Mitochondrial DNA Variation in Striped Bass (Morone saxatilis) from Canadian Rivers

Abstract

Mitochondrial DNA(mtDNA)was analysed to determine the genetic relatedness of striped bass (Morone saxatilis) populations in tributaries to the Gulf of St. Lawrence and the Bay of Funday. Mitochondrial DNA genotype frequencies were compared with those of striped bass from the Shubenacadie River (Bay of Fundy) and the Miramichi and Tabusintac rivers (Gulf of St. Lawrence). These mtDNA genotype frequencies were compared with those of striped bass representative of the Atlantic coastal migratory stock originating in the Hudson River and Chesapeake Bay. Differences in the frequencies of mtDNA length variants permitted discrimination of the Shubenacadie River from the Miramichi River and Tabusintac River populations and all three Canadian populations from the U S. spawned costal migratory stock. No difference in the frequency of mtDNA length variants was observed between Tabusintac River and Miramichi River striped bass. Heteroplasmy for mtDNA length variants was observed in 35% of Gulf of St. Lawrence fish, the highest frequency observed in any striped bass population. These results highlight the genetic heterogeneity of these Canadian striped bass populations and their distinctiveness from U S. stocks. Future efforts to restore these depleted Canadian striped bass populations should consider the impact of stock transfer on endemic striped bass gene pools.