Composition, density and biogeographic affinities of the rocky intertidal fishes on the western coast of the Baja California peninsula, Mexico

The composition, density and biogeographic affinities of the rocky intertidal fishes of the western coast of the Baja California peninsula, Mexico, were studied from June 2006 to January 2009. A total of 5,489 specimens belonging to 48 species, 39 genera and 20 families were registered. Clinocottus analis was the dominant species on the northern and central coast (north to Punta Abreojos), and Entomacrodus chiostictus was dominant farther south. Based on distribution and density of permanent species, the area between Punta San Juanico and Bahia Magdalena represents the distributional boundary for northern (warm-temperate) and tropical fish elements. Most of species (85%) showed zoogeographical affinities with the San Diegan province, followed by species related to the Mexican (58%) and Cortez (56%) provinces. The known northernmost geographical ranges are extended for Sargocentron suborbitalis, Labrisomus multiporosus and Bathygobius ramosus; while the southernmost ranges extended for Clinocottus analis, Oligocottus rubellio and Amphistichus koelzi.