(DRAFT) - Taxonomy
Species halibut, Greenland
Species Id M010086
Date 27 AUG 96
TAXONOMY
NAME - halibut, Greenland
OTHER COMMON NAMES - Greenland turbot, Newfoundland turbot, Turbot, Black halibut, Blue hailbut, Lesser halibut, Mock halibut, Bastard halibut and Fr: Fletan du Groenland
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - ,
CLASS AND SUBCLASS - Osteichthyes,
ORDER AND SUBORDER - Pleuronectiformes,
FAMILY AND SUBFAMILY - Pleuronectidae,
GENUS AND SUBGENUS - Reinhardtius,
SPECIES AND SSP - hippoglossoides,
SCIENTIFIC NAME - Reinhardtius hippoglossoides
AUTHORITY - Walbaum,1792
TAXONOMY REFERENCES - 258
COMMENTS ON TAXONOMY -
Greenland halibut from the northwest Atlantic, Gulf of St. Lawrence, and
Bering Sea have been analyzed electrophoretically to determine the level of
genetic differentiation. The degree of divergence between the Atlantic
Ocean and Bering Sea stocks was considered to be at a subspecific level
*258*.
Taxonomy - 1 (DRAFT) - Status
Species halibut, Greenland
Species Id M010086
Date 27 AUG 96
STATUS
Coded Status
Migrant
Commercial/consumption
See Comments
REFERENCES FOR STATUS - 258
COMMENTS ON STATUS -
Greenland halibut make a general movement to spawning grounds beginning
about September, and to return to summer feeding grounds after spawning
*258*.
The Greenland halibut has been exploited commercially by Newfoundland
fishermen at least since 1857. Longlines (hooks) were used until about the
1960s when they were replaced by nylon gill nets. It is also caught by
otter trawls, often as a by-catch when seeking redfish (Sebastes spp.)
*258*.
The various regional fisheries - Baffin Island/West Greenland, Labrador/East
Newfoundland - have been under quota regulations since 1974. The total
allowable catch (TAC) in these fisheries in 1986 by all countries was 25,000
t and 100,000 t respectively, with a 5000 t TAC placed on the Gulf of St.
Lawrence stock in recent years. These constitute the three management units
for regulation of Canadian fishery. Less than 10,000 t are taken annually
by foreign fleets (mainly Poland, German Democratic Republic, USSR, and
Japan) *258*.
In 1968, when a controversy arose over the use of the name Greenland halibut
sparked by Pacific halibut producers and processors, the American Fisheries
Society was asked to eliminate the word 'halibut' from the name. However,
because the name was deeply entrenched in the language, and used in a
variety of annual reports and bulletins issued by many international
commissions, including the Food and Agriculture Organization of the United
Nations, the Greenland halibut was retained in the List of Common and
Scientific Names of Fishes, published by the society in 1970 and 1980.
However, Greenland halibut exported from Canada to United States markets
must now be labeled 'Greenland turbot.' *258*.
The Greenland halibut is a relatively fat fish with a rich flavor.
Traditionally it was salted for local use and export. It is now processed
and sold mainly as fresh-frozen fillets. An attractive smoked product is
produced by West Germany *258*.
Status - 1 (DRAFT) - Distribution
Species halibut, Greenland
Species Id M010086
Date 27 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - MARINE
REFERENCES FOR HABITAT - 258
LAND USE -
Water
REFERENCES FOR LAND USE - 258
COMMENTS ON HABITAT ASSOCIATIONS -
A deepwater species occurring on bottom at temperatures of -0.5 oC to about
6.0 oC; usually more abundant at temperatures of 0.0-4.5 oC. Such
temperatures may occur at considerable depths or higher latitudes. In the
northwest Atlantic, off northern Newfoundland - southern Labrador,
Greenland halibut are usually taken in depths in excess of 457m. Total
depth range 90-1600 m. Larger fish are usually caught at greater depths,
to 1600 m. Tagging experiments have shown that Greenland halibut may move
considerable distances. Some tagged off White Bay, NFLD, were recaptured
off northern Labrador, Baffin Island, and west Greenland. But tag returns
are genearally poor. Tagging experiments off Iceland have shown a tendency
for fish to remain near the site of release during summer, then to make a
general movement to spawning grounds beginning about September, and to
return to summer feeding grounds after spawning *258*.
Unlike to most flatfishes, the Greenland halibut apparently spends much
time off bottom, behaving pelagically *258*.
ANIMAL/PLANT SPECIES ASSOCIATIONS -
Greenland shark
White whales
Narwhals
Hooded seals
Cod
Salmon
Greenland halibut
Trematode (Brachyphallus crenatus)
Trematode (Derogenes varicus)
Trematode (Fellidostomum furcigerum)
Nematode - 1 sp.
REFERENCES FOR SPECIES ASSOCIATIONS - 258
COMMENTS ON SPECIES ASSOCIATIONS -
Predation and Competition: The Greenland halibut seems to have many
enemies. The Greenland shark is considered the most important predator but
white whales, narwhals, and hooded seals also prey upon them. Among the
fishes, cod, salmon, and even Greenland halibut consume the youne *258*.
Parasites and Disease: The parasites of the Greenland halibut appear to
have received little attention. A study listed three species of trematodes
(Brachyphallus crenatus, Derogenes varicus, Fellidostomum furcigerum) and
one nematode, unspecified. The incidence of blood parasites in many of the
specimens examined from the Labrador-Newfoundland area was noted *258*.
Habitat Associations - 1 (DRAFT) - Food Habits
Species halibut, Greenland
Species Id M010086
Date 27 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 258
LIFESTAGE FOOD FOOD PART
General Salmoniformes Not Specified
General Gadiformes Not Specified
General Perciformes Not Specified
General Myctophiformes Not Specified
General Pleuronectiformes Juvenile stage
General Crustaceans Not Specified
General Squid, Octopus Not Specified
General Benthos Not Specified
General Osteichthyes Not Specified
REFERENCES FOR GENERAL FOOD - 258
COMMENTS ON FOOD -
The Greenland halibut is a voracious, bathypelagic predator, feeding on a
great variety of other organisms. The position of the left eye on top of
the head and the elongate muscular body enable it to feed successfully off
bottom. Summer and autumn appear to be seasons of heaviest feeding. Large
fish in deep water eat larger prey than do smaller fish in shallower water.
Major species eaten include capelin, Atlantic cod, polar cod, young
Greenland halibut, roundnose grenadier, barracudinas, redfishes, sand lance,
crustaceans, especially Pandalus borealis, and cephalopods (squid); small
amounts of many species of benthic invertebrates are also eaten *258*.
Food Habits - 1 (DRAFT) - Environment Associations
Species halibut, Greenland
Species Id M010086
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 Water Temperature: Below 15 degrees C
G Water Temperature: Specified in Comments
G Water Depth Preference: 500-1000 ft.
G Water Depth Preference: 200-500 ft.
G Water Depth Preference: Greater than 1500 ft.
G Water Depth Preference: Specified in Comments
BA Water Depth Preference: Greater than 1500 ft.
BA Water Depth Preference: Specified in Comments
BA Water Temperature: Below 15 degrees C
BA Water Temperature: Specified in Comments
E Water Temperature: Below 15 degrees C
E Water Temperature: Specified in Comments
L Water Depth Preference: 500-1000 ft.
L Water Depth Preference: Specified in Comments
L Aquatic Habitat Zonation: Open water [pelagic zone]
L Aquatic Habitat Zonation: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 258
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 258
REFERENCES FOR LARVAE ENVIRONMENTAL ASSOC_ - 258
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 258
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
A deepwater species occurring on bottom at temperatures of -0.5 oC to about
6.0 oC; usually more abundant at temperatures of 0.0-4.5 oC. Such
temperatures may occur at considerable depths or higher latitudes. In the
northwest Atlantic, off northern Newfoundland - southern Labrador,
Greenland halibut are usually taken in depths in excess of 457m. Total
depth range 90-1600 m. Larger fish are usually caught at greater depths,
to 1600 m. Tagging experiments have shown that Greenland halibut may move
considerable distances. Some tagged off White Bay, NFLD, were recaptured
off northern Labrador, Baffin Island, and west Greenland. But tag returns
are genearally poor. Tagging experiments off Iceland have shown a tendency
for fish to remain near the site of release during summer, then to make a
general movement to spawning grounds beginning about September, and to
return to summer feeding grounds after spawning *258*.
Environment Associations - 1 (DRAFT) - Environment Associations
Species halibut, Greenland
Species Id M010086
Date 27 AUG 96
Unlike to most flatfishes, the Greenland halibut apparently spends much
time off bottom, behaving pelagically *258*.
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
Spawning is believed to occur in Davis Strait in winter or early spring at
depths of 650-1000m depending on location. North of the Baffin-Greenland
Rise in Davis Strait spawning probably occurs in depths approaching 1000 m
at temperatures of 0 oC or less. South of the Rise, it probably occurs at
depths of about 650 m and at temperatures of 3-4 oC *258*.
COMMENTS ON LARVAE ENVIRONMENTAL ASSOC_ -
During this pelagic phase, living at depths to 250 m, the young are
drifted by the currents in Davis Strait *258*.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
Such details as time to hatching are not known but the temperatures during
incubation probably approximate the temperatures during spawning, i.e., 0
oC or slightly less and 3-4 oC depending on locality *258*.
Environment Associations - 2 (DRAFT) - Life History
Species halibut, Greenland
Species Id M010086
Date 27 AUG 96
LIFE HISTORY
Reproduction: Spawning is believed to occur in Davis Strait in winter or
early spring at depths of 650-1000m depending on location. North of the
Baffin-Greenland Rise in Davis Strait spawning probably occurs in depths
approaching 1000 m at temperatures of 0 oC or less. South of the Rise, it
probably occurs at depths of about 650 m and at temperatures of 3-4 oC.
Potential spawners are considered to move or migrate northward to Davis
Strait region to reproduce, but not to make a return journey. This view is
based on tagging and experimental fishing. Spawning is also thought to occur
in the Laurentian Channel, Gulf of St. Lawrence, during winter *258*.
Greenland halibut may produce 30,000 to 300,000 eggs per female. The number
of eggs is correlated with the length of the female; longer females produce
more eggs. Egg production or fecundity has been studied, but such studies
are difficult because of the great depths and northern location of the
spawners *258*.
Fertilized eggs are clear, large, 4.0-4.5 mm in diameter. Soon after
hatching the young rise to about 30 m below the surface where they live
until about 70 mm long. Such details as time to hatching are not known but
the temperatures during incubation probably approximate the temperatures
during spawning, i.e., 0 oC or slightly less and 3-4 oC depending on
locality. During this pelagic phase, living at depths to 250 m, the young
are drifted by the currents in Davis Strait. Eventually they are carried
southward to the continental shelf and slopes of Labrador and Newfoundland.
They descend to greater depths but do not become as closely associated with
bottom living as do most flatfishes *258*.
Growth: The life history of the Greenland halibut, including aspects of
reproduction and growth, presents unresolved problems, many of which have
been discussed in a study. In it, it studied age and growth from seven
regions off the Canadian east coast from the Gulf of St. Lawrence and the
Grand Bank on the south, northward to Baffin Bank. Age composition varied in
all regions but older fish were more abundant in northern deep waters. Large
numbers of young were found in the Baffin Bank region, suggesting it may be
a nursery area *258*.
In general, males and females grow at about the same rate for the first 5-7
years, until reaching a length of about 45 cm, but the age and size varies
for each region. From then on females grow faster and live longer than
males. On the northern Grand Bank 5-yr-olds average about 40 cm long,
8-yr-olds about 50 cm, 10-yr-olds females 70 cm, and 10-yr-olds males 60 cm.
Males grow to 70-80 cm and age 12-14 yr, but all fish over 90 cm are
females. A study records females off Labrador and northward to lengths of
110 cm and 19 yr old, but large older fish are difficult to age *258*.
Age determinations are made by otolith examination, preferably the saccular
otolith *258*.
Description: Body elongate, moderately laterally compressed, both sides
equally muscular. Head large; mouth large, strong conical teeth in jaws, 2
strong canines in upper jaw, lower jaw obviously projecting; eyes large,
Life History - 1 (DRAFT) - Life History
Species halibut, Greenland
Species Id M010086
Date 27 AUG 96
widely spaced, left eye on edge of forehead, on right side. Gill rakers
short, stout, 10-12 on lower arm of anterior arch. Branchiostegals 7. Fins:
soft rayed; dorsal 92-102, beginning slightly behind left eye and extending
to caudal peduncle; caudal emarginate to square, not rounded; anal 71-76;
pelvics smaller than pectorals; pectorals 13-15 (on eyed side). Scales
small, cycloid. Lateral line straight, about 110 pores. Vertebrae 59-64.
Size to a maximum of 25 kg and 120 cm long. Color: eyed side usually very
dark, black, sometimes very dark brown; blind side white in young but gray
to dark gray in adults *258*.
Predation and Competition: The Greenland halibut seems to have many
enemies. The Greenland shark is considered the most important predator but
white whales, narwhals, and hooded seals also prey upon them. Among the
fishes, cod, salmon, and even Greenland halibut consume the young *258*.
Parasites and Disease: The parasites of the Greenland halibut appear to
have received little attention. A study listed three species of trematodes
(Brachyphallus crenatus, Derogenes varicus, Fellidostomum furcigerum) and
one nematode, unspecified. The incidence of blood parasites in many of the
specimens examined from the Labrador-Newfoundland area was noted *258*.
Summer and autumn appear to be seasons of heaviest feeding *258*.
LIFE HISTORY CODES -
Breeding/Spawning Season: December
Breeding/Spawning Season: January
Breeding/Spawning Season: February
Breeding/Spawning Season: March
Breeding Spawning Season: April
Average Number of Offspring/Reproductive Effort: Grea
Periodicity: Most active in late summer
Periodicity: Most active in fall
REFERENCES FOR LIFE HISTORY- 258
Life History - 2 (DRAFT) - Management Practices
Species halibut, Greenland
Species Id M010086
Date 27 AUG 96
MANAGEMENT PRACTICES
Management Practices - 1 (DRAFT) - References
Species halibut, Greenland
Species Id M010086
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