Seawolf (fish)
Encyclopedia
The Atlantic wolffish (Anarhichas lupus), also known as the Seawolf, Atlantic catfish, ocean catfish, wolf eel (the common name for its Pacific relative
), or sea cat, is a marine fish, the largest of the wolffish family Anarhichadidae
. They are commonly sighted throughout Asia. The numbers of the Atlantic wolffish are rapidly depleting due to overfishing
and by-catch
, and is currently a Species of Concern
according to the National Oceanic and Atmospheric Administration
's (NOAA) National Marine Fisheries Service
(NMFS). Although it looks fearsome, the Atlantic wolffish is only a threat to humans when defending itself out of the water. Apart from their unique appearance wolffish are distinguished by the natural antifreeze they produce to keep their blood moving fluidly in their very cold habitat, involvement by both the male and female in brood bearing, and the large size of their eggs. They are also an important factor in controlling green crab and sea urchin
populations, which can become overly disruptive to habitats if left unchecked. Wolffish population success is also an important indicator of the health of other bottom dweller populations, such as cod.
). The largest specimen recorded measured 150 cm (almost 5 ft) long and weighed almost 18 kg (40 lbs) Its body is long, subcylindrical in front, compressed in the caudal portion, smooth and slippery, the rudimentary scales being embedded and almost hidden in the skin. Atlantic wolffish vary in color, usually seen as purplish-brown, a dull olive green, or blueish gray. An even dorsal fin extends the whole length of the back, and a similar fin from the vent to the caudal fin, as in blennies. The pectorals are large and rounded and the pelvic fins are entirely absent. Its obtuse eel-like body type makes the fish swim slowly, undulating from side to side, like an eel.
The Atlantic wolffish's distinguishing feature, from which it gets its common name, is its extensive teeth structure. Its dentition (teeth) distinguishes the Atlanitic wolffish from all the other members of the Anarhichadidae family. Both the lower and upper jaw are armed with four to six fang-like, strong conical teeth. Behind the conical teeth in the upper jaw, there are three rows of crushing teeth. The central row has four pairs of molars and the outer rows house blunted conical teeth. The lower jaw has two rows of molars behind the primary conical teeth. The wolffish's throat is also scattered with serrated teeth.
The Atlantic wolffish inhabit both the west and east coasts of the Atlantic. They are seen as far north as the Davis Strait
, of the Canadian territory of Nunavut
, populating the shores of Greenland
and Nova Scotia
, extending down as far as Cape Cod
. Although they are seldom seen south of Cape Cod, there have been sightings in New Jersey
. The most dense populations of wolffish are in Georges Bank
, the Gulf of Maine
and the Great South Channel.
The Atlantic wolffish are primarily stationary fish, rarely moving from their rocky home. They are benthic dwellers, living on the hard ocean floor, frequently seen in nooks and small caves. They like cold water, at depths of 76 to 120 meters (250 to 400 ft). They are usually found in waters of 34-37°F (1-2°C) and sometimes as low as 30°F (-1°C). Since they live in nearly freezing waters, in order to keep their blood moving smoothly, their blood contains a natural antifreeze.
Atlantic wolffish are inhabitants of the northern seas of both east and west hemispheres, being common off the coasts of the Americas
, and also of Scandinavia
, north Britain
, Iceland
, and Greenland
. Two related species occur in the corresponding latitudes of the North Pacific Ocean
. In the north they are esteemed as food, both fresh and preserved. They are marketed in Britain as "Scotch Halibut" and "Scarborough Woof", or, simply "Woof" in other areas of the north-east coast, and are a popular ingredient in fish and chips
. The oil extracted from the liver
is said to be equal in quality to the best cod liver oil
.
In Iceland, the Seawolf is called steinbítur, which literally translates to "stone biter".
), cockle (bivalve)
(Polynices, Chrysodomus and Sipho), sea clams (Mactra
), large hermit crabs, starfish, sea urchins and green crabs (Carcinus maenas
). They are an important predator of sea urchins and green crabs, whose populations escalate rapidly and can negatively effect the health of a marine system.
water, sticking together in loose clumps, surrounded by seaweed and stones. Atlantic wolffish mature relatively late, at age six.
According to data compiled by the National Marine Fisheries Service, since 1983 the landings from U.S. fishing vessels of Atlantic wolffish as by-catch has declined 95% landing 64.7 metric tons (mt) in 2007. In 1950, when the NMFS started collecting their data, 1,098 mt of Atlantic wolffish were landed, worth $137,008. In 1970, 271.2 mt; the landings peaked in 1983 at 1,207 mt, bringing in $455,291; rapidly depleting again and by 1990 the landings were down to 400 mt and by 2002, 154 mt. The last available data from the NMFS was in 2007 at 64.7 mt, worth a total of $100,341.
Currently, the Atlantic wolffish is categorized as a Species of Concern under the National Marine Fisheries Service. Species of Concern are those species about which the U.S. Government’s National Oceanic and Atmospheric Administration, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act(ESA).
On October 1, 2008, the Conservation Law Foundation (CLF), along with Dr. Erica Fuller and Dr. Les Watling, petitioned the US National Marine Fisheries Service for the protection of the Atlantic wolffish under the ESA. The petition called for the protection of the Atlantic wolffish and wolffish habitat throughout the US northwest Atlantic waters. It recommended that there be a designation of critical habitat that closes off both commercial and recreational fishing in those areas (which would overlap closed areas for various other fishing industries for the benefit of fishermen), the development of catch and release protocols, educational programs for fishermen in the Gulf of Maine area, and possession prohibitions. On January 1, 2009 the National Marine Fisheries Service announced a positive 90-day finding that the petition was warranted. This finding triggered the initiation of a status review which will result in a decision on whether to list the species under the ESA. On November 6, 2009, the NMFS issued a finding that proposed protections were not warranted.
Wolf eel
The wolf eel is a member of the family Anarhichadidae together with the wolffishes of the genus Anarhichas. The wolf eel is monotypic within the genus Anarrhichthys. This superficially eel-like fish feeds on crustaceans, sea urchins, mussels, clams and some fishes, crushing them with its strong jaws...
), or sea cat, is a marine fish, the largest of the wolffish family Anarhichadidae
Anarhichadidae
The wolffish are a family, Anarhichadidae, of perciform fish. They are native to cold waters of the northern Atlantic and Pacific Oceans, where they live on the continental shelf and slope, to depths of about . They are bottom-feeders, eating hard-shelled invertebrates such as clams, echinoderms...
. They are commonly sighted throughout Asia. The numbers of the Atlantic wolffish are rapidly depleting due to overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
and by-catch
By-catch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
, and is currently a Species of Concern
Species of Concern
In wildlife conservation, Species of Concern is an informal term, not defined in the federal Endangered Species Act. The term commonly refers to species that are declining or appear to be in need of concentrated conservation actions. Many agencies and organizations maintain lists of these at-risk...
according to the National Oceanic and Atmospheric Administration
National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration , pronounced , like "noah", is a scientific agency within the United States Department of Commerce focused on the conditions of the oceans and the atmosphere...
's (NOAA) National Marine Fisheries Service
National Marine Fisheries Service
The National Marine Fisheries Service is a United States federal agency. A division of the National Oceanic and Atmospheric Administration and the Department of Commerce, NMFS is responsible for the stewardship and management of the nation's living marine resources and their habitat within the...
(NMFS). Although it looks fearsome, the Atlantic wolffish is only a threat to humans when defending itself out of the water. Apart from their unique appearance wolffish are distinguished by the natural antifreeze they produce to keep their blood moving fluidly in their very cold habitat, involvement by both the male and female in brood bearing, and the large size of their eggs. They are also an important factor in controlling green crab and sea urchin
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...
populations, which can become overly disruptive to habitats if left unchecked. Wolffish population success is also an important indicator of the health of other bottom dweller populations, such as cod.
Characteristics
In spite of its large size the Atlantic wolffish has retained the bodily form and general external characteristics of small blennies (BlennioideiBlennioidei
The common name blenny is ambiguous at best, as it has been applied to several families of perciform marine, brackish and some freshwater fishes all sharing similar morphology and behaviour. There are six families considered "true blennies", all grouped together under the suborder Blennioidei; its...
). The largest specimen recorded measured 150 cm (almost 5 ft) long and weighed almost 18 kg (40 lbs) Its body is long, subcylindrical in front, compressed in the caudal portion, smooth and slippery, the rudimentary scales being embedded and almost hidden in the skin. Atlantic wolffish vary in color, usually seen as purplish-brown, a dull olive green, or blueish gray. An even dorsal fin extends the whole length of the back, and a similar fin from the vent to the caudal fin, as in blennies. The pectorals are large and rounded and the pelvic fins are entirely absent. Its obtuse eel-like body type makes the fish swim slowly, undulating from side to side, like an eel.
The Atlantic wolffish's distinguishing feature, from which it gets its common name, is its extensive teeth structure. Its dentition (teeth) distinguishes the Atlanitic wolffish from all the other members of the Anarhichadidae family. Both the lower and upper jaw are armed with four to six fang-like, strong conical teeth. Behind the conical teeth in the upper jaw, there are three rows of crushing teeth. The central row has four pairs of molars and the outer rows house blunted conical teeth. The lower jaw has two rows of molars behind the primary conical teeth. The wolffish's throat is also scattered with serrated teeth.
The Atlantic wolffish inhabit both the west and east coasts of the Atlantic. They are seen as far north as the Davis Strait
Davis Strait
Davis Strait is a northern arm of the Labrador Sea. It lies between mid-western Greenland and Nunavut, Canada's Baffin Island. The strait was named for the English explorer John Davis , who explored the area while seeking a Northwest Passage....
, of the Canadian territory of Nunavut
Nunavut
Nunavut is the largest and newest federal territory of Canada; it was separated officially from the Northwest Territories on April 1, 1999, via the Nunavut Act and the Nunavut Land Claims Agreement Act, though the actual boundaries had been established in 1993...
, populating the shores of Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
and Nova Scotia
Nova Scotia
Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
, extending down as far as Cape Cod
Cape Cod
Cape Cod, often referred to locally as simply the Cape, is a cape in the easternmost portion of the state of Massachusetts, in the Northeastern United States...
. Although they are seldom seen south of Cape Cod, there have been sightings in New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
. The most dense populations of wolffish are in Georges Bank
Georges Bank
Georges Bank is a large elevated area of the sea floor which separates the Gulf of Maine from the Atlantic Ocean and is situated between Cape Cod, Massachusetts and Cape Sable Island, Nova Scotia ....
, the Gulf of Maine
Gulf of Maine
The Gulf of Maine is a large gulf of the Atlantic Ocean on the east coast of North America.It is delineated by Cape Cod at the eastern tip of Massachusetts in the southwest and Cape Sable at the southern tip of Nova Scotia in the northeast. It includes the entire coastlines of the U.S...
and the Great South Channel.
The Atlantic wolffish are primarily stationary fish, rarely moving from their rocky home. They are benthic dwellers, living on the hard ocean floor, frequently seen in nooks and small caves. They like cold water, at depths of 76 to 120 meters (250 to 400 ft). They are usually found in waters of 34-37°F (1-2°C) and sometimes as low as 30°F (-1°C). Since they live in nearly freezing waters, in order to keep their blood moving smoothly, their blood contains a natural antifreeze.
Atlantic wolffish are inhabitants of the northern seas of both east and west hemispheres, being common off the coasts of the Americas
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
, and also of Scandinavia
Scandinavia
Scandinavia is a cultural, historical and ethno-linguistic region in northern Europe that includes the three kingdoms of Denmark, Norway and Sweden, characterized by their common ethno-cultural heritage and language. Modern Norway and Sweden proper are situated on the Scandinavian Peninsula,...
, north Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...
, and Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...
. Two related species occur in the corresponding latitudes of the North Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. In the north they are esteemed as food, both fresh and preserved. They are marketed in Britain as "Scotch Halibut" and "Scarborough Woof", or, simply "Woof" in other areas of the north-east coast, and are a popular ingredient in fish and chips
Fish and chips
Fish and chips is a popular take-away food in the United Kingdom, Australia, New Zealand and Canada...
. The oil extracted from the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
is said to be equal in quality to the best cod liver oil
Cod liver oil
Cod liver oil is a nutritional supplement derived from liver of cod fish. It has high levels of the omega-3 fatty acids, EPA and DHA, and very high levels of vitamin A and vitamin D. It is widely taken to ease the symptoms of arthritis and for other health benefits...
.
In Iceland, the Seawolf is called steinbítur, which literally translates to "stone biter".
Diet
Atlantic wolffish use their strong jaws to eat hardshell mollusks, crustaceans, and echinoderms. They do not eat other fish. They are known to frequently eat large welks (BuccinumBuccinum
Buccinum is a genus of medium-sized sea snails with an operculum, marine gastropod mollusks in the family Buccinidae, the true whelks.Snails in this genus are commonly called whelks, a name that is however shared with several related and unrelated species...
), cockle (bivalve)
Cockle (bivalve)
Cockle is the common name for a group of small, edible, saltwater clams, marine bivalve molluscs in the family Cardiidae.Various species of cockles live in sandy sheltered beaches throughout the world....
(Polynices, Chrysodomus and Sipho), sea clams (Mactra
Mactra
Mactra is a genus of medium-sized marine bivalve mollusks or clams, commonly known as trough shells or duck clams. Mactra is the type genus within the family Mactridae....
), large hermit crabs, starfish, sea urchins and green crabs (Carcinus maenas
Carcinus maenas
Carcinus maenas is a common littoral crab, and an important invasive species, listed among the 100 "world's worst alien invasive species". It is native to the north-east Atlantic Ocean and Baltic Sea, but has colonised similar habitats in Australia, South Africa, South America and both Atlantic and...
). They are an important predator of sea urchins and green crabs, whose populations escalate rapidly and can negatively effect the health of a marine system.
Reproduction
The manner of which Atlantic wolffish fertilize their eggs distinguishes them from many fish. Instead of the female depositing her eggs in the open ocean for the male fish to fertilize and then continue on his way, they are internally fertilized and the male wolffish stays with the nest and protects the eggs for as long as four months, until the brood is strong enough to gain independence. Their eggs are 5.5–6 mm in diameter, (among the largest fish eggs known), yellow tinted and opaque. The eggs are laid on the ocean floor, many times in shoalShoal
Shoal, shoals or shoaling may mean:* Shoal, a sandbank or reef creating shallow water, especially where it forms a hazard to shipping* Shoal draught , of a boat with shallow draught which can pass over some shoals: see Draft...
water, sticking together in loose clumps, surrounded by seaweed and stones. Atlantic wolffish mature relatively late, at age six.
Conservation status
According to scientific data, the Atlantic wolffish's population has decreased drastically due to overfishing and by-catch. Bottom trawling vessels also disrupt the wolffish's rocky underwater habitat when they drag large nets across the ocean floor, with heavy weights holding the nets to the ocean bottom. The nets are indiscriminate in what they catch and the heavy weights and nets are harmful to the benthic terrain and its inhabitants. Recreational fishing has also threatened the survival of the Atlantic wolffish.According to data compiled by the National Marine Fisheries Service, since 1983 the landings from U.S. fishing vessels of Atlantic wolffish as by-catch has declined 95% landing 64.7 metric tons (mt) in 2007. In 1950, when the NMFS started collecting their data, 1,098 mt of Atlantic wolffish were landed, worth $137,008. In 1970, 271.2 mt; the landings peaked in 1983 at 1,207 mt, bringing in $455,291; rapidly depleting again and by 1990 the landings were down to 400 mt and by 2002, 154 mt. The last available data from the NMFS was in 2007 at 64.7 mt, worth a total of $100,341.
Currently, the Atlantic wolffish is categorized as a Species of Concern under the National Marine Fisheries Service. Species of Concern are those species about which the U.S. Government’s National Oceanic and Atmospheric Administration, National Marine Fisheries Service, has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the U.S. Endangered Species Act(ESA).
On October 1, 2008, the Conservation Law Foundation (CLF), along with Dr. Erica Fuller and Dr. Les Watling, petitioned the US National Marine Fisheries Service for the protection of the Atlantic wolffish under the ESA. The petition called for the protection of the Atlantic wolffish and wolffish habitat throughout the US northwest Atlantic waters. It recommended that there be a designation of critical habitat that closes off both commercial and recreational fishing in those areas (which would overlap closed areas for various other fishing industries for the benefit of fishermen), the development of catch and release protocols, educational programs for fishermen in the Gulf of Maine area, and possession prohibitions. On January 1, 2009 the National Marine Fisheries Service announced a positive 90-day finding that the petition was warranted. This finding triggered the initiation of a status review which will result in a decision on whether to list the species under the ESA. On November 6, 2009, the NMFS issued a finding that proposed protections were not warranted.
External links
- NMFS Landing Query Results of Atlantic Wolffish from 1950-2007
- NMFS Species of Concern: Altantic Wolffish
- Petition for ESA Ruling of the Atlantic Wolffish
- Summary of Petition by CLF, Fuller and Watling
- CLF Fact Sheet on Altantic Wolffish
- CLF Atlantic Wolffish
- Conservation Law Foundation
- Map of Density of Wolffish in Gulf of Maine Region and Georges Bank Area
- Associated Press Petition Coverage
- Boston Globe's Press on Petition
- Distribution, Biology and Management.
- General information on the Atlantic Wolffish
- Atlantic wolffish devouring a crab.
- Atlantic wolffish eating a sea urchin
- Atlantic Wolffish pair
- Britains ugliest fish
