Environmental stress as a potential threat for conservation of Franciscana dolphin (Pontoporia blainvillei), a vulnerable species in coastal waters of Buenos Aires

GERPE, MARCELA SILVIA; ROMERO, MARÍA BELÉN; CHIODI BOUDET, LEILA NATALIA; ROBLES, ALICIA DANIELA; RODRIGUEZ, DIEGO; POLIZZI, PAULA SABRINA

Liege

Conferencia; 28th CONFERENCE OF THE EUROPEAN CETACEAN SOCIETY; 2014

Pontoporia blainvillei (Franciscana or La Plata river dolphin) is a small coastal dolphin that lives exclusively estuarine and marine habitats on the Atlantic coast of South America (18º and 42ºS). It is probably the most endangered cetacean of the Southwestern Atlantic due that die annually between 2000 and 3000 dolphins incidentally caught in fishing artisanal nets from coasts of Brazil, Uruguay and Argentina. In Argentine waters, the geographical distribution of the P. blainvillei is mainly along the Buenos Aires province coast, presenting genetic discrete units. This species inhabits environments with different characteristics Contracting (oceanogra-phic, hydrological, pollution, etc.) so it can be exposed to different stressors. There are two geo-graphic groups of Franciscana, estuarine and marine, the former are living in waters influenced by La Plata River, being an impacted environment. The Franciscana dolphin from Argentine waters is legally protected from any commercial exploitation; it is also included in the Appendix II of the Convention on International Trade in Endangered Species (CITES), Appendix I of the Convention on Migratory Species (CMS) and classified as Vulnerable (A3d) by the Internatio-nal Union for Conservation of Nature (IUCN) Red List of Threatened Species, due to the projection of decline more than 30% within three generations. The objective of the project P. blainvillei is to evaluate, in an integral way, body condition and environmental stress of dol-phins from different geographic-genetic groups by assessing the feeding habits and trophic dynamics, inorganic body, fat reserves, inorganic and organic contaminants and biomarkers. So far, the obtained results have indicated differences between the two geographic groups. Cd le-vels were higher in marine dolphins, associated with their diet rather than anthropogenic sources. The concentrations of Cu and Zn were similar and represent normal physiological values in relation to the MTs levels. These proteins were higher in liver and decreased with age. LT-weight curves, dietary ecology and body condition were established, showing also differen-ces between groups. The percentage of plastics in estuarine dolphins was higher than those found in marine organisms, this suggest an association with urban-industrial waste that receives the La Plata river. Currently are initiating the analysis of stable isotopes of C and N, and are still pending the analysis of organic contaminants.