Résultats préliminaires du relevé écosystémique d'août 2024 dans l'estuaire et le nord du golfe du Saint-Laurent

Abstract

Fisheries and Oceans Canada conducts an annual multidisciplinary survey in the Estuary and the northern Gulf of St. Lawrence. The objectives of this survey are varied: estimate the abundance of groundfish and invertebrates; assess physical, chemical and biological (phytoplankton and zooplankton) oceanographic conditions; assess the biodiversity of species found in the demersal zone; monitor the pelagic ecosystem; and collect samples for various research projects. In 2024, the survey was conducted between August 2 and September 4 on board the Canadian Coast Guard Ship (CCGS) John Cabot. During this survey, 163 trawl tows were completed. In addition, 79 vertical profiles of the water column were carried out to characterize oceanographic conditions and 41 zooplankton samples were also collected. This report presents the results of catches of the successful tows. In total, 79 fish taxa and 212 invertebrate taxa were identified during the survey. Historical perspectives (catch rates, spatial distribution and length frequency) are presented for 26 taxa. These commercial fishery-independent data will be used in several stock assessments including Atlantic Cod (Gadus morhua), Redfish (Sebastes spp.), Greenland Halibut (Reinhardtius hippoglossoides), Atlantic Halibut (Hippoglossus hippoglossus), Witch Flounder (Glyptocephalus cynoglossus), and Northern Shrimp (Pandalus borealis). The preliminary analysis of water temperature measurements in 2024 shows conditions that have slightly cooled at depths of 150 m and more for a second consecutive year, since the centennial records reached in 2022. The summer temperature of the cold intermediate layer was similar to that of 2023; it would be the 4th warmest that has been measured with modern instruments since 1985. The surface water temperature was above normal during the periods of July-August and May-August, close to record values.