Abstract
To determine the origin of Florida largemouth bass (Micropterus salmoides floridanus) introduced into Lake Biwa, haplotype variation in the control region of mitochondrial DNA (mtDNA) of largemouth bass (Micropterus salmoides) was analyzed for 107 individuals from Lake Biwa and Lake Nishinoko (the Lake Biwa region), 39 individuals from Ikehara Reservoir, and 10 individuals from a fishery company that had previously cultivated Florida largemouth bass. Based on direct sequencing or single-strand conformation polymorphism (SSCP) analysis of the mtDNA control region, 3 haplotypes belonging to northern largemouth bass (M. s. salmoides) and 10 haplotypes belonging to Florida largemouth bass were identified. All four Florida largemouth bass haplotypes from the Lake Biwa region were also observed in Ikehara Reservoir. In contrast, all 10 individuals from the fishery company showed only one haplotype, which belonged to northern largemouth bass. Analysis of molecular variance (AMOVA) based on haplotype frequency indicated heterogeneity among populations within the Lake Biwa region. These results suggest that Florida largemouth bass of the same lineages as those found in Ikehara Reservoir were released multiple times in the Lake Biwa region.
