Isotopic niche variation in franciscana dolphin Pontoporia blainvillei from Argentina

PASO VIOLA MARÍA NATALIA; DENUNCIO PABLO; CAPPOZZO HUMBERTO LUIS; RICCIALDELLI LUCIANA; TESSONE AUGUSTO; DIEGO H. RODRIGUEZ; PANARELLO H

San Clemente del Tuyú, Mundo Marino

Workshop; ESOCC - Franciscana Workshop 2019; 2019

YAQU PACHA & Zoo y Mundo Marino

The use of stable isotopes data to infer population trophic niche width has become increasinglycommon. We assessed intra-specific variation in the isotopic niche of franciscana along the entirecoast of Buenos Aires (FMA IV), its southern distribution range. For this, we analyze the isotopiccomposition of muscle of 96 dead specimens in artisanal fishing nets from distinct locations (BahíaSamborombón, Partido de la Costa, Necochea-Claromecó and southern Buenos Aires) usingSIBER (Stable Isotope Bayesian Ellipses in R). 13C and 15N values showed a clear segregationbetween the different environments analyzed. The groups of estuarial waters had a wider isotopicniche than those from marine environments. The trophic differentiation between these groupsagrees with the existence of genetically distinct populations recently found in the study area. Thisstudy reveals geographical variations in the isotopic niche of franciscana dolphin, supporting thenew delineation of distinct franciscana populations in Argentine waters.