Science Advisory Report 2020/019

Redfish (Sebastes mentella and S. fasciatus) Stocks Assessment in Units 1 and 2 in 2019

Summary

• During the ongoing 2019-2020 fishery management year (preliminary data as of December 2019), Redfish landings reached 592 t in Unit 1 under the combined TAC for the index fishery (2,000 t) and the experimental fishery (3,950 t).
• From 2017 to 2019, the Unit 1 index fishery catch-per-unit-effort (CPUE) increased by a factor of 6.7, reaching the highest value since 1980.
• Bycatch represented 9% of total landings in the Redfish index and experimental fisheries in Unit 1 from 2000 to 2019. The main bycatch species were Greenland Halibut, White Hake, Atlantic Cod, and Atlantic Halibut. Forecasted increase in Redfish fishing effort could increase the incidental catch of several species, including some depleted species.
• Based on historical knowledge and preliminary analysis, bycatch and undersized Redfish catches could be mitigated by modifying fishing gear, fishing deeper than 300 m, and avoiding fishing during winter in the Laurentian Channel. However, reducing bycatch of multiple species could be challenging.
• Total minimum research survey trawlable biomass of S. mentella in 2019 was estimated at 4,365,000 t, the highest value observed in the time series (since 1984). Of that amount, 3,044,000 t were for fish larger than 22 cm (minimum regulatory size) and 497,000 t for fish larger than 25 cm.
• Total minimum research survey trawlable biomass of S. fasciatus was estimated to be 78,000 t in 2019, suggesting a decrease from 2017. Of that amount 57,000 t were for fish larger than 22 cm and 18,000 t for fish larger than 25 cm.
• In the summer 2019, the modal size for the 2011 to 2013 Redfish cohorts was 23 cm. If the anticipated growth of these cohorts continues, 51% of the individuals of the 2011 cohort should be larger than 25 cm by 2020.
• In the research survey in 2019, Redfish accounted for 90% of the total captured biomass as compared to 15% between 1995 and 2012. This relative biomass of Redfish is unprecedented and could have important ecological impacts on other species.
• A limit reference point (LRP), and proposed upper stock reference point (USR) were estimated for the two species for both management Units 1 and 2, based on surveys in Unit 1. For S. mentella, LRP and USR were estimated at 43 kt and 265 kt, respectively. For S. fasciatus, LRP and USR were estimated at 25 kt and 168 kt, respectively.
• In 2019, based on the empirical reference points, S. mentella was well above its proposed USR and therefore would be considered in the Healthy Zone. Estimates of adult abundance for 2019 were at or above levels that preceded declines since the mid-1980s that led the COSEWIC to designate the Gulf of St. Lawrence and Laurentian Channel Designable Unit (equivalent to Units 1 and 2) as endangered in 2010.
• In 2019, based on the empirical reference points, S. fasciatus was between the LRP and proposed USR and therefore would be considered in the Cautious Zone.
• Advice for Redfish in Unit 2 could not be provided due to data limitations and meeting time constraints.

This Science Advisory Report is from the January 20-22 2020 meeting on the Assessment of Redfish Stocks (Sebastes mentella and S. fasciatus) in Units 1 and 2. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada Science Advisory Schedule as they become available.

Science Advisory Report 2020/019 (PDF, 2,207 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.