Sea temperature links to fixed-effort spatial dissimilarity were uncertain in four US trawl samples in 1982-2019

We tested whether warm years had more similar recorded marine communities across fixed survey strata. We used 21,372 hauls from the Eastern Bering Sea and Northeast US Fall surveys in 1982-2019. An exact draw calculation fixed effort at two hauls per stratum. Spatial dissimilarity was a ratio of expected shared and total detected richness, averaged over fixed stratum pairs. Four region-period models controlled linear year. All four adjusted temperature intervals included zero. Slopes ranged from -0.378 to 0.095 dissimilarity points per C. A negative one-haul link in late Bering did not repeat in the main measure or consecutive-year changes. The evidence did not establish a common warm-year homogenization pattern. Short series, detection, survey changes and coarse surface temperature limit inference. These are survey associations, not causal climate effects. Pollution and timing were not measured. The package includes code, sufficient data, raw hashes, a figure and independent numerical checks.

biodiversity · spatial dissimilarity · biotic homogenization · sampling effort · rarefaction · sea temperature · trawl survey · null result