Distribution of megafaunal species in the Southwestern Atlantic: key ecological areas and opportunities for marine conservation

MANDIOLA, A.; SECO PON, JP; MIANZAN, H; FAVERO, M.; ALEMANY, D.; PROSDOCIMI, L; ACHA, M.; COPELLO, S.; GONZALEZ CARMAN, V; DASSIS, M.; PONCE DE LEON, A.; RODRIGUEZ, D.

ICES JOURNAL OF MARINE SCIENCE

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2016 vol. 73 p. 1579 - 1588

1054-3139

During the last centuries, populations of marine megafauna?such as seabirds, turtles, andmammals?were intensively exploited. At present, otherthreats such as bycatch and pollution affect these species, which play key ecological roles in marine ecosystems as apex consumers and/or nutrienttransporters. This study analyses the distribution of six megafaunal species (Chelonia mydas, Caretta caretta, Dermochelys coriacea, Thalassarchemelanophris, Otaria flavescens, and Arctocephalus australis) coexisting in the Southwestern Atlantic to discuss their protection in terms of currentmanagement strategies in the region. Through the prediction of the species potential distributions and their relation to bathymetry, sea temperatureand oceanographic fronts, key ecological areas are defined from a multi-taxa perspective. Information on the distribution of 70 individuals (18sea turtles, 19 albatrosses, and 33 otariids) was obtained through satellite tracking conducted during 2007?2013 and analysed using a GeographicInformation System and maximum entropy models. During the autumn?winter period, megafaunal species were distributed over the continentalshelves of Argentina, Uruguay, and Brazil, mainly over the Argentine Exclusive Economic Zone and the Argentina-Uruguay Common Fishing Zone.Despite some differences, all megafaunal species seems to have similar environmental requirements during the autumn?winter period. Mostlywaters shallower than 50 m were identified as key ecological areas, with the Rı´o de la Plata as the habitat with the highest suitability for all thespecies. This area is highly productive and sustains the main coastal fisheries of Uruguay and Argentina, yet its role as a key ecological area for megafaunalspecies has been underestimated until now. This approach provides a basis to analyse the effect of anthropic activities on megafaunal speciesthrough risk maps and, ultimately, to generate knowledge to improve national and bi-national management plans between Argentina and Uruguay.