On the relative catchability of Atlantic cod in the Newfoundland and Labrador multispecies trawl surveys

Abstract

Multispecies bottom trawl surveys have been conducted annually in the spring and fall in the Newfoundland and Labrador region using a Campelen 1800 survey trawl aboard the Canadian Coast Guard Ship (CCGS) Teleost and CCGS Alfred Needler (or its sister ship the Wilfred Templeman) since 1995. The data collected during these surveys are used to estimate the distribution and abundance of many fish and invertebrate species, to determine species life history characteristics, and to form the basis of a number of ecosystem indicators. The CCGS Wilfred Templeman was previously retired, and the CCGS Alfred Needler and CCGS Teleost will no longer be used for these surveys after 2022 and 2023, respectively, and will be replaced by the Offshore Fishery Science Vessels (OFSVs) CCGS John Cabot and CCGS Capt. Jacques Cartier. The Campelen 1800 survey trawl will continue to be used, with a few modifications. Comparative fishing has been ongoing since 2021 to determine differences in catchability between the outgoing vessels and the new vessels with the modified Campelen trawl. Limited spatial distribution of comparative fishing from 2021-2022 only allowed for development of conversion factors of the CCGS Alfred Needler in fall for North Atlantic Fisheries Organization (NAFO) divisions 3KL, before this vessel’s decommissioning in February 2022. As a result, further spring comparative fishing was undertaken between the CCGS Teleost and CCGS John Cabot. Results indicate an equal catchability between the CCGS Teleost and CCGS John Cabot for spring 2023. This result is consistent across space, season, and vessel with all available data indicating no conversion factor is required for Atlantic Cod (Gadus morhua) in the Newfoundland and Labrador surveys moving from the CCGS Teleost and the CCGS Alfred Needler to the CCGS Capt. Jacques Cartier and CCGS Cabot.