

Fish. Bull. (U.S.) 96:686-726.
Page iii

FOREWORD

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 NMFS to assist the

regional fishery management councils in the implementation

of EFH in their respective fishery management plans.

NMFS 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 this series of 30

EFH species reports (plus one consolidated methods report).

The EFH species reports comprise a survey of the important

literature as well as original analyses of fishery-independent

JAMES J. HOWARD MARINE SCIENCES LABORATORY

HIGHLANDS, NEW JERSEY

SEPTEMBER 1999

data sets from NMFS 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 have understandably begun to be referred to

as the “EFH source documents.”

NMFS 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.

Identifying and describing EFH are the first steps in the

process of protecting, conserving, and enhancing essential

habitats of the managed species. Ultimately, NMFS, 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.

A historical note: the EFH species reports effectively

recommence a series of reports published by the NMFS

Sandy Hook (New Jersey) Laboratory (now formally known

as the James J. Howard Marine Sciences Laboratory) from

1977 to 1982. These reports, which were formally labeled

as Sandy Hook Laboratory Technical Series Reports, but

informally known as “Sandy Hook Bluebooks,” summarized

biological and fisheries data for 18 economically important

species. The fact that the bluebooks continue to be used two

decades after their publication persuaded us to make their

successors – the 30 EFH source documents – available to

the public through publication in the NOAA Technical

Memorandum NMFS-NE series.

JEFFREY N. CROSS, CHIEF

ECOSYSTEMS PROCESSES DIVISION

NORTHEAST FISHERIES SCIENCE CENTER
Page v

Contents

Introduction...............................................................................................................................................................................................1

Life History ...............................................................................................................................................................................................1

Habitat Characteristics ..............................................................................................................................................................................4

Geographical Distribution.........................................................................................................................................................................6

Status of the Stocks ...................................................................................................................................................................................7

Research Needs .........................................................................................................................................................................................8

Acknowledgments.....................................................................................................................................................................................8

References Cited .......................................................................................................................................................................................8

Tables

Table 1. Summary of the distribution and abundance of Atlantic mackerel in northwestern Atlantic estuaries......................................12

Table 2. Summary of the distribution and abundance of Atlantic mackerel in southern New England and Mid-Atlantic estuaries .......14

Table 3. Summary of life history and habitat parameters for Atlantic mackerel, Scomber scombrus......................................................16

Figures

Figure 1. The Atlantic mackerel, Scomber scombrus (from Goode 1884)............................................................................................18

Figure 2. Abundance of the major prey items in the diet of Atlantic mackerel collected during NEFSC bottom trawl surveys...........19

Figure 3. Abundance of Atlantic mackerel eggs relative to water temperature and depth based on NEFSC MARMAP surveys ........20

Figure 4. Abundance of Atlantic mackerel larvae relative to water temperature and depth based on NEFSC MARMAP surveys......21

Figure 5. Abundance of juvenile Atlantic mackerel relative to water temperature and depth based on NEFSC trawl surveys ............22

Figure 6. Abundance of juvenile/adult Atlantic mackerel relative to temperature and depth based on Massachusetts surveys............23

Figure 7. Abundance of juvenile Atlantic mackerel relative to bottom depth and temperature based on Narragansett Bay surveys....24

Figure 8. Abundance of adult Atlantic mackerel relative to water temperature and depth based on NEFSC trawl surveys .................25

Figure 9. Distribution and abundance of Atlantic mackerel eggs collected during NEFSC MARMAP ichthyoplankton surveys .......26

Figure 10. Distribution and abundance of Atlantic mackerel larvae collected during NEFSC MARMAP ichthyoplankton surveys.....28

Figure 11. Distribution and abundance of juvenile and adult Atlantic mackerel collected during NEFSC bottom trawl surveys..........30

Figure 12. Distribution and abundance of juvenile and adult Atlantic mackerel in Massachusetts coastal waters.................................32

Figure 13. Distribution and relative abundance of juvenile Atlantic mackerel collected in Narragansett Bay .......................................33

Figure 14. Distribution, abundance, and length frequency distribution of juvenile/adult Atlantic mackerel in Long Island Sound ......34

Figure 15. Commercial landings and stock biomass for Atlantic mackerel from Labrador to North Carolina .......................................35
Page 1

INTRODUCTION

Atlantic mackerel, Scomber scombrus L. (Figure 1), is

a fast swimming, pelagic schooling species distributed in the

northwest Atlantic from the Gulf of St. Lawrence to Cape

Lookout, North Carolina (Sette 1943, 1950; Anderson 1976;

MAFMC 1994). While there are two separate spawning

contingents in the northwest Atlantic (Sette 1950), since

1975 all mackerel in this area have been assessed as a unit

stock (Anderson 1982) and are considered one stock for

management purposes (MAFMC 1994). Atlantic mackerel

are managed under the Mid-Atlantic Fishery Management

Plan for Atlantic mackerel, squid and butterfish (MAFMC

1994). This EFH source document provides information on

the distribution, life history and habitat characteristics of

Atlantic mackerel in the northwest Atlantic extending from

Cape Hatteras to Georges Bank and the Gulf of Maine.

LIFE HISTORY

A brief synopsis of the life history of Atlantic mackerel

is provided in Amendment #5 to the Fishery Management

Plan for Atlantic Mackerel, Squid and Butterfish Fisheries

(MAFMC 1994). More specific information is provided

here and in other reviews (see Sette 1943, 1950; Bigelow

and Schroeder 1953; Collette, in prep.). Since there is an

important winter fishery on Atlantic mackerel on the eastern

continental shelf where they occur (Maguire et al. 1987), the

two major spawning contingents (see below) are managed as

a single transboundary stock. Thus, where appropriate,

information will be provided on both northern and southern

groups.

EGGS

The eggs of Atlantic mackerel are pelagic and spherical,

ranging in size from 1.01-1.28 mm (avg. = 1.3 mm) in

diameter, and have one oil globule ranging from 0.22-0.38

mm (avg. = 0.29 mm) in diameter (Berrien 1975). Sampling

in the Gulf of St. Lawrence indicates that egg size decreased

over time and in relation to ambient temperatures (Ware

1977).

LARVAE

Larvae average about 3.1-3.3 mm standard length (SL)

at hatching and have a large yolk sac; the eyes are large and

unpigmented (Sette 1943; Bigelow and Schroeder 1953;

Colton and Marak 1969; Berrien 1975; Ware and Lambert

1985; Scott and Scott 1988). Hatching occurs at 90-120 h

post-fertilization at an average temperature of 13.8°C

(Berrien 1975). The 50% threshold for the onset of feeding

is 3.8 mm (Ware and Lambert 1985). At about 4-6 mm the

yolk sac is absorbed by which time there is a considerable

change in body pigmentation and by 192 h, teeth are present

(Berrien 1975). Larvae undergo major changes in body

form and Sette (1943) describes a transition stage between

the larval and post-larval stages (~ 9-10 mm) where fins are

in various stages of development. This probably enhances

successful prey capture as well as predator avoidance (Ware

and Lambert 1985). To maintain rapid growth rates, with

average digestive times of 1-2 h, Peterson and Ausubel

(1984) concluded that the larvae must feed constantly.

JUVENILES

Post-larvae gradually transform from planktonic to

swimming and schooling behavior at about 30-50 mm (Sette

1943). Fish reach a length of about 50 mm in approximately

two months at which time they closely resemble adults and

reach 20 cm in December after about one year of growth

(Sette 1943; Bigelow and Schroeder 1953; Anderson and

Paciorkowski 1980; Berrien 1982; Collette, in prep.).

Kendall and Gordon (1981) show somewhat faster larval

and juvenile growth rates based on daily growth increments

from otoliths taken from fish collected in the Middle

Atlantic Bight; i.e., approximately 70-80 mm in two months;

however, these were not verified by comparison with fish of

known age. Ware and Lambert (1985) found that in St.

Georges Bay, Nova Scotia, at 15-17°C, growth rates of

juveniles (> 15 mm) averaged 0.73 mm/d from birth to

metamorphosis, similar to the estimates by Kendall and

Gordon (1981). Using daily growth rings, D’Amours et al.

(1990) estimated that young mackerel from the northern

contingent would grow faster earlier in their first growing

season which would be consistent with Sette’s (1950)

conclusions. However, Simard et al. (1992) calculated that

growth curves of juvenile Atlantic mackerel, based on

otolith samples from the northern and southern spawning

groups were not significantly different at least up to 90 days

in age.

ADULTS

By the end of their second year, Atlantic mackerel

attain a size of about 26 cm and after five years about 33 cm

(Anderson 1973; Isakov 1973; Stobo and Hunt 1974). Fish

that are 6 years old can reach a length of 39-40 cm. Based

on studies of Canadian mackerel, MacKay (1967) theorized

that growth is population density dependent; i.e., that

abundant year classes grow more slowly than less abundant

year classes, although Moores et al. (1975) did not find this

to be true for Newfoundland fish. Overholtz (1989) found

the 1982 cohort to be one of the slowest growing on record;

it is one of the largest recruiting year-classes recorded.

Large differences in mackerel growth suggest that year-class

size partially influences the initial pattern of growth during

a cohort’s first years (Overholtz et al. 1991b). Thus, early

growth may be related to year-class size, while stock size
Page 2

may be more influential after the juveniles join the offshore

adults (Overholtz et al. 1991b; Collette, in prep.).

The adults are highly mobile and school. They are

obligate swimmers due to the absence of a swimbladder and

the necessity for ram gill ventilation to meet blood

oxygenation demands (Roberts 1975). Nevertheless this

species exhibits diurnal changes in activity, swimming faster

during the day than at night (Olla et al. 1975, 1976). Under

laboratory conditions, at temperatures ranging from 7.3-

15.8°C (within their preferred range), swimming speed of

adults averaged 36 cm/s during the day and 29 cm/s at night

(Olla et al. 1975, 1976). The fish continued to school both

day and night although there were diurnal changes in

cohesiveness of the group.

REPRODUCTION

There is some variation in estimates of size and age at

maturity. Based on samples of Atlantic mackerel collected

from 1987-1989 by the Northeast Fisheries Science Center

(NEFSC) groundfish surveys, median length at maturity

(L50) was 25.7 cm for females and 26.0 cm for males;

median age (A50) was 1.9 years for both (O’Brien et al.

1993). By age 3, 99% of the females and 97% of the males

were mature (O’Brien et al. 1993). Fish collected in

Newfoundland waters from June-September 1970-1973 had

higher values for L50 of 34 cm and 35 cm for females and

males respectively (Moores et al. 1975). MacKay (1967)

reported first spawning for mackerel occurred at age 2 and

at lengths > 30 cm for fish collected in May-July 1965-1966

from the Gulf of St Lawrence and coastal Nova Scotia and

Massachusetts. These differences in median maturity may

be due to the slower growth of larger year classes that may

delay spawning from one to three years (MacKay 1973;

Overholtz 1989). Consequently, both year-class size and

adult stock size may be important factors regulating growth

in Atlantic mackerel (Overholtz 1989; Overholtz et al.

1991b).

Spawning occurs during spring and summer and

progresses from south to north as the surface waters warm

and fish migrate (Sette 1943). There are two spawning

contingents; a southern group that spawns primarily in the

Mid-Atlantic Bight and Gulf of Maine from mid-April to

June and a northern contingent that spawns in the southern

Gulf of St. Lawrence from the end of May to mid-August

(Berrien 1982). The southern contingent begins the spring

spawning migration by moving inshore between Delaware

Bay and Cape Hatteras, usually between mid-March and

mid-April depending to some extent on water temperature

(Berrien 1982). The northern contingent begins to move

inshore off southern New England usually in late May,

mixing temporarily with part of the southern contingent

before migrating eastward along the coast of Nova Scotia.

Here other mackerel schools from offshore join the fish

before moving into the Gulf of St. Lawrence to spawn

(Berrien 1982). Small fish (< 30 cm) lag behind larger fish

and spawn later (Berrien 1982).

Most of the spawning occurs in the shoreward half of

continental shelf waters, although there is some spawning on

the shelf edge and beyond (Berrien 1982; Collette, in prep.).

Sette (1943) described the area bordered by southern New

England and the Middle Atlantic states as the most

important spawning grounds for mackerel. Current

information indicates that the oceanic bight between

Chesapeake Bay and southern New England is the most

productive area. The Gulf of St. Lawrence is somewhat less

so although the southern side is considered extremely

productive for the northern contingent (MacKay 1973) while

the Gulf of Maine and coast of outer Nova Scotia are the

least (Sette 1950; Collette, in prep.). Some open bays; i.e.,

Cape Cod Bay and Massachusetts Bay, are sites of some

importance with spawning fish abundant or common from

May to July and August (Table 1). While according to

Wheatland (1956), spawning occurs rarely in Gardiner’s

Bay and Long Island Sound, recent assessments of relative

abundance of eggs and larvae in these areas show that both

life stages are highly abundant and abundant in April and

May (Table 2). Well-enclosed bays, especially those

receiving considerable river inflow such as Chesapeake Bay

and Delaware Bay show little evidence of spawning (Table

2).

Atlantic mackerel are serial, or batch spawners, with

estimates of total fecundity ranging from 285,000 to 1.98

million eggs for southern contingent mackerel between 31

and 44 cm fork length (FL) (Morse 1980). Based on a very

limited sample of northern contingent mackerel, fecundity

estimates ranged from 211,000 to 397,000 eggs for 35 and

40 cm females respectively (MacKay 1973). Analysis of

egg diameter frequencies indicate that five to seven egg

batches are spawned by each female (Morse 1980).

FOOD HABITS

Atlantic mackerel are opportunistic feeders that can

ingest prey either by individual selection of organisms or by

passive filter feeding (Pepin et al. 1988). Filter feeding

occurs when small plankton are abundant and mackerel

swim through patches with mouth slightly agape, filtering

food through their gill rakers (MacKay 1979). According to

MacKay (1979), particulate feeding is the principal feeding

mode in the spring and fall, while filter feeding

predominates in the summer in the Gulf of St. Lawrence.

Moores et al. (1975) maintain that the diet of fish from

Newfoundland suggests that particulate feeding occurs there

throughout the season.

Larvae feed primarily on zooplankton (Collette, in

prep.). First-feeding larvae (3.5 mm) collected from Long

Island Sound were found to be phytophagous while slightly

larger individuals (> 4.4 mm) fed on copepod nauplii

(Peterson and Ausubel 1984; Ware and Lambert 1985).

Fish > 5 mm fed on copepodites of Acartia and Temora
Page 3

while diets of fish > 6 mm contained adult copepods

(Peterson and Ausubel 1984). Larvae > 6.4 mm were also

cannibalistic, feeding on 3.5-4.5 mm conspecifics (Peterson

and Ausubel 1984; Fortier and Villeneuve 1996).

Consumption rates of larvae average between 25 and 75%

body weight per day and they probably feed continuously.

Larvae feed selectively, primarily on the basis of prey

visibility (Peterson and Ausubel 1984). Fortier and

Villeneuve (1996), studying larval mackerel from the

Scotian Shelf, found that with increasing larval length, the

diet shifted from copepod nauplii to copepod and fish

larvae; the fish larvae included yellowtail flounder, silver

hake, redfish and a large proportion of conspecifics.

Predation was stage-specific; only the newly hatched larvae

of a given species were ingested. However, piscivory was

limited at densities of fish larvae < 0.1/m3

 and declined with

increasing density of nauplii and with increasing number of

alternative copepod prey ingested.

Juveniles eat mostly small crustaceans such as

copepods, amphipods, mysid shrimp and decapod larvae

(Collette, in prep.). They also feed on small pelagic

mollusks (Spiratella and Clione) when available (Collette,

in prep.). Adults feed on the same food as juveniles but

diets also include a wider assortment of organisms and

larger prey items. For example, euphausiid, pandalid and

crangonid shrimp are common prey; chaetognaths,

larvaceans, pelagic polychaetes and larvae of many marine

species have been identified in mackerel stomachs (Collette,

in prep.). Bigelow and Schroeder (1953) found many Gulf

of Maine mackerel feeding on Calanus as well as other

copepods. Larger prey such as squids (Loligo) and fishes

(silver and other hakes, sand lance, herring, and sculpins)

are not uncommon, especially for large mackerel (Bowman

et al. 1984). Under laboratory conditions, mackerel also fed

on Aglantha digitale, a small transparent medusa common

in temperate and boreal waters (Runge et al. 1987). The

1973 -1990 NEFSC bottom trawl survey data on food habits

for two size classes of mackerel (11-30 cm; 30-50 cm) for

1973-1980 and 1981-1990 reflects this diversity (Figure 2).

While there is variability between the two size classes and

between the two survey periods, copepods, euphausiids and

various crustaceans could be considered relative staples in

the diet.

Immature mackerel begin feeding in the spring; older

fish feed until gonadal development begins, stop feeding

until spent and then resume prey consumption (Berrien

1982; Collette, in prep.). Under experimental conditions in

which larval fish (3-10 mm in length) were presented as part

of natural zooplankton assemblages, prey preference by

mackerel was positively size selective and predation rates

were not influenced by larval fish density (Pepin et al.

1987). Subsequent studies indicated that mackerel may

achieve a higher rate of energy intake by switching to larger

prey and increasing search rate as prey size and total

abundance increase (Pepin et al. 1988). Filter feeding

activity also increased with increasing prey density and

Pepin et al. (1988) suggest that feeding rates under natural

conditions of prey abundance (0.1 g wet weight/m3

) indicate

that mackerel would not be satiated if foraging were

restricted only to daylight.

PREDATION

Predation has a major influence on the dynamics of

northwest Atlantic mackerel (Overholtz et al. 1991b). In

fact, predation mortality is probably the largest component

of natural mortality on this stock, and based on model

predictions, may be higher than previously thought

(Overholtz et al. 1991b). Atlantic mackerel serve as prey

for a wide variety of predators including other mackerel,

dogfish, tunas, bonito, and striped bass (Collette, in prep.).

Small mackerel are prey for Atlantic cod and squid, which

feed on fish < 10 to 13 cm in length (Collette, in prep.).

Pilot whales, common dolphins, harbor seals, porpoises and

seabirds are also significant predators (Smith and Gaskin

1974; Payne and Selzer 1983; Overholtz and Waring 1991;

Montevecchi and Myers 1995). Other predators include

swordfish, bigeye thresher, thresher, shortfin mako, tiger

shark, blue shark, spiny dogfish, dusky shark, king mackerel,

thorny skate, silver hake, red hake, bluefish, pollock, white

hake, goosefish and weakfish (Scott and Tibbo 1968;

Maurer and Bowman 1975; Stillwell and Kohler 1982,

1985; Bowman and Michaels 1984; Collette, in prep.).

MIGRATION/STOCK STRUCTURE

As stated previously, the two major spawning

contingents are managed as a single transboundary stock.

Sette (1950) described northern and southern population

contingents of Atlantic mackerel in the northwest Atlantic

with different spring and autumn migration patterns and

summer distributions. Various methods have attempted to

discriminate the two contingents in the northwest Atlantic,

including meristic analyses (MacKay and Garside 1969),

comparison of parasitic fauna (Isakov 1976), genetic

variability (Maguire et al. 1987) and differences in otoliths

(Gregoire and Castonguay 1989; Castonguay et al. 1991).

While there were some significant differences, overlaps in

character distributions have prevented the development of a

useful discrimination method.

During the winter, Atlantic mackerel apparently

overwinter in deep water of the continental shelf from Sable

Island Bank, off Nova Scotia to the Chesapeake Bay region

and in spring move inshore and northeast; this pattern is

reversed in the fall (Sette 1950; Leim and Scott 1966;

MacKay 1967; Berrien 1982). In April and early May the

fish form the two spawning aggregations; i.e., a southern

contingent that spawns off New Jersey and New York, and

a northern contingent that spawns in the Gulf of St.

Lawrence.

As fish from the southern contingent move northeast

along the coast, they are joined by the schools from the
Page 4

northern contingent which are also moving inshore. The

overwintering area and timing of migration varies annually,

probably influenced by meteorological events or regional

conditions with low spring temperatures significantly

delaying the timing, extent and duration (Murray et al. 1983;

Murray 1984). In fact, the seasonal cycle in temperature in

the waters of the Mid-Atlantic and southern New England

[well-mixed water column in winter with temperatures < 4o

C

near the coast to > 8o

C near the shelf edge; warming surface

layers in spring and gradual warming from south (to 25o

C)

to north (to about 18°C) and subsequent fall cooling] is

certainly an important environmental factor influencing

migration and distribution (Overholtz et al. 1991a). This is

supported by field studies that have shown that mackerel are

intolerant of temperatures < 5-6o

C or > 15-16oC (Overholtz

and Anderson 1976) and laboratory studies that have

confirmed that as temperatures departed from preferred

ranges (7.3-15.8o

C) swimming speeds of adult mackerel

increased, reflecting thermal avoidance (Olla et al. 1975,

1976). By late April and May, the southern contingent is

distributed off New Jersey and Long Island moving into the

western side of the Gulf of Maine by June and July, and

returning to the shelf edge probably between Long Island

and Chesapeake Bay by October (Sette 1950; Berrien 1982).

The northern contingent, by late spring, has moved

inshore off southern New England, mixing temporarily with

the southern contingent before migrating eastward along the

coast of Nova Scotia, and moving into the Gulf of St.

Lawrence where they spawn in June and July. Some fish

however, remain along the coasts of Maine and Nova Scotia

throughout the summer. These fish again mix with fish from

the southern group in late fall in the Gulf of Maine before

moving to the outer shelf between Sable Island Bank and

Long Island to overwinter (Sette 1950; Parsons and Moores

1974; Moores et al. 1975). Temperature may not be as

limiting for this contingent since D’Amours and Castonguay

(1992) found that mackerel occurred in June in the Cabot

Strait off of eastern Cape Breton Island at 2.8o

C, 4oC colder

than the 7o

C isotherm proposed by Sette (1950) as the

thermal barrier to northern migration.

HABITAT CHARACTERISTICS

An extensive literature review and synthesis has

provided detailed information on the life history and habitat

requirements of Atlantic mackerel (Table 3). The review is

primarily limited to U.S. waters; however, due to the

intermixing of the two contingents, some information also

relates to fish in Canadian waters.

EGGS

The eggs are pelagic in water over 34 ppt (Fritzsche

1978), floating in surface waters above the thermocline or in

the upper 10-15 m (Sette 1943; Berrien 1982). Incubation

time depends primarily on temperature: at 11o

C, 7.5 days; at

13o

C, 5.5 days and at 16oC, 3.6 days (Worley 1933).

Lanctot (1980) had similar results: at 11o

C, 8 days; at 13oC,

5.8 days and at 16o

C, 3.9 days.

Based on the NEFSC Marine Resources Monitoring,

Assessment, and Prediction (MARMAP) offshore

ichthyoplankton surveys, eggs were collected at near surface

temperatures ranging from 5-23o

C with the largest

proportion between ~ 7o

C and 16oC (Figure 3). In April, the

highest abundances were collected from 7-9o

C; in May, from

9-12o

C; in June, from 10-12oC; while the few collected in

July and August were at a wide range of temperatures (11-

23o

C) (Figure 3). This is consistent with findings by Berrien

(1978) who reported that for May 1966, the weighted mean

surface temperature for all eggs collected from Martha’s

Vineyard to Chesapeake Bay was 11.0o

C (range 6.3-16.9oC)

with 97% collected at 8.7-13.8o

C. Sette (1943), for eggs

collected in 1932, reported a weighted mean of 10.9o

C

surface temperature with 98% occurring from 9.0-13.5o

C.

Mortality may be influenced by acclimation

temperatures of adult fish (Lanctot 1980). Worley (1933)

found minimal mortality at 16o

C which corresponded to

capture temperature of the adults. Lockwood et al. (1977)

found mortalities < 20% between 9.4 and 15.1o

C. Ware and

Lambert (1985) also found that egg mortality rates of

mackerel from St. Georges Bay, Nova Scotia were highly

correlated with the rate of warming during the spawning

season.

Salinities may also affect survival. Peterson and

Ausubel (1984) attributed high egg mortality to unusually

low salinities (23 ppt) in Long Island Sound as compared

with usual values of 25-27 ppt.

Eggs were collected at depths in the water column

ranging from 10-325 m; the majority were collected from

30-70 m (Figure 3). In April, the highest numbers of eggs

were collected at depths of 10-30 m; in May from 30-50 m;

in June, July and August, at depths of 30-70 m (Figure 3).

Ware and Lambert (1985) found that mackerel eggs in St.

Georges Bay tended to concentrate near the surface,

particularly under light winds and declined exponentially

with depth with the rate of decline a function of egg

diameter and temperature gradient in the top 5 m.

LARVAE

Based on the NEFSC MARMAP ichthyoplankton

surveys, larvae are found at water column temperatures

ranging from 6-22o

C with the largest proportion between

about 8o

C and 13oC (Figure 4). In May, the majority of

larvae were found at 8-10o

C; in June at 8-11oC; in July at

8o

C and 10-11oC; and in August at 9oC and 12-13oC (Figure

4). For larvae collected during May, June and August 1966,

Berrien (1978) indicated that surface water temperatures

ranged from 12.3-20.7o

C with 96% occurring from 13.7-

16.8o

C. Ware and Lambert (1985) found that larval

mortality rates (~ 42 %/d) were positively correlated with
Page 5

temperature.

Larvae were collected at depths ranging from 10-130 m

(Figure 4). With the exception of July when 50% were

collected at a depth of 70 m, larvae were primarily

distributed at depths ≤ 50 m (Figure 4). Sette (1943) reports

that larvae vertically migrate diurnally from the surface at

night to the thermocline during the day. Ware and Lambert

(1985) found that in St. Georges Bay, recently-hatched

larvae were collected at depths of 5-10 m and as they grew,

moved progressively closer to the surface during the day; at

sizes ranging from 3-8 mm, median depth increased at a rate

of 0.7 m/d.

JUVENILES

Based on the 1963-1997 NEFSC bottom trawl surveys,

juveniles in the fall were caught at temperatures ranging

from 4-22o

C, with the majority (> 55%) occurring at 10oC.

In the winter 90% were collected at 5-6o

C (range: 3-12°C)

(Figure 5). The temperatures at which juveniles were found

were a little broader in spring (4-17o

C) and summer (4-

19o

C). Although the majority of juveniles (> 60%) were still

found at 5-6o

C in the spring, by summer they wee found at

higher temperatures with > 40% collected at 8o

C and 40%

at 13o

C (Figure 5).

In the fall, the majority of juveniles (> 77%) were at

depths of 20-40 m (range: surface to 320 m); in the winter >

60% were at slightly deeper depths (50-70 m) while by

spring they were widely dispersed through the water column

(surface to 340 m) but concentrated (> 75%) at depths

ranging from 30-90 m (Figure 5). By summer, fish were

higher in the water column (surface to 210 m) with ~ 94%

distributed from 20-50 m in two peaks (Figure 5).

Based on collections from the 1978-1996

Massachusetts inshore bottom trawl surveys, juveniles were

most abundant at 11o

C in spring and 9 and 13oC in autumn,

and at depths of 10 and 50 m in the spring and 25 and 60 m

in the autumn (Figure 6).

Based on collections from the 1990-1996 Rhode Island

Narragansett Bay bottom trawl surveys, juveniles were

captured in summer at bottom depths between 6.1-15.2 m

(20-50 ft) and were most abundant at 12.2-15.2 m (40-50 ft)

(Figure 7). They were caught at bottom temperatures of

19o

C in summer and at 11 and 15oC in autumn (Figure 7).

Juveniles collected in otter trawl surveys in the HudsonRaritan estuary (New York and New Jersey) during July

1997 were found at depths ranging from 4.9-9.8 m.

Salinities ranged from 26.1-28.9 ppt, dissolved oxygen from

7.3-8.0 mg/l and temperatures from 17.6-21.7o

C (S. Wilk,

NMFS, NEFSC, James J. Howard Marine Sciences

Laboratory, Highlands, NJ, personal communication).

ADULTS

Based on the NEFSC bottom trawl surveys, adults in

the fall were found at a slightly narrower range of

temperatures (4-16o

C) with > 80% caught from 9-12°C

(Figure 8). Winter distribution was similar to that of the

juveniles with nearly 70% at 5-6o

C (range: 3-13oC) (Figure

8). In the spring, temperature ranges were similar (2-14o

C),

but adults were distributed more evenly through a

temperature band of 5-13o

C with > 25% at 13oC (Figure 8).

By summer, fish were found at temperatures ranging from

4-14o

C with > 30% at 10-11oC and > 35% at 14oC (Figure

8). These temperatures are within the ranges previously

reported for mackerel. In addition, Bigelow and Schroeder

(1953) indicate that the highest temperature at which

mackerel are commonly found is 20o

C while commercial

catches are sometimes taken at 7o

C. In the northern Gulf of

St. Lawrence, concentrations of mackerel were found at 4o

C;

however, the overall probability of occurrence inshore was

higher when near-bottom temperatures were ≥ 7o

C

(Castonguay et al. 1992).

As stated previously in the migration section, field

studies have shown that mackerel are intolerant of

temperatures < 5-6o

C or > 15-16oC (Overholtz and

Anderson 1976) and laboratory studies have confirmed that

as temperatures departed from preferred ranges (7.3-

15.8o

C), swimming speeds of adult mackerel increased,

reflecting thermal avoidance (Olla et al.1975, 1976). Again,

temperature may not be as limiting for the northern

contingent since D’Amours and Castonguay (1992) found

that mackerel occurred in June off of eastern Cape Breton

Island at 2.8o

C, 4oC colder than the 7oC isotherm proposed

by Sette (1950) as the thermal barrier to northern migration.

Based on the NEFSC bottom trawl surveys, adults in

the fall were spread from 10-340 m; however > 50% were

caught at 60-80 m (Figure 8). By winter, while fish were

still found at depths of 10-270 m, ~ 50% were found at

depths of 20-30 m (Figure 8). By spring fish were broadly

dispersed from the surface to as deep as 380 m; however,

around 25% were at depths of 160-170 m (Figure 8). By

summer, schools had again moved upward in the water

column, swimming at depths of 10-180 m with > 60% at

depths of 50-70 m (Figure 8). This depth range is broader

than reported by Bigelow and Schroeder (1953) who stated

that while mackerel can swim as deep as 183 m, in spring,

summer and into fall they swim at depths of 46-55 m or less.

According to Sette (1950) larger fish tend to swim deeper

than smaller ones.

In the northern Gulf of St. Lawrence, vertical

distribution was greatest at 15 and 35 m with mackerel

occurrences positively correlated with downwelling events

and the onshore advection of warm surface waters

(Castonguay et al. 1992).

Based on Massachusetts inshore bottom trawl surveys,

adults were most abundant at 14°C in spring with the few

found in autumn at 10 and 15o

C. They were also found at

depths of 10 m in the spring while the few found in the

autumn were at 50 m (Figure 6).

Based on Rhode Island Narragansett Bay bottom trawl

surveys, a single adult was caught in winter at a depth of
Page 6

30.5 m and at a bottom temperature of 5o

C.

Factors controlling spawning time are unclear. Morse

(1980) indicated that the regularity in spawning shown by

Ware (1977) points to an internal control or constant

external stimulus; e.g., photoperiod changes, which ensures

that peak hatching occurs at the time of maximum

zooplankton abundance. Based on field investigations

(Nichols and Warnes 1993) and laboratory observations

(Walsh and Johnstone 1992), there appears to be no diel

periodicity in spawning and no significant peaks either

during the day or night. Sette (1943) noted that temperature

< 7o

C is a limiting factor in migration which subsequently

affects timing of spawning in specific locations. Based on

the NEFSC MARMAP ichthyoplankton surveys, spawning

does not begin until temperatures reach ~ 7-8o

C, with most

occurring between 9 and 14o

C (Berrien 1982; Collette, in

prep.). Sette (1943) stated that peak spawning occurs within

that range at around 10-12o

C at salinities > 30 ppt. These

temperatures were in the preferred range (7-16o

C)

determined for adult mackerel in the laboratory (Olla et al.

1975, 1976). Thus the spawning season is progressively

later as water temperatures warm and fish migrate from

south to north.

GEOGRAPHICAL DISTRIBUTION

Northwest Atlantic mackerel are primarily found in the

open sea (although rarely beyond the continental shelf) from

Black Island, Labrador (Parsons 1970) to Cape Lookout,

North Carolina (Collette and Nauen 1983). Eggs, larvae and

juveniles also found at varying levels of abundance in bays

and estuarine areas from New Jersey north through New

England and into Canadian waters (see also Sette 1950;

Tables 1, 2).

EGGS

The NEFSC MARMAP ichthyoplankton surveys found

eggs from offshore waters off Chesapeake Bay to Georges

Bank and the Gulf of Maine (Figure 9). Egg production

progressed northward from April through May, June and

July as would be expected based on the spawning/migratory

patterns of adults. For example, egg production in April

extended from Chesapeake Bay to coastal New Jersey and

along the south shore of Long Island. In May, egg

production extended from the shelf waters off New Jersey to

Nantucket, the southern edge of Georges Bank and the

western Gulf of Maine; in June production extended off

southern Rhode Island, in the region of Massachusetts Bay

and the western Gulf of Maine (Figure 9). By July, some

eggs were collected along Georges Bank, while by August,

few, if any, eggs were found. Highest densities (eggs/10 m2

)

were in May (> 39,000) and June (> 53,000). This pattern

of production and distribution is consistent with previous

reports (Sette 1943; Bigelow and Schroeder 1953; Collette,

in prep.). Eggs have been collected from early June to midAugust on the southern side of the Gulf of St. Lawrence

(Sette 1943) and this area is considered an extremely

productive spawning ground (Collette, in prep.).

LARVAE

The NEFSC MARMAP ichthyoplankton surveys also

found larvae (< 13 mm) from waters off Chesapeake Bay to

the Gulf of Maine, although more were concentrated

offshore of Delaware Bay to Massachusetts Bay from

inshore waters to the seaward limits of the survey (Figure

10). Larvae were collected from May through August with

the highest average mean density (> 10,000/10 m2

)

occurring in June and ranging from inshore to offshore from

southern New England to the Hudson Canyon with

considerable numbers collected north of Cape Cod. This

was north of where larvae were most abundant (> 2000/10

m2

) in May. Mean densities were low in July (≤ 102/10 m2)

with few, if any, (≤ 32/10 m2

) collected in August (Figure

10). Berrien (1978) reported that in May 1966, larvae were

caught between Chesapeake Bay and Oregon Inlet, North

Carolina across the continental shelf, while by June larvae

had spread from Martha’s Vineyard to Currituck Beach,

North Carolina. The highest abundance was off Montauk

Point, New York. By June, most larvae occurred to the

north, while in August few were caught. This pattern also

corresponds with previous reports by Sette (1943).

JUVENILES AND ADULTS

Collections of Atlantic mackerel from the NEFSC

bottom trawl surveys show that the distributions of juveniles

(≤ 25 cm) and adults (≥ 26 cm) ranged from Cape Hatteras

to Georges Bank, and southwestern Nova Scotia and the

Gulf of Maine (Figure 11). The distribution of both life

stages was generally similar although in spring adults tended

to be distributed further offshore than the juveniles, along

the outer edge of the Continental Shelf. In the fall, a few

juveniles were collected in the near coastal waters of the

Mid-Atlantic Bight and southern New England, particularly

eastern Long Island, while adults were absent. The mean

number of fish caught was highest in winter for adults

(106/station) and in summer for juveniles (351/station), with

more collected in the spring than in the fall reflecting the

movements of the southern spawning contingent inshore.

The highest abundance in spring occurs in the oceanic

waters between Chesapeake Bay and southern New England,

as the fish move north. Winter and summer distributions are

presented as presence/absence data, precluding a discussion

of abundances.

Based on the Massachusetts inshore bottom trawl

surveys, occurrences of Atlantic mackerel were higher for

juveniles in the autumn and for adults in the spring (Figure

12). In the autumn, most juveniles (10 to < 1391 fish/tow)
Page 7

were caught in and around the waters off Cape Ann although

small numbers (1 to < 500 fish/tow) were collected in Cape

Cod Bay, primarily off Race Point. In the spring, the catch

was highest (100 to < 101 fish/tow) along Vineyard Sound.

In the fall, only two adults were collected (one in Cape Cod

Bay, one off Cape Ann). In spring, the greatest numbers of

fish (25 to < 37 fish/tow) were found in Nantucket Sound

with lesser numbers (5 to < 25 fish /tow) also collected there

and south of Cape Ann in the northern end of Massachusetts

Bay. From 1 to < 5 fish/tow were also caught at several

stations in and around Cape Cod in the spring. This would

correspond with the spawning and migration patterns

described above.

From 1960-1970, 112 species of fishes were collected

in coastal Massachusetts waters as part of the Massachusetts

coastal zone survey (Clayton et al. 1978). Indices were

prepared on percent frequency of occurrence of various life

stages with the term “random” used to designate marine

species which may randomly occur in the estuary and

percentages based on the total number of fish (all species)

collected in the whole survey. The following list indicates

areas where Atlantic mackerel were recorded, the life stage,

and relative frequency.

Location Life stage Frequency of

Occurrence

Annisquam/

Gloucester

Adults Random; < 1% of

collection

Salem Harbor Eggs Random; < 1% of

collection

Lynn/Saugus Adults Random; < 1% of

collection

Rocky Point/

Plymouth

Eggs/larvae Common; 1-4.99%

of collection

Cape Cod

Canal

Eggs/larvae No information

Taunton River/

Mount Hope

Bay

Adults Random; < 1% of

collection

A total of 92 Atlantic mackerel were caught during the

Rhode Island Narragansett Bay bottom trawl surveys. They

were captured in low numbers at all but four stations and in

all years except 1990 and 1995. Juveniles were present in

summer and autumn and a single adult was caught in winter.

The length frequencies by season show juveniles from 7-17

cm total length (TL) occurred in summer and from 18-23 cm

TL occurred in winter. Juveniles were caught throughout

much of the Bay but the highest catch was made at the ocean

station in autumn (2.3 fish/tow; Figure 13). The single adult

was caught farther up the Bay near Newport.

Survey data from the Connecticut bottom trawl surveys

in Long Island Sound indicated that although few Atlantic

mackerel were collected, analysis of length-frequency data

indicated that both juveniles and adults were present at

different times and distributed differently (Gottschall et al.,

in review). This is confirmed by recent analysis of the 1992-

1997 survey results (Figure 14). Adults (> 28 cm; range 36-

49 cm) were present in the spring and according to

Gottschall et al. (in review) into midsummer and distributed

throughout the sound. In contrast, juveniles ranging from

12-24 cm were collected in the autumn (primarily September

and October) at depths < 18 m from Norwalk to the

Housatonic River along the Connecticut shore (Gottschall et

al., in review).

Few (n=12) Atlantic mackerel were collected in otter

trawl surveys in the Hudson-Raritan estuary from 1992 to

1997. All were juveniles ranging from 7-8 cm and were

collected during one survey in July 1997; most were

collected on the eastern edge of Staten Island (S. Wilk,

personal communication).

Estuarine Distribution (ELMR)

The NOAA/National Ocean Service (NOS) Estuarine

Living Marine Resources (ELMR) program reviewed the

distribution and relative abundances of mackerel in estuaries

from Waquoit Bay, Massachusetts to the Cape Fear River,

North Carolina. The data were based on three salinity

zones, i.e., tidal (0.0-0.5 ppt), mixed (0.5-25 ppt) and

seawater (> 25 ppt). Summaries of these distributions are

presented in Table 1 for northwestern Atlantic estuaries

(Jury et al. 1994) and in Table 2 for southern New England

and Mid-Atlantic estuaries (Stone et al. 1994).

STATUS OF THE STOCKS

Total domestic landings, including commercial and

recreational, of Atlantic mackerel in the northwest Atlantic

were 32,100 metric tons (mt) in 1993, 16% less than 1992

landings (Anderson 1995; Figure 15). Canadian landings

totaled 26,900 mt in 1993, a record since 1986, whereas

United States commercial and recreational landings in 1993

were only 4,500 and 500 mt, respectively (Anderson 1995).

Recent improvements in recruitment and reduced average

annual landings enabled the Atlantic mackerel stock to

recover from low biomass levels in the late 1970's

(Anderson 1995; Figure 15).

From 1973-1977, Total Allowable Catches (TAC) were

set for the southern spawning contingent in Northwest

Atlantic Fisheries Organization (NAFO) Subareas 5 and 6

and for the northern contingent. However, there is no

evidence for genetic differences between the contingents

(MacKay 1967) and distinctions have not been made to

determine individual contingent contributions to the total

population (Garrod 1975). As a result, Atlantic mackerel

have been managed as a unit stock since 1975 (Anderson

1982).

Atlantic mackerel landings reached a peak in the early

1970s of approximately 400,000 mt but were drastically

reduced to 30,000 mt in the late 1970s (Anderson 1995;
Page 8

Figure 15). Throughout 1980-1988, landings increased to

an average 82,700 mt until Total Allowable Level of

Foreign Fishing (TALFF) regulations for distant water fleet

fishing activities in the northwest Atlantic were eliminated

in 1992 and landings subsequently decreased to 32,000 mt

in 1993 (Anderson 1995).

Northeast Fisheries Science Center fall and spring trawl

survey data and assessment analyses indicate Atlantic

mackerel stock biomass levels increased from 300,000 mt to

1.6 million mt in the years 1962-1969; however, levels

decreased to an average 776,000 mt during 1977-1981

(Anderson 1995; Figure 15). Stock biomass increased

steadily throughout the 1980s and in 1990 to approximately

3 million mt, which is the current estimated biomass level

(Anderson 1995; Figure 15). Spawning stock biomass (50%

of age 2 and 100% of age 3 and older mackerel) increased

from 600,000 mt in 1982 to more than 2 million mt in 1990,

and has remained at or above that level since that time.

Regulations on landings of Atlantic mackerel were

enforced in 1976 in hopes of reducing fishing effort so as to

ensure reproductive success in the population by keeping

spawning stock levels above devastating levels.

Recruitment has increased since 1976-1980 and strong year

classes were evident in 1982, 1987, 1988, and 1990-1993

(Northeast Fisheries Science Center 1996). The northwest

Atlantic mackerel stock is currently at a high level of

biomass and is underexploited (Northeast Fisheries Science

Center 1996).

RESEARCH NEEDS

As stated by Overholtz et al. (1991b) and based on the

results of model projections, unless the impacts of

compensatory mechanisms are accounted for, evaluations of

current stock status using the current standard assessment

methodology may in fact be optimistic and risky if catches

are increased to high levels. These authors indicate that two

advances would help to improve assessments: (1) an

MSVPA to provide correctly scaled estimates of

recruitment, and (2) a general prediction mortality model

that would provide useful estimates of M2’s for forecasting

purposes. Other data that will be important include

monitoring weights of individual fish to assess future

changes, annual tracking of sexual maturity of age 2 and age

3 fish, additional food habits sampling at critical times and

places and information on predation mortality of age-0

mackerel. Improved predation models that account for

predator preference and prey abundance would allow for

more accurate predictions of the impacts of these factors.

In addition, even though Atlantic mackerel is managed

and assessed as one stock throughout the U.S. EEZ, the

question of multiple stocks still needs to be settled from a

scientific standpoint. This could be addressed via new

technologies such as microconstituent analysis of otoliths

using inductively coupled plasma mass-spectrometry

(ICPMS).

ACKNOWLEDGMENTS

The authors thank Cathy McBride for providing an

early draft of the habitat table and references. The literature

review was greatly aided by the draft update to the Bigelow

and Schroeder (1953) section on Atlantic mackerel provided

by Bruce Collette. Joe Vitaliano provided gut contents data

from the food habits database made available by Rodney

Rountree. The authors also wish to thank Lois Olsen for

editorial assistance, and Rande Ramsey-Cross, Judy Berrien,

and Claire Steimle for library assistance. We are also

indebted to William Overholtz, Frank Almeida, and others

in the NEFSC for their thoughtful reviews and advice.

REFERENCES CITED

Anderson, E.D. 1973. Assessment of Atlantic mackerel in

ICNAF Subarea 5 and Statistical Area 6. Int. Comm.

Northwest Atl. Fish. (ICNAF) Res. Doc. 73/14: 38 p.

Anderson, E.D. 1976. Measures of abundance of Atlantic

mackerel off the northeastern coast of the United States.

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

12: 5-21.

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Page 12

Table 1. Summary of the distribution and abundance of Atlantic mackerel in northwestern Atlantic estuaries based on

Jury et al. (1994). Data reliability: *** = Highly Certain, ** = Moderately Certain, * = Reasonable Inference. Relative

abundance: H = highly abundant, A = abundant, C = common, R = rare, 0 = not present, N = no data presented, NI = no

data available, NZ = zone not present.

Relative Abundance and Distribution (months)

Estuaries and Rivers Life Stage months shown as (1)-(12); i.e., January = (1)

Tidal Fresh

0.0-0.5 ppt

Mixing Zone

0.5-25 ppt

Seawater Zone

> 25 ppt

Data

Reliability

 Passamaquoddy Bay Adults (A) 0 C(6-9), R(10) C(6-9), R(10) **

 Spawning adults (S) 0 0 0 **

 Eggs (E) 0 0 NI *

 Larvae (L) 0 0 NI *

 Juveniles (J) 0 C(6-9), R(10) C(6-9), R(10) **

 Englishman/Machias Bay A 0 C(6-9), R(10) C(6-9), R(10) *

 S 00 0 *

 E 0 0 NI *

 L 0 0 NI *

 J 0 R(6-10) R(6-10) *

 Narraguagus Bay A 0 C(6-9), R(10) C(6-9), R(10) *

 S 00 0 *

 E 0 0 NI *

 L 0 0 NI *

 J 0 R(6-10) R(6-10) *

 Blue Hill Bay A 0 C(6-9), R(10) C(6-9), R(10) *

 S 00 0 *

 E 0 0 NI *

 L 0 0 NI *

J 0 R(6-10) R(6-10) *

 Penobscot Bay A 0 C(6-9), R(10) C(6-9), R(10) **

 S 0 0 0 **

 E 0 0 R(6-7) **

 L 0 0 R(6-7) **

 J 0 C(6-9), R(10) C(6-9), R(10) **

 Muscongus Bay A 0 C(6-9), R(10) C(6, 8-9), A(7), R(10) *

 S 0 0 0 **

 E 0 0 0 **

 L 0 0 0 **

 J 0 C(6-9), R(10) C(6, 8-9), A(7), R(10) *

 Damariscotta River A 0 C(6-9), R(10) C(6, 8-9), A(7), R(10) **

 S 0 0 0 **

 E 0 0 0 **

 L 0 0 0 **

 J 0 C(6-9), R(10) C(6, 8-9), A(7), R(10) **

 Sheepscot River A 0 C(6-9), R(10) C(6, 8-9), A(7), R(10) ***

 S 0 0 0 **

 E 0 0 0 **

 L 0 0 0 **

 J 0 C(6-9), R(10) C(6, 8-9), A(7), R(10) ***

 Kennebec/Androscoggin Rivers A 0 C(6-9), R(10) C(6, 8-9), A(7), R(10) **

 S 0 0 0 **

 E 0 0 0 **

 L 0 0 0 **

 J 0 C(6-9), R(10) C(6, 8-9), A(7), R(10) **
Page 13

Table 1. cont’d.

Relative Abundance and Distribution (months)

Estuaries and Rivers Life Stage months shown as (1)-(12); i.e., January = (1)

Tidal Fresh

0.0-0.5 ppt

Mixing Zone

0.5-25 ppt

Seawater Zone

> 25 ppt

Data Reliability

 Casco Bay A 0 C(6-9), R(10) C(6-9), R(10) *

 S 0 0 0 **

 E 0 0 NI *

 L 0 0 NI *

 J 0 C(6-9), R(10) C(6-9), R(10) *

 Saco Bay A 0 C(6-9), R(10) C(6-9), R(10) *

 S 0 0 0 **

 E 00 0 *

 L 00 0 *

J 0 C(6-9), R(10) C(6-9), R(10) *

 Wells Harbor A NZ R(6-10) R(6-10) *

 S NZ 0 0 **

 E NZ 0 0 *

 L NZ 0 0 *

 J NZ R(6-10) R(6-10) *

 Great Bay A 0 0 R(5-11) *

 S 0 0 0 ***

 E 0 C(5-7) C(5), A(6-7) *

 L 0 C(5-7), R(8) C(5-7), R(8) *

 J 0 0 C(5-11) *

 Merrimack River A 0 R(5-10) NZ **

 S 0 0 NZ **

 E 0 H(5-6), C(7) NZ **

 L 0 C(5-8) NZ **

 J 0 R(5-10) NZ **

 Massachusetts Bay A NZ NZ C(5-10), R(11) ***

 S NZ NZ C(5-8) *

 E NZ NZ C(5), A(6,7), R(8) *

 L NZ NZ C(5), A(6,7), R(8) *

 J NZ NZ C(5-10) ***

 Boston Harbor A NZ R(5), C(6-9) R(5), C(6-9) **

S NZ 0 0 *

 E NZ R(5, 8), C(6,7) C(5,8), A(6,7) *

 L NZ R(5), C(6-8) C(5), A(6,7) R(8) *

 J NZ R(5), C(6-10) R(5), C(6-10) **

 Cape Cod Bay A NZ C(5-8), R(9) A(5-7), C(8-11) **

 S NZ 0 A(5-7) *

 E NZ C(5-8) H(5,6), A(7), C(8) **

 L NZ C(5-8) H(5,6), A(7), C(8) **

 J NZ C(5-10) A(5-8), C(9-11) **
Page 14

Table 2. Summary of the distribution and abundance of Atlantic mackerel in southern New England and Mid-Atlantic

estuaries based on Stone et al. (1994). Data reliability: *** = Highly Certain, ** = Moderately Certain, * = Reasonable

Inference. Relative abundance: H = highly abundant, A = abundant, C = common, R = rare, 0 = not present, N = no data

presented, NI = no data available, NZ = zone not present.

Relative Abundance and Distribution (months)

Estuaries and Rivers Life Stage months shown as (1)-(12); i.e., January = (1)

Tidal Fresh

0.0-0.5 ppt

Mixing Zone

0.5-25 ppt

Seawater Zone

> 25 ppt

Data

Reliability

Waquoit Bay Adults (A) NZ 0 R(5,6), C(7-9) *

 Spawning adults (S) NZ 0 0 **

 Eggs (E) NZ 0 R(5-8) *

 Larvae (L) NZ 0 R(5-8) *

Juveniles (J) NZ 0 R(5-9) *

 Buzzards Bay A NZ 0 C(3,4,11,12), R(5-9) **

 S NZ 0 0 **

 E NZ R(5-8) A(5,6), C(7), R(8) *

 L NZ R(6-8) R(5-8) *

J NZ R(5-9) R(5-9) *

 Narragansett Bay A 0 0C(5-9) *

 S 0 0 0 **

 E 0 R(5-7) A(5,6), C(7) **

 L 0 R(5-7) C(5,6), R(7) *

J 0 R(5-9) C(5-9) *

 Long Island Sound A 0 0C(4-11) *

 S 0 0R(4-6) ***

 E 0 0C(4,6), A(5) ***

 L 0 0C(5), R(6) ***

J 0 R(4,5) C(4-11) *

 Connecticut River A 0 0 NZ **

 S 0 0 NZ ***

 E 0 0 NZ **

 L 0 0 NZ **

J 0 0 NZ **

 Gardiners Bay A NZ 0 C(4,5), R(6-11) *

 S NZ 0 R(4-6) *

 E NZ 0 H(4), A(5), C(6) **

 L NZ 0 H(4), A(5), C(6) **

J NZ 0 C(4-11) **

 Great South Bay A NZ 0 C(4,5), R(6-11) *

 S NZ 0 0 **

 E NZ 0 C(4) **

 L NZ 0 C(5) **

J NZ 0 C(4-11) *

 Hudson/Raritan River A 0 0 C(4,5,10,11), R(6,9,12) *

 S 00 0 *

 E 00 0 *

 L 00 0 *

J 0 R(4-6,10-12) C(4-6,10,11), R(7-9,12) *

 Barnegat Bay A 0 0 0 ***

 S 0 0 0 ***

 E 0 0R(4-6) **

 L 0 0R(4-6) **

J 0 0R(5-9) **

 NJ Inland Bays A 0 0 0 ***

 S 0 0 0 ***

 E 0 0R(4-6) **

 L 0 0R(4-6) **

J 0 0R(5-9) **

 Delaware Bay A 0 0R(3-5) **

 S 0 0 0 ***

 E 0 0 0 ***

 L 0 0 0 ***

J 0 0 0 ***
Page 15

Table 2. cont’d.

Relative Abundance and Distribution (months)

Estuaries and Rivers Life Stage months shown as (1)-(12); i.e., January = (1)

Tidal Fresh

0.0-0.5 ppt

Mixing Zone

0.5-25 ppt

Seawater Zone

> 25 ppt

Data Reliability

 Delaware Inland Bays A NZ 0 R(3-5) **

 S NZ 0 0 ***

 E NZ 0 0 ***

 L NZ 0 0 **

J NZ 0 0 **

 Chincoteague A NZ NZ 0 ***

 S NZ NZ 0 ***

 E NZ NZ 0 ***

 L NZ NZ 0 ***

J NZ NZ 0 ***

 Chesapeake Bay A 0 R(1-3) R(1-3) **

 S 0 0 0 ***

 E 0 0 0/NI(4-5) **

 L 0 0R(5) **

J 0 R(1-4,11,12) R(1-4,11,12) **

 Chester River A 0 0 NZ ***

 S 0 0 NZ ***

 E 0 0 NZ ***

 L 0 0 NZ ***

J 0 0 NZ ***

 Choptank River A 0 0 NZ ***

 S 0 0 NZ ***

 E 0 0 NZ ***

 L 0 0 NZ ***

J 0 0 NZ ***

 Patuxent River A 0 0 NZ ***

 S 0 0 NZ ***

 E 0 0 NZ ***

 L 0 0 NZ ***

J 0 0 NZ ***

 Potomac River A 0 0 NZ ***

 S 0 0 NZ ***

 E 0 0 NZ ***

 L 0 0 NZ ***

J 0 0 NZ ***

 Tangier/Pocomoke A NZ 0 NZ ***

 S NZ 0 NZ ***

 E NZ 0 NZ ***

 L NZ 0 NZ ***

J NZ 0 NZ ***

 Rappahannock River A 0 R(1-3) NZ **

 S 0 0 NZ ***

 E 0 0 NZ ***

 L 0 0 NZ ***

J 0 R(1-4,11,12) NZ **

 York River A 0 R(1-3) NZ **

 S 0 0 NZ ***

 E 0 0 NZ ***

 L 0 0 NZ ***

J 0 R(1-4,11,12) NZ **

 James River A 0 R(1-3) NZ **

 S 0 0 NZ ***

 E 0 0 NZ ***

 L 0 0 NZ ***

J 0 R(1-4,11,12) NZ **
Page 16

Table 3. Summary of life history and habitat parameters for Atlantic mackerel, Scomber scombrus.

Life Stage Size and Growth Geographic Location Habitat Temperature

Eggs 1

Diameter: 1-1.3 mm, avg. = 1.1

mm. 1 oil globule, avg. 0.3 mm

diameter. In Gulf of St.

Lawrence egg size decreased

over time and in relation to

ambient temperature (avg.

diam. = 1.3 mm in June, 1.1

mm in August).

Offshore waters of Chesapeake Bay to

southern side of Gulf of St. Lawrence

with majority on shoreward side of

continental shelf. Varying abundances

in bays and estuaries from New Jersey

to Canada. Highest abundances in May,

June in southern New England - MidAtlantic region.

Eggs pelagic, distributed at

depths ranging from 10-

325 m, majority from 30-

70 m; depth varies with

season, egg diameter,

thermocline.

Eggs collected at 5-23o

C, highest abundance

from ~ 7-16o

C with range related to season. In

May, weighted mean surface temperature =

11o

C for eggs from Martha’s Vineyard. Egg

mortality rates (~ 41%/d) correlated with rate of

warming during spawning season since

acclimation temperature of adults related to egg

mortality. Mortality < 20% from 9.4-15.1o

C.

Incubation temperature dependent: 7.5 d at 11o

C

to ~ 3 d at 20o

C. Temperatures must be > ~ 7oC

for development.

Larvae 2

Larvae average 3.1-3.3 mm SL

with large yolk sac. Postlarvae

are 11-50 mm. Teeth present at

192 h after hatching.

Larvae (< 13 mm) occur primarily in

offshore waters from Chesapeake Bay

to southern Gulf of St. Lawrence.

Similar to distribution of eggs, some

larvae also collected in open bays and

estuaries. Highest abundances in May

offshore from Delaware Bay to Hudson

Canyon; by June, highest abundance

ranges from Hudson Canyon north to

southern New England and north of

Cape Cod.

Most distributed at depths

from 10-130 m, usually at

< 50 m. Depth varies

diurnally, also with age

and with thermocline; i.e.,

newly hatched larvae

found between 5-10 m

during the day, however,

as they grow they’re at

depths closer to the

surface.

Hatching occurs ~ 90-120 h at average

temperature of 13.8o

C. Yolk sac stage complete

by 137 h at this temperature. Larvae collected at

6-22o

C; highest abundance at 8-13oC. Changes

in abundance at different temperature ranges

related to season; i.e., increasing from May

through August. Larval mortality rates (~ 35-

42%/d) may be partially correlated with

temperature.

Juveniles 3

Postlarvae transform from

planktonic to swimming and

schooling behavior at ~ 30-50

mm; reach 50 mm in ~ 2

months; 20 cm after 1 y (rates

may be faster in mid-Atlantic: ~

70-80 mm in 2 months).

Northern contingent fish may

grow faster in 1st year than

southern contingent, but may

not be significantly different for

first 90 days.

Southwestern Nova Scotia, Gulf of

Maine, Georges Bank to Cape Hatteras

- distribution changes seasonally. Late

summer/fall primarily along western

shores of Gulf of Maine, around Cape

Ann, inshore areas of New England

(includes estuaries in Rhode Island,

Connecticut), eastern Long Island. In

spring, although common offshore,

some are further inshore than adults

and found in some Mid-Atlantic

estuaries until fall.

Depth varies seasonally.

Offshore in fall, most

abundant at ~ 20-40 m,

range from 0-320 m. In

winter, 50-70 m. Spring,

although dispersed through

water column,

concentrated 30-90 m.

Move higher in summer to

20-50 m, range from 0-210

m.

At 15-17o

C growth rates of fish > 15 mm

averaged 0.73 mm/d. Juveniles found from 4-

22o

C, most at 10oC. Temperature distribution

offshore changes seasonally as average

temperature ranges increase: in winter/spring,

most found 5-6o

, in summer at 8-13oC. Similar

associations inshore: Massachusetts, 11o

 in

spring, 9 and 13o

 in fall; Rhode Island, 19o in

summer, 11 and 15o

C in fall.

Adults 4

Males/females grow at same

rate, reaching maximum age of

~ 20 y, with maximum fork

length of ~ 47 cm. Reach 26 cm

by second year, 33 cm by fifth

year. By age 6, may be 39-40

cm. Spring weight for 35 cm

fish is ~ 0.5 kg; fall is 0.6 kg.

Growth may be population

density dependent; year class

size partially influences initial

growth during cohort’s first

years.

Two major contingents in NW Atlantic.

Fish overwinter in deep water of shelf

from Nova Scotia to Cape Hatteras. In

spring, two groups formed: fish from

southern group move inshore and

northward along coast, joined by

northern group moving inshore. By late

Apr./May southern group found off

New Jersey, Long Island, moving to

western Gulf of Maine by summer,

returns to shelf edge between Long

Island - Chesapeake Bay in Oct.

Northern group mixes briefly with

southern group late spring off New

England, migrates east along Nova

Scotia into Gulf of St. Lawrence; some

fish remain along Maine/Nova Scotia

coast. By late fall, this contingent

mixes with southern group in Gulf of

Maine before returning to outer shelf.

Depth changes seasonally,

perhaps influenced by prey

availability. Fall: 10-340

m, > 50% at 60-80 m.

Winter: ~ 50% at 20-30 m.

Spring: down to 380 m, ~

25% at 60-170 m.

Summer: > 60% at 50-70

m. Larger fish deeper than

smaller ones. Distribution

may also be correlated

with downwelling events

and onshore advection of

warm surface water.

Seasonal temperature cycles influence

migration/distribution. Field studies: intolerant

of temperatures < 5-6oC or > 15-16oC. Lab:

prefer 7-16o, lethal at < 2o or > 28.5o. Offshore

distribution varies with seasonal temperature

changes. Fall: > 80% at 9-12o. Winter: ~ 70% at

5-6o. Spring > 25% at 13o. Summer: > 30% at

10-11o, > 35% at 14o. Massachusetts: spring

most at 14o, fall at 10o and 15o. In northern Gulf

of St. Lawrence, adults in colder temperatures

(4o); however, probability of occurrence higher

when temperatures ≥ 7oC.

Spawning

Adults 5

L50 for females = 25.7 cm,

males = 26.0; A50 for both = 1.9

y. By age 3, 99% of females,

97% of males mature.

Newfoundland fish have higher

L50 values: females = 34 cm,

males = 35 cm. Gulf of St.

Lawrence, coastal Nova Scotia,

Massachusetts fish spawn first

at age 2, lengths > 30 cm.

Differences in median maturity

may be due to slower growth of

larger year classes that may

delay spawning from one to

three years.

Spawning progresses from south to

north. Southern contingent spawns in

Mid-Atlantic Bight and Gulf of Maine

mid-Apr.-June, northern in southern

Gulf of St. Lawrence May-Aug. Most

spawning in shoreward half of

continental shelf, some on shelf edge

and beyond. Most productive between

Chesapeake Bay/southern New

England, less in Gulf of St. Lawrence,

Gulf of Maine, Nova Scotia coast.

Some spawning in open bays; e.g.,

Cape Cod, Massachusetts Bays. Less in

enclosed bays; e.g., Chesapeake,

Delaware Bays.

Spawning begins when temperatures are ≥ 7o

C

(peak 9-14o

C) and progresses from southern to

northern waters during adult migration.

References on next page
Page 17

Table 3. cont’d.

Life Stage Salinity Prey Predators Notes

Eggs 1

Although eggs are collected

in waters ranging from

estuaries (18-25 ppt) to full

seawater (> 30 ppt),

mortality is higher at lower

salinities (< 25 ppt).

Larvae 2

Although larvae are

occasionally collected in

open bays and estuaries at

salinities < 25 ppt, the

largest abundances are

found in higher salinities of

> 30 ppt in offshore waters.

Mortality may be related to

salinities of ≤ 23 ppt.

50% threshold for first feeding is 3.8 mm, all

larvae feeding by 4.5 mm. Diet related to

larval size: first feeding larvae may be

phytophagous; individuals > 4.4 mm feed on

copepod nauplii; > 5 mm, copepodites; > 6

mm adult copepods. Diets of larger larvae shift

to include fish larvae: yellowtail flounder,

silver hake, redfish; > 6 mm are cannibalistic

on smaller conspecifics which may make up as

much as 20% of larval fish consumed.

However, piscivory is density dependent; i.e.,

limited at densities of fish larvae < 0.1 m3

 and

declines with increasing density of nauplii,

switching to copepods.

Mackerel > 6 mm are

cannibalistic on smaller

conspecifics of 3.5-4.5 mm.

Calculated mean digestive times ~

1-2 h; to maintain rapid growth rates

larvae must feed continually for

about 15 h/d. Diet may reflect most

abundant food items capable of

being ingested due to width of

mouth gape. Factors influencing

mortality include zooplankton

abundance, wind driven surface

currents, epizootics in addition to

temperature and appropriate food

supply.

Juveniles 3

Juveniles found in some

inshore bays and estuaries

as well as offshore at

salinities > 25 ppt.

Principal prey include small crustaceans, such

as copepods, euphausiids, amphipods, mysid

shrimp, decapod larvae. Also small pelagic

mollusks, chaetognaths, nematodes,

ammodytes, other larval fish.

Same as for adults, but for

juveniles specifically: Atlantic

cod, squid, seabirds.

Atlantic mackerel are opportunistic

feeders that can ingest prey either by

individual selection of organisms or

by filter feeding (see adults, below).

Adults 4

Found in open sea although

occasionally in open bays

with lower salinity limits of

~ 25 ppt.

Opportunist feeders. Filter feeding or

individual selection. Diet similar to juveniles,

but wider range and larger prey items. Includes

euphausid, pandalid, and crangonid shrimps;

chaetognaths, larvaceans, pelagic polychaetes,

squids. Calanus and other copepods,

amphipods, other planktonic organisms.

Fishes: sand lances, herring, silver and other

hakes, sculpins. Lab studies: small medusae

common to temperate waters; also, where prey

abundance is only 0.1 g wet weight/m3

,

mackerel may not be satiated if feeding was

restricted to daylight.

Mortality from predation may

be the most important source of

natural mortality. Predators

include conspecifics, tunas,

bonito, striped bass, pilot

whales, common dolphins,

harbor seals, porpoises,

seabirds, swordfish. Sharks:

shortfin mako, tiger, blue,

bigeye thresher, spiny dogfish.

Other predators: king mackerel,

thorny skate, silver hake, red

hake, bluefish, pollock, white

hake, goosefish, weakfish.

Although there are two major

contingents of the population they

are managed as a single

transboundary stock. Shifts in

feeding mode may be related to

season for fish in the Gulf of St.

Lawrence while diet of fish in

Newfoundland indicates that

particulate feeding may occur

throughout the season.

Spawning

Adults 5

Peak spawning occurs at

salinities > 30 ppt.

Fish feed until gonadal development begins,

then stop feeding until spent, feeding then

resumes.

Same as for adults in general. Mackerel are serial, or batch,

spawners. Fecundity of southern

contingent: 285,000-1.98 million

eggs for 31-44 cm fish. Northern

contingent: 211,000 to 397,000 eggs

for 35 and 40 cm females,

respectively, with 5-7 batches.

Control of spawning time is unclear

although there may be both

endogenous and exogenous factors

which ensures peak hatching at the

time of maximum zooplankton

abundance. No evidence of diel

periodicity in spawning.

1 Worley (1933), Jury et al. (1994), Sette (1943), Berrien (1975, 1978), Ware (1977), Fritzsche (1978), Lanctot (1980), Peterson and Ausubel (1984), Ware and

 Lambert (1985), Stone et al. (1994), Collette (in prep.) 2 Sette (1943), Bigelow and Schroeder (1953), Colton and Marak (1969), Berrien (1975, 1978, 1982), Peterson and Ausubel (1984), Ware and Lambert (1985),

 Scott and Scott (1988), Jury et al. (1994), Stone et al. (1994), Fortier and Villeneuve (1996), Collette (in prep.) 3 Sette (1943, 1950), Bigelow and Schroeder (1953), Anderson and Paciorkwski (1980), Kendall and Gordon (1981), Berrien (1982), Ware and Lambert (1985),

 Pepin et al. (1988), D’Amours et al. (1990), Simard et al. (1992), Jury et al. (1994), Stone et al. (1994), Collette (in prep.) 4 Sette (1950), Leim and Scott (1966), MacKay (1967), Scott and Tibbo (1968), Anderson (1973), Isakov (1973), Parsons and Moores (1974), Stobo and Hunt

 (1974), Maurer and Bowman (1975), Moores et al. (1975), Olla et al. (1975), Overholtz and Anderson (1976), MacKay (1979), Berrien (1982), Stillwell and

 Kohler (1982, 1985), Murray et al. (1983), Bowman and Michaels (1984), Bowman et al. (1984), Murray (1984), Runge et al. (1987), Dery (1988), Pepin et al.

 (1988), Overholtz et al. (1991b), Castonguay et al. (1992), Collette (in prep.) 5 Sette (1943), MacKay (1967, 1973), Ware (1977), Morse (1980), Berrien (1982), Overholtz (1989), Overholtz et al. (1991b), Walsh and Johnstone (1992),

 Nichols and Warne (1993), O’Brien et al. (1993), Jury et al. (1994), Stone et al. (1994), Collette (in prep.)
Page 18

Figure 1. The Atlantic mackerel, Scomber scombrus (from Goode 1884).
Page 19

Figure 2. Abundance (percent occurrence) of the major prey items in the diet of Atlantic mackerel collected during

NEFSC bottom trawl surveys from 1973-1980 and 1981-1990. The 11-30 cm size range corresponds, at least roughly, to

juveniles, and the 30-50 cm size class corresponds to adults. The category “animal remains” refers to unidentifiable

animal matter. Methods for sampling, processing, and analysis of samples differed between the time periods [see Reid et

al. (1999) for details].

Nematoda 16.2%

Chaetognatha 8.1% Decapoda 7.2%

Copepoda 16.2%

Hyperiidae 16.2%

Mysidacea 9.5%

Euphausiidae 4.1%

Other Crustacea 9.9%

All Other Prey 12.6%

Nematoda 4.3%

Amphipoda 10.8%

Hyperiidae 7.9% Decapoda 10.1%

Euphausiidae 10.1%

Mysidacea 4.3%

Copepoda 9.4%

All Other Crustacea 6.5%

Animal Remains 10.1% All Other Prey 11.5%

Chaetognatha 15.1%

Animal Remains 29.2%

Copepoda 17.7%

Crustacea 5.3%

Other Crustacea 27.4%

Other Fish 3.5%

Cephalopoda 4.4%

Ammodytes sp. 12.4%

Animal Remains 16.2%

Euphausiidae 11.5%

Crustacea 11.5%

Other Crustacea 16.9%

Copepoda 19.6%

Ammodytes sp. 7.4%

Other Fish 10.1%

All Other Prey 6.8%

b) 1981-1990

30-50 cm

(n=41)

11-30 cm

(n=105)

31-50 cm

(n=128)

11-30 cm

(n=49)

a) 1973-1980
Page 20

Figure 3. Abundance of Atlantic mackerel eggs relative to surface water temperature (0-15 m) and bottom depth based

on NEFSC MARMAP ichthyoplankton surveys (April to August 1978-1987; 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

).

April

0

10

20

30

40

Stations

Egg Catch

May

0

10

20

June

Percent

0

10

20

30

40

50

July

0

10

20

August

Near-surface Water Temperature (0-15m, C)

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

0

10

60

70

Atlantic mackerel Eggs

April

0

20

40

60

Stations

Egg catch

May

0

10

20

30

40

June

Percent

0

10

20

30

40

July

0

10

20

30

40

August

Bottom Depth (m), Interval Midpoint

10

30

50

70

90

110

130

150

170

190

210

230

250

270

290

325

375

450

750

1250

1750

>2000

0

10

20

60

65
Page 21

Figure 4. Abundance of Atlantic mackerel larvae (< 13 mm) relative to water column temperature (to a maximum of 200

m) and bottom depth based on NEFSC MARMAP ichthyoplankton surveys (May to August 1977-1987; 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

).

May

0

10

20

30

40

Stations

Larva Catch

June

Percent

0

10

20

30

July

0

10

20

30

August

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

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

0

10

20

30

Atlantic mackerel Larvae (<13.0mm Length)

May

0

10

20

30

40

Stations

Larva Catch

June

Percent

0

10

20

30

40

50

July

0

10

20

30

40

50

August

Bottom Depth (m), Interval Midpoint

10

30

50

70

90

110

130

150

170

190

210

230

250

270

290

325

375

450

750

1250

1750

>2000

0

10

20

30

40

50
Page 22

Figure 5. Seasonal abundance of juvenile Atlantic mackerel relative to bottom water temperature and depth based on

NEFSC bottom trawl surveys (1963-1997; 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

).

SPRING

0

10

20

30

40

50

60

0 2

0

4

0

6

0

8

0

1

0

0

1

2

0

1

4

0

1

6

0

1

8

0

2

0

0

2

2

0

2

4

0

2

6

0

3

2

0

DEPTH (m)

PERCENT

STATIONS N=756

CATCHES N=49041

SUMMER

0

10

20

30

40

50

60

0 1

0

2

0

3

0

4

0

5

0

7

0

9

0

1

2

0

1

3

0

1

8

0

2

1

0

DEPTH (m)

PERCENT

STATIONS N=53

CATCHES N=18620

FALL

0

10

20

30

40

50

60

0 3

0

6

0

9

0

1

2

0

1

5

0

1

8

0

2

1

0

2

8

0

DEPTH (m)

PERCENT

STATIONS N=464

CATCHES N=39165

WINTER

0

10

20

30

40

50

60

1

0

2

0

3

0

4

0

5

0

6

0

7

0

8

0

9

0

1

0

0

1

1

0

1

2

0

1

3

0

1

4

0

1

5

0

DEPTH (m)

PERCENT

STATIONS N=151

CATCHES N=7647

Juveniles: < 26 cm TL

FALL

0

10

20

30

40

50

60

70

35791

1

1

3

1

5

1

7

1

9

2

1

BOTTOM TEMERATURE (C)

PERCENT

STATIONS N=411

CATCHES N=36184

WINTER

0

10

20

30

40

50

60

70

34567891

0

1

1

1

2

BOTTOM TEMPERATURE (C)

PERCENT

STATIONS N=151

CATCHES N=7647

SPRING

0

10

20

30

40

50

60

70

4567891

0

1

1

1

2

1

3

1

4

1

5

1

6

1

7

BOTTOM TEMPERATURE (C)

PERCENT

STATIONS N=635

CATCHES N=42254

SUMMER

0

10

20

30

40

50

60

70

457891

0

1

1

1

2

1

3

1

4

1

5

1

6

1

7

1

8

1

9

BOTTOM TEMPERATURE (C)

PERCENT

STATIONS N=49

CTACHES N=18608
Page 23

Figure 6. Abundance of juvenile (≤ 25 cm) and adult (≥ 26 cm) Atlantic mackerel relative to bottom water temperature

and depth based on spring and autumn Massachusetts inshore bottom trawl surveys (1978-1996; 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

).

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

0

20

40

60

80

100

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

0

20

40

60

0

10

20

30

40

0

20

40

60

80

0

20

40

60

80

100

0

20

40

60

80

100

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

0

20

40

60

80

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

0

20

40

60

80

Juveniles Adults

Stations

Catches

Spring Spring

Spring Spring

Autumn Autumn

Autumn Autumn

Bottom Depth (m) Bottom Depth (m)

Bottom Depth (m) Bottom Depth (m)

Bottom Temperature (C) Bottom Temperature (C)

Bottom Temperature (C) Bottom Temperature (C)

Mass. Inshore Trawl Surveys

Atlantic Mackerel
Page 24

Figure 7. Seasonal abundance of juvenile Atlantic mackerel (< 26 cm) relative to bottom depth and bottom water

temperature based on Rhode Island Narragansett Bay trawl surveys (1990-1996; all years combined). Open bars

represent the proportion of all stations surveyed, while solid bars represent the proportion of the sum of all catches.

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

0

10

20

30

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

0

5

10

15

20

25

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

100

Winter

Autumn

Summer

Spring

Stations

Catches

Atlantic Mackerel

Juveniles (< 26 cm)

Bottom Depth (ft)

-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

100

-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

4

8

12

16

20

Bottom Temperature (C)

Winter

Spring

Summer

Autumn

Atlantic Mackerel

Juveniles (< 26 cm) Stations

Catches
Page 25

Figure 8. Seasonal abundance of adult Atlantic mackerel relative to bottom water temperature and depth based on

NEFSC bottom trawl surveys (1963-1997; 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

).

SPRING

0

5

10

15

20

25

30

35

40

45

50

0 3

0

6

0

9

0

1

2

0

1

5

0

1

8

0

2

1

0

2

4

0

2

7

0

3

0

0

3

5

0

DEPTH (m)

PECERNT

STATIONS N=1143

CATCHES N=67582

SUMMER

0

5

10

15

20

25

30

35

40

45

50

1

0

2

0

3

0

4

0

5

0

6

0

7

0

8

0

9

0

1

0

0

1

1

0

1

2

0

1

3

0

1

5

0

1

8

0

DEPTH (m)

PERCENT

STATIONS N=79

CATCHES N=1767

FALL

0

5

10

15

20

25

30

35

40

45

50

1

0

4

0

7

0

1

0

0

1

3

0

1

6

0

1

9

0

2

2

0

2

7

0

DEPTH (m)

PERCENT

STATIONS N=479

CATCHES N=7393

Adults: ≥ 26 cm TL

WINTER

0

10

20

30

40

50

60

1

0

3

0

5

0

7

0

9

0

1

1

0

1

3

0

1

6

0

DEPTH (m)

PERCENT

STATIONS N=172

CATCHES N=18277

SUMMER

0

5

10

15

20

25

30

35

40

45

50

4567891

0

1

1

1

2

1

3

1

4

BOTTOM TEMPERATURE (C)

PERCENT

STATIONS N=76

CATCHES N=1727

SPRING

0

5

10

15

20

25

30

35

40

45

50

234567891

0

1

1

1

2

1

3

1

4

BOTTOM TEMPERATURE (C)

PERCENT

STATIONS N=974

CATCHES N=60837

FALL

0

5

10

15

20

25

30

35

40

45

50

4681

0

1

2

1

4

1

6

BOTTOM TEMPERATURE (C)

PERCENT

STATIONS N=435

CATCHES N=7120

WINTER

0

10

20

30

40

50

60

34567891

0

1

1

1

2

1

3

BOTTOM TEMPERATURE (C)

PERCENT

STATIONS N=165

CATCHES N=18193
Page 26

Figure 9. Distribution and abundance of Atlantic mackerel eggs collected during NEFSC MARMAP ichthyoplankton

surveys from April to August, 1977-1987 [all years combined; see Reid et al. (1999) for details]. Egg densities are

represented by dot size.

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

35

36

37

38

39

40

41

42

43

44

45

Atlantic mackerel

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

April to August; 1977 to 1987

Number of tows = 5138; with eggs = 1029

Eggs / 10m2

1 to <10

10 to <100

100 to <1000

1000 to <10000

10000 to <53220

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

35

36

37

38

39

40

41

42

43

44

45

Atlantic mackerel

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

April; 1977 to 1987

Number of tows = 1211; with eggs = 118

None

1 to <10

10 to <100

100 to <1000

Eggs / 10m2

1000 to 4006

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

35

36

37

38

39

40

41

42

43

44

45

Atlantic mackerel

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

May; 1977 to 1987

Number of tows = 1357; with eggs = 531

None

1 to <10

10 to <100

100 to <1000

Eggs / 10m2

1000 to <10000

10000 to 39149

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

35

36

37

38

39

40

41

42

43

44

45

Atlantic mackerel

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

June; 1977 to 1987

Number of tows = 779; with eggs = 294

None

1 to <10

10 to <100

100 to <1000

Eggs / 10m2

1000 to <10000

10000 to 53220
Page 27

Figure 9. 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

Atlantic mackerel

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

July; 1977 to 1987

Number of tows = 782; with eggs = 63

None

1 to <10

10 to <100

100 to 312

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

Atlantic mackerel

Eggs

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

August; 1977 to 1987

Number of tows = 1009; with eggs = 23

None

1 to <10

10 to 79

Eggs / 10m2
Page 28

Figure 10. Distribution and abundance of Atlantic mackerel larvae collected during NEFSC MARMAP ichthyoplankton

surveys from May to August, 1977-1987 [all years combined; see Reid et al. (1999) for details]. Larval densities are

represented by dot size.

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

35

36

37

38

39

40

41

42

43

44

45

MARMAP Ichthyoplankton Surveys

61-cm Bongo Net; 0.505-mm mesh

May to August (1977 to 1987)

Atlantic Mackerel

Number of Tows = 4451, with larvae = 306

(Larvae <13.0 mm)

1 to < 10

10 to < 100

100 to < 1000

1000 to < 10000

Number of Larvae / 10m2

10000 to 10840

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

35

36

37

38

39

40

41

42

43

44

45

May (1977 to 1987)

Number of Tows = 1472, with larvae = 117

None

1 to < 10

10 to < 100

100 to < 1000

1000 to 2397

Number of Larvae / 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 (1977 to 1987)

Number of Tows = 893, with larvae = 124

None

1 to < 10

10 to < 100

100 to < 1000

1000 to < 10000

Number of Larvae / 10m2

10000 to 10840

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

35

36

37

38

39

40

41

42

43

44

45

July (1977 to 1987)

Number of Tows = 938, with larvae = 51

Number of Larvae / 10m2

None

1 to < 10

10 to < 100

100 to 102
Page 29

Figure 10. 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 (1977 to 1987)

Number of Tows = 1148, with larvae = 14

Number of Larvae / 10m2

None

1 to < 10

10 to 32
Page 30

Figure 11. Seasonal distribution and abundance of juvenile (≤ 25 cm) and adult (≥ 26 cm) Atlantic mackerel collected

during NEFSC bottom trawl surveys, 1963-1997 (all years combined). Densities are represented by dot size in spring

and fall plots, while only presence and absence are represented in summer and winter plots [see Reid et al. (1999) for

details].
Page 31

Figure 11. cont’d.
Page 32

Figure 12. Distribution and abundance of juvenile (< 26 cm) and adult (≥ 26 cm) Atlantic mackerel in Massachusetts

coastal waters collected during the spring and autumn Massachusetts inshore trawl surveys [1978-1996, all years

combined; see Reid et al. (1999) for details].

Atlantic Mackerel

Mass. Inshore Trawl Survey

 Spring 1978 - 1996

 Juveniles (<26cm)

Number/Tow

 1 to <10

 10 to <25

 25 to <50

 50 to <100

 100 to <101

Atlantic Mackerel

Mass. Inshore Trawl Survey

 Autumn 1978 - 1996

 Juveniles (<26cm)

Number/Tow

 1 to <10

 10 to <50

 50 to <100

 100 to <500

 500 to <1391

Atlantic Mackerel

Mass. Inshore Trawl Survey

 Spring 1978 - 1996

 Adults (>=26cm)

Number/Tow

 1 to <2

 2 to <5

 5 to <10

 10 to <25

 25 to <37

Atlantic Mackerel

Mass. Inshore Trawl Survey

 Autumn 1978 - 1996

 Adults (>=26cm)

Number/Tow

 1 to <1
Page 33

Figure 13. Seasonal distribution and relative abundance of juvenile (< 26 cm) Atlantic mackerel collected in

Narragansett Bay during Rhode Island bottom trawl surveys (1990-1996; all years combined). The numbers shown at

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

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0 0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0

0.0 0.0

0.0

0.0

0.1

0.0

0.0

0.0

0.0

0.6

0.0

0.7

0.0

0.4 1.0

2.3

0.0

0.2

0.0

0.0

0.0

0.3

0.1

0.1

0.1

0.0

0.0 0.1

Spring

Summer Autumn

Winter

Juveniles (< 26 cm)
Page 34

Figure 14. Distribution, abundance, and length frequency distribution of juvenile and adult Atlantic mackerel collected

in Long Island Sound during spring and autumn Connecticut bottom trawl surveys [1992-1997, all years combined; see

Reid et al. (1999) for details].

Number/Tow

 1 to <2

 2 to <3

Number/Tow

 1 to <2

 2 to <3

 3 to <4

 4 to <6

 6 to <7

State of Connecticut DEP

Fisheries Division

Long Island Sound Trawl Survey

SPRING 1992 - 1997

State of Connecticut DEP

Fisheries Division

Long Island Sound Trawl Survey

AUTUMN 1992 - 1997

Atlantic Mackerel

Atlantic Mackeral
Page 35

Figure 15. Commercial landings and stock biomass for Atlantic mackerel from Labrador to North Carolina.

Labrador - North Carolina

Year

1960 1965 1970 1975 1980 1985 1990 1995 2000

Landings (mt x 1000)

0

100

200

300

400

500

Stratified mean catch/tow (kg)

0

500

1000

1500

2000

2500

Landings (mt)

Stock biomass (age 1+; kg)

NORTHEAST FISHERIES SCIENCE CENTER

Dr. Michael P. Sissenwine, Science & Research Director

CAPT John T. Moakley, Operations, Management & Information Services Staff Chief

Teri L. Frady, Research Communications Unit Chief

Jon A. Gibson, Biological Sciences Editor & Laura S. Garner, Editorial Assistant

Publishing in NOAA Technical Memorandum NMFS-NE

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and 17 (decapod crustaceans) of the American Fisheries Society

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Authors must submit one paper copy of the double-spaced

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Send all materials and address all correspondence to:

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National Marine Fisheries Service

166 Water Street

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Research Communications Unit

Northeast Fisheries Science Center

National Marine Fisheries Service, NOAA

166 Water St.

Woods Hole, MA 02543-1026

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STANDARD

 MAIL A