Research Document - 2004/049

Determination of Allowable Harm for Spotted (Anarhichas minor) and Northern (Anarhichas denticulatus) Wolffish

By Kulka D. W., and Simpson, M.R.

Abstract

General Prohibitions, Sect. 32 (1) of the Species at Risk Act, specifies that “no person shall kill, harm, harass, capture or take an individual of a wildlife species that is listed as an extirpated species, an endangered species or a threatened species”. However, Sect. 73 (1), also provides for exceptions where: “The competent minister may enter into an agreement with a person, or issue a permit to a person, authorizing the person to engage in an activity affecting a listed wildlife species, any part of its critical habitat or the residences of its individuals” subject to certain condition. Schedule 1 of the Act lists spotted (Anarhichas minor) and northern (A. denticulatus) wolffish as “threatened”. Thus, starting June 1 2004, prohibitions have been placed on the capture of those species. This paper examines conditions that would be required to allow the capture of spotted and northern wolffish without affecting their recovery.

We discuss the efficacy of measures aimed at reducing harm for wolffish species such as live release, spatial/temporal closures and gear restrictions. Due to their widespread distribution, diverse habitat preferences, and lack of particular spawning or feeding aggregations spatial closures are considered to be an ineffective method to reduce wolffish by-catch at this time. As well, since specific information on critical periods in the life history of these species is unknown, the efficacy of temporal closure is also limited. Preliminary studies indicate that a wide variety of gears capture wolffish species and as yet few gear modifications have been identified that effectively exclude wolffish. The exception is the Nordmore grate attached to shrimp trawls that exclude most wolffish (and other fish species) > 15-20 cm. At present, wolffish live-release, which is particularly feasible in fisheries where the gear does not harm wolffish is considered to be the most viable strategy to reduce wolffish mortality with minimal disruption to commercial fishing activities.

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