Abstract

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 in the influence of important environmental factors such as ocean warming and habitat availabil-ity. Here we use the Mean Temperature of the Catch to test the hypothesis that, for the period of 1971 – 2010, regional variation in species-turnover of exploited reef fish assemblages among nine Caribbean countries can be explained by differences in the rate of warming, species’ thermal preferences and available reef habitat across the region. Sea surface temperature and the mean temperature of the catch displayed rates of increase of 0.14oC/decade and 0.19oC/decade respectively, slightly higher than the global average and more so when compared to the global average for all tropical fisheries. These rates also varied across across the nine countries, ranging from 0.04 – 0.18 oC/decade for sea surface temperature and 0.10 – 0.62oC/decade for the mean temperature of the catch. Four countries displayed asymptotic MTC trends, explained by stark declines in Scomberomorus regalis, a species of particularly low thermal tolerance. Finally, model comparisons revealed that the interaction between the rate of sea surface temperature change and available reef habitat best explained regional variation in the rate of change in the mean temperature of the catch. These results suggest that reef fish communities in areas with less available reef habitat may be more sensitive to ocean warming and future decreases in available habitat, driven by climate or human stressors may exacerbate this relationship.

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