Standardized CPUE of Russian commercial trawl fishery of chub mackerel in the Northwest Pacific up to 2024
We estimated index of abundance based on catches per vessel-day derived from commercial trawl catches, which can serve as an indicator of exploitable biomass (EB) for the Pacific mackerel population. Generalized additive models (GAMs) were applied to commercial trawl catch data for the period from 2016 to 2024 in the Russian EEZ covering the main mackerel feeding areas. This document contains key background material and diagnostic results of this standardization in accordance with the "CPUE Standardization Protocol for Mackerel".
The standardized catch per unit effort (CPUE) index reached its maximum value in 2017, but since then there has been a steady negative trend, with 2023 and 2024 recording the lowest values since 2016. As no significant weaknesses were identified during the GAM diagnostic, it is proposed that the calculated index be used as a exploitable biomass indicator for the upcoming stock status assessment of mackerel in the Working Group on Stock Assessment of this species.
This approach integrates the spatial and temporal characteristics of fisheries in the Russian EEZ, providing a sound basis for resource management in the face of changing fishing pressure and environmental factors.