Évaluation des ressources en holothurie touffue (Cucumaria frondosa) sur le banc de Saint-Pierre (sous-division 3Ps de l’OPANO) en 2022

Abstract

Environment and Ecosystem The ocean climate in Northwest Atlantic Fisheries Organization (NAFO) Subdiv. 3Ps has been experiencing significant warming in recent years. In 2022, surface and bottom temperature reached all-time highs, and 2021 is the second warmest year on record for the same metrics. Overall conditions of the past 3–4 years are indicative of improved productivity at the lower trophic levels along the NL bioregion (Divs. 2J3KLNO and Subdiv. 3Ps). This includes earlier phytoplankton blooms, higher chlorophyll concentrations, and increased zooplankton biomass with a higher abundance of larger, more energy-rich Calanus copepods. Marine ecosystem conditions indicated overall limited productivity of the fish community. Total biomass of the entire fish community remained below pre-collapse. The ecosystem has undergone structural changes with increased dominance of warm water species starting in 2010. In recent years (2019–21), ecosystem indicators have suggested that conditions could be improving. However, the lack of conversion factors for new offshore survey vessels in 2022 prevented an updated evaluation of these trends. Stock Status Resource status of sea cucumbers in NAFO Subdiv. 3Ps was assessed based on commercial catch data, emerging fishery survey (2004–08), and DFO sea cucumber survey (2016, 2017, 2022). The sea cucumber fishery was initiated in the northwest area in 2003, with the allocation gradually increasing to 2,242 t in 2013, where it has remained. The fishery opened in the southeast area in 2017 with an allocation of 3,773 t and increased to 4,717 t in 2019, where it has remained. In 2022, landings were 2,065 t in the northwest area and 4,019 t in the southeast area. Sea cucumbers may be decreasing in size in both areas throughout the time series. A spatiotemporal model was used to estimate biomass and abundance indices. In 2022, the biomass index for the northwest area increased from 2017 to near the average observed during the emerging fishery (2004–08). In 2022, the biomass index for the southeast area also increased from 2017 but remains below the average biomass index observed from 2004–08. There is more uncertainty around the biomass and abundance estimates in recent years. The abundance index in the northwest area increased in 2022 from 2017, with a general increasing trend since the beginning of the survey. The abundance index in the southeast area varied without trend throughout the time series. Exploitation rate indices are anticipated to remain relatively stable in 2023, assuming status-quo total allowable catch (2.4% in the northwest area and 2.9% in the southeast area). Sustainable exploitation rates are unknown for this species. Exploitation rate indices are a minimum estimate due to variation in sea cucumber landed water loss. Given the uncertainty with the assessment of stock status of this species, there is no scientific basis for assessing the risk of the current or any change in the harvest level.