Biochemical Genetic Evidence for Fish Stocks in Lake Trout (Salvelinus namaycush), Bloater (Coregonus hoyi), and Brook Trout (Salvelinus frontalis) in the Great Lakes Region
File(s)
Date
1983-05Author
DuVall, Brian M.
Publisher
University of Wisconsin-Stevens Point, College of Natural Resources
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Show full item recordAbstract
Electrophoretic analysis of polymorphic isoenzyme systems in lake
trout (Salvelinus namaycush) from the Apostle Islands, Lake Superior, in
the bloater (Coregonus hoyi) from the western region of Lake Michigan, and
in brook trout (Salvelinus fontinalis) from a central Wisconsin stream and
from a state hatchery, was carried out to determine if intraspecific genetic
differences could be found as evidence of the existence of genetically
discrete stocks in these three species. Lake trout liver tetrazolium
oxidase allele frequencies were homogenous among three samples from
different areas in the Apostle Islands region, but liver NADP dependent
isocitrate dehydrogenase gamete frequencies were significantly different
among these groups of lake trout. Bloater muscle glycerol-3-phosphate
dehydrogenase allele frequencies were homogenous among five samples
collected over the range from Algoma to Kenosha, Wisconsin. Bloater muscle
isocitrate dehydrogenase allele frequencies differed among all sample pairs
on the basis of a best-fit genetic model. The latter differences support
data of the Wisconsin Department of Natural Resources on the possibility
of separate stocks of bloaters based on different age composition data of
samples from various areas of western Lake Michigan. Samples of brook
trout from Brewer Creek, Juneau County, Wisconsin collected in the year
before and after stocking was discontinued were compared genetically with
hatchery fish from Langlade Hatchery, Langlade County, Wisconsin on the
basis of malate dehydrogenase, glycerol-3-phosphate dehydrogenase, and
lactate dehydrogenase. Allele frequencies were significantly different in
at least one system among all three samples. Nei similarity indices
indicated that the hatchery sample was most similar to the stream sample
collected before stocking was discontinued and that the two stream samples,
collected before stocking was discontinued were most dissimilar. These data indicate a genetic effect of stocking on stream population.