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

Parasite Host Specificity—Jaccard Coefficients
Forty-one parasite species reported from fish in two or more families make up 18% of all the
parasites reported from fish in this lake. These 41 parasite species have indirect life cycles with
fish becoming infected by eating intermediate hosts or paratenic hosts, except for
Ichthyophthirius multifiliis, Gyrodactylus avalonia, Myzobdella lugubris, Argulus catostomi, and
Ergasilus spp. Most of the 41 species were digenetic trematodes (29%) and nematodes (27%).
Only one monogenean species was shared between fish families. There are 185 parasite species
that are host specific to one fish species or family in Lake Ontario.
Jaccard coefficients of similarity for the parasite communities between individuals in the five
fish-family comparisons were low, indicating these families did not share many parasite species.
As was the case in Lakes Huron and Erie, the highest coefficient (0.1158) involved the Percidae
and Centrarchidae. Although fish in Centrarchidae and Percidae have the most parasite species
(69 and 58, respectively), these two families shared only 17 parasite species and this maximum
coefficient was the lowest maximum in the Great Lakes. The next highest coefficient involved the
Percidae and Cyprinidae (0.1136).,
Fish Families—Parasite Communities
The monogeneans were the most-common parasite group, in terms of percentage, infecting the
cyprinids, catostomids, and centrarchids. The digenetic trematodes were the most-common group
in the percids. Cestodes were the most-common parasite group found in the salmonids.
Most fish species examined for parasites from Lake Ontario were cyprinids (12 species) followed
by salmonids (9 species). Cyprinids and salmonids harbored 47 and 21 parasite species,
respectively. The centrarchids were infected with the most parasite species (69) followed by the
percids (58 species). Catostomids were infected with 25 parasite species and had the highest
percentage of autogenic helminth species. Cyprinids had the highest percentage (38%) of
allogenic helminth species. As with the other Great Lakes, allogenic species did not make up 50%
or more of the parasites found in these fish families. Based on the literature regarding the
numbers of fish species examined in each family and the number of parasite species found, Lake
Ontario is characterized by a mixture of cyprinids, centrarchids, and percids and their autogenic
helminth species followed by the catostomids and salmonids with their autogenic parasites.
The autogenic helminth species found that mature in fish include the larval/immature digenetic
trematodes (Bucephalus sp., Centrovarium lobotes), larval/immature cestodes (Bothriocephalus
cuspidatus, bothricephalid plerocercoids, Proteocephalus ambloplitis, Proteocephalus sp.,
Triaenophorus crassus, T. nodulosus, T. stizostedionis) and larval/immature nematodes
(Hysterothylacium brachyurum, Hysterothylacium sp., Raphidascaris acus, Camallanus
oxycephalus, Spinitectus sp., Philometra cylindracea, Rhabdochona sp.). Of the allogenic
helminth species found in fish, larvae of the digenetic trematodes of Clinostomum complanatum,
Crassiphiala bulboglossa, Diplostomum adamsi, D. spathaceum, D. spathaceum huronensis,
Diplostomum sp., Neascus sp., Posthodiplostomum minimum, P. minimum centrarchi, Uvulifer
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