Regional variability in the sensitivity of Caribbean reef fish assemblages to ocean warming.

Ocean warming is expected to impact biodiversity and fisheries in the tropics through shifts in species’ distributions, leading to local extinctions and changes in species composition of catches. However, regional-scale patterns may differ from global trends due to the influence of important environmental factors such as ocean warming, fishing and habitat availability. Here, we used the mean temperature of the catch to test the hypothesis that, for the period of 1971 to 2010, regional variation in species-turnover of exploited reef fish assemblages among 9 Caribbean countries can be explained by differences in the rate of warming, species’ thermal preferences, changes in trophic structure due to fishing and potential reef habitat across the region. Sea surface temperature and the mean temperature of the catch displayed rates of increase of 0.14 and 0.19°C decade-1respectively, on par with the global average and higher when compared to the global average for all tropical fisheries. These rates also varied across the 9 Caribbean countries, ranging from 0.04 to 0.18°C decade-1 for sea surface temperature and 0.10 to 0.62°C decade-1 for the mean temperature of the catch. The negative interaction between potential reef habitats in each country and sea surface temperature in relation to the mean temperature of the catch suggests possible moderating effects of available habitats on the sensitivity of fish communities to warming. In addition, the negative relationship of trophic level with the mean temperature of the catch suggests that fishing increases their vulnerability. Findings from this study can help elucidate factors driving variations in the sensitivity of exploited fish communities to warming, and have implications for the management of living marine resources in the Caribbean region.