No abstract

Bahía Magdalena, Baja California Sur (Mexico), is an interesting place where, because of its geographic location and environmental characteristics, a high biodiversity is found. In spite of marine resources of economic importance, few reports or papers dealing with the bay’s biodiversity have been published. To date a comprehensive check-list of the fishes of Bahía Magdalena has not been published. In the present work an integrated record of ichthyofauna is given; the list includes those species caught in a six-year survey, which are catalogued in the biological collection of the Centro Interdisciplinario de Ciencias Marinas (CICIMAR, IPN) at La Paz, Baja California Sur. The check-list includes 161 species belonging to 120 genera and 61 families, of which 20 correspond to the elasmobranchs and 141 to bony fishes.

No abstract

We analyzed the composition, diversity, and abundance of marine fi sh at rocky reefs off San José island, Mexico between October 2001 and August 2002. Fish species were recorded using a visual census in 5 sampling areas of 50 by 5 meters at 2 depths, shallow (1-3 meters) and intermediate (5-7 meters). A total of 26 946 organisms were counted, belonging to 84 species. The families Serranidae (9 species), Labridae (8), Pomacentridae (7), and Haemulidae (6) were the most representative. We measured the rugosity of the bottom surface, which showed a positive relationship with abundance, richness, and fi sh diversity. The ocean bottom off San José island is covered with various size rocks that offer more feeding and refuge areas to fi sh assemblages than other areas. The ecological index increased during the warm season. Diversity and richness showed signifi cant variations (P<0.05) by depth, with the highest values in exposed locations around the island (Conejo, Pardito, and San Francisquito). The biological value index indicated that the most representative fi sh species were Stegastes rectifraenum, Abudefduf troschelii, Thalassoma lucasanum, Scarus ghobban, and Mulloidichthys dentatus. The depth and wave exposure were the 2 environmental variables with the most infl uence on the structure of rocky-reef fi sh assemblages.