Structure of the coastal fish assemblage from the channels and fjords of central Chilean Patagonia (48 degrees-52 degrees S)

摘要

The central coast of Patagonia (48 degrees-52 degrees S) is a particular area to assess the diversity and structure of fish assemblage due to the different oceanographic gradients. In this study, we determined the identity, richness, and diversity indices, and characterized the structure of the coastal fish assemblage by non-parametric analysis of variance using permutations and multidimensional scaling including 6 localities with oceanic influence and 6 localities with continental influence, associated with Western and Eastern sectors of the channel system, respectively. A total of 380 coastal fish specimens, belonging to 17 species from 12 families, were collected. Species richness showed significant differences between the locations analyzed, with greater richness in locations associated with the sectors of East. In turn, there were no significant differences using the Shannon diversity index between groups of stations. Significant differences were found in the composition of assemblages between clusters East-West, identifying 8 species that contributed to the dissimilarity between assemblages by SIMPER test. The Patagonian blenny, Eleginops maclovinus, was the species that most contributed to the dissimilarity, followed by the notothenioid fish Patagonotothen cornucola and silverside Odontesthes regia. The changes observed in species richness and assemblage composition, suggest that the fish from the coastal ecosystem of the channels and fjords of central Patagonia, presents a longitudinal pattern of structuring; regarding the composition of the assemblage between East and West locations, which could be related to environmental variables (e.g., salinity and glacial sedimentation) present in this area.