Isolated Chairs of the Genus Salvelinus (Salmonidae) from Lakes of the Uzon Caldera, Kamchatka: II. Charr of Lake Tsentral'noe

摘要

The charrs of the genus Salvelinus from the upper part of the Shumnaya River basin forage in the shallow thermal lake, and make a downstream spawning migration to the river and its tributaries in early fall. The life span of the fishes is no longer than eleven years, maximum body length and weight reach 55 cm and 1.6 kg, respectively. The abundance of the spawning group is approximately 350—400 individuals. The population is characterized by the presence of single) haplotype of the Cyt b—D-loop region of mtDNA, which is found in Dolly Varden S. malma populations. The charrs of Lake Tsentral'noe and Lake Dal'nee are similar in morphology, and the origin of populations of the Uzon Caldera from a common ancestor is supposed. The charrs of Lake Tsentral'noe differ from anadromous Dolly Varden in larger head with elongated gill cover, deep caudal peduncle, larger number of rays in the unpaired fins, and larger number of pyloric caeca. Based on shapes of the skull bones, the isolated populations from the Uzon Caldera are characterized by narrow sus-pensorium, narrow head of the vomer, shortened anterior part of the parasphenoid, and elongated upper jaw. All observed differences are based on frequency distributions of the traits, and well-defined parameters for discrimination of the isolated populations and anadromous Dolly Varden are not revealed.