The Northern Wolffish . . . a Species at Risk in the North

This species has been identified as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). It is listed under the federal Species at Risk Act (SARA) and was afforded protection under the SARA as of June 2004. Additional protection is afforded through the federal Fisheries Act. Under the SARA, a recovery strategy must be developed for this species.

General Description

Anarhichas denticulatus

© Fisheries & Oceans Canada

Northern Wolffish (Anarhichas denticulatus) are large marine fishes from the Anarhichadidae family. Other common names include the Bull-headed Catfish, Blue Catfish, Broad-headed Catfish, Jelly Wolffish and the Arctic Wolffish. Inuit in the Western Arctic (Bathurst Inlet) do not distinguish between the Northern Wolffish and the Bering Wolffish (A. orientalis), calling both by the name akoak or akoaksaluk (old woman fish). Northern Wolffish have the following characteristics:

• Prominent canine-like teeth in the front of the jaws
• Heavy head with a pointed snout and small eyes
• Long, stout body with no pelvic fins
• Dorsal fin long and extending to base of caudal, with flexible spiny rays
• Caudal fin small and truncated
• Pectoral fins moderately large and fan-like
• Soft, jelly-like musculature
• Grey to deep brown in colour with a violet sheen and indistinct dark spots, which may not be clearly defined and may form a weak bar
• Typically greater than 0.8 m in length (can reach nearly 1.5 m) and weigh 13.5 kg (up to 20 kg)

Distribution

In the Arctic, Northern Wolffish occur primarily in Davis Strait with their northernmost limit in Baffin Bay. There are a few records in the western Arctic including as far west as Prince Patrick Island, NWT. In the North Atlantic, Northern Wolffish are found on both sides of the Ocean, from southern Newfoundland to the Barents Sea. In Canada, it occurs primarily off northeast Newfoundland/Labrador Shelf and the outer Grand Banks.

Northern Wolffish Distribution in Arctic Canada

Permission provided by B.W. Coad (CMN) and J.D. Reist (DFO); prepared by N. Alfonso (CMN).

Habitat and Life History

Northern Wolffish are found offshore in cold water (below 5^oC) at depths ranging between the surface and 1200 m, but most often below 150 m. This fish inhabits a wide range of bottom types including silt, rocky, coarse sand and shell hash. They use large rocks for shelter and nest building. Late in the year, females lay approximately 46,500 large eggs (up to 8 mm in diameter) which sink to the sea floor where they are guarded in nests by the males until they hatch. Growth rates are slow and fish become mature at five years or older. Its lifespan is at least 12 years. Unlike other Wolffishes, the Northern has been found off the bottom during both the juvenile and adult stages. The species does not form large schools or undertake long migrations.

Diet

This fish feeds in open water on comb jellies and jellyfish, and on bottom-living crustaceans and invertebrates such as crabs, sea urchins, brittle stars and starfish.

Threats

There are no direct studies of factors responsible for the observed declines in abundance but it is believed that overfishing and habitat alteration have played a role. This fish species is not targeted by the fishing industry, however, by-catch mortality by offshore trawlers and long-liners is considered a threat. In addition, activities that disturb the ocean bottom, such as trawling, may damage spawning habitat.

Similar Species

The Northern Wolffish can be distinguished from the Spotted Wolffish (A. minor) and the Atlantic Wolffish (A. lupus) by its more uniform body colour and its soft jelly-like musculature. Its head is also proportionally larger to its body and its upper lip is thick and covered with papillae.

Text Sources: Scott and Scott 1988; Quinn 2002 (COSEWIC Status Report); Stock Status Report 2004/031 2003.

For more information, visit the SARA Registry Website at www.SARAregistry.gc.ca.