Science Advisory Report 2018/053
Stock Assessment of Witch Flounder (Glyptocephalus cynoglossus) in NAFO Divisions 2J3KL
- This stock has been under moratorium in Canadian waters since 1995, and in the NAFO regulatory area since 1998. Bycatch of Witch Flounder has been relatively stable, averaging 174 t annually from 2013-17, primarily taken in the Canadian Greenland Halibut fishery.
- This stock is assessed using fall DFO research vessel (RV) survey indices. In 2016 and 2017, indices of abundance and biomass reached the highest levels since 1990, but remained below the levels of the mid-1980s.
- The abundance index of fish <23 cm indicate improved recruitment since 2013.
- Following a contraction of the stock to shelf slope areas through the 1990s, the distribution of the stock has expanded in recent years, returning to deep channels occupied in the mid‑1980s.
- A proxy for BMSY was accepted as the mean of the survey biomass indices from the 1983-84 fall RV surveys. Consistent with the DFO decision-making framework incorporating the precautionary approach, a Limit Reference Point (LRP) of 40% BMSY was adopted. The stock is currently in the critical zone.
- A variable proportion of the population inhabits the deep water of Div. 3L which has only been surveyed in 3 of the last 10 years. In years with incomplete coverage the survey index may underestimate stock size. The magnitude of this cannot be determined, but is not considered to impact stock status relative to the LRP.
This Science Advisory Report is from the May 9, 2018 2J3KL Witch Flounder Stock Assessment. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.
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