Research Document - 2010/126

Recent findings on the life history and catches of wolffish (Anarhichas sp.) in research surveys and in the Sentinel Fisheries and Observer Program for the Estuary and Gulf of St-Lawrence

By J.-D. Dutil, S. Proulx, S. Hurtubise, and J. Gauthier

Abstract

The three species of wolffish that inhabit the eastern Canadian Coast are considered as being at risk. Two species are listed as threatened (Anarhichas denticulatus, Anarhichas minor) whereas the third species (Anarhichas lupus) is listed as being of special concern. Since 2000 and 2001 when the status of those species was first assessed, the Department of Fisheries and Oceans has taken steps to facilitate their recovery. From a research and monitoring perspective, concrete actions included collecting more data and better data on which to base conservation measures in the future, as well as supporting research on life history, distribution and habitat associations of all three species. The present report reviews recent projects and publications on wolffish based on material collected in the Estuary and Gulf of St. Lawrence and addressing the following topics: fish species assemblages to which wolffish are associated, use of shelters by juvenile spotted wolffish, diving and towed camera surveys, metabolism, growth and reproductive biology, including new tools for fish identification and critical reviews of fish identifications on research surveys. Catch and effort data were aggregated using a grid made up of 100 km² square cells. The probability of catching wolffish of a given species in a set and within a cell (relative occurrence) was calculated as the ratio of the number of sets in which a species was recorded and the total number of sets made. This method allows the mapping of catch and effort for numerous time series based on data from different programs in both the whole study area (research surveys and Sentinel Fisheries using bottom trawls and a random stratified design) or in specific areas within the Gulf. The method also allows an estimate of surface areas occupied by each species and lends itself to matching area of occupancy and characteristics of the habitat. The data suggest no temporal trend in abundance. Wolffish represent a small biomass compared to other demersal species, with northern wolffish being very rare. The west coast of Newfoundland appears to be a hot spot for the distribution of spotted and striped wolffish in the Gulf.

Complete document (PDF, 2827 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.