CONSERVATION GENETICS OF BROOK TROUT (SALVELINUS-FONTINALIS) - POPULATION STRUCTURING IN FUNDY NATIONAL-PARK, NEW-BRUNSWICK, AND EASTERN CANADA

To determine the structure of brook trout (Salvelinus fontinalis) gene tic variation in eastern Canada and to assess the potential impact of stocking in Fundy National Park, New Brunswick, 1096 and 445 brook tro ut were examined for allozyme and mitochondrial DNA variation, respect ively. The trout were derived from 33 natural locations and one hatche ry source. Low divergence among the mitochondrial DNA haplotypes sugge sts a single glacial refugium for the trout recolonizing the region. H igh levels of population differentiation were found with allozymes, wi th the majority of the differentiation occurring among branches within drainages of rivers, suggesting little present-day gene flow among mo st populations. Comparisons of both allozyme and mitochondrial DNA var iation between descendants of the hatchery strain used to stock Fundy National Park and present-day populations within the park suggest that hatchery trout made minimal contributions to the gene pools of these populations. Lower levels of heterozygosity were found in brook trout from lakes than from streams, possibly because of intense fishing pres sure.