(DRAFT) - Taxonomy
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
TAXONOMY
NAME - cod, Atlantic
OTHER COMMON NAMES - cod, codfish, lutefisk, torsk, morue commune and cabillaud
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - ,
CLASS AND SUBCLASS - Osteichthyes,
ORDER AND SUBORDER - Gadiformes,
FAMILY AND SUBFAMILY - Gadidae,
GENUS AND SUBGENUS - Gadus,
SPECIES AND SSP - morhua,
SCIENTIFIC NAME - Gadus morhua
AUTHORITY - Linnaeus, 1758
TAXONOMY REFERENCES - 258 and 231
COMMENTS ON TAXONOMY -
Fr.: morue franche
Svetovidov (1948) proposed a number of subspecies of
Gadus morhua, two of which are recognized currently as full species, namely
the Pacific cod, Gadus macrocephalus, and the Greenland cod, Gadus ogac. In
general, subspecies of Atlantic cod are not acknowledged. Although Atlantic
cod vary greatly in many morphological and meristic characters, such as
growth and vertebral numbers, these differences are, in part at least, a
reflection of environmental conditions. A study of genetic variation in
Atlantic cod has indicated a low amount of genetic variability throughout
the total range. There is apparently considerable gene flow between various
cod stocks. Vertebral numbers have been studied and shown to be useful in
identifying cod stocks.*258*
In the family of codfish, medium to large-sized bottom fishes, living in
cool seas, except for one freshwater holarctic genus, Lota. Found mainly in
the northern hemisphere. Most species are bottom fishes inhabiting inshore
waters and continental shelves, some to depths of 1300 m.
Cods are generally heavy-bodied, elongate, usually with a stout caudal
peduncle. Head large: mouth large; teeth usually well developed on upper
(premaxillary) and lower jaws and on head of vomer; eye moderate. Gill
rakers usually short and stubby. Branchiostegals 6-8. Fins are well
developed. Scales cycloid, small. Lateral line well developed. Swim
bladder without pneumatic duct (physoclistous). Vertebrae 42-82. Color
generally somber, ranging from tan to brown to silvery. Predaceous fishes
feeding heavily on other fishes and invertebrates.
Taxonomy - 1 (DRAFT) - Taxonomy
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
The cods are of great economic importance and support extensive commercial
fisheries.*258*
Taxonomy - 2 (DRAFT) - Status
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
STATUS
Coded Status
Sport Fish
Commercial
Commercial/consumption
REFERENCES FOR STATUS - 258
COMMENTS ON STATUS -
The Atlantic cod is one of the leading food fishes in the world and has been
pursued on the fishing banks of the North Atlantic for centuries. It
continues to be Canada's single most important commercial species in terms
of landed value. Canadian fishermen capture 70-75 percent of all cod caught
in the northwest Atlantic, where at least 13 countries engage in the
fishery. In 1983 Canada landed 509,052 t valued at $187,451,000; in 1984,
463,100 t valued at $168,600,000.*258*
Atlantic cod is caught commercially by otter trawls, pair trawls, line
trawls, Danish seines, handlines, jiggers, traps, and gill nets. The cod is
also growing in importance as a sport fish, sought by tourists who fish
from 'party' boats.*258*
The flesh is used fresh, frozen, smoked, salted, and canned. The salt-fish
industry, once of paramount importance for export, has taken second place to
the market for fresh and frozen fillets, frozen blocks and sticks. Special
parts such as cod cheeks and cod tongues are considered delicacies by many
maritime peoples. Additional by-products include fish meal, cod liver oil,
and glue.*258*
Status - 1 (DRAFT) - Distribution
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - MARINE
REFERENCES FOR HABITAT - 258
LAND USE -
Water
REFERENCES FOR LAND USE - 258
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine OW0
Marine OW0
Marine OW0
REFERENCES FOR NWI - 258
COMMENTS ON HABITAT ASSOCIATIONS -
Atlantic cod inhabit cool-temperate to subarctic waters form inshore
regions to the edge of the continental shelf. Adapted for bottom feeding,
they may also spend much time off bottom and may occur from the surface to
depths of 457 m.*258*
Cod occur throughout the Canadian Atlantic area. Bottom types vary greatly
throughout this vast region, which extends from the Bay of Fundy and
northern Georges Bank to northern Labrador.*258*
ANIMAL/PLANT SPECIES ASSOCIATIONS -
Older, larger cod
squid
pollock
harbor seals
grey seals
harp seals
Compete with silver hake for food
REFERENCES FOR SPECIES ASSOCIATIONS - 258
COMMENTS ON SPECIES ASSOCIATIONS -
PREDATION AND COMPETITION: Young cod fall prey to a number of predators
such as older, larger cod, squid, and pollock. Larger cod are eaten in turn
by marine mammals, particularly harbor, grey, and harp seals. Pilot whales
prefer squid but eat cod in the absence of squid. Young cod compete for
food with other gadoid species such as silver hake.*258*
PARASITES AND DISEASE: The Atlantic cod is host to many parasites.
Researchers listed the following species: five protozoans (one of these, a
trypanosome, occurs in the blood), two myxosporidians, one monogeneid, five
trematodes, two cestodes, six nematodes, one acanthocephalan, one hirudinid,
and six copepods, 29 species in all. One parasite, the nematode Phocanema
decipiens, is more important than all the others. This roundworm, commonly
known as the sealworm, invades, as larvae, the musculature of cod and other
groundfishes. When the fishes carrying this larval roundworm are eaten by a
seal, the worm matures in the seal's stomach, mates, and lays eggs which are
voided along with the feces. The eggs hatch in the sea, and the larvae are
Habitat Associations - 1 eaten by small marine invertebrates. When the invertebrates are eaten by
fishes, such as cod, the cycle starts over again.*258*
Cod may also have heavy infections of the microsporidian Loma morhua in both
gills and viscera.258
Habitat Associations - 2 (DRAFT) - Food Habits
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 258
LIFESTAGE FOOD FOOD PART
Larva Copepods Not Specified
Larva Cirripeds Larva stage
Larva Crustaceans Not Specified
Larva See Comments; Food
Juvenile Crustaceans Not Specified
Adult Crustaceans Not Specified
Important Clupeiformes Not Specified
Important See Comments; Food
Adult Comb-jellies Not Specified
Adult Brittle/Serpent Star Not Specified
Adult Sea Cucumbers Not Specified
Adult Worms Not Specified
Adult Pleuronectiformes Not Specified
Adult Gadiformes Not Specified
Adult Atheriniformes Not Specified
Adult Squid, Octopus Not Specified
Adult Snails Not Specified
Adult Bivalve Molluscs Not Specified
Adult See Comments; Food
REFERENCES FOR IMPORTANT FOOD - 258
REFERENCES FOR ADULT FOOD - 258
REFERENCES FOR JUVENILE FOOD - 258
REFERENCES FOR LARVAE FOOD - 258
COMMENTS ON FOOD -
Much attention has been given to the food of Atlantic cod, since growth of
individuals and stocks (or populations) of all species are dependent on
quantity and quality of food eaten. Cod are voracious feeders and their
feeding habits may influence significantly the size of cod populations
through cannibalism, and also the size of populations of other species such
as redfish, capelin, and sand lance.*258*
As fry, cod feed on a variety of small creatures such as copepods,
amphipods, barnacle larvae, and other small crustaceans. Juveniles and
young adults continue to eat crustaceans such as euphausiids, mysids,
shrimps, small lobsters, spider crabs, and hermit crabs. When about 50 cm
long, fish becomes the predominant food. Depending on locality and
availability, capelin, sand lance, redfish, and herring are important foods.
But many other species of fishes are also eaten, sometimes in quantity;
these include alewives, Atlantic and Arctic cod, cunner, flounders,
Food Habits - 1 (DRAFT) - Food Habits
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
haddock, hake, mackerel, shannies (daubed, Arctic and radiated),
snakeblenny, sculpins, and silversides. Molluscs are less important as
food for Canadian cod than for those in United States waters but squid,
banks clam, whelks, mussels, and nudibranchs are eaten. Cod also eat many
other creatures such as tunicates, comb jellies, brittle stars, sand
dollars, sea cucumbers, and marine worms; fish cuttings, including heads
and entrails from fishing boats; and even the occasional seabird.*258*
COMMENTS ON ADULT FOOD -
Juveniles and young adults continue to eat crustaceans such as euphausiids,
mysids, shrimps, small lobsters, spider crabs, and hermit crabs.*258*
When abut 50 cm long, fish becomes the predominant food. Depending on
locality and availability, capelin, sand lance, redfish, and herring are
important foods. But many other species of fishes are also eaten, sometimes
in quantity; these include alewives, Atlantic and Arctic cod, cunner,
flounders, haddock, hake, mackerel, shannies (daubed, Arctic and radiated),
snakeblenny, sculpins, and silversides. Molluscs are less important as
food for Canadian cod than for those in United States waters but squid,
banks clam, whelks, mussels, and nudibranchs are eaten. Cod also eat many
other creatures such as tunicates, comb jellies, brittle stars, sand
dollars, sea cucumbers, and marine worms; fish cuttings, including heads
and entrails from fishing boats; and even the occasional seabird.*258*
COMMENTS ON JUVENILE FOOD -
Juveniles and young adults continue to eat crustaceans such as euphausiids,
mysids, shrimps, small lobsters, spider crabs, and hermit crabs.*258*
COMMENTS ON LARVAE FOOD -
As fry, cod feed on a variety of small creatures such as copepods,
amphipods, barnacle larvae, and other small crustaceans.*258*
Food Habits - 2 (DRAFT) - Environment Associations
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
E Water Temperature: Specified in Comments
BA Water Depth Preference: Specified in Comments
A Water Temperature: Specified in Comments
A Water Depth Preference: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 258
REFERENCES FOR ADULT ENVIRONMENTAL ASSOC_ - 258
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 258
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 258
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Atlantic cod inhabit cool-temperate to subarctic waters form inshore
regions to the edge of the continental shelf. Adapted for bottom feeding,
they may also spend much time off bottom and may occur from the surface to
depths of 457 m. The depth occupied is usually related to temperature;
cool temperatures are preferred, generally in the range of -0.5 to 10
degrees C, but preferred temperatures are influenced by time of year,
geographic location, and size of fish. On the Scotian Shelf, the summer
temperatures preferred by cod ranged from 3-4 degrees C in the
northeastern part to 7-8 degrees C in the southwest. Research results
suggest, however, that biological conditions may take precedence over
temperature preference. Cod may inhabit one depth at a preferred
temperature and make excursions into the level above or below to feed on
capelin or other prey.*258*
Cod occur throughout the Canadian Atlantic area. Conditions such as
temperature, food supply, water, depth, and bottom type vary greatly
throughout this vast region, which extends from the Bay of Fundy and
northern Georges Bank to northern Labrador. In each of
the different regions, there are one or more identifiable cod stocks,
each with its own set of characteristics. There are at least 12-14
recognized stocks, of which the most important is the southern
Labrador--east Newfoundland stock. Others include the northern Labrador
stock, the northern and southern Gulf of St. Lawrence stocks, southern
Grand Bank stock, and Banquereau-Sable Island stock.*258*
Environment Associations - 1 (DRAFT) - Environment Associations
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
Large numbers of cod have been tagged, and a relatively high percentage
recovered. They tend to move in schools and, in some areas at least, move
offshore in winter and onshore in summer. Tagging cod in Passamaquoddy Bay
in 1966 and subsequent recoveries indicated considerable movement across
the Bay of Fundy and on the Scotian Shelf and Georges Bank, and also
movement into the Gulf of Maine.*258*
The depth at which cod spawn varies according to the stock involved and the
locality and is no doubt influenced by temperature. Some stocks may spawn
in depths of less than 110 m while others spawn in depths of over 182
m.*258*
Eggs spawned off northern Labrador in March--April take 50-60 d to hatch
at surface temperatures of -1.5 to 0 degrees C, and those spawned on
Hamilton Bank in March--April take about 40 d at temperatures of -1 to 1
degrees C.*258*
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
Atlantic cod inhabit cool-temperate to subarctic waters form inshore
regions to the edge of the continental shelf. Adapted for bottom feeding,
they may also spend much time off bottom and may occur from the surface to
depths of 457 m. The depth occupied is usually related to temperature;
cool temperatures are preferred, generally in the range of -0.5 to 10
degrees C, but preferred temperatures are influenced by time of year,
geographic location, and size of fish. On the Scotian Shelf, the summer
temperatures preferred by cod ranged from 3-4 degrees C in the
northeastern part to 7-8 degrees C in the southwest. Research results
suggest, however, that biological conditions may take precedence over
temperature preference. Cod may inhabit one depth at a preferred
temperature and make excursions into the level above or below to feed on
capelin or other prey.*258*
Cod occur throughout the Canadian Atlantic area. Conditions such as
temperature, food supply, water, depth, and bottom type vary greatly
throughout this vast region, which extends from the Bay of Fundy and
northern Georges Bank to northern Labrador. In each of
the different regions, there are one or more identifiable cod stocks,
each with its own set of characteristics. There are at least 12-14
recognized stocks, of which the most important is the southern
Labrador--east Newfoundland stock. Others include the northern Labrador
stock, the northern and southern Gulf of St. Lawrence stocks, southern
Grand Bank stock, and Banquereau-Sable Island stock.*258*
Large numbers of cod have been tagged, and a relatively high percentage
recovered. They tend to move in schools and, in some areas at least, move
offshore in winter and onshore in summer. Tagging cod in Passamaquoddy Bay
in 1966 and subsequent recoveries indicated considerable movement across
the Bay of Fundy and on the Scotian Shelf and Georges Bank, and also
movement into the Gulf of Maine.*258*
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
The depth at which cod spawn varies according to the stock involved and the
locality and is no doubt influenced by temperature. Some stocks may spawn
Environment Associations - 2 (DRAFT) - Environment Associations
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
in depths of less than 110 m while others spawn in depths of over 182
m.*258*
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
Eggs spawned off northern Labrador in March--April take 50-60 d to hatch
at surface temperatures of -1.5 to 0 degrees C, and those spawned on
Hamilton Bank in March--April take about 40 d at temperatures of -1 to 1
degrees C.*258*
Environment Associations - 3 (DRAFT) - Life History
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
LIFE HISTORY
MORPHOLOGY/DESCRIPTION: Body heavy, elongate, compressed posteriorly. Head
large; snout blunt; mouth large, terminal, lower jaw slightly shorter than
upper, many small teeth in jaws and on vomer; distinct barbel near tip of
lower jaw; eye moderate. Gill rakers 21-28. Branchiostegals 7. Fins:
dorsals, 3, first of 13-16 rays, second 19-24, third 18-21, all distinctly
separate; caudal square to only slightly concave, total rays 50-56; anals,
2, first of 20-24 rays, second 17-22; pelvics located slightly in front of
pectorals, second ray slightly prolonged and filamentous; pectorals high on
sides, fan-like. Scales small, cycloid. Lateral line distinct, arched over
pectoral fin, complete, pale in color. Peritoneum leaden-silvery, with black
dots. Vertebrae 50-59. Size averages about 2.3-3.6 kg. Color varies widely
depending on surroundings; usually gray to green or brown to red, back and
sides with numerous rounded brownish to reddish spots; lateral line pale,
belly white, fins of same hue as body. Individual cod have ability to change
color pattern according to living conditions but the place of origin of the
cod limits the amount of change.*258*
REPRODUCTION: Over the whole Canadian Atlantic region, spawning begins in
the north as early as February and ends in the south as late as December.
Cod spawn over a wide area of the continental shelf but the area involved is
so large and conditions so varied that generalizations would be
misleading.*258*
The Labrador-northern Newfoundland stock usually spawns as early as February
or March in the northern part of the region, progressively later southward.
On the Grand Bank spawning begins in April, reaches a peak in late May, and
continues into June. In southwestern Gulf of St. Lawrence spawning began in
May, reached a peak in late June, and ended in September. This delayed
spawning is due possibly to migration out of the Gulf during winter
freeze-up and heavy ice cover. On southern Georges Bank, spawning may begin
in December and extend to April.*258*
The depth at which cod spawn varies according to the stock involved and the
locality and is no doubt influenced by temperature. Some stocks may spawn
in depths of less than 110 m while others spawn in depths of over 182
m.*258*
The eggs and sperm are broadcast by the adult fish. The number of eggs
produced increases with the size of the female. A female 51 cm long will
deposit about 200 thousand eggs while a female 140 cm long may deposit 12
million eggs.*258*
The eggs are spherical, transparent, buoyant, and pelagic, and measure
1.2-1.6 mm in diameter. There is no oil globule. After extrusion and
fertilization the eggs rise slowly and remain at or near the surface layers
during incubation. The eggs are very similar to haddock eggs and difficult
to distinguish from them. Incubation time varies. Eggs spawned off
northern Labrador in March-April take 50-60 d to hatch at surface
temperatures of -1.5 to 0 degrees C and those spawned on Hamilton Bank in
March-April take about 40 d at temperatures of -1 to 1 degree C. At 6
degrees C eggs hatch in about 14 d.*258*
Life History - 1 (DRAFT) - Life History
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
GROWTH: Hatching occurs when embryos are 3.3-5.7 mm long. The young remain
pelagic until about 25-50 mm long, when they descend to the bottom.*258*
Growth rates of experimentally reared larval cod and larval haddock showed
that cod grew more rapidly than haddock.*258*
Growth rates vary with stock and locality; annual variations may also occur
within the same stock. In general, growth is slower (and fish live longer)
off Labrador and eastern Newfoundland than on southern Grand Bank, and
slower in the Gulf of St. Lawrence than on the Scotian Shelf. On average,
10 yr-old cod from inshore Labrador measure 57 cm long, from SW Gulf of St.
Lawrence 70.8 cm long, and from Grand Bank about 86.5 cm long.*258*
The average age of cod caught by the commercial fishery in the 1970's was
younger than in the 1950's--that is, the average age declined. On average,
commercially caught inshore cod are 5-6 yr old, about 50-60 cm long, and
weigh around 1.1-2.3 kg.*258*
Older cod are more common in some stocks than others, but cod older than 20
yr are rare. Twenty-six years is usually regarded as the maximum age but
cod up to 29 yr have been recorded.*258*
Although the average weight of commercially caught cod is under 4.5 kg, cod
may grow to a large size. The largest one ever reported was caught on a
line trawl off Massachusetts in 1895 and weighted 95.9 kg. One weighing
50.8 kg was caught in 1963 by fishermen from Shelburne, NS. The all-tackle
world record is 44.79 kg for a cod caught off New Hampshire in 1969.*258*
PREDATION AND COMPETITION: Young cod fall prey to a number of predators
such as older, larger cod, squid, and pollock. Larger cod are eaten in turn
by marine mammals, particularly harbor, grey, and harp seals. Pilot whales
prefer squid but eat cod in the absence of squid. Young cod compete for
food with other gadoid species such as silver hake.*258*
PARASITES AND DISEASE: The Atlantic cod is host to many parasites.
Researchers listed the following species: five protozoans (one of these, a
trypanosome, occurs in the blood), two myxosporidians, one monogeneid, five
trematodes, two cestodes, six nematodes, one acanthocephalan, one hirudinid,
and six copepods, 29 species in all. One parasite, the nematode Phocanema
decipiens, is more important than all the others. This roundworm, commonly
known as the sealworm, invades, as larvae, the musculature of cod and other
groundfishes. When the fishes carrying this larval roundworm are eaten by a
seal, the worm matures in the seal's stomach, mates, and lays eggs which are
voided along with the feces. The eggs hatch in the sea, and the larvae are
eaten by small marine invertebrates. When the invertebrates are eaten by
fishes, such as cod, the cycle starts over again.*258*
Cod may also have heavy infections of the microsporidian Loma morhua in both
gills and viscera.258
LIFE HISTORY CODES -
Breeding/Spawning Season: February
Life History - 2 (DRAFT) - Life History
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
LIFE HISTORY CODES -
Breeding/Spawning Season: March
Breeding Spawning Season: April
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Breeding/Spawning Season: July
Breeding/Spawning Season: August
Breeding/Spawning Season: September
Breeding/Spawning Season: October
Breeding/Spawning Season: November
Breeding/Spawning Season: December
Average Number of Offspring/Reproductive Effort: Grea
REFERENCES FOR LIFE HISTORY- 258
Life History - 3 (DRAFT) - Management Practices
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
MANAGEMENT PRACTICES
Management Practices - 1 (DRAFT) - References
Species cod, Atlantic
Species Id M010593
Date 27 AUG 96
References
258 * Scott, W.B., M.G. Scott. 1988. Atlantic Fishes of Canada.
Canadian Bulletin of Fisheries and Aquatic Sciences (219) (ed.).
University of Toronto Press Toronto, Canada:731.
References - 1