Sea Lamprey (Petromyzon marinus) Populations in Northeastern North America: Genetic Differentiation and Affinities

We examined genetic population structure in 3253 sea lampreys (Petromyzon marinus) sampled at 53 sites in northeastern North America and the British isles. Hierarchical F-statistics of allozyme frequencies indicated that genetic divergence from lake to lake and river to river was greater than divergence among sites within fakes or rivers and also greater than that attributable to the separation of landlocked freshwater from coastal anadromous systems. Lampreys from different lakes varied considerably in the amount of spatial differentiation evident. New York freshwater populations of uncertain invasion history were no more genetically differentiated than were recently introduced upper Great Lakes populations. The apparent reproductive isolation of lampreys in Lake Erie from Lake Ontario populations, despite canal connections, suggests that movement is limited between lakes. Future studies should determine the cause so that management techniques to restrict movement can be developed to control populations.