Temporal and Spatial Structure of the Reef Fish Community of the West Coast of La Paz Bay, México

Abstract

Ecological studies were performed to evaluate the temporal and spatial variation of reef fish communities of eight localities of the west coast of La Paz Bay, from March 2002 to April 2003. Visual census with 48 transects of 100×5 m (500 m2) were performed. Two climate seasons were detected: cold and warm. A total of 26,608 organisms from 112 species and 76 genera were observed. Relative abundance index was used to determine the most important species, which were: Abudefduf troschelii, Thalassoma lucasanum, Stegastes rectifraenum, Mulloidichthys dentatus, Chromis atrilobata, Lutjanus argentiventris, and Scarus ghobban. Diversity determined in February showed the lowest value (3.12 bits/ind.) and October showed the highest value (4.13 bits/ind.). According to the biological value index (BVI), and considering the climate seasons, species that obtained a higher score during the cold months were: Abudefduf troschelii, Mulloidichthys dentatus, Scarus ghobban, Stegastes rectifraenum, Thalassoma lucasanum, and during the warm months the same species were observed but in different order and abundance: Abudefduf troschelii, Scarus ghobban, Stegastes rectifraenum, Thalassoma lucasanum and Mulloidichthys dentatus. A higher number of species and higher abundance of fish were observed in the localities of the eastern part of the island. The principal component analysis (PCA) shows habitat characteristics and ecological features, where a strong correlation between these and rugosity was observed.