Biomass weights gave 12.5 km more mean northward center change than number weights for eight fish species at 194 Bering Sea stations, 1982–1991 to 2015–2025

We tested whether biomass and fish numbers give the same northward change in catch centers. We used 194 fixed eastern Bering Sea stations and ten survey years in each period, 1982–1991 and 2015–2025, without 2020. An earlier SCI study reported point checks for eight species with complete counts. We add paired temporal uncertainty and bounds for 21 species. The eight-species mean change was 19.03 km north with biomass weights and 6.58 km with number weights. The paired difference was 12.45 km. Its approximate 95% three-survey block resampling envelope was 7.72 to 21.30 km. The number-change envelope included zero. Only 32 of 33,681 positive-catch rows lacked counts, but these rows affected 13 species. With each missing count at least one and no upper count limit, the all-species mean number change had limits of −48.56 to +32.94 km. These limits are not biological predictions. If missing-catch mean mass was at least half the smallest observed species mean mass, the conditional bounds were +8.90 to +16.06 km. We verified an exact identity between the center difference and the spatial covariance of catch mean mass and latitude. The package preserves the source snapshot, all count assumptions, results, figures, an independent audit and reproduction code. The results describe recorded catches in a fixed panel. They do not establish individual movement or a climate cause.

species distribution · Bering Sea · bottom trawl · biomass · fish numbers · missing data · partial identification · distribution center