WHAT THE EVIDENCE SAYS
Six sampling programs contributed 21,737 unique events from 1995–2018. Significant changes appeared in different metrics for different taxa: for example, chub and jack mackerel shifted seasonal centers of gravity while several sanddabs and other species shifted latitudinal metrics. Spatial and phenological variability were not tightly coupled, and most environmental covariates did not show simple linear trends across the full domain.
WHY IT MATTERS / OUR READ
Range shift and timing shift should not be treated as interchangeable evidence of climate response. Survey design and life stage matter, and management may need to track geography and phenology separately for recruitment-sensitive species.
CAVEATS / UNCERTAINTY
The synthesis combines programs with different regions and sampling structures, and significance varies by species and metric. The results describe early life stages rather than whole-stock distribution and do not assign every shift to a single environmental cause.
SOURCE
ICES Journal of Marine Science — primary study
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