Biogeographic patterns in the cartilaginous fauna (Pisces: Elasmobranchii and Holocephali) in the southeast Pacific Ocean.

摘要: The abundance and species richness of the cartilaginous fish community continental shelf slope off central Chile is described, based on fishery-independent trawl tows made in 2006 2007. A total 194,705 specimens comprising 20 (9 sharks, 10 skates, 1 chimaera) were caught at depths 100–500 m along a 1,000 km transect between 29.5°S 39°S. Sample site locations grouped to represent eight geographical zones within this latitudinal range. Species fluctuated from 6 per zone. There was no significant trend for but skates showed an increased with latitude. Standardised catch unit effort (CPUE) increasing depth not observed CPUE latitude either sharks or skates. change composition occurred gradient Psammobatis rudis, Zearaja chilensis Dipturus trachyderma dominating communities 100 300 m, small-sized, deep-water dogfishes, such as Centroscyllium spp. dominated 500 m. Cluster ordination analysis identified one widespread assemblage, grouping 58% sites, three shallow-water assemblages. Assemblages low diversity (coldspots) coincided highly productive fishing grounds demersal crustaceans bony fishes. distribution suggested that differences assemblages may be due compensatory changes mesopredator abundance, consequence continuous unselective removal. Distribution patterns quantitative assessment chimaeras presented here complement extant biogeographic knowledge further understanding ecosystem dynamics relation activity south-east Pacific Ocean.