Helminth communities of native and introduced fishes in Lake Pátzcuaro, Michoacán, México.
Helminth communities of 10 common species of fishes (n=598) in Lake Patzcuaro, Mexico, are described. The fishes were sampled concurrently (May and October 1998) and the results are discussed in relation to diet, faunal exchange, translocation and biogeography in a tropical lake system. Of the 19 species of helminths identified (5 digeneans, 2 monogeans, 4 cestodes, 1 acanthocephalan and 7 nematodes), 9 were found as adult stages. Alloophorus robustus (Goodeidae) possessed the richest helminth community. The intestinal communities of native fishes were characterized and dominated by host-specific helminths; introduced species of fishes were also often dominated by host-specific helminths, which had been introduced into the lake with the host. It was concluded that latitude alone does not contribute to a rich and diversified parasite community and that a combination of historical and contemporary factors plays an important role in determining helminth community diversity and structure in these fishes.