Les métaux lourds comme indicateurs d'origine géographique de l'anguille d'Amérique (Anguilla rostrata)

American eels (Anguilla rostrata) were sampled from the St. Lawrence River and many of its tributaries. Heavy metal concentrations (Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn) in muscles were analyzed in relation to collection site, age, length, and weight of the specimens. Among the essential heavy metals, zinc, copper, and especially manganese can be used to distinguish the samples by their origin. In the Saguenay River, which is contaminated by mercury wastes, it is possible to distinguish two types of eels according to their mercury content, weight, and length leading to the hypothesis that these two types lived in different parts of the drainage system. The metal concentrations in the eels seem to depend on the availability of these metals in the bottom sediments. Analysis by flexible grouping and principal coordinates yields groups that are not sufficiently homogeneous and distinct to conclude to a specific pattern of heavy metal contents for all the different origins.