740

NOAA Technical Report NMFS SSRF- 740

Food of Fifteen Northwest
Atlantic Gadiform Fishes

Richard W. Langton and Ray E. Bowman
February 1980

Marine Biological Laboratory
LIBRARY

OCT 1 4 1992

Woods Hole, Mass.

■J

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

NOAA TECHNICAL REPORTS
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702. Length composition of yellowfin, skipjack, and bigeye tunas caught
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706. Food of western North Atlantic tunas {Thunnus) and lancetfishes
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.^„MM0.SP^,^^

NOAA Technical Report NMFS SSRF-740

Food of Fifteen Northwest
Atlantic Gadiform Fishes

Richard W. Langton and Ray E. Bowman
February 1980

Marine Biological Laboratory ;
LIBRARY

OCT 14 1992 i

s

Woods Hole, Mass. j

U.S. DEPARTMENT OF COMMERCE

Philip M. Klutznlck, Secretary

National Oceanic and Atmospheric Administration

Richard A, Frank, Administrator

National Marine Fisheries Service

Terry L. Leitzell, Assistant Administrator for Fisheries

The National Marine Fisheries Service (NMFS) does not approve, rec-
ommend or endorse any proprietary product or proprietary material
mentioned in this publication. No reference shall be made to NMFS, or
to this publication furnished by NMFS, in any advertising or sales pro-
motion which would indicate or imply that NMFS approves, recommends
or endorses any proprietary product or proprietary material mentioned
herein, or which has as its purpose an intent to cause directly or indirectly
the advertised product to be used or purchased because of this NMFS
publication.

CONTENTS

Introduction 1

Methods 1

Food 2

Dietary overlap 2

Results 2

Food 2

Atlantic cod, Gadus morhua 3

Pollock, Pollachius virens 3

Silver hake, Merluccius hilinearis 3

White hake, Urophycis tenuis , 3

Offshore hake, Merluccius albidus 4

Cusk, Rrosme brosme 4

Red hake, Urophycis chuss 5

Spotted hake, Urophycis regius 5

Haddock, Melanogrammus aeglefinus 6

Longfin hake, Phycis chesteri 6

Fourbeard rockling, Enchelyopus cimbrius 6

Marlin-spike, Nezumia bairdi 6

Longnose grenadier, Coelorhynchus carminatus 6

Fawn cusk-eel, Lepophidium cervinum 6

Ocean pout, Macrozoarces americanus 7

Geographic comparisons 7

Atlantic cod, Gadus morhua 7

Pollock, Pollachius virens 8

Silver hake, Merluccius bilinearis 8

White hake, Urophycis tenuis 10

Offshore hake, Merluccius albidus 11

Cusk, Brosme brosme 12

Red hake, Urophycis chuss 12

Spotted hake, Urophycis regius 13

Haddock, Melanogrammus aeglefinus 14

Lx)ngfin hake, Phycis chesteri 15

Fourbeard rockling, Enchelyopus cimbrius 15

Marlin-spike, Nezumia bairdi 15

Longnose grenadier, Coelorhynchus carminatus 16

Fawn cusk-eel, Lepophidium cervinum 16

Ocean pout, Macrozoarces americanus 16

Dietary overlap 17

Discussion 18

Food 18

Atlantic cod 18

Pollock 18

Silver hake 19

White hake 19

Offshore hake 19

Cusk 19

Red hake 19

Spotted hake 20

Haddock 20

Fourbeard rockling 20

Macrouridae 20

Ocean pout 20

Dietary overlap 21

Acknowledgments 22

Literature cited 22

iii

Figures

1. Five geographic areas of the northwest Atlantic composing the samphng area for fish food studies,
1969-72 2

2. Diagrammatic representation of prey of 15 gadiform fishes from five geographic areas in the north-
west Atlantic for both spring and autumn bottom trawl survey cruises, 1969-72 3

3. Percentagesimilarity between the diet of 15 species of gadiform fishes from the northwest Atlantic . 17

Tables

1. Stomach contents of 15 northwest Atlantic gadiform fishes, expressed as percentage weight, collect-
ed during the spring and autumn bottom trawl survey cruises, 1969-72 4

2. Geographic breakdown of food of Atlantic cod, Gadtfcsmor/iua, in the northwest Atlantic 7

3. Geographic breakdown of food of pollock, Po//ac/iiu4(;jreRs, in the northwest Atlantic 9

4. Geographic breakdown of food of the silver hake, Af er/ucciui 6i7j>jeam, in the northwest Atlantic . . 10

5. Geographic breakdown of food of the white hake, t/rop/iycisfenuis, in the northwest Atlantic .... 11

6. Geographicbreakdownoffoodoftheoffshorehake,MeWucciasa/6iduA-, in the northwest Atlantic . 11

7. Geographic breakdown of food of the cusk, Bro.sme 6rosme, in the northwest Atlantic 12

8. Geographic breakdown of food of the red hake, L'rop/iycisc/iuss, in the northwest Atlantic 13

9. Geographic breakdown of food of the spotted hake, t/rop/iycisregjU5, in the northwest Atlantic ... 14

10. Geographic breakdown of food of haddock, Melanogrammus aeglefinus, in the northwest Atlantic . 15

11. Geographic breakdown of food of ocean pout, Macro2oarcesamerjcanus, in the northwest Atlantic . 16

IV

Food of Fifteen Northwest Atlantic Gadiform Fishes

RICHARD W. LANGTON and RAY E. BOWMAN'

ABSTRACT

The food of l.i spocies of Ciidiform fishes occurring in the northwest Atlantic, from Cape Halteras.
N.C., to Nova Scotia, have been investigated for the years l'J(>9-72. The populations of Atlantic cod.
Gaitus morhua; pollock, I'otlachius iirens; silver hake, Merluccius biiinearis; white hake, Vrophycis
tenuis: offshore hake, Merluccius albidus; and eusk, Brosme brosme; have reasonably similar diets,
being primarily piscivorous. The red hake, Vrophycis chuss, and spotted hake. I'rophycLi rcnius, also
have similar diets and are mixed feeders, preying on both fish and invertebrates. The final seven
species, haddock. Melanogrammus aeglefinus; longfin hake, Phycis chesleri; fourbeard rockling.
Enchelyopus cimbrius: marlin-spike, Neiumia bairdi; longnose grenadier, Coelorhynchus car-
minatus; fawn cusk-eel. Lepophidium cervinum; and ocean pout, Macrozoarccs americanus; prey
almost exclusively on invertebrates.

INTRODUCTION

Investigations on the food habits of fish have been a
major topic of research since the beginning of fishery re-
search as a scientific discipHne. Since food availability
ultimately controls production, the literature has be-
come replete with papers describing, in detail, the prey of
numerous species of fish. This vast literature has concen-
trated on the more common commercially important
species, often at the expense of the lesser known but eco-
logically interesting fish. Among the Gadiformes de-
scribed in this report the literature on the cod and had-
dock was found to be the most extensive (see Literature
cited), reflecting the importance of the fishery for these
two animals, while comparative data on the food habits
of fish such as the spotted hake, red hake, and the gren-
adiers is either scanty or completely lacking, especially
for fish from the northwest Atlantic.

In recent years some authors have suggested that man-
agement of a single fish species is untenable and that, in-
stead, the ecosystem must be considered as a whole (Gul-
land 1977). The commercially important species must be
considered in relation to their role in the total marine
environment. Edwards (1976) has gone so far as to say
that, in the context of total ecosystem management, fish
could be ignored as individual species and considered as
a group occupying a specified feeding niche. These niches
are dependent upon the fishes' food habits which are, in
turn, related to the morphology and size of the fish. Food
related size classes for fish have been identified as
"threshold lengths" by Parker and Larkin (1959) or
"feeding stanzas" by Paloheimo and Dickie (1965) and
Tyler (1972). In order to develop such a management
plan, however, it is first necessary to describe quantita-
tively the food of all the major fish populations occurring
within the bounds of the ecosystem and evaluate the role

of each stock relative to the other fish in that same
system.

This report describes the food of 15 northwest Atlantic
gadiform fish populations.

METHODS

Fish utilized for stomach contents analysis were
collected during six bottom trawl survey cruises con-
ducted on the following dates: 8 October-23 November
1969; 3 September-20 November 1970; 9 March-1 May
1971; 30 September- 19 November 1971; 8 March-24 April
1972; and 27 September-20 November 1972. Collections
were made with a # 36 Yankee otter trawl with rollers, 9
m legs, and standard 544 kg oval doors. The cod end and
upper belly were lined with 13 mm mesh netting to retain
smaller fish. A scheme of stratified random sampling was
conducted within the five geographic areas of the north-
west Atlantic (Fig. 1) and sampling continued over 24 h
per day."

A total of 9,158 stomachs was collected from 15 spe-
cies of the Gadiformes. The fish were selected randomly
from the bottom trawl survey catch. Stomachs were ex-
cised aboard ship; labeled according to species, cruise,
and station; and preserved in 109c Formalin. The gen-
eral plan was to obtain a random sample of the popu-
lation for each species, without bias toward a specified
length or sex. Juvenile fish were preserved whole. Only
fish above a specified length are considered in this paper.
The species collected and their minimum fork lengths
are as follows: Atlantic cod, (ladus morhua (Linneaus),
>20 cm; haddock, Melanogrammus aeglefinus (Lin-
naeus), >20 cm; silver hake, Merluccius biiinearis (Mit-
chill), >20 cm; pollock, Pollachius uirens (Linnaeus),

Northeast Fisheries Center Woods Hole Laboratory, National Marine
Fisheries Service, NOAA, Woods Hole, MA 02543.

'Further details of the bottom trawl techniques may be obtained from
the Resource Surveys Investigation, Northeast Fisheries Center Woods
Hole Laboratory. National Marine Fisheries Service, NOAA, Woods
Hole, MA 02543.

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FiKure 1. — Five (^eoeraphic areas of the northwest Atlantic com-
posing the sampling area Tor Tish food studies, 1969-72.

>20 cm; red hake, Urophycis chuss (Walbaum), >20 cm;
white hake, Urophycis tenuis (Mitchill), >20 cm; spot-
ted hake, Urophycis regius (Walbaum), >10 cm; longfin
hake, Phycis chesteri Goode and Bean, >10 cm; offshore
hake, Merluccius albidus (Mitchill), >20 cm; fourbeard
rockling, Enchelyopus cimbrius (Linnaeus), >10 cm;
cusk, Brosme brosme (Miiller), >20 cm; marlin-spike,
Nezumia bairdi (Goode and Bean), >10 cm; longnose
grenadier, Coelorhynchus carminatus ((ioode), >10 cm;
fawn cusk-eel, Lepophidium ceruinum (Goode and
Bean), >10 cm; and the ocean pout, Macrozoarces
amencanus (Bloch and Schneider), >10 cm.

In the laboratory, the preserved stomachs were opened
and the contents emptied onto a fine mesh screen to per-

mit washing without losing any food items. The vauious
prey item« were manually sorted, identified to the low-
est possible taxa (using a dissecting microscope when
necessary), and damp dried on bibulous paper. Each
taxonomically distinct group was weighed to the nearest
0.01 g on a Mettler balance, immediately after blotting.
Parasites in the stomach were included as part of the
stomach contents and are incorf)orated in the tables un-
der "Other Groups."

Food

The food of each species of fish is summarized on a
weight basis as a percentage of the total weight of stom-
ach contents. In the tables the subtotals for the major
prey categories, i.e., subtotals for the major taxa, are off-
set and italicized. The tables follow a standard format to
facilitate comparison of the food between species. In the
text the broader groupings of prey, as presented in the
tables, are discussed in detail. The percentage weight is
included in parentheses after the first mention of a prey
group in order to quantify that particular prey's signifi-
cance in the diet at that taxonomic level.

Dietary Overlap

Percentage similarity, as a measure of dietary over-
lap, was calculated according to the formula of Shorygin
(Ivlev 1961) as follows:

P.S. = 100-0.52 1 a-6 1

or, more simply, by summing the smaller value, in this
case the percentage weight, for all prey shared by the two
predators. Accordingly:

P.S. = 2 min (a,b)

where: P.S. = percent similarity

a = percentage weight for a given prey

group for predator A
b = percentage weight of the same prey
group for predator B.

If a +, indicating <0.1''r weight, was the smallest
value for any prey group in the table it was arbitrarily as-
signed a value equal to 0.05'^c for the calculations.

RESULTS

Food

Since the data are presented as percentages it is
possible to compare the food of each species directly and
independently of the sample size. A detailed comparison
of food between species will be made later but first we
consider separately the food of each species over the en-
tire study area (Table 1, Fig. 2) and then by the geo-
graphic areas (remaining tables) shown in Figure 1.

/ / /

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ii

Figure 2. — Diagrammatic representation of prey of 15 gadiform
fishes from five geographic areas in the northwest Atlantic for both
spring and autumn bottom trawl survey cruises, 19fi9-72. Data are
expressed as percentage weight.

Atlantic cod, Gadus morhua. — Atlantic cod preyed
most heavily on fish (64.0%). Clupeidae (27.4%) were the
most important prey, with the Atlantic herring, Clupea
harengus (IG.T'it ), being the largest single contributor to
the diet. The Gadidae made up 3.7% of the diet while the
Scombridae, represented exclusively by the Atlantic
mackerel. Scomber scombrus, composed 3.1% of the diet.
The Scorpaenidae contributed 3.2% to the diet, of which
2.6% was identified as the redfish, Sebastes marinus.
After fish, the crustaceans were the next most important
prey group, making up 20.7% of the diet by weight. Deca-
pods were the most important crustaceans totaling 16.6%
of the diet. The Cancridae, represented by both species
of Cancer, i.e., C. borealis (l.S"";) and C. irroratus (1.4%),
constituted a major part of the decapod prey totaling
4.7% of the diet. Pandalid shrimp (2.9%), particularly
Dichelopandalis leptocerus (1.3%), and the toad crabs
(2.1%) (family Majidae) of the genus Hyas also ac-
counted for part of the decapod prey. Other phyla played
a less important role. MoUusca composed only 7.6% of
the prey with the pelecypods Placopecten (2.9%) and
Pecten (1.2%) contributing the major fraction. Scallops
were important only on Georges Bank and may repre-
sent the remains of scallops discarded by fishermen
which were then preyed upon by cod. A similar situation
was observed for Georges Bank haddock by Wigley

(1956). Polychaetes and echinoderms composed an even
smaller percentage of the diet, 1.3 and 1.2%, respec-
tively.

Pollock, Pollachius virens. — Almost one-half of the
pollock's diet was fish (47.0%). The majority were clupe-
ids (19.2%) which were identified as Atlantic herring
(14.3%). Gadids (1.4'r) were also preyed on, especially
silver hake (1.2%), and in one instance a juvenile pollock
was identified as part of the stomach contents. A small
percentage of the stomach contents was made up of the
scorpaenid Sebastes marinus (1.5%). "Other Pisces"
(24.9%) accounted for over half the fish, and in this cate-
gory eels (5.7%), lanternfish (2.0%), and the American
sand lance, Ammodytes americanus (0.1%), could be
identified. The remaining half of the diet consisted ex-
clusively of crustaceans (SO.SSc). Euphausiids (35.3%)
made up the majority of the Crustacea, with Meganyc-
tiphanes norvegica contributing 26.5% of the diet by
weight. Other species of euphausiids, such as Thysano-
essa inermis, T. longicaudata, and Euphausia krohnii,
were also identified in the stomach contents, but each of
these species contributed <1% to the total weight of the
prey consumed. Pandalid shrimp (2.5%) of the genera
Pandalus (1.8';) and Dichelopandalus (0.5%) were of
secondary importance, while Pasiphaea multidentata
(10.0%), a pelagic shrimp, listed under "Other Deca-
poda," was of major significance. Annelids (poly-
chaetes), molluscs, echinoderms, and other phyla con-
tributed only 1% of the total diet.

Silver hake, Merluccius bilinearis. — The major pro-
portion of the silver hake's diet was fish (70.9%). These
hake preyed heavily on Atlantic mackerel (18.9%) and on
clupeids (14.6%) such as the Atlantic herring (10.4%)
and the alewife, Alosa pseudoharengus (4.2%). Silver
hake were also cannibalistic; 3.4% of the Gadidae (7.1%)
were silver hake. A large part of the fish could not be
identified due to their state of digestion. Consequently,
30.1% of the prey was included under "Other Pisces."
However, two groups in this category that could be
recognized were the butterfish, Peprilus triacanthus
(1.5%), and the lanternfish (family Myctophidae)
(1.1%). Crustaceans formed the remaining bulk of the
diet, 25.0%. Euphausiids (12.6%), such as Meganycti-
phanes norvegica (7.4%), were the single most important
crustaceans, but the pandalid shrimp, Dichelopandalus
leptocerus (3.2%), was also of some importance. Other
crustaceans which contributed to the diet were the two
caridean shrimp: Crangon septemspinosa (1.4%) and
Pasiphaea (2.0%). The only molluscs of any note were the
cephalopods (2.2%), such as the squid Loligo (1.5%).

White hake, Urophycis tenuis. — White hake preyed
heavily on fish (78.2%). The clupeids (12.5%) were the
single most important group, with Atlantic herring mak-
ing up 4.8% of the total diet. Gadids (10.7%) were also
important, with silver hake (3.0%), red hake (0.8%),
Atlantic cod (0.5%), haddock (0.5%), longfin hake
(0.3%), and white hake (0.2%) all having been identified

Tabic I.— Stomach contenU of 15 northuesl Allanlic gadiform Tishes, expressed as pereentage weight.

Prey/Predaton

Atlantic cod

PoUock

Silver hake White hake OflBhore hake

Cusk

Red hake

19.2
1.4

1.5

0.4
0.2
12.6
5.3
1.4
+

O.I
2.6
2.4

+
+
2.2

+

+
+

14.6

7.1

18.9

2.1

78.2

12.5

10.7

7.3

1.7

5.5

0.9

POLYCHAETA 1.3 0.1 0.2 0.2

Nereidiformia 1.2 + 0.2

Terebelliformia + — -

Sabelliformia _ _ _

Other Polychaeu 0.1 + +

CRUSTACEA 20.7 50.8 25.0 17.3

Amphipoda 0.5 0.1

Mysidacea 0.1 +

Euphausiacea 2.1 35.3

Pandalidae 2.9 2.5

Crangonidae 0.3 +

Axiidae 0.5 —

Paguridae 1.7 —

Majidae 2.1 —

Cancridae 4.7 —

Other Decapoda 4.4 10.4

Other Crustacea 1.4 2.4

MOLLUSCA 7.6 04 2.2

Gastropoda 2.4 0.4

Pelecypoda 4.3 +

Cephalopoda 0.1 -t-

Other Mollusca 0.8 +

ECHINODERMATA 1.2 - +

Echinoidea 0.1 —

Ophiuroidea 0.6 —

Other E^hinodermata 0.5 -

PISCES 64.0 47.0 70.9

Clupeidae 27.4

Gadidae 3.7

Scombridae 3.1

Scorpaenidae 3.2

Bothidae 0.3 -

Pleuronectidae 2.5 — 0.1 -

Other Pisces 23.8 24.9 30.1 46.0

Other groups 0.4 0.5 0.1 0.1 +

Animal remains 3.2 1.2 1.6 2.1 0.2

Sand and rock 1.6 0.1 + +

O.I

0.1

O.I

+

4.3

9.1

0.3

0.1

+

0.3
2.3
0.8

+
+
2.1

+

1.1
2.5

1.9

0.9

93.4

59.9

33.5

20.4

6.8

6.8

71.5

71.5

0.2
0.9
0.2

2.9

-

1.3

-

+

-

O.I

-

1.5

54.1

+

7.4

-

0.1

0.3

3.0

4.1

12.1

-

3.0

-

2.0

-

2.8

1.7

0.1

-

5.3

11.6

13.4

2.7

4.9

6.3

-

3.1

—

+

-

1.3

-

1.9

0.6

25.3

0.1

0.5

0.5
0.4
0.4

0.5

0.1

23.5

0.8
9.6
0.3

Number of stomachs

1.541

639

2.152

912

73

72

I.UO

Percentage of empty stomachs

7.6

11.8

32.8

23.9

57.5

73.6

15.9

Mean weight per stomach (g)

27.9

18.2

2.5

18.0

2.4

3.2

2.3

Mean predator fork length (cm)

54.7

46.8

27.5

46.4

32.2

63.0

30.3

Number of sampling stations

291

160

222

177

14

43

154

in the stomach contents. The Atlantic mackerel (7.3%)
was also imjxirtant prey. Manfyy of the fish in the cate-
gory "Other Pisces" (46''f ) were identified. Among those
fish that could be identified to species were the argen-
tine, Argentina situs (8.9'^ c); wrymouth, Cryptocan-
thodes maculatus (0.8%); American sand lance (0.7%);
and the butterfish (0.4%). Crustacea (17.3%) consti-
tuted most of the remainder of the diet. Of primary im-
portance in this group were the pandalid shrimp (9.1%)
of which four species have been identified, Pandalus
borealis (2.2%), Dichelopandalus leptocerus (0.8%), P.
montagui (0.5%), and P. propinquus (<0.1%).
Euphausiids (4.3%), such as Meganyctiphanes (2.1%)
and Thysanoessa inermis (0.3%), were also of some
dietary significance. Rock crabs of the family Cancri-
dae, i.e., C. borealis (0.2%) and C. irroratus (0.1%), were
also identified as prey. Similarly, Crangon (0.2%) was
identified as being of minor dietary importance. Among
the "Other Decapoda," the red crab, Geryon (0.9%), was
the most important. The only other category that con-

tributed to the diet to any degree was cephalopods (2.1%)
of the genera Loligo (1.2''f ) and Rossia (0.1%).

Offshore hake, Merluccius albidus. — Offshore hake
preyed most heavily on fish, which accounted for 93.4%
of the diet. The Gadidae contributed 59.9% of the diet by
weight but none of the remains in the stomachs could be
identified to lower than the family level. None of the fish
remains in the "Other Pisces" category (33.5%) could be
identified. Crustaceans were of secondary importance
(5.5%) and those that could be identified were the two
genera of pandalid shrimp (2.5'r), Dichelopandalus
leptocerus (2. 4';) and Pandalus (0.1%). Euphausiids
(1.1%), in paTticulsLT Meganyctiphanes norvegica (0.9%),
were of little dietary significance. The only other deca-
pod identified was the pelagic shrimp Pasiphaea (0.9%).

Cusk, Brosme brosme. — Cusk are primarily fish
eaters (71.5'() but none of the prey species could be
identified from the digested remains found in the stom-

collected during the spring and autumn bottom trawl survey cruises, 19tit)-72. (+ indicates present but <ii.\%.)

Spotted hake Haddock Longfm hake Fourbeard reckling Marlin-spike Longnose grenadier Fawn cusk-eel Ocean pout

0.5

47.5

n.5

34.2

+

5.9

0.3

0.1

0.4

7.3
+
+
3.9
4.1
+
0.1
+

6.8

20.8

4.5

0.1
0.2
U.2

+

4.3
3.3

1.8

0.8

24.0

17.6

16.2

3.1

29.9

14.6

2.0
1.6
1.3

12.7

6.4
0.1
2.6
1.4
0.1
0.9
0.4
0.3
0.1
1.8
2.1

0.3
2.3
0.2
0.3

5.7

21.6

2.6

12.9
0.3

+
1.4

1.0
8.9
8.7

97.6

12.5

57.4

60.3
8.7

15.4
13.2

12.5

1.0
+
1.0
9.6
40.7

4.7
0.4

27.5

47.3

27.6

7.8
4.0

+

35.8

24.8

35.8

99

28.8

2.5

27.5
8.0

2.5

23.6
1.2

0.3

1.1

0.3

0.2

0.5

2.3

1.1

+
1.0

+
301

22.4
0.3

2.8
366

29.8
28.5

+

2.4

7.5

4.9

6.4
0.3

+

0.7

16.5

0.2

0.2
0.3

2.3

3.3

11. 1

4.0

70.7

0.1

2.7
4.0
4.1

3.0

+

0.3
5.6

+
+

0.5
0.3
T.9
0.8

1.0

0.6
3.3

0.1

64.9
5.3
0.5

0.1

876

1,131

126

48

23

11

109

377

14.3

7.3

62.7

12.5

8.7

36.4

22.9

25.9

1.1

6.8

0.28

0.30

0.14

0.09

0.03

6.9

18.4

45.6

23.6

24.2

24.2

19.3

22.3

46.0

64

154

15

10

4

4

13

65

achs. Crustaceans are also a major prey category, 20.4%.
Within this group the toad crab (Majidae), Hyas co-
arctatus (l.T^l), and several species of pandalid shrimp
{4.1'>c), Pandalus borealis (3.3'p), P. propinquus (O.V'c),
and Dichelopandalus leptocerus (0.7%), were identified.
The Penaeidea (1.3%) also contributed a small amount
to the diet. The brittle star, Ophiopholus aculeata
(6.8%), was the only echinoderm preyed upon.

Red hake, IJrophycis chuss. — Crustaceans (54.1%)
were the major prey of red hake. A number of different
families contributed to the diet, with the Pandalidae
(12.1%), especially the genus Dichelopandalus Cl.V'i),
being of primary importance. The galatheid crab,
Munida (10.2%), which is included under "Other Deca-
poda," was also a major dietary component. Of second-
ary importance were the Cancridae (5.3%), particularly
C. irroratus (2.1%); the Crangonidae (3.0%); the Axiidae
(2.0%); Axius (0.6%); Calocaris (1.2%); and a variety of
different species of amphipods (7.4%). Fish were also
important prey (25.3%). Clupeids (0.5%), Atlantic mac-

kerel (0.4%), and the gadids (0.4%), such as silver hake
(0.2%) and other red hake (0.2'^c), all contributed to the
diet. The flatfish prey included Gulf Stream flounder,
Citharichthys arctifrons (0.5%), and the winter floun-
der, Pseudopleuronectes americanus (0.1%). Among the
category "Other Pisces" (23.5%), the wrymouth (1.1%)
and the snake eel, Omochelys cruentifer (0.9%), were
identified. The Mollusca also contributed to the diet
(6.3%), however, most of them were not identifiable to
below the class level. Of the gastropods consumed, only
Buccinum (0.2%) was identified to the genus level. Poly-
chaetes were also a minor prey group (2.9%), and a few
genera that could be identified from the partially di-
gested remains were Arenicola (0.1%), Nephtys (0.3%),
Sabella (0.1%), Aphrodita (0.1%), and Ophioglycera
(0.1%).

Spotted hake, Urophycis regius. — Crustacea (47.5%)
form almost half the diet of spotted hake. Among the
most important contributors to this assemblage of
crustaceans were the galatheid crabs, Munida iris

(8.8'"c). A/, valida (4.5^t), remains of iVfumda (3.1^c) that
could not be identified to species, and other galatheids of
the genus Munidopsis (1.7'c). These crabs form the ma-
jority of the animals in the category "Other Decajwda"
and were the single most important prey. Other crusta-
ceans of some significance were amphipods (7.3'c), espe-
cially the Hyperiidae (4.4' t); the rock crab, Cancer
irroratus (4.2''c); the Crangonidae (4.1Tc), such as
Crangon (3.9'~c) and Pontophilus (0.1'i); the pandalid
shrimp, Dichelopandalus (3.7%); and lastly, isopods
(2.0%), which are included in the category "Other Crus-
tacea." Fish constituted over one-third of the spotted
hake's diet, 34.2' t. Gadids (4.3'c), such as silver hake
(2.2''f) and red hake (2.1'c), were important prey, along
with the Atlantic mackerel (3.3' c). The bothid prey
included the Gulf Stream flounder (1.8'c), whereas the
only member of the Pleuronectidae identified was the
yellowtail flounder, Limanda ferruginea (0.5'f). Fish,
considered under the category "Other Pisces," that could
be identified were cusk-eel (family Ophidiidae) (4.4%),
lantemfish (family Myctophidae) (3.0'c), primarily of
the genus Myctophum (1.5'c), and the snake eel (0.1%).
The only other taxon that was of significance as prey is
the Mollusca (11.5'c). Within this phylum, Cepha-
lopoda (11.2%) was the most important class. Two
genera of squid were identified in the stomachs: Loligo
(4.2%) and Rossia (0.4%). Most of the remaining cepha-
lopods (6.6%) could not be identified.

Haddock, Melanogrammus aeglefinus. — Haddock
fed on a variety of benthic invertebrates with echino-
derms (29.9'c) of the subclass Ophiuroidea (21.6'"c) being
of major importance. The brittle stars Uphiura (6.2%)
and Ophiopholis (5.5'c) were the two most important
prey items. Polychaetes, crustaceans, and fish all con-
tributed about equally to the diet, 17.6'c, 16.2'c, and
14.6%, respectively. A number of different polychaetes
were identified in the stomach contents, e.g., Aphrodita
(0.5%), Cistenidae (0.2'^c), Chone infundibulinformis
(0.1%), Sabella (0.1%), and Nephtys (0.1%). The single
most important species was Ammotrypane autogaster
(3.8%) which accounted for more than one-fourth of the
category "Other Polychaeta" (12.7'c). Amphipods
(6.4^c), particularly gammaridean amphipods (4.2%),
were the largest component of the crustacean prey. Other
crustaceems of importance were euphausiids (2.6'f ), such
aa Meganyctiphanes noruegica (1.8%), and the pandalid
shrimp (1.4'r), Pandalus (0.7'c) and Dichelopandalus
leptocerus (0.5' c ) . The importance of fish may be slightly
overemphasized from the present results. The Clupei-
dae appear to be a major food source; however, the entire
weight (r2.9'f) was due to the consumption of herring
eggs rather than adult or juvenile fish. Finally, sand and
rocks made up 8.7' c of the stomach contents by weight,
thus reflecting the haddock's benthic habits.

Longfin hake, Phycia cheateri. — The longfin hake
preyed primarily on Crustacea, as this prey group made
up 97.6' f of the diet. However, the total quantity of prey
examined was relatively small (35.28 g) although it rep-

resented 126 fish. Possibly a more extensive study of the
food of this fish would broaden the spectrum of prey con-
sumed. Nevertheless, in this study the single most im-
portant prey item was the euphausiid, Meganycti-
phones noruegica, which constituted more than half
(55.9' t) of the diet. The only other crustacean identified
to the genus level was the shrimp, Pandalus (8.6'c).

Fourbeard reckling, Enchelyopus cimbrius. — A

large proportion of the diet of the fourbeard rockling was
Crustacea (57.4' c). The primary prey species was
Crangon septemspinosa (40.7%). The pandalid shrimp,
Dichelopandalus leptocerus (9.6' c), was of secondary im-
portance, while euphausiids (I.O'c) and amphipods
(1.0%) contributed little to the diet. Polychaetes (12.5'c)
were also preyed upon but the only identifiable genus
was Ammotrypane (3.3'c). Unidentified animal remains
made up 30.1% of the diet. This is due to the state of di-
gestion of the prey and also, possibly, because of the
small total weight in the stomachs (14.4 g).

Marlin-spike, Nezumia bairdi. — This summary of
the food of the marlin-spike is based on only 23 fish and
an extremely small weight (3.22 g) for the prey. The two
most important prey groups were the crustaceans
(47.3%) and polychaetes (27.5'f). The polychaete re-
mains could not be identified below the class level. Some
of the crustaceans were identifiable, such as hippiolytid
shrimp, Eualus pusiolus (26.0' f), which accounts for
most of the animals included in "Other Decapoda."
Mysids, Neomysis americana (4.0'c), the isopod, Ciro-
lina (O.e'c), and euphausiids (<0.1'c) were the other
crustaceans that could be identified.

Longnose grenadier, Coelorhynchus carmin-
atus. — As has been described for the marlin-spike, the
summary of the food of longnose grenadier is based on a
small sample both in the number of fish analyzed and
the total weight of prey. It is possible that the percent-
age composition of the diet would differ markedly if more
fish were available for analysis. From the available data,
polychaetes and decaptod shrimp were the only identifi-
able prey.

Fawn cusk-eel, Lepophidium cerrinum. — The stom-
ach contents of 109 fawn cusk-eel we-e examined, but the
total weight of the prey amounted to only 3.27 g. For this
reason the percentage weights listed in Table 1 should be
used more as a qualitative guide to the food since a small
change in weight could markedly influence the percent-
age composition of the diet. Bearing this precaution in
mind, the prey items are discussed below.

The most significant prey group was the crustaceans
(28.8%). Within this group the "Other Crustacea" were
the largest contributors, primarily the isopod, Cirolina
(12.6%). A variety of different families of amphipods was
found in the stomachs, the most important being the
Gammaridae (4.6' 0- Other crustaceans that could be
identified were two members of the Crangonidae (6.4'c),
[Crangon (2.3%) and Sabinea (2.6%)], the munid crab.

Munidopsis (0.7%), and the mud shrimp, Calocaris
(O.S'Jp). Polychaetes (9.9%) were moderately important,
with a few identified to the genus level, such as Nephtys
(1.8%), Scalibregma (1.0%), and Nothria (0.6%). "Other
Groups" (29.8%) was the single most important cate-
gory contributing to the stomach contents, and this was
comprised of a large number of parasitic nematodes
(29.4%).

Ocean pout, Macrozoarces americanus. — Ocean
pout preyed most heavily on echinoderms (70.7%), the
single most important species being the sand dollar,
Echinarachnius parma (56.3%). Ophiuroids (5.3%), such
as Ophiopholls (1.1'c) and Ophiura (0.1%), were also
identified in the stomach contents. Crustaceans (11.1%),
most notably the rock crabs of the family Cancridae
(2.9%), both Cancer irroratus (1.0%) and C. borealis
(0.7%), and a number of different amphipods (5.6%)

were also prey items. Polychaetes (3.3%) of the genus
Aphrodita (3.0%) and the tunicate, Cnemidocarpa mollis
(1.7%), which falls into the category "Other Groups,"
were other components of the diet.

Geographic Comparisons

The data on the food of the 15 species of Gadiformes
for each of the five geographic areas (Fig. 1) in the north-
west Atlantic are presented in the following text and/or
Tables 2-11. In this section the data are compared and
contrasted for each species in each of the five areas to
emphasize similarities and differences in food over these
broad geographic regions.

Atlantic cod, Gadus morhua. — In all of the geo-
graphic areas fish was the major prey of Atlantic cod with
the Clupeidae generally being the most important (Table

Tabic 2.— Geographic breakdown of food of Atlantic cod, Gadus morhua. in the northwest Atlantic. Data are
expressed as percentage weight, for fish collected during the spring and autumn bottom trawl survey cruises
1969-72. (+ indicates present but <0.1%.)

Middle

Southern

Gulf of

Western

Prev

Atlantic

New England

George

IS Bank

Maine

Nova Scotia

POLYCHAETA

0.1

64

;.;

0.3

0.8

Nereidiformia

0.1

6.4

1.0

0.2

0.6

Terebelliformia

-

-

-1-

+

-1-

Sabelliformia

-

-

-

-

—

Other Polychaeta

-

-1-

0.1

0.1

0.2

CRUSTACEA

10.2

20.9

15.2

26.1

27.6

Amphipoda

+

1.6

0.7

0.1

0.1

Mysidacea

-

+

0.2

+

+

Euphausiacea

-

-

0.4

1.2

8.8

Pandalidae

0.1

0.7

3.1

2.8

3.9

Crangonidae

1.4

0.3

0.4

0.1

0.1

Axiidae

-

2.4

0.1

+

1.3

Paguridae

3.8

0.9

2.5

0.2

2.2

Majidae

-

+

1.5

0.2

7.4

Cancridae

2.8

12.8

4.4

5.9

-

Other Decapoda

-

1.6

0.7

14.1

1.7

Other Crustacea

2.1

0.6

1.2

1.5

2.1

MOLLUSCA

0.6

1.9

15.6

0.7

0.6

Gastropoda

-

1.4

4.7

0.3

0.3

Pelecypoda

-

0.4

9.4

0.1

-(-

Cephalopoda

-

+

+

0.3

-(-

Other MoUusca

0.6

0.1

1.5

+

0.3

ECHINODERMATA

-

0.8

0.6

0.4

3.6

Echinoidea

_

-1-

-I-

+

0.2

Ophiuroidea

-

0.3

0.3

0.2

1.9

Other Echinodermata

-

0.5

0.3

0.2

1.5

PISCES

86.5

64.1

61.6

69.5

60.6

Clupeidae

-

32.8

37.3

23.3

12.1

Gadidae

12.9

-

2.6

4.5

6.5

Scombridae

-

6.4

-

8.7

1.7

Scorpaenidae

-

-

-

11.6

0.9

Bothidae

-

1.9

0.3

-

-

Pleuronectidae

43.7

-

4.3

-

-

Other Pisces

29.9

23.0

17.1

21.4

39.4

Other groups

+

0.1

0.6

0.3

0.3

Animal remains

2.6

4.8

2.7

2.2

5.4

Sand and rock

+

1.0

2.6

0.5

1.1

Number of stomachs

7

79

667

347

441

Percentage of empty stomachs

1

0.0

6.3

6.9

8.6

8.1

Mean weight per stomach <g)

69.7

46.6

29.6

;

31.9

18.2

Mean predator fork length (cm)

82.0

65.8

50.3

J

57.7

57.9

Number of sampling stations

5

22

90

71

103

2). In the Middle Atlantic, however, only seven Atlantic
cod stomachs were examined and yellowtail flounder
(33.7^t) was the most important prey. In Southern New
Elngland and on Georges Bank most of the clupeids could
be identified as Atlantic herring (27.1 and 31.4'(, re-
spectively). The only other clupeid identified to species
level was an alewife (0.9' c), from Georges Bank.

A variety of other fish was eaten throughout the North-
west Atlantic and is listed by area as follows: Middle
Atlantic— red hake (12.9'(); winter flounder (10.0'c);
beardfishes, Polymyxiidae (9.0'c); cusk-eels, Ophidii-
dae (6.4%); sand lance, Ammodytes (2.7%); and the
longhom sculpin, Myoxocephalus octodecemspinosus
(1.5%). Southern New England — Atlantic mackerel
(6.4%); windowpane, Scophthalmus aquosus (1.9'();
Cryptacanthodidae (2.8%); the Cottidae (1.1%); and a
seahorse. Hippocampus (0.2%). Georges Bank —
yellowtail flounder (3.4%); American plaice, Hippo-
glossoides platessoides (0.9%); summer flounder. Para-
lichthys dentatus (0.1%); windowpane (0.2%); the rock
gunnel, Pholis gunnellus (0.1%); sculpins such as the
grubby, Myoxocephalus aenaeus (<0.1%), the longhom
sculpin (0.5%), and the mailed sculpin, Triglops nybe-
lini (0.1%). Gulf of Maine — the scorpaenids, Helico-
lenus dactylopterus (1.9%) and Sebastes marinus (9.6%);
Atlantic mackerel (8.7%); wolffish, Anarhichadidae
(3.3%); Argentina sp. (3.2%); silver hake (1.6%); and the
wrymouth (0.4'c). Western Nova Scotia — sand Itmce
(11.3%); gadids, including silver hake (1.7%), haddock
(0.7%), and Atlantic cod (0.1%); Atlantic mackerel
(1.7%); redfish (0.9%); wolffish (0.2%); and the rock gun-
nel (0.1%).

Crustacea were generally the second most important
group of prey and, like fish, a variety of different crusta-
ceans were consumed, but only the major groups will be
discussed here. In the Middle Atlantic the only crusta-
cean prey of any significance was hermit crabs, Paguri-
dae (3.8%), and rock crabs (2.5%). Crustaceans com-
posed 20.9% of the Atlantic cod's diet in Southern New
England; and the rock crabs (12.8%), Cancer borealis
(2.8%) and C. irroratus (1.8%), accounted for more than
half of this group. On Georges Bank, rock crabs (4.4%)
were again the most important crustacean prey but
pandalid shrimp (3.1%) [i.e., Dichelopandalus (2.3%)],
and hermit crabs, Pagurus (2.5%), also contributed to
the diet. In the Gulf of Maine rock crabs (5.9%) and
pandalid shrimp (2.8%) were again preyed upon but the
red crab, Geryon (10.1%), was the most important deca-
pod prey. Spider crabs (family Majidae) of the genus
Hyas (7.4%) and euphausiids (8.8%), such as Mega-
nyctiphanes (2.6%), were the primary crustacean prey in
Western Nova Scotia. Of secondary importance were the
Paguridae (2.2%) and the pandalid shrimp (3.9%), Di-
chelopandalus leptocerus (0.8%) and Pandalus montagui
(0.3%).

Two other taxa were of some significance in two of the
geographic areas. In Southern New England polychaetes
of the suborder Nereidiformia made up 6.4% of the diet,
and this was entirely due to the sea mouse, Aphrodita.
The Mollusca accounted for 15.6'c of the prey on Georges

Bank. The pelecypods contributed most of the weight
(9.4'( ), with the scallops, Placopecten (6.3%) and Pecten
(2.6%), accounting for the majority of the prey in this
group but these scallops may be scallop remains dis-
carded by fishermen since only scallop viscera and no ad-
ductor muscles were found in the stomachs.

Pollock, Pollachius virens. — Because only six fish
were collected for stomach content analysis in Southern
New England and the Middle Atlantic, the following
discussion is limited to the other three areas (Table 3).

The major prey of pollock on Georges Bank and in
Western Nova Scotia was crustaceans (71.6 and 61.2%,
respectively). In both of these areas euphausiids com-
prised more than one-half the diet. Of the euphausiids
identified, Meganyctiphanes norvegica was the most
important, contributing 46.6% of the diet on Georges
Bank and 46.2% in Western Nova Scotia. Other euphau-
siids, such as Thysanoessa longicaudata, were preyed
upon in both areas (3.6% on Georges Bank and <0.1% in
Western Nova Scotia), but Euphausia krohnii (0.1%)
was only found in stomachs collected from Georges Bank.
Apart from euphausiids, pandalid shrimp, primarily
Pandalus sp. (2.7% on Georges Bank and 2.9% in
Western Nova Scotia), and "Other Decapoda" such as
Pasiphaea (4.0% in Western Nova Scotia) were the only
other important Crustacea. Fish accounted for the
remaining bulk of the diet and a number of different
species were identified in the stomach contents as fol-
lows: Georges Bank — lanternfish (8.8%); the pearlside,
Maurolicus pennanti (1.2%); silver hake (0.4%); and pol-
lock (0.1%). Western Nova Scotia^the snake eel (5.5%);
redfish (1.3%); haddock (0.7%); silver hake (0.6%); blue-
back herring, Alosa aestivalis (0.5%); and the sand lance,
Ammodytes (0.4%).

In the Gulf of Maine the emphasis shifted from Crus-
tacea (33.8%) to Pisces (64.9%) as the major prey cate-
gory. This difference was almost entirely caused by
heavy predation on the Atlantic herring (29.4%). Few
other fish, except for redfish (2.3%) and silver hake
(1.9%), could be identified from the partially digested re-
mains. Crustaceans remained an important prey group
but the groups composing the category differed from
those of Georges Bank and Western Nova Scotia. "Other
Decapoda" were the most important, with Pasiphaea be-
ing the largest single prey item (5.5%). Euphausiids also
contributed to the diet and. again, Meganyctiphanes
(6.7%) was the most important, although Thysanoessa
inermis (O.Kr) was also present in the stomach con-
tents. Finally, three species of pandalid shrimp were
identified: Dichelopandalus leptocerus (0.9%), Pan-
dalus borealis (0.6%), and P. montagui (<0.1%).

Silver hake, Merluccius bilinearis. — Silver hake are
widespread with the result that stomachs were collected
in reasonably large numbers from all geographic areas
(Table 4). In all five areas fish was the major prey but the

Table 3.— Geographic breakdown of food of pollock, Pollachius virens, in the northwest Atlantic. Data are
expressed as percentage weight, for fish collected during the spring and autumn bottom trawl survey cruises
1969-72. !+ indicates present but <0.1%.)

Prey

Middle
Atlantic

Southern
New England

Georges Bank

Gulf of
Maine

Western
Nova Scotia

POLYCHAETA

Nereidiformia

Terebelliformia

Sahelliformia

Other Polychaeta
CRUSTACEA

Amphipoda

Mysidacea

Euphausiacea

Pandalidae

Crangonidae

Axiidae

Paguridae

Majidae

Cancridae

Other Decapoda

Other Crustacea
MOLLUSCA

Gastropoda

Pelecypoda

Cephalopoda

Other Mollusca
ECHINODERMATA

Echinoidea

Ophiuroidea

Other Echinodermata
PISCES

Clupeidae

Gadidae

Scombridae

Scorpaenidae

Bothidae

Pleuronectidae

Other Pisces
Other groups
Animal remains
Sand and rock

92.7

0.1

71.6

92.7

1.6

7.3 100.0

7.0

22.8

0.3

100.0

1.3
2.6

+

0.1

0.8
0.5

21.5

33.8

64.9

36.9
1.9

2.3

23.i

03
0.8
01

O.I

61.2

0.1

0.5

+

+

0.1

+

-

66.4

11.4

53.7

2.9

2.1

3.1

0.1

-

+

0.4

16.0

4.2

1.2

4.3

0.2

0.1

+

1.6

-

-

-

-

+

_

0.1

+

37.1

4.0
1.3

1.3

30.5

0.3
1.3

+

Number of stomachs

5

1

206

203

224

Percentage of empty stomachs

20.0

0.0

2.9

12.8

18.8

Mean weight per stomach (g)

36.3

13.1

12.7

27.7

14.2

Mean predator fork length (cm)

51.0

82.0

38.2

66.4

44.6

Number of samplmg stations

3

28

32

68

29

species of fish eaten differed. Gadids (13.5%) were of pri-
mary importance in the Middle Atlantic where silver
hake were heavily cannibalistic (12.6%). Yellowtail
flounder (0.7%) was the only pleuronectid eaten and
some of the fish in the "Other Pisces" category were the
butterfish (0.9%); horned lantemfish, Ceratoscopelus
maderensis (0.6%); and the longhom sculpin (0.1%). In
Southern New England the Gadidae (12.6%) were also
important and silver hake were again cannibalistic
(7.4%). The Atlantic mackerel (31.7%), however, was the
primary prey. "Other Pisces" included butterfish (4.8%),
the sand lance, Ammodytes (<0.1%), and an uniden-
tified member of the Cottidae (0.1%). Silver hake
(<0.1%) were again identified as prey on Georges Bank
but their contribution to the diet was insignificant. The
only other fish identified were lantemfish, Myctophidae
(3.2%), and the snakeblenny, Lumpenus lumpre-
taeformis (0.1%). Atlantic mackerel (28.0%); Atlantic

herring (23.1%); alewife (9.4%); silver hake (1.4%); and
butterfish (1.1%) were all preyed upon in the Gulf of
Maine. In Western Nova Scotia the Gadidae (51.2%))
were preyed on extensively but silver hake only com-
posed l.l'c of the diet. None of the other fish were iden-
tified to species.

Crustacea formed the remaining bulk of the diet in all
five geographic areas, and within this category the
Euphausiacea and Pandalidae were the most important.
In the Middle Atlantic, Dichelopandalus (8.2%) was the
only pandalid shrimp identified. Most euphausiids
(7.0%) were identified to the order level, however, those
identified to the species level were found to be Meganyc-
tiphanes noruegica (0.1%). The only other shrimp of any
significance was Crangon septemspinosa (7.4%).
Dichelopandalus teptocerus was also important in
Southern New England and Georges Bank (8.6 and 1.8%,
respectively), as were the euphausiids, Meganyc-

Table 4.— OoKraphic breakdown of food of (he silver hake, Merluccium bilineariii. in the northwest Atlantic.
Data are expressed as pertrntaKe weiKhl, for Tish collected during the spring and autumn bottom trawl
sur\e> cruises l%9-72. (t indicates present but <U.I'7c.)

Middle

Southern

Gulf of

Western

Pre>-

Atlantic

New England

Georges Bank

Maine

Nova Scotia

POLYCHAETA

+

;.;

+

+

+

Nereiditbrmia

_

1.0

_

+

_

Terebelliformia

_

-

-

_

_

Sabelliformia

-

-

-

-

-

Other Polychaeta

+

0.1

+

+

+

CRUSTACEA

27.7

33.6

20.4

27.5

33.8

Amphipoda

1.0

1.3

0.1

+

+

Mysidacea

0.2

0.7

-

0.2

0.1

Euphausiacea

7.0

10.8

13.1

12.5

28.4

Pandalidae

8.5

15.7

2.6

1.7

0.4

Crangonidae

7.5

1.1

2.0

0.1

-

Aziidae

+

-

-

-

-

Pagundae

-

-

-

-

-

Majidae

-

-

-

-

-

Cancridae

0.1

-

+

0.1

-

Other Decapoda

0.7

1.3

0.7

4.8

0.2

Other Crustacea

2.7

2.7

1.9

2.1

4.7

MOLLUSCA

73.6

0.8

0.6

1.3

-

Gastropoda

+

-

-

-

-

Pelecypoda

+

-

-

+

-

Cephalopoda

13.6

0.8

0.6

1.3

-

Other Mollusca

+

-

-

-

-

ECHLNODERMATA

-

-

+

-

_

Ex;hinoidea

_

-

-

-

-

Ophiuroidea

-

-

+

-

-

Other Echinodermata

-

-

+

-

-

PISCES

53.7

61.7

78.2

761

65. i

Clupeidae

-

-

-

32.5

-

Gadidae

13.5

12.6

+

1.4

51.2

Scombridae

-

31.7

-

28.0

-

Scorpaenidae

-

-

-

-

-

Bothidae

-

-

-

-

-

Pleuronectidae

0.7

-

-

-

-

Other Pisces

39.5

17.4

78.2

14.2

13.9

Other groups

0.1

0.2

+

-

+

Animal remains

4.9

2.6

0.8

/.;

1.1

Sand and rock

+

+

+

+

+

Number of stomachs

465

704

248

453

282

Percentage of empty stomachs

34.6

35.8

24.6

30.7

33.3

Mean weight per stomach (g)

1.1

1.5

4.3

6.2

1.0

Mean predator fork length (cm

1) 26.7

27.5

29.9

27.1

27.7

Number of sampling stations

54

62

31

51

24

tiphanes (5.4 and 9.6' c, respectively). In the Gulf of
Maine, Meganyctiphanes was again the major crus-
tacean prey (8.0'c). The shrimp Pasiphaea (4.4%)
replaced the pandalids, but Dichelopandalus (0.5%) and
Pandalus borealis (0.3%) were still eaten in small quan-
tities. In Western Nova Scotia euphausiids (28.4%),
especially Meganyctiphanes (13.4%), were the only crus-
taceans of any significance.

The Mollusca were the only other taxonomic grouping
to warrant discussion and here only in the Middle Atlan-
tic. Cephalopods accounted for 13.6% of the diet with
Loligo (8.3%) and Rossia (1.2%) being the two genera
identified.

White hake, Urophycis tenuis. — White hake fed
heavily on fish (Table 5). In Southern New England,
silver hake (18.1%) and Atlantic mackerel (16.6%), were
the most important prey, but "Other Pisces," such as the

butterfish (2.8%) and wrymouth (1.7%), were also iden-
tified in the stomach contents. White hake taken from
Georges Bank were also found to prey on silver hake
(6.0%), but other gadids, such as red hake (7.7%), had-
dock (3.8%), and to a lesser degree, longfin hake (0.3%),
were important. Clui>eids represented almost half the
fish eaten (27.7'f), and of these almost half (12.rf) were
identified as Atlantic herring. The Clupeidae also
contributed heavily to the diet of white hake in the Gulf
of Maine (17.5%) and at least part of the remains was
identified as Atlantic herring (6.6%). Atlantic mackerel
(9.6%) also accounted for some of the prey as did a
number of fish in the "Other Pisces" category (47.2%).
Some of these other fish were Argentina situs (16.6%);
the wrymouth (l.l'c); pearlsides (0.1' c); and the sand
lance, Ammodytes (0.1'c). In Western Nova Scotia,
Atlantic cod (2.2%), longfin hake (1.3%), and white hake
(0.4%) contributed to the gadid prey. The redfish (4.1%),

10

Table 5.— Geographic breakdown of food of the white hake, Ifro-
phycis tenuis, in the northwest Atlantic. Data are expressed as per-
centage weight, for fish collected during the spring and autumn
bottom trawl surve.v cruises 1969-72. (Middle Atlantic = no samples;
+ indicates present but <0.1%..)

Southern

Western

New

Georges

Gulf of

Nova

Prey

England

Bank

Maine

Scotia

POLYCHAETA 0.1 0.1

Nereidiformia +

Terebelliformia -

Sabelliformia —

Other Polychaeta 0.1

CRUSTACEA 3.7 29.4

Amphipoda

Mysidacea

Euphausiacea

Pandalidae

Crangonidae

Axiidae

Paguridae

Majidae

Cancridae

Other Decapoda

Other Crustacea
MOLLUSC A 11.6 3.8

Gastropoda +

Pelecypoda —

Cephalopoda 11.6

Other MoUusca —

ECHINODERMATA

Echinoidea —

Ophiuroidea —

Other Echinodermata -

PISCES 83.3 62.5

Clupeidae

Gadidae

Scombridae

Scorpaenidae

Bothidae

Pleuronectidae

Other Pisces
Other groups 0.1 +

Animal remains 1.2 4.0

Sand and rock - 0.2

0.3

0.5
0.3
0.2

1.8
0.6

+

0.1

0.1

2.3
21.7
1.1
0.1
0.4

0.4

1.9
1.4

+
+

3.5
0.3

01

21.1

0.1

0.3

10.4

+
-H

6.4

10.7

0.1

-I-

0.2

3.0
0.9

+
+
0.2

0.4

76.5

18.1
16.6

48.6

27.6
17.8

17.5
1.1
9.6
1.1

17.1 47.2

O.I +

2.0 2.3

+ 0.1

0.1

0.2

0.1

-I-

2.9

4.3

0.4

0.1

+

1.9
0.7

0.4

+

86.5

0.8
25.7

4.7

55.3

Number of stomachs

95

173

475

169

Percentage of empty

stomachs

26.3

23.1

27.4

13.4

Mean weight per

stomach (g)

22.5

10.0

18.5

22.6

Mean predator fork

length (cm)

48.3

45.3

46.5

43.7

Number of sampling

stations

24

38

74

41

Tabic 6.— Geographic breakdown of food of the offshore hake, Afcr-
luccius albidus, in the northwest Atlantic. Data are expressed as
percentage weight, for fish collected during the spring and autumn
bottom trawl survey cruises l%9-72. (Gulf of Maine and Western
Nova Scotia = no samples; + indicates present but <0.1%.)

Prey

Middle
Atlantic

Southern
New England Georges Bank

POLYCHAETA

Nereidiformia

Terebelliformia

Sabelliformia

Other Polychaeta
CRUSTACEA

Amphipoda

Mysidacea

Euphausiacea

Pandalidae

Crangonidae

Axiidae

Paguridae

Majidae

Cancridae

Other Decapoda

Other Crustacea
MOLLUSCA

Gastropoda

Pelecypoda

Cephalopoda

Other Mollusca
ECHINODERMATA

Echinoidea

Ophiuroidea

Other Echinodermata
PISCES

Clupeidae

Gadidae

Scombridae

Scorpaenidae

Bothidae

Pleuronectidae

Other Pisces
Other groups
Animal remains
Sand and rock

100.0

3.2

14.0

62.5

37.5

0.8
1.6

0.8

5.1

1.5
6.4

6.1

5.1

96.7

73.8

22.9

80.4

Number of stomachs 4

Percentage of empty stomachs 25.0
Mean weight per stomach (g) 0.1
Mean predator fork length (cm) 31.3
Number of sampling stations 2

+
0.1

0.5

-

-

46

23

58.7

60.9

3.1

1.4

30.9

37.1

9

3

taceans of note were euphausiids, and these primarily in
the Gulf of Maine, where Meganyctiphanes (3.5%) was
the most important species.

sand lance (2.9%), and longhom sculpin (0.2%), are most
of the other fish that were identified.

Crustacea was generally the second most important
taxonomic grouping except in Southern New England
where Cephalopods (11.6'e) such as Loligo (6.5%) were
preyed on. In the Gulf of Maine and on Georges Bank
three species of pandalid shrimp were eaten, Dichelo-
pandalus leptocerus (0.1% in the Gulf of Maine and 3.5%
on Georges Bank), Pandalus borealis (3.9% in the Gulf of
Maine and 0.4Sc on Georges Bank), and P. montagui
(0.5% in the Gulf of Maine and 0.2% on Georges Bank).
In Western Nova Scotia P. propinquus (0.2"^ o) was also
present but P. borealis was not. The only other crus-

Offshore hake, Merluccius a<bi<f«s.— Stomachs were

collected from offshore hake in three of the five geo-
graphic areas (Table 6). In the Middle Atlantic, data
were collected from only four fish, and therefore a dis-
cussion of the food in this area is of little value. Suffice it
to say that the two species of Crustacea eaten, Meganyc-
tiphanes norvegica and Pasiphaea sp., were also preyed
upon in the other geographic areas. In Southern New
England and on Georges Bank, the composition of the
diet was very similar. In both areas fish was the major
prey group (96.7% in Southern New England and 80.4%
on Georges Bank); however, the particular species offish
could not be identified. Crustaceans were of secondary

11

importance, with Dichelopandalus leptocerus (1.5% in
Southern New England and 6.4''c on Georges Bank) be-
ing the main prey item within this group.

Cusk, Brosme brosme. — The areal breakdown of food
for cusk (Table 7) differs significantly from the sum-
mary (Table 1) which combines all areas into a single
group. This is primarily due to the heavy predation on
fish in Western Nova Scotia (98.2' c of the diet). In the
three other areas where cusk were collected the major
prey was either crustaceans or echinoderms. On Georges
Bank only four fish were examined and, of the two which

Table 7. — C^graphic breakdown of food of the cusk. Brosme brosme.
in the northwest .-Xtlantic. Data are expressed as percenlage weight,
for Hsh collected durinK the spring and autumn bottom trawl survey
cruises l%9-72. (Middle Atlantic = no samples; -t- indicates present
but <0.1%.)

Southern

WeBtem

.New

Georges

Gulf of

Nova

Prey

England

Bank

Maine

Scotia

POLYCHAETA

Nereidiformia

Terebelliformia

Sabelliformia

Other Polychaeta
CRUSTACEA

Amphipoda

Mysidacea

Euphausiacea

Pandalidae

Crangonidae

Axiidae

Paguridae

Majidae

Cancridae

Other Decapoda

Other Crustacea
MOLLUSCA

Gastropoda

Pelecypoda

Cephalopoda

Other Mollusca
ECHINODERMATA

Echinoidea

Ophiuroidea

Other Echinodermata
PISCES

Clupeidae

Gadidae

Scombridae

Scorpaenidae

Bothidae

Pleuronectidae

Other Pisces
Other groups
Animal remains
Sand and rock

lOO.O 20.0

100.0

90.6

1.4

20.0

1.7
21.0

55.5
12.4

1.1
0.3

80.0

80.0

4.2

98.2

4.2

98.2

1.3
3.1
0.8

0.4

Number of stomachs

6

4

51

11

Percentage of empty

stomachs

33.3

50.0

78.4

81.8

Mean weight per

stomach (g)

0.01

4.89

0.88

15.03

Mean predator fork

length (cm)

25.5

57.3

64.8

60.5

Number of sampling

stations

1

4

29

9

had food in their stomachs, the prey was either brittle
stars (80.0"^;) or the toad crab, Hyas coarctatus (20.0'"c).
In Southern New England very few fish were examined.
The total quantity of prey was extremely small and con-
sisted exclusively of amphipods, Aoridae (57.1'f) and
Gammaridae (42.9'c). The largest sample of cusk came
from the Gulf of Maine, and here the primary prey was
Crustacea (90.6' c). Of the decapods that could be iden-
tified, the three pandalids, Pandalus borealis (17.0%),
Dichelopandalus leptocerus (3.5' c), and P. propinquus
(0.5%), together with some penaeid shrimp (6.9'c), were
the most important. However, small quantities of
Meganyctiphanes norvegica (1.7't) were also foimd in
the stomach contents. The remainder of the diet consist-
ed of fish (4.2'^<), and "Other Groups" such as brach-
iopods (1.2%), and sand or animal remains (3.9%).

Red hake, Urophycis chuss. — In all five geographic
areas, at least half the red hake's diet was composed of
crustaceans (Table 8). In the Middle Atlantic, munid
crabs of the genera Munida (16.9%) and Munidopsis
(3.3'c) accounted for a large percentage of the crusta-
ceans classified under "Other Decapoda." Pandalid
shrimp (15.7'c) were the next most important prey group
with the majority of these identified as Dichelopandalus
(9.1%). Of secondary importance were the unidentified
amphipods (5.1%); the rock crab. Cancer irroratus (2.6%);
the sand shrimp, Crangon (2.2' c); and the isopod,
Cirolina (1.8' t). In Southern New England the munid
crab, Munida (12.9%), was again of primary impor-
tance, as was Dichelopandalus (5.6'c). Cancer irroratus
(1.6'f) and Crangon (1.5' r) were also preyed upon. On
Georges Bank the hermit crab, Pagurus (10.6'f ). and the
sand shrimp, Crangon (20.6'f), were major prey items.
Cancer crabs (8.7'c) and pandalid shrimp, Dichelopan-
dalus (6.1%), also contributed significantly to the diet.
Euphausiids (18.7'r), some of which could be identified
as Meganyctiphanes (5.6'"r); the pandalid shrimp,
Dichelopandalus (11.6'f); and the crab Cancer (11.2'(),
were of major importance in the Gulf of Maine, while the
pandalids, Dichelopandalus leptocerus (30.9%) and Pan-
dalus montagui (40.3'c), were the primary prey in
Western Nova Scotia.

In three of the geographic areas, Pisces followed the
Crustacea as a major prey category. Many of the fish
eaten in the Middle Atlantic could not be identified.
However, of those identified one of the "Other Pisces"
was the snake eel (5.9'r), and the pleuronectid was the
winter flounder (0.1'c). Red hake were cannibalistic in
Southern New England (0.3' c) but also ate other gadids
such as the silver hake (0.3' <). The wrymouth (1.8'f),
Gulf Stream flounder (0.9' t), and the Atlantic mackerel
(0.6%) made up a small percentage of the other fish
eaten. On Georges Bank clupeids (3.5'f) and "Other
Pisces" (1.8'f) accounted for all the fish prey. Fish re-
mains (23.9' f) from the stomachs of red hake caught in
the Gulf of Maine could not be identified.

12

Table 8.— Geographic breakdown of food of the red hake, Urophycis chuss, in the northwest Atlantic. Data
are expressed as percentage weight, for fish collected during the spring and autumn bottom trawl survey
cruises 1969-72. (+ indicates present but <0.17o.)

Middle

Southern

Gulf of

Western

Prey

Atlantic

New England

George

s Bank

Maine

Nova Scotia

POLYCHAETA

1.4

3.3

3.0

2.9

2.4

Nereidiformia

0.1

1.7

1.1

0.6

0.4

Terebeiliformia

-

-

0.2

-

-

Sabelliformia

-

0.2

+

-

-

Other Polvchaeta

1.3

1.4

1.7

2.3

2.0

CRUSTACEA

52.2

50.8

57.2

64.7

88.5

Amphipoda

5.5

9.6

4.3

1.8

1.9

Mysidacea

0.1

+

+

0.6

0.2

Euphau.siacea

+

1.8

2.0

18.7

2.3

Pandalidae

15.7

9.4

'(.7

19.7

71.2

Crangonidae

2.2

1.5

10.6

0.6

1.9

Axiidae

-

2.9

1.9

-

-

Paguridae

0.5

1.3

10.6

2.3

3.2

Majidae

+

0.1

-

-

-

Cancridae

2.7

4.4

8.7

11.2

-

Other Decapoda

21.7

15.5

3.0

4.4

7.6

Other Crustacea

3.8

4.3

8.4

5.4

0.2

MOLLUSCA

0.3

5.4

17.7

38

-

Gastropoda

0.2

0.1

17.4

3.8

-

Pelecypoda

0.1

+

-

-

-

Cephalopoda

-

2.2

-

-

-

Other MoHusca

+

3.1

0.3

-

-

ECHINODERMATA

0.1

0.6

0.2

2.0

-

Echinoidea

-

0.1

0.2

-

-

Ophiuroidea

-

-

-

-

-

Other Echinodermata

0.1

0.5

+

2.0

-

PISCES

38.5

28.2

5.3

23.9

0.6

Clupeidae

-

-

3.5

-

-

Gadidae

-

0.7

-

-

-

Scombridae

-

0.6

-

-

-

Scorpaenidae

-

-

-

-

-

Bothidae

-

0.9

-

-

-

Pleuronectidae

0.1

-

-

-

-

Other Pisces

38.4

26.0

1.8

23.9

0.6

Other gn-oups

+

1.2

0.2

0.1

5.4

Animal remains

7.2

10.3

16.2

2.5

2.9

Sand and rock

0.3

0.2

0.2

0.7

0.2

Number of stomachs

206

607

208

72

17

Percentage of empty stomachs

16.4

13.3

21.6

19.4

11.8

Mean weight per stomach (g)

1.8

2.4

1.9

2.9

2.6

Mean predator fork length (cm)

29.3

29.6

33.1

34.3

32.6

Number of sampling stations

25

71

30

20

8

The only other taxon that was of any significance, and
then only on Georges Bank, was the MoUusca of the class
Gastropoda (17.4%).

Spotted hake, Urophycis regius. — The areal break-
down of food of the spotted hake is limited to the Middle
Atlantic and Southern New England, since no stomachs
were collected in the Gulf of Maine and Western Nova
Scotia, and only four fish were analyzed from Georges
Bank (Table 9). A comparison between the two areas
showed that the foods were reasonably similar, the major
differcence being due to the importance of cephalopods
(16.1%), especially Loligo (6.8%), in the Middle Atlan-
tic.

Crustaceans were a major prey category. In both the
Middle Atlantic and Southern New England the "Other
Decapoda" was the largest grouping consisting mostly of
the munid crabs. In the Middle Atlantic, Munida (9.4%),

both M. iris (7.4%) and M. ualida (1.7%), together with
Munidopsis (2.8%), were present in the stomach con-
tents, but in Southern New England the species were re-
stricted to M. iris (11.3%) and M. ualida '9.2%). Inter-
estingly, hyperiid amphipods were important, making up
3.4'/o of the diet in the Middle Atlantic and 6.1% in
Southern New England. The rock crab, Cancer irror-
atus (6.7%), composed a significant part of the prey in
the Middle Atlantic. Other crustaceans of secondary
importance were Crangon (4.8% in the Middle Atlantic
and 2.6^c in Southern New England), Dichelopandalus
(S.e'^c in the Middle Atlantic and 4.0% in Southern New
England), and the isopods (3.1% in the Middle Atlantic
only), such as Cirolina polita (0.7%), which are included
under "Other Crustacea."

"Pisces" was the last major grouping. In the Middle
Atlantic, red hake (3.4%) and silver hake (3.3%); the
bothid, Citharichthys arctifrons (1.7%); the pleuro-

13

Table 9.— Geographic breakdown of food of the apolted hake, ('ro-
phycU reffiua, in the northwest Atlantic. Data are expressed as per-
centage weight, fur fish collected during the spring and autumn
bottom trawl survey cruises l%9-72. (Gulf of Maine and Western
Nova Scotia = no samples; ■*■ indicates present but <0. 1%.)

Prey

Middle
Atlantic

Southern
New England Georges Bank

POLYCHAETA 0-4

Nereidiformia

Terebelliformia

Sabelliformia

Other Polvchaeta
CRISTACEA -IS.e

Amphipoda

Mysidacea

Euphausiacea

Pandalidae

Crangonidae

Axiidae

Paguridae

Majidae

Cancridae

Other Decapoda

Other Crustacea
MOLLUSCA 16.6

Gastropoda

Pelecypoda

Cephalopoda

Other Mollusca
ECHINODERMATA

Echinoidea

Ophiuroidea

Other Echinodermata
PISCES 28.5

Ciupeidae

Gadidae

Scorn bridae

Scorpaenidae

Bothidae

Pleuronectidae

Other Pisces
Other groups +

Animal remains 5.7

Sand and rock 0.2

O.l

0.3

8.0

+

+

3.8

5.0

0.1

+
10.3
14.5

6.9

0.1
0.4
16.1

0.6

46.8

1.1

0.1

0.5

6.2

0.1
4.3
2.6
0.1
0.1

1.1

31.9

0.4

1.0
0.1

6.8

71.6

2.9

1.2

0.3
2.4

71.6

45.1

0.3

6.8

1.7

0.8
19.2

0.3
9.1

1.9

0.8

33.0

0.3

0.1
5.8
0.5

+
21.3

Number of stomachs 689 183 4

Percentage of empty stomachs 10.5 31.0 25.0

Mean weight per stomach (g) 0.8 1.9 2.8

Mean predator fork length (cm) 18.2 26.2 24.1

Number of sampling stations 45 17 2

nectid, Limanda ferruginea (0.8%); and "Other Pisces"
(19.2%) such as the snake eel (0.2%), and lanternfish
(family Myctophidae) (3.9%), constituted the fish prey.
In Southern New England the fawn cusk-eel (1.1%) and
some unidentified cusk eels (10.8'c), together with Atlan-
tic mackerel (9.1%), the Gulf Stream flounder (1.9'0,
and silver hake (1.1%), represented a large part of the
fish consumed.

Haddock, Melanogrammus aeglefinus. — Few had-
dock were collected in the Middle Atlantic and South-
em New England and therefore the following discussion
is limited primarily to the three other geographic areas
(Table 10).

Fish accounted for more than one-fourth (28.4'r) of the
haddock's diet on Georges Bank whereas fish were rea-

sonably insignificant in all the other areas. This shift in
food was not, however, due to a change in feeding
strategy but rather was entirely due to the consumption
of herring eggs. This implies that haddock prey heavily
on herring spawn when it is available. Polychaetes were
also more important prey on Georges Bank (23.5%) than
in the other areas. The "Other Polychaeta" category
contributed the largest {percentage (18.3'() with Ammo-
trypane aulogaster (8.3' c) being the most important
animal. Laonice (0.1%), Ophelia (<0.1%), Scalibregma
(<0.1%), and Sternaspis (0.1%) were other polychaetes
identified in the stomach contents. None of the Tere-
belliformia (2.1' c) could be identified below suborder
and Chone infundibuliformis (0.3' c) was the only
Sabelliformia (2.1'f ) identified to species. The third prey
group that was of any significance was the crustaceans
(16.0':'f). Amphipods (7.1'c) made up the largest portion
but the individual species of amphipods usually ac-
counted for <0.1'o. As a group the gammarid amphi-
pods were the most important, with species such as Un-
ciola irrorata (<0.1%), Casco bigelowi (<0.1%), Anonyx
sp. (0.1%), Leptocerus pinguis (0.1%), and Pleustes sp.
(<0.1%) having been found in the haddock stomachs.
Echinoderms (7.8' c) and molluscs (3.8%) were the least
important prey groups for Georges Bank haddock. Brittle
stars, such as Ophiopholis aculeata (2.4'f), were the
most important echinoderms, while pelecypods like
Astarte (0.2%) and Pecten (0.1%) were the more impor-
tant molluscs that could be identified. Sand and rocks
(15.3'f) were more prevalent in the haddock stomachs
collected on Georges Bank than elsewhere, possibly be-
cause polychaetes and pelecyjjods accounted for a larger
percentage of the diet here than in the other areas.

The haddock's food in the Gulf of Maine and Western
Nova Scotia were quite different from those in the other
three geographic areas, but within these two areas the
prey was similar. For example, in both areas half the diet
consisted of echinoderms. Similarly, crustaceans and
polychaetes contributed between 10 and 15% of the diet
and molluscs between 1 and 3%. Brittle stars were the
main food item, with Ophiura (16.2%) being of primary
importance in the Gulf of Maine. However, Amphiura
(0.8'c), Ophiopholis (0.4' c), and Ophiacantha bidentata
(<0.1%), together with unidentified ophiuroid remains
(20.5%), are also included in this prey group. In Western
Nova Scotia three ophiuroids were eaten, Ophiopholis
(13.0'f), Ophiura (8.2'f), and Amphiopolis (0.2%),
together with some unidentifiable ophiuroid remains
(13.0'c). In the Gulf of Maine 15.2'r of the diet was
crustaceans. The "Other Decapoda" was the largest
group (5.9'c) primarily because of the shrimp Pasiphaea
(4.9%). The shrimp Pandalus (2.0%) was of secondary
importance as were euphausiids (1.9%) and gammarid
amphipods (1.8'r). Gammarid amphipods (3.4'c) as well
as the caprellid; Aeginina longicornis (0.3%), were the
main crustacean prey in Western Nova Scotia, while the
Axiide, both Axius (l.S'i) and Calocaris (0.5%), were of
secondary importance. Polychaetes were the only other
group accounting for much of the diet. The majority were
not identified below the order level, but in the Gulf of

14

Table 10.— Geographic breakdown of food of haddock. Melanogrammus aeglefinus, in the northwest Atlantic.
Data are expressed as percentage weight, for fish collected during the spring and autumn bottom trawl sur-
vey cruises 19ti9-72. (+ indicates present but <0.1%.)

Middle

Southern

Gulf of

Western

Prey

Atlantic

New England

Georges Bank

Maine

Nova Scotia

POLYCHAETA

14.3

4.5

23.5

14.7

11.8

Nereidit'ormia

13.4

2.5

1.0

3.0

2.7

Terebelliformia

-

-

2.1

+

1.9

Sabellitbrmia

-

-

2.1

0.5

0.8

Other Polychaeta

0.9

2.0

18.3

11.2

6.4

CRUSTACEA

2.2

82.0

16.0

15.2

14.4

Amphipoda

0.6

75.3

7.1

2.2

5.0

Mysidacea

-

-

0.1

-

+

Euphausiacea

-

-

0.7

2.0

1.7

Pandalidae

-

0.7

1.1

2.9

1.0

Crangonidae

0.3

0.5

0.2

-

0.1

Axiidae

-

-

0.2

0.2

2.3

Paguridae

-

0.9

0.2

0.1

0.8

Majidae

-

0.6

0.1

0.6

0.4

Cancridae

-

0.2

0.2

-

-

Other Decapoda

-

1.0

0.2

5.9

1.7

Other Crustacea

1.3

2.8

2.9

1.4

1.4

MOLLUSCA

0.4

0.7

3.8

1.6

3.0

Gastropoda

0.4

+

0.2

0.5

0.3

Pelecypoda

-

0.7

3.2

0.9

1.9

Cephalopoda

-

+

0.1

-

0.5

Other Mollusca

-

-

0.3

0.2

0.3

ECHINODERMATA

-

1.4

7.8

51.9

49.0

Echinoidea

-

1.2

1.5

10.6

9.0

Ophiuroidea

-

+

6.0

38.0

34.5

Other Echinodermata

-

0.2

0.3

3.3

5.5

PISCES

-

+

28.4

2.2

3.8

Clupeidae

-

-

28.3

-

-

Gadidae

-

-

-

-

0.8

Scombridae

-

-

-

-

-

Scorpaenidae

-

-

-

-

-

Bothidae

-

-

-

-

-

Pleuronectidae

-

-

+

-

-

Other Pisces

-

+

0.1

2.2

3.0

Other groups

1.1

0.1

0.3

0.6

2.0

Animal remains

-

8.3

4.9

11.2

13.0

Sand and rock

82.0

3.0

15.3

2.6

3.0

Number of stomachs

10

27

352

232

510

Percentage of empty stomachs

0.0

U.l

'

1.3

5.6

10.0

Mean weight per stomach (g)

3.2

4.1

10.0

6.6

4.9

Mean predator fork length (cm!

1 20.1

54.8

46.7

56.3

43.4

Number of sampling stations

1

5

45

47

56

Maine some of the more common were Sabella (0.4Vc),
Eunice pennata (0.2';x), Nephtys (0.2%), Goniada
(0.1%), and Lumbrineris (0.1%). In Western Nova Scotia
a variety of polychaetes were identified in the stomach
contents but the only genera contributing >0.1% to the
diet were Cistenides (0.5%), Aphrodita (0.8%), and
Eunice (0.4%).

Longfin hake, Phycis chesteri. — Although longfin
hake were collected in all five geographic areas, a discus-
sion of the areal breakdown of its prey is of little value.
Few fish were collected and, on Georges Bank, where the
largest sample was taken, over half the stomachs were
empty, effectively leaving a maximum of 26 fish from 6
stations to evaluate the food in any one region. Never-
theless, in all areas, crustaceans were the major prey,
with the euphausiid, Meganyctiphanes norvegica, being
the most important.

Fourbeard rockling, Enchelyopus cimbrius. — Four-
beard rockling were collected for stomach contents anal-
ysis in three of the five geographic areas. Only or. Georges
Bank, however, was the total weight of the prey (12.42 g)
and sample size (n = 27) sufficiently large to warrant any
discussion. On Georges Bank crustaceans were the major
prey, accounting for 59.3% of the diet. The two most
important crustaceans were Crangon septemspinosa
(46.3%) and Dichelopandalus leptocerus (11.2%). The
other taxonomic grouping of importance was the Poly-
chaeta (13.6%), and here the only identification to the
genus level was Ammotrypane (3.9%).

Marlin-spike, Nezumia bairdi. — Marlin-spike were
collected in three of the geographic areas. Southern New
England, Gulf of Maine, and Western Nova Scotia, but
in very small numbers. Due to the small sample size,
both in the number of fish examined and the total weight

15

of prey, a meaningful discussion of areal differences in
food is unwarranted. Table 2 adequately summarizes the
available information.

Longnose grenadier, Coelorhynchus car-
minatus. — As has been described for the marlin-spike, a
meaningful discussion of the areal differences in food is
not justifiable because of the small number of fish ex-
amined and the small quantity of prey in the stomachs.

Fawn eusk-eel, Lepophidium cervinum. — Fawn
cusk-eel were collected in significant numbers in the
Middle Atlantic and Southern New England but the
total quantity of prey in the stomachs amounted to only
3.27 g. An areal breakdown of their food is therefore of lit-
tle value, especially since almost 1 g of the total weight
was due to a heavy infestation of parasitic nematodes

(37.1'c) in the fish collected in the Middle Atlantic. For a
summary of the food see Table 2.

Ocean pout, Macrozoarces americanus. — Ocean
pout were collected in all areas but were most abundant
in Southern New England and on Georges Bank (Table
11). In these two areas the major prey was echinoderms,
with the sand dollar being the single most important
species (54.4'^t in Southern New England and 61.6'c on
Georges Bank). In Southern New England, crustaceans
(22.0' () amd polychaetes (7.8' <) made up most of the
remainder of the prey. Amphipods (13. 1"^), such as Un-
ciola sp. (1.0'f) and Leptocerus pinguis (1.2'(), were
important, as were the rock crabs (5. 4';:), particularly
Cancer irroratus (2.0'f ). The majority of the polychaete
prey was identified as Aphrodita (7.4' c). On Georges
Bank, crustaceans (4.3%) were of little significance and

Table II.— Geographic breakdown of food of ocean pout, Macrozoarces americanus. in (he northwest Atlan-
tic. Data are expressed as percentage weight, for fish collected during the spring and autumn bottom trawl
survey cruises 1969-72. (+ indicates present but <0.17(.)

Middle

Southern

Gulf of

Western

Prey

Atlantic

New England

Georges Bank

Maine

Nova Scotia

POLYCHAETA

_

7.8

0.5

0.3

_

Nereidiformia

-

7.7

+

-

-

Terebelliformia

-

—

+

+

-

Sabelliformia

-

-

-

-

-

Other Polychaew

-

0.1

0.5

0.3

-

CRUSTACEA

9.4

22.0

4.3

3.5

+

Amphipoda

0.2

13.1

0.7

2.0

-

Mysidacea

-

-

-

-

-

Euphausiacea

-

-

-

-

-

Pandalidae

-

+

-I-

-

-

Crangonidae

-

+

+

0.2

-

Axiidae

-

-

-

-

-

Paguridae

0.3

0.1

0.8

0.3

-

Majidae

-

-

0.7

-

-

Cancridae

5.7

5.4

1.3

0.1

-

Other Decapoda

-

1.3

0.7

-

-

Other Crustacea

3.2

2.1

0.1

0.9

+

MOLLUSCA

-

1.6

6.1

4.1

-

Gastropoda

-

0.9

0.1

2.0

-

Pelecypoda

-

0.6

5.9

2.1

-

Cephalopoda

-

-

-

-

-

Other Mollusca

-

0.1

0.1

-

-

ECHINODEtlMATA

86.3

63.9

81.1

37.2

99.3

Echinoidea

86.3

63.9

71.5

25.3

-

Ophiuroidea

-

-1-

9.6

6.2

99.3

Other Echinodermata

-

-

-

5.7

-

PISCES

0.5

0.1

+

0.5

+

Clupeidae

-

-

-

-

-

Gadidae

-

-

-

-

-

Scombridae

-

-

-

-

-

Scorpaenidae

-

-

-

-

-

Bothidae

-

-

-

-

-

Pleuronectidae

-

-

-

-

-

Other Pisces

0.5

0.1

+

0.5

+

Other groups

0.2

0.3

1.9

78.5

-

Animal remains

1.8

2.5

5.4

2.5

-

Sand and rock

1.8

1.8

0.7

33.4

0 7

Number of stomachs

20

207

110

34

6

Percentage of empty stomachs

0.0

22.5

[

12.7

26.5

66.7

Mean weight per stomach (g)

6.6

1

5.0

10.6

6.4

0.5

Mean predator fork length (cm!

4-t

.7

45.2

i

J6.5

36.6

32.4

Number of sampling stations

4

23

31

4

3

16

ophiuroids (9.6%), such as Ophiopholis (1.1%), and the
pelecypod, Pecten (4.5%), formed the remaining bulk of
the diet. In the Middle Atlantic few ocean pout were col-
lected, but as on Georges Bank and in Southern New
England, the single major prey species was the sand dol-
lar (86.3%). In the Gulf of Maine echinoderms were
apparently less important although E. parma still ac-
counted for 24.8'; of the prey. "Other Groups" was also
important and the single contributor to this category was
the tunicate, Cnemidocarpa mollis (18.5'o). Sand and
rock (33.4%) made up a large part of the weight of the
stomach contents.

Dietary Overlap

The percentage similarity values (Fig. 3) calculated
from the data in Table 2 range from 1 to a maximum of
75. In order to facilitate the comparison between species,
similarity values have been grouped into three cate-
gories representing low (0 to <30%), intermediate (30 to
<60%), and high (60 to 100%) levels of dietary overlap.
Accordingly, it is obvious that the greatest similarity in
diet exists between the silver and white hake (75%), the
marlin-spike and longnose grenadier (75%), the red and

spotted hake (71%), and the pollock and silver hake
(63%).

The diets of Atlantic cod, pollock, silver hake, white
hake, offshore hake, cusk, red hake, and spotted hake are
reasonably similar. Most of these fish populations are
primarily piscivorous, which accounts for the observed
intermediate and high levels of dietary overlap. The red
and spotted hake, however, qualify as "mixed feeders"
preying on both fish and invertebrates. In contrast to the
eight predators listed above, the remaining seven
species: haddock, longfin hake, fourbeard rockling, mar-
lin-spike, longnose grenadier, fawn cusk-eel, and ocean
pout, prey almost exclusively on invertebrates. Of these
fish only the haddock preyed extensively on other fish
and this was predation on herring eggs rather than on
juvenile or adult fishes. The lack of similarity between
the diet of the invertebrate feeders is in part due to the
more numerous categories of potential prey. In some in-
stances, such as for the marlin-spike, longnose gren-
adier, and fourbeard rockling, estimates of diet similarly
are of limited value because of the small number of fish
examined and/or the small amount of prey found in the
stomachs.

The percentage similarity in diet has also been cal-
culated for each fish in the five individual geographic

Atlonlic
Cod

Poiiocit

Silver
Haiie

White Offstiore
Hoke Hoke

Cusk

Red Hoke

Spoiled
Hoke

Haddock

Longfin
Make

Fourbeard
Rockling

Marlin-
spike

Longnose
Grenadier

Fawn
Cusk-eel

Ocean
Paul

Atlantic Cod

\^

1
1

Pollock

59

Silver Hake

58

63

\^|

White Hake

57

52

75

\

Offstiore Hake

33

32

44

51

\

Cusk

37

42

41

55

39

Red Hoke

53

45

44

45

31

44

\^l

1

Spotted Hake

51

43

47

44

34

44

71

Haddock

34

25

26

24

7

16

33

21

\^

Longfin Hoke

13

53

25

18

7

21

32

26

10

\

Fourbeard

Rockling

13

10

13

16

6

11

31

21

27

16

\

II

1
!

Marlin- spike

13

14

7

6

2

16

37

40

35

25

41

\«

Longnose
Grenadier

9

13

6

6

2

14

27

28

26

18

48

75

\

Fawn Cusk-eel

n

8

10

7

3

^

30

23

30

16

45

44

41

k

Ocean Pout

18

5

5

5

1

9

19

16

34

3

7

15

9

17

\

30
< 60

Figure 3. — Percentage similarity between llic diet of 15 species of gadiform fishes from the northwest .Atlantic. For calculation methods,
seetext. Open boxes = 0 to 00%; ruled boxes = .10 to <607c; solid boxes = 60 to 100%.

17

areas. The 15 species of fish were not omnipresent and
the data were only included in the calculations if 10 or
more individuals of that particular species were collect-
ed in a geographic area for stomach contents analysis.

Only 6 of the 15 predators were collected in suf-
ficiently large numbers in the Middle Atlantic to war-
rant an analysis of dietary overlap. Three of these six
fish — silver, red, and spotted hake — showed inter-
mediate levels of dietary overlap, while the similarity in
diet for the haddock, fawn cusk-eel, and ocean pout was
low.

In Southern New England 10 of the 15 predators were
present. A high degree of similarity in diet occurred be-
tween the red and spotted hake. These two fish fed on
both fish and invertebrates, and shared many of the
same species as prey (Tables 8, 9). Intermediate levels of
dietar>' overlap were generally found between the four
piscivorous predators, Atlantic cod, silver hake, white
hake, and offshore hake, and also between these same
four fish and the red and spotted hake. The only other
intermediate levels of overlap occurred between the fawn
cusk-eel and the red hake and haddock. Little similarity
was found between the diet of the haddock, longfin hake,
fawn cusk-eel, ocean pwut, and the other more pisci-
vorous predators mentioned above.

For the fish taken on Georges Bank high levels of
dietary overlap occurred between the offshore and silver
hake and between the pollock and longfin hake. The high
overlap between the pollock, which have normally been
considered piscivorous, and the longfin hake, an inver-
tebrate feeder, may be explained by the dependence on
Crustacea as a major food source for Georges Bank pol-
lock (Table 3). It should also be noted that the average
length of pollock on Georges Bank was smaller than in
the other geographic areas which might explain the
reliance on crustaceans rather than fish. Intermediate
levels of diet similarity were found for a number of fish.
Most notable is the overlap between Atlantic cod and
haddock which may be traced to the heavy predation on
herring eggs by the Georges Bank haddock. Since Atlan-
tic cod were preying on either juvenile or adult herring,
this measure of overlap is somewhat misleading. Low
levels of similarity were again observed between the
invertebrate feeders.

In the Gulf of Maine high and intermediate levels of
dietary overlap were found between the Atlantic cod,
pollock, silver hake, white hake, and red hake, but little
similarity was observed between the diet of these same
predators and the haddock, longfin hake, fourbeard
rockling, and ocean pout. The cusk showed an inter-
mediate level of dietary overlap with the pollock, red
hake, and fourbeard rockling while the diet of the ocean
pout was found to have an intermediate degree of simi-
larity with the haddock. All the remaining fish showed a
low level of dietary overlap.

In Western Nova Scotia the highest level of dietary
overlap was found between the Atlantic cod and white
hake. Intermediate overlap was generally found between
the diets of the Atlantic cod, pollock, silver hake, white
hake, and cusk. Longfm hake also showed an inter-

mediate level of overlap with the pollock, silver hake,
and marlin-spike. The last intermediate level occurred
between the marlin-spike and haddock. Little similarity
in diet was found for the other gadiform fish collected on
the Scotian Shelf.

DISCUSSION

Food

Atlantic cod. — Data on the diet of the Atlantic cod
occurring off the U.S. coast in the Gulf of Maine have
been summarized by Bigelow and Schroeder (1953) (see
also Wise 1961), but, surprisingly, there is little other
information for the region of the present study (e.g., Ken-
dall 1898; Tyler 1972). The Canadian cod stocks in the
Gulf of St. Lawrence and off Newfoundland have, how-
ever, been more thoroughly investigated (Powles 1958;
Popova 1962; Templeman 1965; Kohler and Fitzgerald
1969; Minet and Perodou 1978).

From some of the earliest studies it was concluded that
Atlantic cod will eat almost any food available. Despite a
wide diversity in the species composition of the diet, a
rather simple picture of the cod's food habits may be
drawn from most of the available data. In general, crus-
taceans and fish are the major prey, while the actual
percentage of the diet made up of each of these two tax-
onomic groups is determined by prey size and prey avail-
ability. Small cod prey on small crustaceans, such as am-
phipods and mysids. Slightly larger cod prey more on
decapod crabs and shrimp. The larger cod prey almost
exclusively on fish. Our observations on the food of
Atlantic cod caught off the U.S. coast are in agreement
with this rather simplistic description. Although we did
not separate the data into size classes, it can be seen that
fish and crustaceans were the most important prey cate-
gories (Table 1). We did not include the smaller cod (<20
cm) in our data base, and the average length of the 1,541
animals we analyzed was 54.7 cm (Table 1). Cod of
approximately 50 cm FL (fork length) have previously
been shown to prey heavily on both fish and crustaceans
(Powles 1958; Popova 1962; Rae 1968) so that our data
may be taken as confirmation that the diet of the U.S.
cod stocks is very similar to the other populations which
have previously been investigated.

Pollock.— The diet of pollock was equally divided be-
tween fish and crustaceans (Table 1). Atlantic herring
was the major species of fish preyed upon while the
euphausiid, Meganyctiphanes norccgica, was the single
most important prey. The significance of euphausiids in
the diet of pollock had previously been noted by Kendall
(1898) who found that Thysanopoda were virtually the
exclusive prey for pollock taken off Eastport, Maine. Big-
elow and Schroeder (1953) included Kendall's observa-
tions in their treatise on fishes in the Gulf of Maine but
also mentioned that young herring were an equally im-
portant prey. Steele (1963) and Dexter (1969) again con-
firmed the importance of euphausiids such as M. nor-
vegica as major prey for pollock in the Gulf of Maine.

18

However, Steele also remarked that fish were eaten in
addition to euphausiids by the larger (75+ cm) pollock.
The mean predator fork length for pollock taken in the
Gulf of Maine (Table 3) during the present study (66.4
cm) was greater than for the fish caught on either
Georges Bank (38.2 cm) or in Western Nova Scotia (44.6
cm). Accordingly, fish, especially Atlantic herring, were
much more important as prey for the Gulf of Maine pol-
lock than in either of the other two areas. In European
waters the food of pollock appears to be similar to that of
their American counterparts as they have also been
reported to prey heavily on euphausiids (Wagner 1959;
Mironova 1961; and see Nagabhushanara 1965 for a brief
review in tabular form).

Silver hake.— Fish accounted for almost three-fourths
of the diet of silver hake, with crustaceans making up the
remaining prey (Table 1). Fish had previously been
recognized as the major prey of the silver hake by Bige-
low and Schroeder (1953). They described these pre-
dators as preying on herring or most any other smaller
schooling fish or even the young of almost any of the fish
commonly found in the Gulf of Maine. For example,
Nichols and Breder (1927) found 75 herring, 7.62 cm
long, in the stomach of a 59 cm silver hake. Bigelow and
Schroeder (1953) also noted that silver hake ate squid if
available while smaller hake fed on the shrimp Pandalus.
Jensen and Fritz (1960) reported on the diet of silver
hake collected in the northwest Atlantic. Expressing
their data as the frequency of occurrence of prey, they
also found that fish predominated in the stomachs of the
larger silver hake while crustaceans, mostly euphau-
siids, were more common in the stomachs of the smaller
fish. More recently, Vinogradov (1972) examined a total
of 42,515 silver hake stomachs collected from fish caught
in the northwest Atlantic. He also found that the smaller
hake preyed on crustaceans, especially euphausiids, with
a shift to fish as the major prey for hake >40 cm FL.
Interestingly, all of these authors have commented on
the cannibalistic nature of silver hake which was again
recognized in this report, especially for fish taken in the
Middle Atlantic (Table 4).

White hake. — The white hake and red hake resemble
each other closely and the landings of these hakes have
only been reported separately since 1944. Therefore,
studies on the food habits of white hake alone are rela-
tively rare. Linton (1901 ) examined the stomachs of some
white hake but they were empty, and Hansen (1915)
found some euphausiids, Thysanoessa inermis, in the
stomachs he examined. Bigelow and Schroeder (1953)
consider the food of the two hakes together although they
specifically mention the occurrence of squid, crabs,
butterfish, mackerel, and flounder in the stomachs of
small white hake. Apart from the data given here (Table
1), which identifies white hake as being primarily pisci-
vorous, the only other recent reports discussing the food
of this fish are by Tyler (1971, 1972) and Petrov (1973).
Tyler (1971) observed seasonal changes in the distri-
bution and the diet of fishes in Passamaquoddy Bay,

New Brunswick, Canada. White hake were present in the
bay during summer and autumn. For the smaller white
hake (total length range 15-26 cm) Tyler identified
mysids, amphipods, and euphausiids as principal prey
while the larger fish (28-45 cm) preyed upon shrimp,
euphausiids, and fish. The data reported here are gener-
ally for larger fish (average total = 46.4 cm FL, see Table
1) than those considered by Tyler and this may explain
our observation that white hake are primarily pisci-
vorous. Petrov (1973) collected food habits data for the
years 1969, 1971, and 1972 in ICNAF (International
Commission for the Northwest Atlantic Fisheries)
Subarea 3 which is north of our study area, off the
eastern coast of Canada. Petrov's data are based on a
subsample of the entire population and, although based
on frequency of occurrence, show very similar results to
those reported here (Table 1). He found that fish predo-
minated in the diet with crustaceans being of secondary
importance.

Offshore hake. — Biological data on the offshore hake
is rare, and information on its food has only just become
available. Rohr and Gutherz (1977) described the off-
shore hake as an active predator, preying on crustaceans
and fish including other offshore hake. Juveniles were
found to prey heavily on shrimp while maturing adults
fed on fish, shrimp, and squid. The primary prey of
adults was fish, but they also preyed upon caridean
shrimp and squid. The offshore hake examined during
the course of the present study confirm the observations
of Rohr and Gutherz. The hake we examined preyed
heavily on fish but also consumed crustaceans (i.e.,
caridean shrimp and euphausiids) and squid (Table 1).

Cusk. — Cusk were identified as being primarily fish-
eaters, although crustaceans and echinoderms were also
important prey, but to a lesser extent (Table 1). The
cusk's piscivorous habits may be accounted for because
of its heavy reliance on fish as prey in Western Nova
Scotia (Table 7). In contrast, crustaceans made up 90%
of the diet in the Gulf of Maine (Table 7), but because of
the total weight of fish prey when all five geographic
areas are combined, crustaceans are of secondary impor-
tance (Table 1). Little comparative data exist on the food
of this animal, but it has been reported that crabs and
occasionally molluscs were found in the stomachs of
several cusk caught on Piatt's Bank in the Gulf of Maine
in 1924 (Bigelow and Schroeder 1953). Leim and Scott
(1966) also noted that the cusk eat crabs and molluscs
together with an occasional starfish. Our data confirm
these observations but add fish as an important poten-
tial prey. Bigelow and Schroeder (1953) mention that the
cusk is not fastidious as to the bait it will accept, taking
clams, cockles, and herring quite readily. The diversity
in the prey for the different geographic areas (Table 7)
tends to corroborate their observations, that is, the cusk
will prey on whatever animals are available.

Red hake. — The dietary information summarized by
Bigelow and Schroeder (1953) is generally for both red
and white hake combined although they do mention one

19

instamce where the belhes of red hake were distended
with sand lance, Ammodytes sp. In an earher paper,
Linton (1901) reported finding shrimp, araphipods, and
the lenses of some small fish in red hake stomachs, and
Breder (1922) noted that the one stomach he examined
was full of prawns. From the current study (Table 1), red
hake has been identified as a mixed feeder, preying on
both fish and invertebrates. Crustaceans were the most
important prey, followed by fish, molluscs, polychaetes,
and echinoderms, in decreasing quantities. Vinogradov
(1972) examined the stomachs of 5,486 red hake col-
lected in the northwest Atlantic and, based on fre-
quency of occurrence, found that invertebrates were the
most important prey although substantial numbers of
fish and squid were also consumed. Vinogradov's study
was conducted from 1965 through 1967, and our study
from 1969 through 1972. Over these years the major prey
of northwest Atlantic red hake appears to have been the
same, with any differences observed in the species com-
position of the diet most likely relating to differences in
the sampling sites and local abundance of certain prey.

Spotted hake.— Spotted hake were identified as mix-
ed feeders, relying on both crustaceans and fish as major
prey (Table 1), although cephalopods were also some-
what important. Comparative data on the diet of these
predators are scanty. Hildebrand and Schroeder (1928)
noted mysids in the stomachs of small hake from Chesa-
peake Bay and Bigelow and Schroeder (1953) only men-
tioned the food of spotted hake in passing, noting that it
fed on fish, squid, and crustaceans. More recently, Si-
kora et al. (1972) examined the gut contents of 341 juven-
ile spotted hake and identified crustaceans, especially
the macruran mud shrimp, L'pogebia affinis, as the most
important prey, while fish ranked second in the diet.
Comparative information on the food of adult spotted
hake is completely lacking.

Haddock. — Haddock has a long history of com-
mercial importance and as a result a voluminous amount
of dietary information has been collected over the years
and the literature on the North American stocks alone is
reasonably extensive: Atwood 1866; Verrill 1871, 1873;
Baird 1889; Willis 1890; Kendall 1898; Clapp 1912;
Needier 1929; Vladykov 1933; Homans and Needier 1944;
Bigelow and Schroeder 1953; Wigley 1956; Templeman
1965; Wigley and Theroux 1965; Kohler and Fitzgerald
1969; Tyler 1972.

In one of the earliest papers, Baird (1889) remarked
that a complete listing of the prey of haddock would in-
clude almost all the fauna of any given area. An ex-
amination of the papers listed above gives much cred-
ibility to such a statement. It would be impossible to
generally classify the haddock's dietary preferences ex-
cept to say that they usually prey more heavily on
benthic invertebrates than fish although they are highly
opportunistic and will prey on, for example, fish eggs if
they are available. Within one of the geographic areas
considered here the diversity in the haddock's diet has
been clearly demonstrated by Wigley (1956). He inves-

tigated the haddock's food habits on Georges Bank and
found that the data warranted a division of the bank into
three different food-type areas.

The results from our study (Table 1) indicate that
ophiuroids were the most important prey and that poly-
chaetes, crustaceans, and fish eggs ranked second in
importance. The significance of fish eggs in the diet is of
some interest. Bigelow and Schroeder (1953) stated that
haddock have been accused of feeding on herring spawn
but they doubted that this was true. Our observations
do, in fact, confirm that haddock will prey greedily on
herring spawn as had also been reported by Bowman
(1923) and Nikolsky (1963). This type of feeding be-
havior is not uncommon since haddock have also been
found to consume quantities of fish eggs when the
capelin, Mallotus villosus, spawn in the Barents Sea
(Tseeb 1960) and on the Grand Banks of Newfoundland
(Templeman 1965). These results confirm the benthic
nature of haddock feeding.

Fourbeard rockling. — According to Bigelow and
Schroeder (1953) the food habits of the fourbeard rock-
ling have not been investigated on this side of the Atlan-
tic. From reports on the stomach contents of British and
Scandinavian fish they concluded that the American
fourbeard rockling would probably eat shrimp, isopods,
other small crustaceans, and fish fry. Leim and Scott
(1966) commented that much of the biolog>' of the
fourbeard rockling is unknown since it is rarely caught in
commercial trawls because of its small size. They also
suggested that it would eat small crustaceans and fish
but gave no further details. In the study reported here, a
total of 48 stomachs was examined and our observations
confirm the suppositions of these previous authors. The
major prey were found to be crustaceans, with the sand
shrimp, Crangon septemspinosa, being of primary im-
portance (Table 1).

Macrouridae. — There is little information on the food
of either the marlin-spike or the longnose grenadier; how-
ever, other grenadiers are generalists in their feeding
habits (Pearcy and Ambler 1974; Haedrich and Hender-
son 1974). We found that crustaceans and polychaetes
were the major prey of the marlin-spike (Table 1). While
too few fish were collected to make any firm conclusions
regarding the feeding habits, our results agree with ob-
servations by Hansen (1915) and Bigelow and Schroeder
(1953).

Ocean pout. — Ocean pout are a bottom fish which
prey heavily on echinoderms and crustaceans (Table 1).
Almost three-fourths of their diet consisted of the sand
dollar while rock crabs and amphipods accounted for the
majority of the crustaceans. Olsen and Merriman (1946)
collected ocean pout in the southwestern part of the Gulf
of Maine and in Southern New England where they iden-
tified the sand dollar as the major prey. They reported
rock crabs and the amphipod, Unciota, as being of sec-
ondary importance although some fish had also eaten bi-
valve molluscs such as Yoldia and Pecten. Smith (1950)

20

examined the stomach contents of ocean pout collected
in Block Island Sound, in Southern New England. The
primary prey in this area was the amphipod, Lep-
tocherius pinguls, with the sand dollar being the second
most important prey. Tunicates were also important,
making up almost 10' i of the diet by weight. In the pres-
ent study tunicates were again found to be a reasonably
significant prey item but only in the Gulf of Maine. Bige-
low and Schroeder (1953) examined the stomachs of
ocean pout taken in Massachusetts Bay in 1924 and near
the Nantucket Lightship in 1950. They found that the
rather large specimen from Massachusetts Bay was full
of brittle stars and spider crabs while the animals taken
near the Lightship were full of small sea scallops.

Dietary Overlap

The percentage similarity in diet (Fig. 3 and text) is a
relative measure of overlap of the food habits, where
overlap is simply defined as the use of the same resource
by more than one predator regardless of the resource
abundance. In contrast, resource competition exists only
if the demand for prey outstrips the immediate supply
(Weatheriey 1963; Keast 1965, 1977; Zaret and Rand
1971). The index of diet overlap presented here, there-
fore, just highlights the potential for food resource com-
petition between these fish populations which could exist
if certain prerequisites were met, as discussed below.

The distribution of many of these fish, especially the
commercially important species, has been documented
from the groundfish- survey data collected by the per-
sonnel at the Woods Hole Laboratory (Colton 1955, 1972;
Fritz 1965; Grosslein and Bowman 1973; Grosslein and
Clark 1976'). The ranges of many of these predators over-
lap, however, the major concentrations of the different
species of fish are not usually the same. Fritz (1965), for
example, has summarized the distribution of seven
gadids from the autumn groundfish survey data, 1955-61.
His results showed that silver hake were ubiquitous, but
over the 6-yr study they were most abundant off Cape
Cod and to the south, and also on the western and south-
eastern parts of Georges Bank. Atlantic cod occurred
north of lat. 41°00' and were abundant off Nantucket,
north of Cape Cod, and southeast of Nova Scotia. The
haddock, pollock, and white hake might be considered
boreal species as they, like the Atlantic cod, all occurred
north of lat. 41°00'. The major concentration of haddock
was on the northern edge of Georges Bank and on Browns
Bank. Pollock were abundant near Nova Scotia but also
occurred in moderate concentrations in the Gulf of
Maine. White hake were found along the northeastern
edge of Georges Bank and also in the Gulf of Maine. Red
hake occurred throughout the area ranging from Nova
Scotia to Cape May, N.J., being most abundant south of

'Grosslein. M. D.. and S. H. Clark. 1976. Distribution of selected
fish species and status of major fisheries in the Northwest Atlan-
tic. Technical reference document for bilateral negotiations between
USA and Canada. NOAA, NMFS, Northeast Fisheries Center Lab.
Ref. 76-12. 171 p.

Cape Cod. A more recent summary of the groundfish sur-
vey data has been prepared by Grosslein and Clark (see
footnote 3). This document includes both spring and
autumn cruise data which gives some idea of the seasonal
changes in the distribution of the commercially impor-
tant gadoids. Although certain species, such as red hake,
have distinct seasonal migrations, the overall distribu-
tion of many of these fish is reasonably constant through-
out the year and even from year to year. Colton (1972),
for example, found no major change in the general dis-
tribution of the haddock during the period 1950-68
despite changing trends in seawater temperature. From
this survey data it may tentatively be concluded that, on
a broad scale, although some spatial overlap occurs be-
tween many of the 15 gadiform fishes we have studied,
the major concentrations of each fish are usually suf-
ficiently distinct so that competition between the various
populations for the same food resource would be mini-
mal. On a more localized scale, however, spatial overlap
may occasionally be severe as has been documented by
Grosslein and Bowman (1973). They considered the
problem of bycatch in ICNAF Subareas 5 and 6 (Georges
Bank to Cape Hatteras), pointing out that a bottom
trawl fishery in these areas could not be conducted with-
out harvesting a substantial mixture of species. In par-
ticular, aggregates of red and silver hake are con-
sistently found in Southern New England as are mixtures
of Atlantic cod, haddock, and hake on Georges Bank. For
situations such as these, food habits studies would have
to be conducted on fish collected from mixed catches to
determine if the fish are feeding on the same prey at the
same time or if there is significant resource partitioning,
thus eliminating the potential for competition as was
found by Jones (1978) for some gadoid fishes in Euro-
pean waters.

Even if spatial overlap were to occur on a significant
scale, it may further be counteracted by short-term tem-
poral changes in predator distribution and activity. Dai-
ly activity cycles may effectively function to segregate
predators although the predators would, at times, share
the same prey (Graham 1924; Rae 1967; Brunei 1972;
Daan 1973; Arntz 1974; Jenkins and Green 1977).

Finally, even when the spatial and temporal distri-
bution of these species is accounted for, it is difficult to
make firm conclusions regarding resource limitation
without an extensive knowledge of the benthic com-
munity available for exploitation. StueUes such as those
conducted by Arntz (1971, 1973, 1974) which combine
food habits investigations, feeding chronology exper-
iments, and a quantitative evaluation of the macro-
benthos are needed before we can quantitatively de-
termine the degree to which food resource competition
actually exists.

A number of nonbiological factors may also influence
the calculation of dietary overlap and these must be
accounted for when interpreting overlap data. The level
of identification of the prey will affect the overlap cal-
culations since broader taxonomic groupings actually in-
crease the observed degree of overlap. Moyle (1977) gave
an example of this when comparing the diet of sculpins

21

and some salmonids, noting that the greatest overlap oc-
curred when the prey was only identified to the order
level. In the present study the same effect may be
observed. If, for example, the percentage similarity is
calculated for the diet of Atlantic cod and silver hake at
the highest taxonomic level given in Table 2, the simi-
larity increases from 58' c (Fig. 3) to 89' r. On the other
hand, Keast (1977) justified the use of broader tax-
onomic groupings for sorting prey; he argued that the
body size of the prey rather than finer taxonomic iden-
tity is important for studies on fish food habits. It would
appear that there exists an optimal level of taxonomic
classification for prey identified for dietary overlap cal-
culations. This optimum is piobably primarily depen-
dent on the size of the prey, provided the prey shares a
similar ecological niche, since size dependent prey selec-
tion has been well-documented for fish (Keast 1965;
Tyler 1972; Daan 1973; see also Edwards 1976). Apart
from the level of taxonomic identification, sample size is
probably the second most important nonbiological factor
influencing dietar>' overlap calculations. The smaller the
sample the more variable the percentage similarity. This
effect was noted in the results for the marlin-spike and
longnose grenadier where a relatively small change in
sample size, and, consequently, in the quantity of prey
consumed, could have a large influence on the observed
composition of the diet and any resulting overlap esti-
mates.

Bearing in mind some of the limitations discussed
above, an overall pattern emerges from calculating and
categorizing the percentage similarity between the
fishes' diets (Fig. 3) which is not as readily apparent from
a cursory examination of the tables on stomach contents
for each of the 15 predators alone. Generally, the great-
est block of similarity occurs in the upper left section of
Figure 3 while the lowest level of overlap is in the upper
right-hand section of the same figure. This reflects two
distinct feeding types as revealed by an examination of
the data in Table 2. Thus, fish populations such as
Atlantic cod, pollock, silver hake, white hake, offshore
hake, and cusk are decidedly piscivorous while the had-
dock, longfin hake, fourbeard rockling, marlin-spike,
longnose grenadier, fawn cusk-eel, and ocean pout are
characterized more as benthic, invertebrate feeders. Red
and spotted hake are intermediate, resulting in a very
similar diet which overlaps both the piscivores and
benthic invertebrate feeders.

ACKNOWLEDGMENTS

We thank Roland Wigley for his guidance in the pre-
paration of the manuscript and also Deborah Hartley,
Martha Hill, Ray Maurer, Thomas Morris, and Janet
Murphy who helped collect, analyze, and tabulate the
data.

LITERATURE CITED

ARNTZ, W. E.

1971. Biomasse und Produktion des Makrobenthos in den tieferen

Teilen der Kieler Bucht im Jahr 1968. [In Ger., Engl. summ..
abstr.l Kiel. Meersforsch. 27:36-72.

1973. Periodicity of diel food intake of cod Gadu» morhua in the
Kiel Bay. Oikos suppl. 15:138-145.

1974. A contribution to the feeding ecology of juvenile cod {Gadus
morhua L.) in the western Baltic. Rapp. P.-V. Reun. Cons.
Perm. Int. Explor. Mer 166:13-19.

ATWOOD. N. E.

1866. On the habits and distribution of the haddock. Proc. Boston
See. Nat. HUt. 10:322-323.
BAIRD. S. F.

1889. The sea fisheries of eastern .Vorth America. U.S. Comm.
Fish Fish.. Part 14. Rep. Comm. 1886, append. A:33-34. 73-80.
BIGELOW. H. B.. and W. C. SCHROEDER.

1953. Fishes of the Gulf of Maine. U.S. Fish Wildl. Ser^ .. Fish.
Bull. 53, 577 p.
BOWMAN. A.

1923. Spawny haddock: The occurrence of the "spawny" haddock
and the locus and extent of herring spawning grounds. (G.B.)
Fish. Board Scotl.. Sci. Invest. 1922, IV.

BREDER, C. M.. Jr.

1922. The fishesofSandy Hook Bay. Zoologica (N.Y.) 2:330-351.
BRUNEL. P.

1972. The Gaspe cod ecosystem in the Gulf of St. Lawrence. III.
The daily and seasonal vertical migrations of cod (Gadus morhua)
in 1960-62. Nat. Can. (Que. I 99:287-357.
CLAPP. W. F.

1912. Collecting from haddock on the Georges Bank. Nautilus
25:104-106.
COLTON, J. B.

1955. Spring and summer distribution of haddock on Georges
Bank. U.S. Fish Wildl. Ser\'., Spec. Sci. Rep. Fish. 156, 65 p.
COLTON. J. B.. .Jr.

1972. Temperature trends and the distribution of groundfish in
continental shelf waters. Nova Scotia to Long Island. Fish. Bull.,
U.S. 70:637-657.

DAAN. N.

1973. A quantitative analysis of the food intake of North Sea cod,
Gadus morhua. Neth. J. Sea Res. 6:479-517.

DEXTER. R. W.

1969. Studies on the food habits of whiting, redfish. and pollock in
the Gulf of Maine. J. Mar. Biol. Assoc. India ll(l&2):288-294.
EDWARDS. R. L.

1976. Middle Atlantic fisheries: Recent changes in populations and
outlook. Am. Soc. Limnol. Oceanogr., Spec. Symp. 2:302-311.

FRITZ. R. L.

1965. Autumn distribution of groundfish species in the Gulf of

Maine and adjacent waters. 1955- 1961. Ser. Atlas Mar. Environ.,

Am. Geogr. Soc. Folio 10, 3 p., 22 plates.
GRAHAM. M.

1924. The annual cycle in the life of the mature cod in the North
Sea. (G.B.) Fish. Invest. Minist. Agric, Fish. Food, Ser. 2, 6, 77

P-
GROSSLEIN. M. D., and E. BOWMAN.

1973. Mixture of species in Subareas 5 and 6. Int. Comm. North-
west Atl. Fish. Redb. 1973(III):163-207.

GULLAND, J. A.

1977. Ck>als and objectives of fishery management. FAO Tech.
Pap. 166, 14 p.

HAEDRICH. R. L.. and N. R. HENDERSON.

1974. Pelagic food of Coryphaenoides armatus, a deep benthic rat-
tail. Deep-Sea Res. 21:739-744.

HANSEN, H. J.

1915. The Crustacea Euphausiacea of the United States National
Museum. Proc. U.S. Natl. Mus. 48:59-114.
HILDEBR.AND. S. F., and VV. C. SCHROEDER.

1928. Fishes of Chesapeake Bay. Bull. [U.S.) Bur. Fish. 43(11,388

P
HOMANS. R. E. S.. and A. W. H. NEEDLER.

1944. Food of the haddock. Proc. N.S. Inst. Sci. 21:15-49.
IVLEV. V. S.

1961. Experimental ecology of the feeding of fishes. Yale Univ.
Press. New Haven, 302 p.

22

JENKINS, B. W.. and J. M. GREEN.

1977. A critique of field methodology for determining fish feeding
periodicity. Environ. Biol. Fish. 1;209-214.

JENSEN, A. C, and R. L. FRITZ.

1960. Observations on the stomach contents of the silver
hake. Trans. Am. Fish. Soc. 89:239-240.
JONES, R.

1978. Competition and co-existence with particular reference to
gadoid fish species. Rapp. P.-V. Reun. Cons. Perm. Int. Expior.
Mer 172:292-300.

KEAST, A.

196.5. Resource subdivision amongst cohabiting fish species in a
bay. Lake Opinicon, Ontario. Great Lakes Res. Div., Univ.
Mich. Publ. 13:106-132.

1977. Diet overlaps and feeding relationships between the year
classes in the yellow perch (Perca flauescens). Environ. Biol.
Fish. 2:53-70.

KENDALL, W. C.

1898. Notes on the food of four species of the cod family. U.S.
Comm. Fish Fish., Part 22. Rep. Comm. 1896:177-186.
KOHLER, A. C, and D. N. FITZGERALD.

1969. Comparisons of food of cod and haddock in the Gulf of St.
Lawrence and on the Nova Scotia banks. J. Fish. Res. Board
Can. 26:1273-1287.
LEIM, A. H., and W. B. SCOTT.

1966. Fishes of the Atlantic coast of Canada. Fish. Res. Board
Can.. Bull. 155. 485 p.
UNTON, E.

1901. Parasitesof fishes of the Woods Hole region. Bull. U.S. Fish
Comm. 19:407-492.
MINET, J. P., and J. B. PERODOU.

1978. Predation of cod. Gadus morhua. on capelin, Mallotus vil-
losus, off eastern Newfoundland and in the Gulf of St.
Lawrence. Int. Comm. Northwest Atl. Fish., Res. Bull. 13:11-20.

MIRONOVA. N. V.

1961 . Feeding and age of young gadoid fishes in the coastal zone of
the eastern Murman._ Monograph published by the Academy of
Sciences of the U.S.S.R., Moscow and Leningrad, 1956, 98 p.
(Transl. Minist. Agric, Fish. Food, Fish- Lab., L<;)westoft, Engl.,
72 p.)

MOYLE, P. B.

1977. In defense of sculpins. Fisheries (Bethesda) 2:20-23.
NAGABHUSHANAM, A. K.

1965. On the biology of the commoner gadoids in Manx waters. J.
Mar. Biol. Assoc. U.K. 45:615-657.
NEEDLER, A. W. H.

1929. Unpigmented elvers {Anguitla rostrata Lesueur) in haddock
stomachs at Ingonish, Cape Breton. Copeia 171:41-42.
NICHOLS, J. T., and C. M. BREDER, Jr.

1927. The marine fishes of New York and southern New Eng-
land. Zoologica (N.Y.) 9:1-192.
NIKOLSKY. G. V.

1963. The ecolog>' of fishes. Acad. Press Inc., N.Y., 352 p.
OLSEN, Y. H., and D. MERRIMAN.

1946. The biology and economic importance of the ocean pout,
Macrozoarces americanus {Bloch and Schneider). Bull.
Bingham Oceanogr. Collect., Yale Univ. 9, 4:1-184.
PALOHEIMO, J. E., and L. M. DICKIE.

1965. Food and growth of fishes. I. A growth curve derived from
experimental data. J. Fish. Res. Board Can. 22:521-542.
PARKER, R. R., and P. A. LARKIN.

1959. A concept of growth in fishes. J. Fish. Res. Board Can.
16:721-745.
PEARCY, W. G., and J. W. AMBLER.

1974. Food habits of deep-sea macrourid fishes off the Oregon
coast. Deep-Sea Res. 21:745-759.
PETROV, V. N.

1973. Maturity, feeding length and age composition of white hake,
Urophycis tenuis (Mitch.), in ICNAF Subarea 3, 1969-72. Int.
Comm. Northwest Atl. Fish. Redb. 1973(III):101-104.
POPOVA, 0. A.

1962. Some data on the feeding of cod in the Newfoundland area of
the Northwest Atlantic. In Yu. Yu. Marti (chief editor), Soviet

fisheries investigations in the Northwest Atlantic. Transl. Isr.
Prog. Sci. Transl., Jerusalem, 1963, p. 228-249.
POWLES, P. M.

1958. Studies of reproduction and feeding of Atlantic cod iGadus
callarias L.) in the southwestern Gulf of St. Lawrence. J. Fish.
Res. Board Can. 15:1383-1402.

RAE, B. B.

1967. The food of cod in the North Sea and on west of Scotland
grounds. Mar. Res. Dep. Agric. Fish. Scotl. 1967(1), 68 p.

1968. The food of cod in Icelandic waters. Mar. Res. Dep. Agric.
Fish. Scotl. 1968(6), 19 p.

ROHR, B. A., and E. J. GUTHERZ.

1977. Biology of offshore hake, Merluccius albidus. in the Gulf of
Mexico. Fish. Bull., U.S. 75:147-158.
SIKORA, W. B., R. W. HEARD, and M. D. DAHLBERG.

1972. The occurrence and food habits of two species of hake, Uro-
phycia ref^ius and U. floridanus in Georgia estuaries. Trans. Am.
Fish. Soc. 101:513-525.
SMITH, F. E.

1950. The benthos of Block Island Sound. I. The invertebrates,
their quantities and their relations to the fishes. Ph.D. Thesis,
Yale Univ., New Haven, Conn., 213 p.
STEELE, D. H.,

1963. Pollock (I'ollachius virens (L.)) in the Bay of Fundy. J.
Fish. Res. Board Can. 20:1267-1314.
TEMPLEMAN, W.

1965. Some instances of cod and haddock behaviour and con-
centrations in the Newfoundland and Labrador areas in relation to
food. Int. Comm. Northwest Atl. Fish., Spec. Publ. 6:449-461.
TSEEB, R. YA.

1960. Yearly fluctuations in the food of haddock off the Murman
coast. Tr. Murm. Morsk. Biol. Inst. Akad. Nauk SSSR 2(61:186-
202. (Avail, from Isr. Prog. Sci. Transl., Jerusalem, 1964.)

TYLER, A. V.

1971. Monthly changes in stomach contents of demersal fishes in
Passamaquoddy Bay, N.B. Fish. Res. Board Can. Tech. Rep.
288, 114 p.

1972. Food resource division among northern, marine, demersal
fishes. J. Fish. Res. Board Can. 29:997-1003.

VERRILL, A. E.

1871. On the food and habits of some of our marine fishes. Am.

Nat. 5:397-400.
1873. Lists of species found in the stomachs of fishes — food of
fishes. U.S. Comm. Fish Fish., Part 1, Rep. Comm. 1871-1872,
1:514-521.
VINOGRADOV, V. I.

1972. Studies of the food habits of silver and red hake in the North-
west Atlantic area, 1965-67. Int. Comm. Northwest Atl. Fish., Res.
Bull. 9:41-50.
VLADYKOV, V. D.

1933. High temperature stops haddock fishing. Prog. Rep. Fish.
Res. Board Atl. Coast Stn. 7:10-11.
WAGNER, G.

1959. Untersuchungen uber die Tagesperiodizitat der Nahrung-
saufnahme bei PoUachius virens L. Kurze Mitt. Inst. Fischerei-
biol., Univ. Hamburg 9:61-103.

WEATHERLEY, A. H.

1963. Notions of niche and competition among animals, with
special reference to freshwater fish. Nature (Lond.) 197:14-17.
WIGLEY. R. L.

1956. Food habits of Georges Bank haddock. U.S. Fish Wildl.
Serv., Spec. Sci. Rep. Fish. 165, 26 p.
WIGLEY, R. L., and R. B. THEROUX.

1965. Seasonal food habits of highlands ground haddock. Trans.
Am. Fish. Soc. 94:243-251.
WILLIS, J. R.

1890. Nova Scotia shells. Proc. N.S. Inst. Sci. 7:419-428.
WISE, J. P.

1961. Synopsis of biological data on cod, Gadus morhua Linnaeus,
1758. FAO Fish. Biol. Synop. 21.

ZARET, T. M., and A. S. RAND.

1971. Competition in tropical stream fishes: support for the com-
petitive exclusion principle. Ecology 52:336-342.

23

NOAA TECHNICAL REPORTS

NMFS CIRCULAR AND SPECIAL SCIENTIFIC REPORT— FISHERIES

GUIDELINES FOR CONTRIBUTORS

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