Helminth communities in eels Anguilla anguilla from Adriatic coastal lagoons in Italy

The composition and diversity of the total and intestinal component and inf ra-communities were determined in eels Anguilla anguilla from three shallow lagoons on the Adriatic coast of Italy to determine whether the helminth c ommunities would differ in composition and structure from those in eels fro m lagoons on the Tyrrhenian coast. The lagoons differed in respect of their management regimes and the extent of freshwater influx. Both freshwater an d marine species of helminths were found in the eels in all three lagoons, but the freshwater component was richer in Valle Figheri. A suite of three digenean eel specialist species occurred in all three lagoons, of which any two members dominated each community. This conferred a high degree of simi larity between the communities of the three lagoons. The same three species also dominated helminth communities in eels in lagoons along the Tyrrhenia n coast of Italy, and compositional similarity levels were similar within a nd between western and eastern groups. Species richness was higher in the c omponent communities of the eels of the Adriatic lagoons when compared to t he Tyrrhenian ones, but diversity and dominance indices were of a similar o rder of magnitude and range. Intestinal helminth communities were richer an d more diverse in two of the Adriatic lagoons because the proportion of eel s with zero or one helminth species was, unusually, in the minority. It was nevertheless concluded that infracommunity structure was similar in eels f rom both western and eastern lagoons and that the hypothesis that it would differ in Adriatic lagoons could not be supported. The findings provide fur ther evidence of the similarity in composition and structure of helminth co mmunities in eels from coastal lagoons throughout Europe.