Oxidative stress: biomarker of effects and exposure in two sympatric otariids with contrasting population trends.

GERPE, MS; POLIZZI, P; ROMERO, MB; CHIODI BOUDET, LN; RODRIGUUEZ, D; ALBERTO PONCE DE LEON

Liege

Workshop; 28th Conference of the European Ceatcean Society; 2014

European Cetacean Society

Marine mammals are top predators of trophic web and may be exposed to different types of environmental stressors; chemical (heavy metals, persistent organic compounds) and biological-ecological (qualitative quantitative prey depletion, niche overlapping). Individually or in groups cause stress, which can be assessed by biomarkers. Sea lions one and two hairs (Otaria flavescens and Arctocephalus australis ) South Americans are dominant top predators of northern Argentina , Uruguay and southern Brazil and its population scenarios are contrasting , with a marked decline and a sustained increase O.flavescens of A.australis . So far not studied the possibility of some kind of environmental stress , with the objective of this project to assess the ecotoxicological and environmental status of both species from the study of biomarkers in blood , complemented by the comparison of veterinary clinical parameters and foraging strategies . Determination of heavy metals with physiological functions (zinc and copper) and those without ( cadmium and total mercury ) , and essential non-metals (selenium ) levels of both species is proposed , as well as analyze the mercury - selenium relationship as detoxification mechanism . In addition the biomarker study environmental stress is proposed in different blood fractions, such as levels of metallothionein ( MT ) , oxidative effects by analyzing lipid oxidation (LPO ) and protein (OP ) , activity of enzymes of the antioxidant system ( superoxide dismutase ( SOD) , catalase (CAT ) , glutathione peroxidase (GPX ) and glutathione- s - transferase (GST ) ) , and its relation to serological and haematological parameters. These measurements were performed on individuals of which their movements are recorded by satellite telemetry in open sea and oxygen consumption at rest is analyzed by open flow respirometry . Thus it is expected to have an overview of the relationship between stress levels and different strategies for obtaining energy, and its association with potential opposing population trends. It is hoped that the knowledge of the stress state of these species multiparameter relevant as a diagnostic tool and a future for the interpretation and the establishment of their conservation status .