Remote sensing and fish-habitat relationships in coral reef ecosystems: review and pathways for multi-scale hierarchical research.

Understanding spatial variations in alpha, beta, and gamma coral reef fish diversity, as well as both local community and regional metacommunity structures, is critical for science and conservation of coral reef ecosystems. This quest implies that fish-habitat relationships are characterized across different spatial scales. Remote sensing allows now for a routine description of habitats from global-regional to detailed reef scales, thus theoretically offering access to hierarchical spatial analysis at multiple scales. To judge the progress in using remotely sensed habitat variables for reef fish study, existing peer-reviewed papers on the subject are reviewed. We tabulated the significant fish-habitat relationships given the different study sites, fish and habitat variables, statistical analysis, sampling efforts and scales. Studies generally do not corroborate each other. Instead, the exercise provides a diversity of thematic results from which lessons remain equivocal. It is thus justified to recommend more systematic and hierarchical remote-sensing based research in the future. We advocate the use of remote-sensing early in the design of the fish study, as part of a coherent conceptual scheme spanning all spatial scales.