Abstract

Essential Fish Habitat (EFH) is a concept easily understood for single species but difficult to define and incorporate into management across the complex of exploited coral reef fishes. We define EFH by examining distribution patterns across life stages for 28 species of surgeonfishes, groupers, snappers, grunts and parrotfishes in La Parguera, PR. Patterns were mapped on a Cross-Shelf Habitat (CSH) framework that incorporates and defines both habitat types and geomorphic zones of the insular shelf to create a matrix of individually unique CSHs. Visual counts of 21,877 fishes were mapped on habitats in 24x4-m transects. Patterns were summed across species for early juveniles, juveniles and adults to determine community-scale patterns. Fishes use a wide variety of CSHs during ontogeny, yet certain CSHs stand out in importance. For early juveniles these include vegetated areas (mangrove and Thalassia) inside the inner reef line, low relief dead coral areas on the Inner Shelf, and in the Outer Shelf in coral dominated areas associated with the emergent reef. The intermediate-depth forereef of the inner emergent reef is of importance for all life stag-es. Nevertheless, it would be difficult to target for protection specific CSHs occurring within a broad seascape, especially since some threats (turbidity, eutrophication) act at the seascape scale. Management should target larger scale priority areas where the full complement of essential CSHs occurs or where threats can be isolated. Management of threats in such priority areas could protect areas critical for fish production and be an important component in regional coastal and marine spatial planning efforts.

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