Preliminary results of the winter bottom-trawl survey on board the NM Mersey Venture in the Gulf of St. Lawrence, Laurentian Channel and Laurentian Fan in 2022, 2023 and 2024 / by Manuelle Beaudry-Sylvestre,... : Fs97-6/3777E-PDF

"Many demersal and benthic species occur in the Laurentian Channel and its associated channels within and outside the Gulf of St. Lawrence (GSL) in winter. However, knowledge of their spatial distribution during this time of year dates back more than 30 years, limiting the capacity to plan for the consequences of specific human activities such as reopening fisheries targeted at redfish (Sebastes spp.) in the sector. To overcome these deficiencies, the Canadian Department of Fisheries and Oceans (DFO) conducted a winter bottom-trawl survey on board the Motor Vessel Mersey Venture in 2022, 2023 and 2024 in the deep waters (> 150 m) of the Laurentian Channel, within and outside the GSL (NAFO Divisions 3P4RSTV). The survey employed an unaligned systematic design and led to a total of 413 successful tows. The 88 taxa occurring in 25 tows or more were subjected to (1) a simple visualization of catches in weight and number, (2) spatial interpolations of catches, either with or without an effect of depth, within the sdmTMB framework, (3) analyzes of cumulative distribution curves based on environmental variables (depth, temperature and oxygen) and (4) estimation of length frequencies and length-weight relationships. The 202 taxa present in less than 25 tows were subjected instead to presence-absence maps combining the three survey years. This report employed some of the best available tools to describe the spatial and environmental distribution of fish and invertebrates associated with the Laurentian Channel in winter"--Abstract, page iv.

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