Population or Stock Structure of Lake Whitefish, Coregonus clupeaformis, in Northern Lake Michigan as Assessed by Isozyme Electrophoresis

Abstract

Electrophoretic analysis of three polymorphic isozymes (lactate, malate, and glycerol-3-phosphate dehydrogenases) from lake whitefish, Coregonus clupeaformis, indicated that at least four populations exist in northern Lake Michigan. Cluster analysis of Nei genetic identity indices revealed much temporal and spatial overlap among population ranges. The overlap did not appear complete since the LDH A allele exhibited clinal variation with increasing frequency from south to north. Because population ranges overlap spatially and temporally, commercial catches are likely to contain fish from more than one population.Key words: population (stock), isozyme electrophoresis, lake whitefish, Lake Michigan