Helminths in an intensively stocked population of lake trout, Salvelinus namaycush, from Lake Huron

Eighty stocked lake trout Salvelinus namaycush (Salmonidae), collected from 2 locations in Lake Huron in May 1995, were examined for parasites. The pa rasite fauna of this top predator in Lake Huron was characterized by only 6 helminth species. Echinorhynchus salmonis infected all lake trout with a m ean intensity of 163.9. The intensity of this acanthocephalan species signi ficantly increased with host length and weight. Eubothrium salvelini infect ed 78 lake trout with a maximum number of 81 scoleces counted. Diplostomum sp., Cyathocephalus truncatus, Capillaria salvelini, and Neoechinorhynchus sp. infrequently infected lake trout. The low parasite species richness in these lake trout is believed to be due ro their large size at stocking and to the loss of historical enzootic host-parasite relationships that followe d the absence of this fish species in Lake Huron for 26 yr.