(DRAFT) - Taxonomy
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
TAXONOMY
NAME - cod, Arctic
OTHER COMMON NAMES -
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - ,
CLASS AND SUBCLASS - ,
ORDER AND SUBORDER - ,
FAMILY AND SUBFAMILY - ,
GENUS AND SUBGENUS - Boreogadus,
SPECIES AND SSP - saida,
SCIENTIFIC NAME - Boreogadus saida
AUTHORITY -
TAXONOMY REFERENCES - 232
Taxonomy - 1 (DRAFT) - Status
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
STATUS
Coded Status
Migrant
See Comments
REFERENCES FOR STATUS - 232
COMMENTS ON STATUS -
Arctic cod make onshore-offshore migrations, which are associated both with
spawning and the movements of ice. Arctic cod are usually found near the ice
edge and descend to greater depths when the ice melts or breaks and the sea
surface temperatures rise. The migration paths and areas of concentration
depend mainly on the distribution of ice. The circumpolar distribution of
arctic cod consists of separate stocks, which have different feeding and
spawning areas and migration routes. The stock in the Barents Sea, north of
Norway, moves inshore in mass concentrations from June through August. When
the water temperature rises in August and September, the cod move to deeper
water. Prespawning and spawning concentrations form in open northeastern
areas of the Barents Sea from September-October to the end of February of
the Barents Sea from September-October to the end of February. A local stock
of arctic cod in the Laptev Sea, north of Siberia, feeds in the open sea and
spends the winter, probably spawning, in the coastal zone. In the southern
Chukchi and northern Bering seas, the abundance of cod increases in winter
and decreases in summer. In the Beaufort Sea, arctic cod were abundant in
the nearshore waters of Simpson Lagoon in August and September. Some cod
remained in Simpson Lagoon in early winter, but all apparently vacated the
shallow waters by February. The nearby deeper coastal areas of Stefansson
Sound, however, were inhabited by arctic cod throughout the winter. The
distribution and abundance of yoy arctic cod varies annually and
geographically. In spring and most of summer, yoy are planktonic and are
found primarily in surface waters. The planktonic yoy become highly
dispersed and can probably be transported considerable distances from the
spawning areas. In surveys done in Norton Sound and the southeastern Chukchi
Sea, either cold, deep waters or regions north of the Bering Strait provided
the areas of highest density of young fish *232*.
The Alaska Department of Fish and Game has managerial authority over arctic
cod extending to 3 mi offshore. However, because harvesting of arctic cod
is minimal, no management plan has been formulated *232*.
Status - 1 (DRAFT) - Distribution
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - MARINE
REFERENCES FOR HABITAT - 232
LAND USE -
Water
Snow or Ice: All Classes
REFERENCES FOR LAND USE - 232
COMMENTS ON HABITAT ASSOCIATIONS -
Arctic cod occurs in areas between the limits of pack ice and drift ice.
Arctic cod are widely assumed to associate with the ice undersurface. They
can also occur near the bottom and in open water. Arctic cod are often
found near the ice edge where the mass development of phytoplankton and
zooplankton occurs. Arctic cod move inshore to warmer coastal waters and
mouths of rivers for spawning. Spawning usually occurs under ice cover.
Yoy are planktonic and are found primarily in surface waters *232*.
ANIMAL/PLANT SPECIES ASSOCIATIONS -
Sea birds
Spotted seal
Ringed seal
Arctic char
Fulmar
Kittiwake
Murre
Guillemot
Narwhal
Belukha whale
Polar bear
Arctic fox
REFERENCES FOR SPECIES ASSOCIATIONS - 232
COMMENTS ON SPECIES ASSOCIATIONS -
Young-of-the-year were found at depths from 20 to 40 m probably in order to
avoid predation by sea birds *232*.
Arctic cod are an important summer food source of spotted seals in the
Chukchi Sea and a fall and winter food of ringed seals in the Beaufort Sea.
Arctic char in the Canning River area of the Beaufort Sea eat juvenile
arctic cod, and arctic char in the Prudhoe Bay area were found with arctic
cod in their stomachs. Fulmars, kittiwakes, murres, guillemots, ringed
seals, and narwhals feed on arctic cod along the ice edges in Baffin Bay
near Greenland. Arctic and saffron cod are probably the most important prey
of belukha whales during autumn and winter in Norton sound and the Chukchi
Sea *232*.
Polar bears, arctic foxes, and the local human population rely on beached
arctic cod as a winter food source *232*.
Habitat Associations - 1 (DRAFT) - Food Habits
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 232
LIFESTAGE FOOD FOOD PART
General Phytoplankton Not Specified
General Zooplankton Not Specified
General Zooplankton Not Specified
General Crustaceans Not Specified
General Osteichthyes Juvenile stage
General Copepods Not Specified
General Malacostraca Not Specified
General See Comments; Food See Comments
REFERENCES FOR GENERAL FOOD - 232
COMMENTS ON FOOD -
The diet of yoy arctic cod consists of phytoplankton and very small or early
stages of zooplankton. After the first summer, phytoplankton are of minor
importance as food, and the older cod prey on zooplankton, substrate and
ice-associated crustaceans, and young fish. Several studies have indicated
that the diet of adult arctic cod may be influenced by the food availability
or the habitat. Arctic cod in offshore waters and near offshore ice edges
eat primarily copepods and some pelagic amphipods. Arctic cod in
nearshore, shallower water habitats feed on benthic or epibenthic mysids,
amphipods, shrimps, and some copepods. Mysids, which are the primary food
in nearshore areas, are nearly absent from the diet of arctic cod in
offshore waters. Arctic cod prefer to eat mysids rather than amphipods when
both are available. Some amphipod species burrow into the substrate, thus
becoming less accessible to arctic cod *232*.
Types of Feeding Areas Used: Arctic cod are often found near the ice edge
where the mass development of phytoplankton and zooplankton occurs. Arctic
cod is the main plankton feeder in this habitat, which has resulted in its
great abundance. The diet of cod in both inshore and offshore waters is
apparently influenced by the presence of ice. Certain copepod, mysid, and
amphipod species are closely associated with the ice undersurface and cod
collected near ice had these species in their stomachs *232*.
Factors Limiting Availability of Food: The diet of arctic cod, especially
in offshore areas, is dominated by copepods and amphipods, which in turn
feed on diatoms. Thus the food available to arctic cod is closely dependent
upon primary production. In polar waters, there is no productivity
throughout most of the year, and an outburst of exceedingly high
productivity occurs in the short summer season. Primary production in
arctic waters is usually limited by available sunlight and, less often, by
the availability of nutrients for phytoplankton *232*.
Food Habits - 1 (DRAFT) - Environment Associations
Species cod, Arctic
Species Id M010591
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
G
L Substrate: Specified in Comments
L Relation to Substrate: Specified in Comments
G
G
G
G Turbidity: Specified in Comments
G
G
G
G Turbidity: Clear water
G Turbidity: Murky water [High turbidity]
J Water Depth Preference: 50-100 ft.
J Water Depth Preference: 100-200 ft.
J Water Depth Preference: 200-500 ft.
J Water Depth Preference: 25-50 ft.
J Water Depth Preference: Specified in Comments
A Water Depth Preference: Specified in Comments
A Water Depth Preference: 500-1000 ft.
A Water Depth Preference: Greater than 1500 ft.
A Water Depth Preference: 1000-1500 ft.
A Water Depth Preference: 50-100 ft.
A Water Temperature: Specified in Comments
A Water Temperature: Below 15 degrees C
G Water Temperature: Specified in Comments
E Water Temperature: Below 15 degrees C
E Water Temperature: Specified in Comments
L Water Temperature: Below 15 degrees C
L Water Temperature: Specified in Comments
G Aquatic Habitat Zonation: Specified in Comments
G Aquatic Habitat Zonation: Open water [pelagic zone]
BA Water Temperature: Specified in Comments
BA Coastal Features: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR ADULT ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 232
Environment Associations - 1 (DRAFT) - Environment Associations
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
REFERENCES FOR JUVENILE ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR LARVAE ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 232
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Water Quality: No information is available on the pH and dissolved oxygen
requirements of arctic cod. Arctic cod occurs in areas between the limits
of pack ice and drift ice in waters that are less saline, with salinities
from 15 to 30 ppt. Arctic cod in Simpson Lagoon, on the Beaufort Sea, were
tolerant of widely ranging salinities and turbidities during the open-water
season. For at least short periods of time, fish were able to cope with
conditions ranging from nearly fresh to salt water (3-28 ppt) and from
clear to very turbid water *232*.
Water Temperature: Adult arctic cod usually inhabit waters with
temperatures of 0 to -1.8 oC. Adult have been found in waters with
temperatures up to 3 or 4 oC. In Simpson Lagoon, in the Beaufort Sea,
arctic cod were found in waters ranging from 0 to 13.5 oC during the
open-water season. Egg development occurs when the water temperature is
less than 0 to 2 oC; larval development and growth occur at 2 to 5 oC; and
fry development and growth occur from 5 to 7 oC and possibly higher *232*.
Substrate and Cover Requirements: Arctic cod are widely assumed to
associate with the ice undersurface; however, they can also occur near the
bottom and in open water. Near the ice edge, the mass development of
phytoplankton and zooplankton occurs, and arctic cod are plankton feeders.
In a study near Greenland, arctic cod were more abundant in areas where the
under-ice surface was rough than in areas where it was smooth; this
difference may be related to the better protection from predators offered
by the rough under-ice areas. Cod captured offshore tend to be smaller and
younger than those taken inshore. At the end of their first summer, larval
cod leave the water column and become associated with a substrate, usually
the ice undersurface *232*.
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
Water Depth: The maximum depths to which adult or subadult arctic cod can
be found are unknown, as is their preferred depth range. The bottom of
shallow seas, such as the northern Bering, Chukchi, and southern Beaufort
seas are within the depth range of arctic cod. The have been collected at
depths of 300 m in the Canadian high arctic, 930 m in Baffin Bay, and 400 m
in the northern Chukchi and Beaufort seas. In Norton Sound and the
southeastern Chukchi Sea, arctic cod were found in high abundance at depths
greater than 20 m *232*.
Water Temperature: Adult arctic cod usually inhabit waters with
temperatures of 0 to -1.8 oC. Adult have been found in waters with
temperatures up to 3 or 4 oC *232*.
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
Reproductive Habitat: Arctic cod move inshore to warmer coastal waters and
mouths of rivers for spawning, often forming large concentrations. Spawning
Environment Associations - 2 (DRAFT) - Environment Associations
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
usually occurs under ice cover. On the basis of their widespread
distribution, arctic cod are assumed to spawn in many areas of the arctic.
The only identified spawning area in the North American arctic is in
Stefansson Sound in the Alaskan Beaufort Sea *232*.
COMMENTS ON JUVENILE ENVIRONMENTAL ASSOC_ -
Water Depth: Young-of-the-year (yoy) arctic cod in the eastern Chukchi Sea
to be much more numerous at depths from 20 to 40 m than they are above
those depths. This depth preference may be in order to avoid predation by
sea birds. The densities of yoy arctic cod were related to season, depth,
year, and location. From June to mid August, arctic cod near Greenland
were most abundant at 10 to 20 m depths and rare at the surface. Densities
decreased below 20 m, and no yoy were caught at depths greater than 250 m.
It appears that yoy are concentrated in the upper 40 to 50 m *232*.
COMMENTS ON LARVAE ENVIRONMENTAL ASSOC_ -
Water Temperature: Larval development and growth occur at 2 to 5 oC *232*.
At the end of their first summer, larval cod leave the water column and
become associated with a substrate, usually the ice undersurface *232*.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
Water Temperature: Egg development occurs when the water temperature is
less than 0 to 2 oC *232*.
Environment Associations - 3 (DRAFT) - Life History
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
LIFE HISTORY
Reproductive Habitat: Arctic cod move inshore to warmer coastal waters and
mouths of rivers for spawning, often forming large concentrations. Spawning
usually occurs under ice cover. On the basis of their widespread
distribution, arctic cod are assumed to spawn in many areas of the arctic.
The only identified spawning area in the North American arctic is in
Stefansson Sound in the Alaskan Beaufort Sea *232*.
Reproductive Seasonality: In Soviet waters, arctic cod spawn from December
through March, mainly in January and February. In coastal waters of the
Beaufort Sea, arctic cod spawn beteeen late November and early February
*232*.
Reproductive Behavior: Arctic cod spawn under the ice, and little
information on spawning areas exists. Spawning behavior has not been
observed *232*.
Age at Sexual Maturity: Arctic cod attain sexual maturity at two to four
years of age according different studies *232*.
Frequency of Breeding: The arctic cod is a relatively small fish that
rarely attains a length of over 300 mm or an age of five years. With a
reported age at maturity of from two to four years, arctic cod would not be
expected to spawn more than several times in their lifetime *232*.
Fecundity: Arctic cod produce the largest and fewest eggs of all species in
the cod family. Fecundity varies from 9,000 to 21,000, with average of
12,000 eggs. The egg diameter ranges from 1.5 to 1.9 mm, and the membrane
is very thin and easily damaged. Fish species in low water temperatures
usually produce large eggs and that a thin membrane is an adaptation to a
calm spawning habitat such as one under ice cover without waves *232*.
Incubation Period: The egg stage of arctic cod lasts from 1.5 to 3 months
and that larvae appear in the sea from May through July. The larval stage
lasts about two months in the Barents and Siberian seas, from June through
July. Transition to the juvenile state occurs at 3 to 5 cm in August *232*.
Movements Associated With Life Functions: Arctic cod make onshore-offshore
migrations, which are associated both with spawning and the movements of
ice. Arctic cod are usually found near the ice edge and descend to greater
depths when the ice melts or breaks and the sea surface temperatures rise.
The migration paths and areas of concentration depend mainly on the
distribution of ice. The circumpolar distribution of arctic cod consists of
separate stocks, which have different feeding and spawning areas and
migration routes. The stock in the Barents Sea, north of Norway, moves
inshore in mass concentrations from June through August. When the water
temperature rises in August and September, the cod move to deeper water.
Prespawning and spawning concentrations form in open northeastern areas of
the Barents Sea from September-October to the end of February of the Barents
Sea from September-October to the end of February. A local stock of arctic
cod in the Laptev Sea, north of Siberia, feeds in the open sea and spends
the winter, probably spawning, in the coastal zone. In the southern Chukchi
Life History - 1 (DRAFT) - Life History
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
and northern Bering seas, the abundance of cod increases in winter and
decreases in summer. In the Beaufort Sea, arctic cod were abundant in the
nearshore waters of Simpson Lagoon in August and September. Some cod
remained in Simpson Lagoon in early winter, but all apparently vacated the
shallow waters by February. The nearby deeper coastal areas of Stefansson
Sound, however, were inhabited by arctic cod throughout the winter. The
distribution and abundance of yoy arctic cod varies annually and
geographically. In spring and most of summer, yoy are planktonic and are
found primarily in surface waters. The planktonic yoy become highly
dispersed and can probably be transported considerable distances from the
spawning areas. In surveys done in Norton Sound and the southeastern
Chukchi Sea, either cold, deep waters or regions north of the Bering Strait
provided the areas of highest density of young fish *232*.
Natural Factors Influencing Populations: Arctic cod are key species in the
arctic marine ecosystem, which channels the energy flow from plankton to
high-level consumers through a few key links. Arctic cod may influence the
distribution and movements of marine mammals and seabirds in arctic waters.
Arctic cod are an important summer food source of spotted seals in the
Chukchi Sea and a fall and winter food of ringed seals in the Beaufort Sea.
Arctic char in the Canning River area of the Beaufort Sea eat juvenile
arctic cod, and arctic char in the Prudhoe Bay area were found with arctic
cod in their stomachs. Fulmars, kittiwakes, murres, guillemots, ringed
seals, and narwhals feed on arctic cod along the ice edges in Baffin Bay
near Greenland. Arctic and saffron cod are probably the most important prey
of belukha whales during autumn and winter in Norton Sound and the Chukchi
Sea. Populations of a small, early maturing, highly fecund species such as
arctic cod may be influenced more strongly by physical factors in the
environment than by predation. In the autumn or winter, when the fish have
moved close to shore along the USSR, they are often washed ashore in great
quantities by gales. On islands and on the coast of the Kara Sea, heaps of
dead arctic cod from 5 to 10 m wide and 3 to 5 m high, extending over tens
of kilometers, accumulate after storms. Polar bears, arctic foxes, and the
local human population rely on beached arctic cod as a winter food source.
Little evidence of the effects of competition on populations of arctic cod
exists. However, in Newfoundland the distribution and diets of arctic cod
and capelin overlap. The recent dramatic increase of arctic cod in that
area could be a response to a large reduction in zooplankton consumption by
capelin in the region that has occurred since 1976 *232*.
Human-related Factors Influencing Populations: Arctic cod eggs are buoyant,
and yoy are planktonic. These characteristics make them vulnerable to
potential toxicants, such as hydrocarbons, formation waters, disinfectants,
algicides, heavy metals, heated waters, drilling muds, and other chemicals
that may be releases during drilling and production. Arctic cod inhabit and
feed at the ice edge where mass plankton blooms occur, and any perturbation
of the ice edge environment could have negative effects on the population.
The habit of arctic cod of using small cracks in the ice could make them
prone to being entrapped where they would be unable to avoid lethal
substances. Some arctic cod spawn in nearshore waters, and the same
spawning areas are used by the cod every year. These regions coincide with
areas delineated for hydrocarbon development, and the potential exists for
disruption of spawning activities through acoustical disturbances, exposure
Life History - 2 (DRAFT) - Life History
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
to contaminants, unnatural ice movements, thicknesses or clearances, and
shock waves due to explosives. A summary of the possible impacts from
human-related activities includes: changes in biological oxygen demand or
nutrient loading; changes in chemical composition of water; changes in
dissolved oxygen, temperature, pH, and salinity; entrapment; changes in
sedimentation rates, turbidity, suspended solids; physical barriers to
movement; shock waves, blasting; and increased susceptibility to harvest or
predation *232*.
LIFE HISTORY CODES -
Breeding/Spawning Season: December
Breeding/Spawning Season: January
Breeding/Spawning Season: February
Breeding/Spawning Season: March
Breeding/Spawning Season: November
Average Number of Offspring/Reproductive Effort: 1,00
Average Number of Offspring/Reproductive Effort: Grea
Gestation/Incubation Period: 1-2 months
Gestation/Incubation Period: 3-4 months
REFERENCES FOR LIFE HISTORY- 232
Life History - 3 (DRAFT) - Management Practices
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Developing/maintaining suitable pH
Beneficial Developing/maintaining suitable salinity
Adverse Salinity alteration
Beneficial Controlling sedimentation
Adverse Migration barriers
Adverse Underwater explosions
Beneficial Regulating harvest of species being described
Adverse Other management practices [specified in comments]
Beneficial Other management practices [specified in comments]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 232
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 232
COMMENTS ON MANAGEMENT PRACTICES -
Arctic cod eggs are buoyant, and yoy are planktonic. These characteristics
make them vulnerable to potential toxicants, such as hydrocarbons, formation
waters, disinfectants, algicides, heavy metals, heated waters, drilling
muds, and other chemicals that may be releases during drilling and
production. Arctic cod inhabit and feed at the ice edge where mass plankton
blooms occur, and any perturbation of the ice edge environment could have
negative effects on the population. The habit of arctic cod of using small
cracks in the ice could make them prone to being entrapped where they would
be unable to avoid lethal substances. Some arctic cod spawn in nearshore
waters, and the same spawning areas are used by the cod every year. These
regions coincide with areas delineated for hydrocarbon development, and the
potential exists for disruption of spawning activities through acoustical
disturbances, exposure to contaminants, unnatural ice movements, thicknesses
or clearances, and shock waves due to explosives. A summary of the possible
impacts from human-related activities includes: changes in biological oxygen
demand or nutrient loading; changes in chemical composition of water;
changes in dissolved oxygen, temperature, pH, and salinity; entrapment;
changes in sedimentation rates, turbidity, suspended solids; physical
barriers to movement; shock waves, blasting; and increased susceptibility to
harvest or predation *232*.
Management Practices - 1 (DRAFT) - References
Species cod, Arctic
Species Id M010591
Date 27 AUG 96
References
232 * State of Alaska Department of Fish, and Game. 1986. Alaska
Habitat Management Guide: Life Histories and Habitat
Requirements of Fish and Wildlife. (ed.). Alaska Department of
Fish and Game Juneau, Alaska:763.
References - 1