Shore fishes and biogeographic subdivisions of the Tropical Eastern Pacific

We examined the geographic distributions of 1135 species of resident shore fishes to assess biogeographic subdivision of the Tropical Eastern Pacific (TEP), which stretches from the Gulf of California to northern Peru. Using hierarchical clustering refined by Analysis of Similarity (ANOSIM), we determined geographic groupings in the distributions of the entire fauna, of regional endemics and of 3 functional (habitat) groups of species. We also examined the distributions of local endemics throughout the TEP and how differences in faunal size versus faunal composition among sites contribute to the subdivision pattern. Our results indicate that: (1) the continental coast contains 2 provinces, the Cortez (Gulf of California and lower Pacific Baja) and the Panamic (southward), each of which has a peak in abundance of local endemics and of overall species richness;