Évaluation des stocks d'oursins verts (Strongylocentrotus droebachiensis) de l'estuaire et du nord du golfe du Saint-Laurent en 2024

Abstract

Status Since there are no indicators or reference points for the urchin stocks, their status cannot be assessed as per the Fishery Decision-Making Framework Incorporating the Precautionary Approach. Mean catch per unit effort (CPUE) values during the 2022-2024 period were higher than the reference means in subareas 8D (2018-2021) and 8E (2003-2021), but lower than the reference mean in subarea 9-1 (2004-2021). According to the data from the fishery-independent survey, mean densities of legal-sized urchins were high in subarea 9-1, and have remained fairly stable since 2016. Trends Even in the absence of stock status indicators, the available data suggest that stocks in all actively fished areas (subareas 8D, 8E, 9-1, and area 11) have been relatively stable in recent years. Stock trends in fishing areas 1 to 7, 9 (except for subarea 9-1), 10, and 12 to 14 are unknown, as these areas have not been fished, or have only been lightly fished, since the late 1990s. Ecosystem and Climate Change Considerations The Green Sea Urchin is one of the most important structuring elements of the coastal Saint Lawrence ecosystem. Its close relationship with aquatic vegetation, including seaweeds, influences ecosystem productivity and the availability of critical habitats for many marine species. Bottom water temperatures where urchins are harvested in the Estuary and Gulf of St. Lawrence are increasing, as is the abundance of crustacean predators such as lobster and rock crab. However, these ecosystem changes and their impacts on the productivity of urchin stocks have not been quantified, and data are not available at the appropriate spatial and temporal scales to assess the impact on the stocks. Stock Advice The current removal levels in area 11 and subareas 8D, 8E and 9-1 do not appear to pose a significant risk to urchin stocks in the short term, given the relative stability of the densities of legal-sized individuals from the survey, CPUE values from the fishery, and the size structures in landings from recent years. In addition, the species has a wide distribution, while the fishery is only concentrated in certain areas.