Parasites of Fish from the Great Lakes - Great Lakes Fishery ...

affect its distribution. If the appropriate intermediate and/or fish hosts are absent, the parasite will
be too.
The parasite community of a fish species is composed of the: 1) parasites specific to that species,
or more commonly, a higher phylogenetic grouping of fish; 2) parasites whose specificity is
determined by an intermediate stage in their life cycle; and 3) parasites that exhibit little host
specificity. Fish are not only infected by parasites specific to them, but also by species
secondarily acquired from prey. These latter parasite species will vary according to the
environment inhabited by the specific fish species and the other fish species present.
Based on the occurrence of parasite species in fish in the Great Lakes, many parasite species
show strict host specificity to a single host species (e.g., many protozoan species and most
monogenean species), some species show host specificity to a fish family (e.g., Thelohanellus
notatus, Phyllodistomum staffordi, Lissorchis attenuatus, Glaridacris catostomi, Octospinifer
macilentus), while other parasite species show no host specificity infecting several fish species in
different fish families (e.g., Crepidostomum cooperi, Camallanus oxycephalus, Acanthocephalus
dirus, Echinorhynchus salmonis). Other examples of parasite species in each of these specificity
groupings can be found in the tables for each of the Great Lakes.
Jaccard Coefficients of Similarity for Parasite Communities Among the
Five Great Lakes
Jaccard coefficients of similarity for the parasite communities among the five major fish families
(Centrarchidae, Cyprinidae, Catostomidae, Percidae, and Salmonidae) in each Great Lake were
low, indicating that fish in these families do not share many parasite species, and as well, parasite
communities in each family were not similar among the five Great Lakes (Tables 30-34). The
centrarchids in Lake Michigan do not share many parasite species with centrarchids in the other
Great Lakes, with the lowest coefficient involving Michigan and Superior (0.0689) (Table 30).
The highest value involved centrarchids from Huron and Erie (0.4347), followed by Huron and
Ontario (0.4090). Cyprinids in Lake Michigan share the smallest number of parasite species with
cyprinids from the other lakes (Table 31). The lowest value (0.0588) involved cyprinids from
Michigan and Erie. Parasite coefficients ranged from 0.1466 to 0.2941 involving cyprinids from
Superior, Huron, Erie, and Ontario. For catostomids, the highest coefficients were between
Superior and Ontario (0.4250) and between Erie and Ontario (0.4210) (Table 32). Overall, the
parasite communities of percids in the Great Lakes were the most similar, with the highest
coefficients between Lakes Huron and Ontario (0.5000) and between Lakes Huron and Erie
(0.4938) and the lowest coefficient between Michigan and Erie (0.2714) (Table 33). The
salmonids in Lake Superior shared the largest number of parasite species with salmonids in Lake
Huron (0.4761), followed by salmonids in Superior and Ontario (0.3000) (Table 34). Parasite
faunas of salmonids in Erie and Michigan are most dissimilar with a value of 0.1250. Lakes
Michigan and Erie are very different in their physical habitat; however, the habitat used by
salmonids in these lakes may not be so different.
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