Bull trout (Salvelinus confluentus) populations from Alberta river drainage systems were compared using molecular techniques. Restriction fragment length polymorphisms (RFLP's) within the NDI and ND5/6 regions of the mitochondrial genome were observed. In addition, randomly amplified polymorphic DNA profiles (RAPD's) from total genomic DNA extracts were compared. Interdrainage comparisons using mtDNA revealed significant population heterogeneity among Alberta bull trout. Percent sequence divergence in mtDNA ranged from 0.14% to 0.92%. Most fish in each population were composed of a small number of common haplotypes, and the remaining fish displayed rare or locally unique haplotypes. RAPD profiles were used to calculate genetic distance values for Alberta, Canada and Montana, U.S.A. populations. Both Nei and Cavalli-Sforza distance values were used to generate neighbor-joining, FITCH and KITSCH distance trees. Two genetically distinct groups of bull trout were revealed by the RAPD analysis and the possiblity that post-glacial bull trout populations are derived from two separate refugia is suggested. / xvii, 161 leaves : ill. ; 28 cm.