Isotopic niche variation in franciscana dolphin Pontoporia blainvillei from Argentina.

TESSONE, A; CAPPOZZO, H. L.; DENUNCIO, P; RODRIGUEZ, D; PASO VIOLA, M. N.; PANARELLO, H.; RICCIALDELLI, L.

San Clemente del Tuyú

Congreso; ESOCC Franciscana WS 2019, Argentina,; 2019

Yaqu Pacha, IUCN

The use of stable isotopes data to infer population trophic niche widthhas become increasingly common. We assessed intra-specificvariation in the isotopic niche of franciscana along the entire coast ofBuenos Aires (FMA IV), its southern distribution range. For this, weanalyze the isotopic composition of muscle of 96 dead specimens inartisanal fishing nets from distinct locations (Bahía Samborombón,Partido de la Costa, Necochea-Claromecó and southern Buenos Aires)using SIBER (Stable Isotope Bayesian Ellipses in R). 􀀀13C and 􀀀15Nvalues showed a clear segregation between the differentenvironments analyzed. The groups of estuarial waters had a widerisotopic niche than those from marine environments. The trophicdifferentiation between these groups agrees with the existence ofgenetically distinct populations recently found in the study area. Thisstudy reveals geographical variations in the isotopic niche offranciscana dolphin, supporting the new delineation of distinctfranciscana populations in Argentine waters.