PARASITES OF LAKE HERRING (COREGONUS-ARTEDI) FROM LAKE SUPERIOR, WITHSPECIAL REFERENCE TO USE OF PARASITES AS MARKERS OF STOCK STRUCTURE

We examined parasites of 152 lake herring (Coregonus artedi) collected from three locations in Wisconsin waters of Lake Superior in 1994, fo ur locations in Wisconsin waters in 1996, and one location in Minnesot a waters in 1996 to determine: 1) the species composition and relative abundances of parasites in lake herring, 2) the differences in parasi te relative abundances across locations sampled, and 3) the utility of parasite relative abundances as markers of stock structure. Parasites form 19 taxa infected lake herring collected in 1994 and 1996; Henneg uya zschokkei, Chloromyxum sp., and Cyathocephalus truncatus were repo rted in fishes from Lake Superior for the first time, and Clinostomum marginatum was reported in lake herring for the first time. Significan t differences in abundances of eight parasite taxa were found across l ocations sampled in 1996, with most of the differences occurring betwe en fish from Minnesota and Wisconsin waters Nonparametric discriminant function analyses correctly classified 105 of the 108 fish (97%) from Wisconsin waters in 1994 and 1996 and also correctly classified 9 of the 13 fish (69%) from the one location in Minnesota waters. This indi cated that little mixing of lake herring from those regions occurred a nd that the potential exists to use parasite abundances as a marker of lake herring stock structure. This was the first time that multivaria te analysis of parasites have been used in the Great Lakes to access s tock structure of fishes. Because the technique was highly successful at classifying locations of our samples, we recommend that parasite ab undances in lake herring from all areas of the lake be analyzed as par t of a larger study to determine whether lake herring from populations throughout the lake can be as accurately classified as were fish in o ur study.