Regional climatic warming drives long-term community changes of British marine fish

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Description/Abstract

Climatic change has been implicated as the cause of abundance fluctuations in marine fish populations
worldwide, but the effects on whole communities are poorly understood. We examined the effects of
regional climatic change on two fish assemblages using independent datasets from inshore marine (English
Channel, 1913–2002) and estuarine environments (Bristol Channel, 1981–2001). Our results show that
climatic change has had dramatic effects on community composition. Each assemblage contained a subset
of dominant species whose abundances were strongly linked to annual mean sea-surface temperature.
Species’ latitudinal ranges were not good predictors of species-level responses, however, and the same
species did not show congruent trends between sites. This suggests that within a region, populations of the
same species may respond differently to climatic change, possibly owing to additional local environmental
determinants, interspecific ecological interactions and dispersal capacity. This will make species-level
responses difficult to predict within geographically differentiated communities.