Research Document 2017/002
Preliminary results from the groundfish and shrimp multidisciplinary survey in August 2016 in the Estuary and northern Gulf of St. Lawrence
By Bourdages, H., Brassard, C., Desgagnés, M., Galbraith, P., Gauthier, J., Légaré, B., Nozères, C. and Parent, E.
Abstract
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 sea bottom, estimate the abundance of groundfish and invertebrates, assess physical and biological oceanographic conditions (phytoplankton and zooplankton), monitor the pelagic ecosystem, take inventories of marine mammals and seabirds, and collect samples for various research projects. In 2016, the survey was conducted between August 1 and September 2 on board the CCGS Teleost. The survey successfully carried out 167 trawl tows as well as 109 CTD water column casts, and 70 zooplankton samples.
This report presents the results from catches from the 167 tows. In total, 76 fish taxa and 196 invertebrate taxa were identified during the mission. Historical perspectives (catch rates, spatial distribution and length frequency) are presented for 23 taxa. These commercial fishery-independent data will be used in several stock assessments (e.g., cod, redfish, Greenland Halibut, Atlantic Halibut and Northern Shrimp). The increase in biomass of Deepwater Redfish (Sebastes mentella) is significant, accounting for almost two thirds of the total catch. The biomass of Cod, Greenland Halibut and Atlantic Halibut remains steady while the biomass of Northern Shrimp is decreasing.
A preliminary analysis of water temperature data collected in 2016 shows that conditions have remained warm in deep waters (150 m and 200 m) and have warmed further (record since 1915) at 300 m. The August cold intermediate layer and summer surface waters were slightly warmer on average in 2016 than during the same period in 2015.
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