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Research Document 2022/011

Preliminary results from the ecosystemic survey in August 2021 in the Estuary and northern Gulf of St. Lawrence

By Bourdages, H., Brassard, C., Chamberland, J.-M., Desgagnés, M., Galbraith, P., Isabel, L. and Senay, C.


Fisheries and Oceans Canada conducts an annual multidisciplinary survey in the Estuary and northern Gulf of St. Lawrence. The objectives of this survey are varied; assess the biodiversity of species found near the bottom; estimate the abundance of groundfish and invertebrates; assess physical and biological (phytoplankton and zooplankton) oceanographic conditions; monitor the pelagic ecosystem; and collect samples for various research projects. In 2021, the survey was conducted between July 25 and August 26 on board the CCGS Teleost. The survey successfully carried out 149 trawl tows as well as 74 CTD water column casts, and 57 zooplankton samples.

This report presents the results of the 149 tows. In total, 82 fish taxa and 214 invertebrate taxa were identified during the mission. Historical perspectives (catch rates, spatial distribution and length frequency) are presented for 25 taxa. These commercial fishery-independent data will be used in several stock assessments including cod (Gadus morhua), redfish (Sebastes spp.), Greenland halibut (Reinhardtius hippoglossoides), Atlantic halibut (Hippoglossus hippoglossus), witch flounder (Glyptocephalus cynoglossus) and northern shrimp (Pandalus borealis).

A preliminary analysis of water temperature data collected in 2021 shows that conditions have warmed at 150 m and deeper, reaching new records since 1915 at 150, 200 and 300 m. The August cold intermediate layer (CIL) minimum temperature was much warmer in 2021 than in 2020, reaching the highest values of the modern CTD era. Surface waters temperatures were near normal in July-August.

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