An annotated distributional checklist of the freshwater fish from Baja California Sur, Mexic\o

An annotated distributional checklist of the freshwater fish recorded historically and recently in Baja California Sur, México, is provided. This checklist is supported with 4,857 specimens collected at freshwater localities during the period of May 1991 to April 2002, and complemented with a review of specimens in museums and in the literature. The native ichthyofauna is represented by 19 species belonging to 16 genera and 12 families, with only two cases of endemism (Fundulus lima and Gobiesox juniperoserrai). The first occurrence of Centropomus viridis in freshwater environments of Baja California peninsula is reported here. The families Eleotridae and Mugilidae are the most diverse with 3 species each. Zoogeographically, most of the species are of tropical affinity (panamanian 63%, tropical amphiamerican 16% and circumtropical 5%) and of marine ecological derivation (sporadic 53%, complementary 26%, vicarious 16% and diadromous 5%). Six species are exotic in this region, of which Cyprinus carpio, Xiphophorus helleri and Tilapia cf. zilli are of recent introduction. The current status of the endemic killifish (Fundulus lima is determined as endangered due to competition with Tilapia cf. zilli and other exotic fish.