Science Advisory Report 2024/002

Newfoundland & Labrador Comparative Fishing Analysis – Part 1

Summary

• A comparative fishing program was undertaken in the Newfoundland and Labrador (NL) Region in the fall of 2021 and spring and fall of 2022 to quantify differences in catchability between the outgoing vessels Canadian Coast Guard Ship (CCGS) Alfred Needler and CCGS Teleost with the new Offshore Fishery Science Vessels (OFSVs) CCGS John Cabot and CCGS Capt. Jacques Cartier.
• Conversion factors to calibrate multispecies survey catches were estimated for the CCGS Teleost fall survey in Northwest Atlantic Fisheries Organization (NAFO) Divisions (Div.) 2HJ3KL and CCGS Alfred Needler fall survey in Div. 3KL. Conversion factors are intended to be applied to the vessel, season, and area for which they were derived and are not interchangeable between the CCGS Teleost and CCGS Alfred Needler time-series.
• For the CCGS Teleost, conversion factors were defined for 14 taxa including 2 with significant length effects, 18 taxa showed no significant difference in relative catchability, and 9 evaluated taxa had insufficient data to determine if a conversion factor is appropriate.
• For the CCGS Alfred Needler, conversion factors were defined for 15 taxa including 6 with significant length effects, 17 taxa showed no significant difference in relative catchability, and 12 evaluated taxa had insufficient data to determine if a conversion factor is appropriate.
• Sample size and spatial coverage of paired tows are generally insufficient to estimate standard conversion factors for the CCGS Alfred Needler survey time-series in Div. 3LNOPs in the spring or in Div. 3NO in the fall. With the CCGS Alfred Needler already decommissioned (i.e., no additional comparative fishing possible), data collected in 3NOPs by the new vessels will represent the beginning of a new time series for the majority of species and will not be directly comparable to the previous time series.
• Consistency in environmental and biological characteristics across seasons allowed a unique approach to estimating a conversion factor for Yellowtail Flounder applicable across the Div. 3LNO fall and 3LNOPs spring CCGS Alfred Needler time-series.
• Data gaps exist for small Atlantic Cod and small Snow Crab in the CCGS Teleost comparative fishing program. Conversion factors have been estimated for larger individuals and will be re-evaluated for the full length range following the fall 2023 comparative fishing program.
• An additional data gap in the CCGS Teleost comparative fishing program exists for deep water species including Greenland Halibut. Conversion factors have not been estimated at this time but will be evaluated following the fall 2023 comparative fishing program.

This Science Advisory Report is from the July 10-13 Newfoundland & Labrador Comparative Fishing Analysis – Part 1 Regional Peer Review. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

Science Advisory Report 2024/002 (PDF, 1,567 KB)

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