Northern Wolffish

Northern Wolffish (retrieved from:
http://www.sararegistry.gc.ca/images/photos/spp667p1.jpg)

The Northern Wolffish (Anarhichas denticulatus) is a large marine fish which resides in fairly deep waters within many locations around the world including off the Northeast coast of Newfoundland and Labrador. It utilizes benthic crustaceans and invertebrates, such as sea urchins, as a food source. In 2001, this particular species of wolffish was listed as threatened by COSEWIC (Committee on the Status of Endangered Wildlife in Canada) as well as threatened by SARA (Species at Risk Act). Why has this species been listed as threatened by two different conservation groups within Canada?

COSEWIC currently has the following reason listed for its designation as:

"Numbers of this large, slow-growing, long-lived, solitary, nest-building fish have declined over 95% in three generations, and the number of locations where the fish is found has decreased." (COSEWIC, 2001).

Catch occurrences of Wolffish within Eastern Canada
1975-1994 (retrieved from: http://www.sararegistry.gc.ca/
virtual_sara/files/cosewic/sr%5Fnorthern%5Fwolffish%
5F0501%5Fe%2Epdf)

The Northern Wolffish does not have a direct fishery and it's numbers have been drastically decreasing over a short period of time. The reason behind this decline is due mainly to two different factors: by-catch and habitat alteration by bottom trawling. This particular fish have been found inside lobster pots, feeding on crabs, lobsters & bait and then get pulled up by fisherman. It is not the most popular species among crab and lobster fishermen, so most fisherman do not care if the fish gets released safely or not. Bottom trawling is also another way in which the Northern Wolffish numbers have been declining. Whether it be them getting trapped within the nets, destroying their habitat, diminishing food supplies or destroying eggs which the wolffish has reproduced, the bottom trawling performed are reducing numbers drastically.

Due to the fact of there not being a direct fishery for the Northern Wolffish, it is very hard to help with recovery of the species (eg. catch limits). The IUCN (International Union for the Conservation of Nature) has not evaluated this species as of yet but under it's criteria, which states:

"The Northern Wolffish, with its 98% decline rate, would fall in the category of Critically Endangered, defined as a population decline rate at least 80% in 10 years or 3 generations." (IUCN, 2001).

There is currently a management plan (recovery strategy) underway to help improve the numbers of the Northern Wolffish within Atlantic Canada. This recovery plan has five main objectives in order to achieve this goal:

1. Enhance understanding of the life history of the wolffish
2. Identify, protect and conserve current wolffish habitats
3. Minimize human impacts
4. Promote growth and recovery
5. Educate the public

Through these five objectives, SARA is hoping to increase population numbers dramatically. This is not only for the sake of the wolffish but for the sake of other organisms within the sea. Wolffish feed upon sea urchins as a main source of prey which helps to control sea urchin numbers. In the recent past with the decreasing wolffish numbers, sea urchin numbers have been on the rise due to a lack of predation. These sea urchins will graze almost every and any habitat available, ultimately wiping it out. Wolffish are a necessary species to help control the sea urchins within these areas.

References:

COSEWIC 2001. COSEWIC assessment and status report on the northern wolffish Anarhichas denticulatus in Canada. Commitee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 21 pp. (www.sararegistry.gc.ca/status/status_e.cfm)

Kulka, D., C. Hood and J. Huntington. 2007. Recovery Strategy for Northern Wolffish (Anarhichas denticulatus) and Spotted Wolffish (Anarhichas minor) and Management Plan for the Atlantic Wolffish (Anarhichas lupus) in Canada. Fisheries and Oceans Canada: Newfoundland and Labrador Region. St. John's, NL. x + 103 pp.