Towards regionalization of the chondrichthyan fauna of the Southwest Atlantic: a spatial framework for conservation planning

SABADÍN, DAVID; LUCÍFORA, LUIS O.; BARBINI, SANTIAGO; FIGUEROA, DANIEL; KITTLEIN, MARCELO J.

ICES JOURNAL OF MARINE SCIENCE

OXFORD UNIV PRESS

Año: 2020 p. 1 - 12

1054-3139

Biogeographic regionalization identifies natural species assemblages of a given region. In this study, the geographic distribution of chondrichthyanspecies richness and species assemblages for the Southwest Atlantic were identified. The geographic distribution of 103 chondrichthyanswas estimated through modelling. Based on the obtained binary maps, the distribution of chondrichthyan richness was obtainedat four taxonomic levels: class Chondrichthyes (chondrichthyans), subclass Holocephali (chimaeras), division Selachii (sharks), and divisionBatomorphi (batoids). The continental shelf off Uruguay and southern Brazil presented the highest levels of chondrichthyan richness, and asmaller peak was found in El Rinco´n (northern Argentina). Shark richness concentrated mainly off Lagoa dos Patos (southern Brazil). Batoidrichness was maximal off Uruguay and northern Argentina, including modes in El Rinco´n, San Jorge Gulf, and slope of the Argentinean shelf.Classification analyses revealed the presence of a hierarchical regionalization, with three main and six minor assemblages. Main assemblagesare hierarchically identifiable as provinces and minor ones as ecoregions or districts. Two of the main assemblages correspond with theArgentinean and Magellanic Provinces; the third one is identified here for the first time, the Patagonian Slope Province. This regionalizationprovides the basis for the design of protected area networks for conservation or management purposes.