Genetic Differentiation of the Resident and Anadromous Sockeye Salmon Populations of the Kamchatka Peninsula: An Evolutionary Scenario for the Origin of the Resident Sockeye Salmon in Lake Kronotskoye

The genetic differences between the sockeye salmon populations of the Kamchatka Peninsula were studied. The time of divergence between the resident sockeye salmon, which are reproductively isolated in Lake Kronotskoye, and the anadromous sockeye salmon is estimated using data on microsatellite markers. A weak unidirectional gene flow is observed from resident sockeye salmon into the population of anadromous sockeye salmon spawning in the Kronotskaya River, which is a channel of Lake Kronotskoye. The obtained point estimate of the time of divergence between the resident and anadromous sockeye forms (ca. 10 000 years) is consistent with the geological estimates for the time of formation of the modern Kronotsky lake–river drainage basin. The conclusion was made that the resident sockeye salmon of Lake Kronotskoye originated from the anadromous sockeye salmon of Lake Paleo-Kronotskoye and formed under the conditions of the reproductive isolation from other sockeye populations and the loss of connection with the sea. The necessity for conservation of the Kronotsky resident sockeye salmon, which implies prevention of its mixing with anadromous sockeye salmon, is discussed.