Demersal fish assemblages of the continental shelf off Colima and Jalisco, Mexico (spring, 1995)

Abstract

The structure of the soft-bottom demersal fish assemblages of the continental shelf off Jalisco and Colima, Mexico, was studied in an area of 410 km². The classification of the 32 most abundant species resulting from the cluster analysis shows eight groups (three from the inner shell; four from the intermediate shelf and one from the slope shelf). The ordination through detrended correspondence analysis (DCA) defined seven units; the affinity and composition of these units were similar to that of the other technique. The multiple contrasts of the analysis of variance, using the depth/temperature/salinity scores, were significantly correlated with the group of stations and with the eigenvalues calculated for the species with the DCA. This confirms the presence of a bathymetric/thermic gradient and that the shallow thermocline has a segregation effect on the demersal assemblages of soft-bottom fishes.