American Lobster (Homarus americanus) stock assessment in the Gaspé (LFAs 19-21), Quebec, in 2022

Abstract

Landings in the Gaspé increased sharply in 2022, reaching 3,796 t, one of the highest values in the time series. They were 64.1% higher in 2022 than in 2018 and 169.9% higher than the average of the previous 25 years (1,407 t, 1997–2021). Fishing effort has been stable since 2019 at 2.34 million traps, which is 23.1% below the average for the 1994–2005 period. In 2022, 75.6% of landings in Gaspé came from LFA 20, 9.9% came from LFA 21 and 14.5% from Area 19. For the entire Gaspé area, the catch per unit effort (CPUE) by weight from commercial sampling has been increasing significantly since 2014. In LFA 19C, the CPUE in 2022 (3.51 kg/trap) was 33% higher than in 2018. In LFA 20, the CPUE rose by 40.8% between 2018 and 2022 (1.22 kg/trap). The logbook CPUEs followed the same trend for the latter. In LFA 21B, the CPUE increased by 13.2% between the fall of 2018 and the fall of 2022 (4.99 kg/trap). In LFA 19C, the demographic indicators show that the average size of commercial lobsters sampled was larger in 2022 at 97.6 mm, which is 1.9% greater than the 2018 value. In LFA 20, the average size has also been trending upward, reaching 90.7 mm in 2022, which is more than 1.4% of the 2018 value. In LFA 21B, average sizes have been trending downward in the fall and spring fisheries since 2015, reaching 91.2 mm in 2022, which is 1.7% below the 2018 value. Fishing pressure indicators could not be estimated for LFAs 19 and 21. In LFA 20, the exploitation rates have been showing a slight decline since 2008. The rate was 78.1% in 2021, which is above the average for the 2016–2018 period (73.7%). In LFA 20, the productivity indicators have remained high. The abundance of berried females has been increasing since 2011. Theoretical egg production was 1.2 times higher in 2022 than in 2018 and 10.3 times higher than during the 1994–1996 period. Indicators of fishery pre-recruitment in LFA 20 were stable between 2018 and 2022, at a rate of 3.06 lobsters per trap. The number of degree-days of the 2022 fishing season (284 DD) was 7.2% below the average for the previous 25 years. Small rock crab are a key prey source for lobster. Despite the low fishing effort observed in recent years in the Gaspé, the size structures of commercial dockside sampling suggest a low abundance of rock crab below the legal size in LFA 19. In addition, the CPUE of rock crab in the commercial fishery has been in decline in that Area since 2017. In 2022, it was below the average for the 2000–2021 period. However, these trends were not observed in LFAs 20 and 21. High abundance, productivity and landings indicate that the Gaspé lobster stock is in good condition and in the healthy zone according to the precautionary approach. The health indicators of rock crab in Gaspé were examined from an ecosystem approach. Unlike in LFAs 20 and 21, the population status of this essential prey for lobster in LFA 19 is of concern. To ensure the sustainability of the lobster stock and that of its preferred prey while preserving their trophic link, a low rock crab mortality rate should be favoured.