Local-Scale Variation in Seawater Temperature: Implications for Coral Reef Conservation Management

Conservation management of marine ecosystems relies heavily on an understanding of the state of and change in environmental conditions to which those ecosystems are exposed. In the absence of a local network of observations, conservation managers often use regional averages or coarse-resolution data derived from satellites. The underlying assumption, especially in regions, such as the Tropics, is that environmental conditions are spatially homogeneous at small scales. This research investigates the degree of local variability present in seawater temperature surrounding Little Cayman Island. Accurate information on sea water temperature is critical to forecasting and mitigating thermally-induced coral stress. Resolving variability at subregional scales can enhance management effectiveness by allowing resources to target local locations where thermal stress is greatest. While absolute spatial variability around Little Cayman is found to be low, there exist sufficient and, in some cases, significant localized differences that can play a role in the vulnerability of the island’s coral reefs to thermally-induced coral bleaching. These variations appear to be related to the geographic position of the observations around the island and their proximity to the Cayman Trench.