Arctic cod and Pacific cod were caught together less often in small cold-pool years at 82 eastern Bering Sea stations, 1982–2025

We tested whether a smaller cold pool was linked to more bottom trawls with both Arctic cod and Pacific cod. We used unchanged NOAA records for 3,526 hauls at 82 fixed eastern Bering Sea stations in 43 surveys from 1982 to 2025. Joint catch was lower in small cold-pool years. With a linear time term, 100,000 square kilometres more cold-pool area was linked to 6.53 percentage points more joint catch. The approximate 95% calendar HAC interval was 3.45 to 9.61 points. A four-year calendar-block bootstrap gave 2.64 to 9.09 points. The smallest and largest cold-pool quarters had mean joint-catch fractions of 3.66% and 18.96%. Pacific cod was caught in 98.1% of hauls, so the joint pattern mainly followed Arctic cod detection. We split joint catch into the product of annual species catch fractions and a remainder. Their cold-pool slopes were +6.75 and -0.23 points. The primary remainder interval included zero, but larger recent panels had negative remainder intervals while joint slopes stayed positive. The package has source data, provenance, all code and results, figures, and offline repeat instructions. Independent source checks passed. A clean repeat matched 22 numerical files and both figures. This fixed shelf subset does not measure fish contact, predation, true occupancy, or a causal cold-pool effect.

eastern Bering Sea · Arctic cod · Pacific cod · cold pool · joint catch · species distributions · reproducible analysis