Differences in Early Development Among Lake Trout (Salvelinus namaycush) Populations

Abstract

Genetic differences among surviving lake trout (Salvelinus namaycush) populations might be important for the reestablishment of self-sustaining populations in the Great Lakes, but little relevant information is available to guide stocking practices. I studied eggs and fry of four populations, two from Lake Superior, one from Trout Lake, and one (the Green Lake strain) derived in part from Lake Michigan. I found significant interpopulation differences in hatching and emergence times as well as in indices of morphological development rates. Interpopulation differences in morphological development at the times of emergence suggest that the Green Lake strain emerges at an earlier stage of morphological development than do the other populations. Between-lake differences are the most important sources of variability in my data; the Lake Superior populations were similar to one another, and variation among crosses within populations was small.