The status of redfish (S. mentella and S. fasciatus) in Divisions 3LN and two medium term scenarios (when recruitment is low, Risk Based Management Strategy or common sense?)

• Main Authors: Ávila-de-Melo, Antonio, Brites, Nuno, Alpoim, Ricardo, González-Troncoso, Diana, González-Costas, Fernando, Pochtar, María
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Centro Oceanográfico de Vigo; Pesquerías; Baffin Island; Baffin; Northwest Atlantic; Sebastes mentella
• Online Access: http://hdl.handle.net/10508/15348; http://hdl.handle.net/10261/329390

There are two species of redfish in Divisions 3L and 3N, the deep-sea redfish (Sebastes mentella) and the Acadian redfish (Sebastes fasciatus) that have been commercially fished and reported collectively as redfish in fishery statistics. Both species, occurring on Div. 3LN and managed as a single stock, don’t belong to isolated local populations but, on the contrary, are part of a large Northwest Atlantic complex ranging from the Gulf of Maine to south of Baffin Island. The ASPIC assessment of this stock is based on the logistic form of a non-equilibrium surplus production model (Schaeffer, 1954; Prager, 1994), adjusted to a standardized commercial catch rate series (Power, 1997) and to all stratified-random bottom trawl surveys conducted in various years and seasons in Div. 3L and Div. 3N from 1978 onwards. Both CPUE and surveys were used with all observations within each series. The 2020 assessment proceed on the threshold of the new 2014 approach, with MSY fixed at 1960- 1985 average catch and the rest of the approved 2014 assessment framework updated. ASPIC results present a stock stable from the 1960’s to the first half of the 1980’s while sustaining an average yield of 21 000t. Stock declined with a sudden rise of the catch over the late 1980’s first half of the 1990’s, and started to gradually recover after catches fell to a residual level in response to stock collapse. The maximum observed sustainable yield (MSY) of 21 000 t is linked to a Fmsy at 0.11/year and a Bmsy at 185 000 t. There is a high probability (>90%) that the stock was at least 38% above Bmsy at the beginning of 2020, after crossing 2019 under a fishing mortality not higher than 46% Fmsy.