Parasites of fish of Algonquin Park lakes.

Abstract In the study of the parasites of fish from lakes in Algonquin Park, Ontario, 560 fish of 22 species were examined and 84.3 per cent carried at least one form. Many of the fish carried larval trematodes which have fish-eating birds as their definitive hosts. Lakes containing smallmouth black bass had several species of fish infested with larval cysts of the cestode, Proteocephalus ambloplitis (Leidy). Fish from lakes that did not contain smallmouth black bass did not carry this cestode. Proteocephalus fluviatilis Bangham, described previously only as a parasite of black basses in streams, was secured in black bass from seven Algonquin Park lakes. A leech, Actinobdella triannulata Moore, not previously reported as a parasite of fish was found on 24 per cent of the common suckers. Ten species of fish examined were of the family Cyprinidae. Of these minnows, 64.4 per cent were infested with at least one species of parasite. The parasites of the minnows were of few different species and the majority o...