Digenean diversity in labrid fish from the Bay of Bizerte in Tunisia.

Six species of digeneans (Proctoeces maculatus (Looss, 1901), Helicometra fasciata (Odhner, 1902), Helicometra pulchella (Odhner, 1902), Macvicaria alacris (Looss, 1901), Peracreadium genu (Nicoll, 1909) and Zoogonus rubellus (Olson, 1868)) were found for the first time in labrid fish (Symphodus tinca (Linnaeus, 1758), Labrus merula (Linnaeus, 1758) and Labrus viridis (Linnaeus, 1758)) from the Bay of Bizerte. Except for P. maculatus and Z. rubellus, which are limited to the rectum, these helminths colonize the entire digestive tract. The study of the seasonal prevalence, abundance and mean intensity shows that three parasites, P. maculatus, H. fasciata and P. genu are present throughout the year while H. pulchella, M. alacris and Z. rubellus are less frequent and appear only in spring (H. pulchella and M. alacris) or in spring and summer (Z. rubellus). The levels of infection and digenean faunal diversity in labrid fish from the Tunisian coasts are generally lower than those from localities within the western Mediterranean.