Terms of Reference

Identification of Comparative Fishing Conversion Factors for DFO Research Surveys on the Scotian Shelf and Bay of Fundy

Regional Peer Review – Maritimes Region

January 23-25, 2024

Dartmouth, NS

Chairperson: Tara McIntyre

Context

Fisheries and Oceans has conducted a summer bottom-trawling survey annually since 1970 on the Scotian Shelf, Bay of Fundy, and Gulf of Maine. The main objective of these surveys is to obtain biomass estimates for several species, including some that are commercially important (Atlantic Cod, Haddock, Pollock, redfish, Atlantic Halibut, and Lobster). The surveys are used to estimate the distribution and abundance of many fish and invertebrate species and to determine their life history characteristics. Since 1983, surveys have been conducted from the Canadian Coast Guard ship (CCGS) Alfred Needler, equipped with a Western IIA trawl. In years when the CCGS Needler was unavailable, the CCGS Teleost was used, equipped with the same Western IIA trawl. It is planned that the CCGS Alfred Needler and CCGS Teleost will no longer be used for these surveys after 2023 and will be replaced by the CCGS Captain Jacques Cartier. In addition, the Western IIA trawl will be replaced with the same trawl used by the Northeast Fisheries Science Centre, part of the National Oceanic and Atmospheric Administration Fisheries Directorate of the United States of America. Comparative fishing was conducted in 2022 and 2023 to be able to estimate species/taxon specific differences in catchability between the vessel-trawl combinations. The summer survey series is an important source of data for the assessment of multiple species on the Scotian Shelf, Bay of Fundy, and Gulf of Maine. The estimation of the correction factors is required to make the two series comparable despite vessel and gear changes.

Objectives

The specific objectives of this peer review meeting are:

• To estimate the corrections that must be applied to catches made by the CCGS Alfred Needler and the CCGS Teleost to make them equivalent to those that would have been made under the same conditions on the CCGS Jacques Cartier for the Scotian Shelf and Bay of Fundy. These corrections will be estimated from the results of comparative fishing.
• Additionally, a review of historical comparative fishing experiments conducted between the CCGS Needler and the CCGS Teleost, will be completed to determine if previously estimated correction factors are appropriate, and if not, to estimate appropriate corrections to be applied to historical catches.

Expected Publications

• Research Document

Expected Participation

• Fisheries and Oceans Canada Science
• Fisheries and Oceans Canada Fisheries Management