Communities of metazoan parasites in open water fishes of Cold Lake, Alberta

Communities of metazoan parasites in ten species of fishes from Cold Lake, Alberta are described and compared. Relative abundances in the overall community of parasites in the lake were estimated using data on abundance in each host species, plus estimates of the relative abundances of the species of hosts. Parasites of the numerically dominant salmonid fishes dominated the overall community, with over half of the individual parasites being Metechinorhynchus salmonis . Exchange of parasites between host species was greatest between related and/or abundant host species. Parasite communities in cisco and whitefish, Coregonus spp., were relatively rich in species and diverse (Simpson's index) compared with communities in those species in other lakes in North America; communities in lake trout, Salvelinus spp., and the non‐salmonid fishes were poor in species and low in diversity compared with communities in other lakes. Parasite species overlaps (Jaccard index) between related host species in Cold Lake were greater than overlaps within host species between lakes. The same pattern is seen in data from some other lakes. These features support the hypothesis of Wisiewski (1958); that the parasite community within an ecosystem is characterized by parasites of the numerically dominant hosts.