Abstract

Shelf edge reefs provide valuable habitat to a wide variety of fish and other organisms. The proper classification and subsequent management of these reefs is becoming increasingly critical in areas with high fishing pressures. In order to investigate the relationship between habitat complexity and parrotfish habitat utilization, this study has concentrated on the effect that rugosity has on Scaridae abundance and biomass. Rugosity and habitat complexity have been classified using new techniques that minimize bias in geographical data associated with the slope of the substrate. These new techniques have been developed for remotely sensed data sets as well as in situ measurements. An empirical orthogonal function analysis showed that parrotfish abundance on the shelf was associated primarily with structural variables in the reef environment (Rugosity and Coral Cover). A secondary factor that contributed to parrotfish habitat utilization involved levels of algae cover. Within this secondary factor, an inverse relationship was found among turf and lobophora algae. More direct relationships were apparent using the newly calculated rugosity measurements than with classical measurement techniques, both via remote sensing software and field measurements. The results obtained from this study provide a novel approach to data interpretation that can be used in determining critical habitat to sensitive fish species.

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