Thirty-six enzyme loci were surveyed for 22 largemouth bass (Micropterus salmoides) populations from 7 watersheds in Alabama. Twenty-one loci were polymorphic. Nei's normalized genetic identity (I) and Rogers' genetic similarity (S) showed little divergence among the populations (I = 0.990 and S = 0.9792). However, several drainages contained unique alleles in frequencies greater than 0.05 and several alleles were identified that were not found in a previous nationwide survey. Significant intrapopulational heterogeneity was indicated by hierarchical F-statistics and contingency chi-square analysis. Clinal distribution of MDH-B alleles significantly affected populational differentiation. Allelic variation at MDH, AAT and IDH loci accounted for 82% of the total population differences. Variability of largemouth bass populations differed among the physiographic regions of Alabama. Frequencies of alleles from the Florida subspecies, M. s. floridanus. were increased through supplemental stocking programs in Alabama.
