Abstract
European eel parasites, in particular invasive species, are suspected to have a strong influence on the population dynamics of their host. The aim of this work was to study the relationship between parasitic fauna of yellow eels caught at Salses-Leucate lagoon and the fluctuating asymmetry (FA) of some functional bilateral traits: pectoral fins, eyes and otoliths. Epidemiological distance matrices and FA distance matrices were calculated on the basis of Euclidian distances between each pair of eel and were then compared wiht a Mantel test in order to establish if there was a relationship between parasitism and FA. Our results revealed different morphological characteristics between eels caught at different dates; only otoliths were found asymmetric. The parasite richness was of 10 species, 1 Nematoda, 1 Acantocephala, 1 Monogenea and 7 Digenea. We failed to find a significant relationship between asymmetry and parasitism, except fo parasites found in the stomach. We discussed the results in the light of the eel life cycle, the specificity of parasite-eel systems and the impact of parasites on the host physiology