Terms of Reference

Identification of comparative fisheries conversion factors for DFO surveys in the northern and southern Gulf of St. Lawrence

Zonal Peer Review – Quebec Region and Gulf Region

January 25-26, 2023
Virtual Meeting

Chairperson: Daniel Duplisea

Context

A summer bottom-trawling survey for groundfish and shrimp has been conducted annually since 1984 in the Estuary and northern Gulf of St. Lawrence, and since 1971 in the southern Gulf of St. Lawrence. The main objective of these surveys is to obtain biomass estimates for several species, including some that are commercially important (cod, Greenland Halibut, redfish and northern shrimp). The surveys are used to estimate the distribution and abundance of many fish and invertebrate species and to determine their life history characteristics. Since 2004–2005, surveys have been conducted from the CCGS Teleost, which is equipped with a Campelen trawl in the northern Gulf survey and a Western IIA trawl in the southern Gulf survey. It is planned that the CCGS Teleost will no longer be used for these surveys after 2022 and will be replaced by the CCGS John Cabot in the northern Gulf and the CCGS Capt. Jacques Cartier in the southern Gulf. In addition, the trawl used in the southern Gulf survey will be replaced with a Northeast US trawl (NEST). Comparative fishing was conducted in 2021 and 2022 in order to be able to estimate species/taxon specific differences in catchability between the vessel-trawl combinations in each of the two surveys. The summer survey series are an important source of data for the northern and southern Gulf, and it is important to make the two series comparable despite vessel changes through the correction factors that will be estimated.

Objectives

To estimate the corrections that must be applied to catches made by the CCGS Teleost to make them equivalent to those that would have been made under the same conditions on the CCGS John Cabot for the northern Gulf and on the CCGS Cartier for the southern Gulf. These corrections will be estimated from the results of comparative fishing. To present the preliminary results of the August 2022 ecosystem survey in the Estuary and northern Gulf of St. Lawrence. The historical perspectives (catch rate, spatial distribution, length frequency) will incorporate the new correction factors between the two vessels.

Expected Publications

• Research Document

Expected Participation

• Fisheries and Oceans Canada (DFO) Science and Fisheries Management 
• Academia