Be. Vanzee et al., MORPHOLOGICAL AND ELECTROPHORETIC EXAMINATION OF STIZOSTEDION SAMPLESFROM LEWIS AND CLARK LAKE, SOUTH-DAKOTA, Journal of freshwater ecology, 11(3), 1996, pp. 339-344
Cellulose acetate electrophoresis was used to screen muscle and liver
samples from 50 Stizostedion individuals collected from Lewis and Clar
k Lake, South Dakota to determine the degree of hybridization between
walleye (Stizostedion vitreum) and sauger (Stizostedion canadense) and
to assess the accuracy of morphological identification. Electrophoret
ically, 40 fish were identified as sauger, five as walleye, and five a
s hybrids. Thus, there was approximately a 10% hybridization rate for
this sample from Lewis and Clark Lake. Identification based on morphol
ogical characteristics significantly (P < 0.05) overestimated the perc
entage of hybrids compared to the electrophoretic analysis. Morphologi
cally, 34 fish were identified as sauger, seven as walleye, and nine a
s hybrids. Eight fish (16%) were incorrectly identified using external
traits. Because the electrophoretic and morphological identification
differed, biologists should be cautious when monitoring these fishes o
r when using wild broodstock from systems in which both species are pr
esent.