Peces arrecifales (original) (raw)

A characterization of the reef fish assemblages is presented for the region of Bahía de los Ángeles. For this study, 14 sites distributed along the peninsular coast and islands, covering a distance of 75 km from the north (Cantiles de Guadalupe) to the south (Los Choros) boundaries were investigated. The number of species and their abundance was determined by means of visual censuses. Ninety-three species of fish of 32 families were recorded, most of which corresponded to the families Serranidae (9), Chaenopsidae (8), Gobiidae and Haemulidae (7) and Labrisomidae (6). Thirteen species are endemic to the Gulf of California. The most abundant functional trophic groups corresponded to territorial omnivores (mean = 0.25 individuals m-2) and zooplanktivores (0.17 individuals m-2), although, the most frequent were cryptic zoobenthyvores (100%) and conspicuous zoobenthyvores (97.5%). Fish were classified into four groups (rare, frequent, common, and typical), with Crocodilichthys gracilis (1.36 individuals m-2), Lythrypnus dalli (0.39 individuals m-2) and Stegastes rectifraenum (0.25 individuals m-2) being the dominant species regarding their abundance and frequency of occurrence (>80%). Limbaugh´s chromis, Chromis limbaughi, a species with great abundance (1.15 individuals m-2), was associated with deep sites and strong currents; not withstanding, its frequency was low (37.5%). The average number of species was highest in shallow zones (mean = 17.56 spp.) and decreased in the middle and deep strata (14.66 spp.), while the mean density of each strata (from 3.09 to 9.91 individuals m-2) showed an opposite pattern. The cluster analysis separated the deep sites of Alcatraz, Coronadito and El Quemando as well as El Suspiro, in Isla Ángel de la Guarda, from the rest. Analysis per habitat shiwed that bare sites presented higher density of individuals than those covered by macroalgae and did not show significant differences when compared with rocky walls with kelp, or with calcareous rock and Padina spp. This suggests a generalized spatial distribution of species, with the separation of habitats being determined solely the density of a few species. Comparisons with other locations in the Gulf of California demonstrate the substitution of a few species and functional groups for others (i.e. lutjanus for labridae), just as the distribution of the determined dominance of species varies between several to a few species.