Abstract

Understanding habitat use and connectivity at the local scale is critical for defining and protecting essential fish habitat, designing effective networks of marine reserves, and developing ecosystem-based management in coral reef ecosystems. This requires a combination of studies on the species-specific patterns of habitat use, and the rates, pathways and timing of migrations across the seascape at multiple spatial and temporal scales. Off La Parguera, Puerto Rico, we have combined visual census surveys across the insular shelf and tagging studies in an attempt to understand connectivity patterns across the shelf. Patterns of habitat use through ontogeny for 28 species from five families of reef fishes show variations among species, even within family, ranging from habitat changes within location to both location and habitat changes across the shelf. While species patterns can be combined to indicate key habitats and locations, these studies do not provide information on the processes and pathways controlling ontogenetic migrations. Tagging studies of small and large juvenile French grunts show that they migrate toward forereef areas through a series of shifts into existing schools characterized by increasing average fish length. Distance moved was related to fish length, and pathways followed habitat terrain. While preliminary, these illustrate that offshore migrations are not random and may respond to changing stimuli with age

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