HELMINTH COMMUNITY STRUCTURE OF CHIROSTOMA-ATTENUATUM (OSTEICHTHYES, ATHERINIDAE) IN 2 MEXICAN LAKES

Helminth community structure of Chirostoma attenuatum from two lakes o f Michoacan State, Mexico, was analyzed and compared. Helminths from 7 2 fish were counted and collected for taxonomical determination. Helmi nthological record oi C. attenuatum includes five species, three of th em shared by fishes of both localities. Helminth communities are consi dered to be isolationist and depauperate due to the low values of rich ness, abundance and diversity obtained; the digenean Posthodiplostomum minimum was the species numerically dominant. We conclude that the di fferences observed in helminth community structure between localities are due to differential biotic and abiotic conditions; in Patzcuaro La ke, conditions favor the increase of fish-eating bird populations that serve as definitive hosts to allogenic species such as P. minimum.