Évaluation du stock de merluche blanche (Urophycis tenuis) jusqu'en 2022 dans le sud du golfe du Saint-Laurent, zone 4T de l'OPANO

Abstract

Status Spawning Stock Biomass (SSB) of southern Gulf of St. Lawrence (sGSL) White Hake has been in the Critical Zone of the Precautionary Approach (PA) Framework since 1992. The SSB of White Hake in 2022 is 6.1 kilotonnes (kt) and has 100% probability of being in the Critical Zone. Trends SSB increased between 1978 and 1980, followed by a decrease until 2000 when it reached a minimum. Between 2001 and 2022, SSB fluctuated at low levels without trend. Natural mortality at all ages increased between 1978 and the 2000s. Natural mortality of fish age 4+ then slowly decreased until 2022 while natural mortality of younger fish (ages 2 and 3) kept increasing. Since 1995, natural mortality was very high and the dominant source of mortality. Fishing mortality of fish age 6+ varied between 0.2 and 0.4 in the 1970s and 1980s before increasing to a peak at 0.72 in 1992. Fishing mortality then decreased in 1995 with the implementation of the moratorium and has since remained low. Recruitment rates were low between 1980 and 1994. Rates increased until the early 2000s and remained high between 1995 and 2022. Ecosystem and Climate Change Considerations High natural mortality of older individuals is most likely caused by predation from Grey Seals. Stock Advice At current natural mortality and recruitment rates, the probability that SSB will increase over the Limit Reference Point by 2052 (30-year projection period) is 0%, even in the absence of fishery removals. The probability of SSB declining below 2,000 t by 2052 was 45%.