Assessment of Iceland Scallop in the Canada-France Transboundary Zone of St. Pierre Bank (NAFO Subdivision 3Ps)

Abstract

Marine ecosystem conditions indicated overall limited productivity of the fish and shellfish community in Northwest Atlantic Fisheries Organization (NAFO) Subdivision 3Ps. The ecosystem has undergone structural changes, with increased dominance of warm water species starting in 2010. In recent years (2019–22), ecosystem indicators have suggested that conditions could be improving. Sea surface temperature in 2023 in NAFO Subdivision 3Ps was at the second warmest level on record (2022 being the record). Bottom temperatures were back to normal after being at record-warm levels in 2021 and 2022. This warmer climate corresponded with improved conditions observed at the lower trophic levels, including increased concentrations of chlorophyll-a, earlier spring blooms, and increased zooplankton abundance and biomass. Directed fishing started in 1989 and peaked at 6,000 t in 1992. There was no directed fishing activity between 1997 to 2016, and there has been minimal fishing activity since 2017. Since 2018, the total allowable catch (TAC) has been 990 t (for the CORE area). In 2023, the minimum dredgeable biomass index was among the lowest in the survey time series, a 45% decrease since the last survey in 2017 and is 8% of the average in the early-1990s. The number of scallop meats per 500 g (i.e., average meat count) remains near the survey timeseries high, which indicates smaller-sized scallop meats. Natural mortality has sharply increased since the last survey in 2017, but remains far below the survey timeseries high. Biomass of predatory sea stars generally corresponds with natural mortality levels.