Abstract

Coral reef fishes use a variety of habitats throughout daily, ontogenetic, and spawning migrations, therefore requiring a suite of habitats to complete their life cycle. The use of multiple habitats by grunts (Haemulidae) and snappers (Lutjanidae) was investigated at Mona Island, a remote island off western Puerto Rico. The objective of this study was to determine if the distribution of three different life stages was random in relation to benthic habitat types. Coral reef fish were sampled throughout all habitat types randomly over a period of six months. For seven species of grunts and snappers median fork length was significantly different by habitat type identifying critical habitats for juveniles distinct from adult habitats. Within a life stage significant differences were observed in fish density by habitat type. Early juvenile grunts and snappers were more abundant in habitats of depths less than 5 m, mainly in rocky shores and seagrass areas with patches of coral or other hard structures. Larger juveniles were significantly more abundant in depths less than 5m in coral dominated habitats. Adults were abundant throughout the habitats of all depth ranges, except for two species Haemulon chrysargyreum and Lutjanus mahogoni, which were limited to shallower habitats. This suggests that coral reef fishes utilize specific habitats depending on life stage more so than species, therefore measuring species abundances without considering their life stage may provide misleading patterns of habitat use since ontogenetic migrations include a variety of habitats which are not necessarily the most abundant

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