Multivariate Analysis of Biomarker Responses in European and American Yellow Eels in the Gironde and St. Lawrence Estuaries

This study is part of an international program ‘IMMORTEEL’ investigating the possible contribution of habitat contamination in the decline of Atlantic eels. Biomarker responses and muscle concentrations of persistent organic contaminants (POPs) were examined in European eels (Anguilla anguilla) and American eels (Anguilla rostrata) in the Gironde and St. Lawrence Rivers basins. In 2011 and 2012, yellow eels were collected at two reference sites (Certes and Dordogne in France and Rivière Sud-Ouest and Rivière Saint-Jean in Quebec, Canada) and two contaminated sites (Garonne and Gironde in France and Lake Saint-Pierre and Lake Saint François in Quebec). Principal component analysis was useful to discriminate effects of natural ecological gradients and anthropogenic contaminant gradients on biological responses, over a large geographic scale. Patterns of contamination differed markedly between France and Quebec, with higher PCB concentrations relative to other POPs from France. In 2012 but not in 2011, hepatic ethoxyresorufin O-deethylase induction and increased density of splenic melanomacrophage centers were detected in eels from Garonne and Gironde compared to reference sites. In Quebec, morphometric characteristics were the major discriminant factors between upstream contaminated and downstream reference sites. Links between biomarker responses, exposure to other groups of contaminants and health impacts will be discussed.