Assessment of Atlantic Wolffish (Anarhichas lupus) population trends on the Scotian Shelf

Abstract

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assessed the status of Atlantic Wolffish (Anarhichas lupus) as special concern in 2000. The Atlantic Wolffish was added to Schedule 1 of the Species at Risk Act in 2003. COSEWIC re-evaluated the status in 2012 and determined its status to remain as special concern. As the department responsible for the management of aquatic species at risk, Fisheries and Oceans Canada (DFO) undertook this assessment to examine recent trends in abundance and distribution of the portion of the Atlantic Wolffish population residing on the Scotian Shelf using data from DFO Research Vessel (RV) and industry surveys, commercial landings, at-sea commercial fishing observations and Species at Risk Act (SARA) logbooks. Based on the available data, the decrease in abundance of Atlantic Wolffish on the Scotian Shelf reported in the 2012 assessment has persisted over the last decade. Atlantic Wolffish are concentrated on the eastern Scotian Shelf (North Atlantic Fishery Organization [NAFO] Divisions 4VW), the western Scotian Shelf (Division 4X) around Browns Bank and west of German Bank, as well as isolated areas inshore of the 50-fathom line in Divisions 4WX, which have limited sampling. Both immature and mature abundance has declined since 1970. On the northeast peak of Georges Bank (Division 5Z), there is a small aggregation of Atlantic Wolffish that has declined > 90% since 1986, and remains very low today. Although there are no directed fisheries for Atlantic Wolffish in the Maritimes Region, the species is caught as bycatch in other fisheries. Annual landings of wolffish in 5Z and 4VW have been near 4 t since the 1990s; landings in 4X decreased rapidly in the early 2000s, and have remained below 10 t over the past decade. Atlantic Wolffish discards are observed in multiple fisheries; however, estimates of total discards were not determined. The levels of fishing removals from various fisheries are, therefore, not known. The Maritimes Region Ecosystem Summer RV survey has the longest time series and most comprehensive coverage of the Scotian Shelf, making it the primary source to monitor abundance trends and to inform management actions for the species.