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

prevalence of cestodes (tapeworms) may be the result of a change in the diet of S. vitreus due to
reduced abundance of Alosa pseudoharengus, which was a principal prey fish for S. vitreus. In
response to reduced abundance of A. pseudoharengus, S. vitreus changed its diet to include more
of other kinds of forage fish, including a variety of cyprinid minnows and Perca flavescens that
serve as second intermediate hosts and paratenic hosts for the cestodes Bothriocephalus sp. and
Proteocephalus sp.
CONCLUSIONS
The small number of studies performed on the parasites of fish in the Great Lakes after 1990 is
not surprising since there are few fish parasitologists working in the Great Lakes area. This
shortage is attributable to fewer fish parasitologists being trained, few fish parasitologists being
employed by agencies and institutions in the Great Lakes area, and the lack of funds to support
fish parasitological studies. The deficiency of research on the parasites of fishes and on the
ecology of fish diseases in the Great Lakes and connecting waterways is disturbing. Furthermore,
the entry of exotic parasites and exotic invertebrates and fishes with their parasites into the Great
Lakes makes increased vigilance a necessity.
There are probably large numbers of parasite species present in fish of the Great Lakes and their
connecting bodies of water that are still to be found, described, and/or recorded. It is difficult to
even estimate the total number of parasite species in fish from each lake since many fish species
have not been examined, and several fish species have only been examined once. A great deal of
work is needed before we have a more-complete list of parasites of fish from the Great Lakes.
Even if this list is completed, there will remain the greater task of examining and mapping the
distribution of the parasites in relationship to a variety of variables in the Great Lakes. It is our
view that this synopsis is a starting place for future parasite studies. We believe that a holistic and
integrative approach to research should be undertaken to study the parasites of fish in each Great
Lake that involves parasitologists, fish health specialists, ichthyologists, fisheries biologists, and
other researchers from various agencies and institutions.
ACKNOWLEDGMENTS
We gratefully acknowledge the Great Lakes Fishery Commission, Ann Arbor, Michigan, for their
support of this synopsis. We thank James W. Peck for his detailed edit of an earlier version of this
report and Michael Lima for his technical assistance in compiling some information for this
synopsis.
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