Arctic cod occurred less often in 2022–2026 cold trawls than in matched 2006–2013 trawls on the eastern Bering Sea shelf

We tested if fish catch occurrence returned to an earlier level at eastern Bering Sea stations with similar local cold conditions. We matched 2022–2026 NOAA trawls at or below 2°C with 2006–2013 trawls at the same station. Matches controlled bottom temperature, survey date, and swept area. Each target had at least two earlier matches. The main test used 241 target hauls at 109 stations in shelf strata 10–62. With equal station weights, Arctic cod occurrence was 2.1% in the target period and 21.2% in the matched baseline. The difference was −19.1 percentage points. Its 95% spatial block bootstrap interval was −28.0 to −11.4 points. Bering flounder occurrence was 18.8% versus 35.2%, a difference of −16.4 points. Both deficits remained with tighter temperature matches and with 2022–2024 alone. A larger repeat-station set and a small same-vessel subset gave the same direction. However, matched Arctic cod occurrence was already lower in 2014–2017. The result therefore does not identify an effect of the 2018–2019 extremes. Similar summer cold conditions did not predict a return of earlier local occurrence in this shelf subset. The intervals condition on the observed years. The package preserves raw data, source hashes, all match pairs, code, figures, and reproduction checks.

Arctic cod · Bering flounder · Bering Sea · cold pool · fish distribution · matched observations · ecological change · open data · reproducibility