Science Response 2021/027

Update of the Status of Cusk (Brosme brosme) in NAFO Divisions 4VWX5Z for 2020

Context

Cusk (Brosme brosme) is caught as bycatch in certain directed fisheries. Most landings are in the groundfish longline fisheries. Commercial catch rates for Cusk declined after the 1980s. Changes to management measures (e.g., reductions to trip limits, overall caps, and bycatch percentages) may have contributed to this reduction in catch rates (and landings); however, it is thought the decline in Catch Per Unit Effort (CPUE) is also due to a decline in Cusk abundance (Harris and Hanke 2010). The extent of the decline in abundance is not known.

The Industry-Fisheries and Oceans Canada (DFO) Halibut Fixed Station Longline Survey (Halibut Survey) catch per station has been accepted as the ongoing index for monitoring Cusk biomass. The Upper Stock Reference (USR) and Limit Reference Point (LRP) for Cusk were set at 26.6 kg and 13.3 kg per 1000 hooks, respectively (Harris et al. 2012). The 3-year geometric mean of the biomass index was accepted as the metric for monitoring Cusk status relative to the USR and LRP. Cusk biomass has remained above the LRP since 2008 (DFO 2014).

Cusk was assessed as threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) in 2003 and later reassessed as endangered (COSEWIC 2012). In 2013, the Governor in Council decided not to add Cusk to the List of Wildlife Species at Risk set out in Schedule 1 of the Species at Risk Act (SARA; Minister of Justice, Canada 2013).

DFO’s Resource Management Sector asked Science to determine what the 3-year geometric mean of the Cusk index is from the Halibut Survey relative to the USR and the LRP. The information will be used by DFO Resource Management as guidance in discussions with various industry stakeholders on recommendations for management measures.

The current 3-year geometric mean (2018–2020) of the Cusk biomass index remains above the LRP at 15.7 kg.

This Science Response Report results from the Regional Science Response Process of December 1-2, 2020, on the Stock Status Updates of Groundfish Stocks in the Maritimes Region.

Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

Science Response 2021/027 (PDF, 313 KB)

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