REPRODUCTIVELY ISOLATED ECOTYPES OF KILLER WHALES ORCINUS ORCA IN SEAS OF THE RUSSIAN FAR EAST

Two ecotypes of killer whales - fish-eating and mammal-eating - were found in the waters of the Russian Far East. However, in order to confirm their status, genetic studies of animals with known phenotype and foraging specialization should be performed. This paper presents the results of analyzing the nuclear genetic markers, isotopic composition of tissues and phenetic trait (coloration of saddle patch) of killer whales from different regions of Far Eastern seas. According to the analysis of the allelic composition of 9 microsatellite loci of nuclear DNA, killer whales were divided into two distinct clusters; the difference between them was high enough to indicate a reproductive isolation. The content of stable nitrogen isotope N-15 in the tissues of whales from the first cluster was significantly lower than that from the second cluster. The difference in the delta N-15 values between the individuals from different clusters was about 3 parts per thousand, which corresponds to the difference between adjacent trophic levels. Obviously, the first cluster included fish-eating, and the second - mammal-eating animals The ratio of saddle patch coloration types also differed between the clusters. The whales from the first cluster had five types of coloration in different proportions, while the whales from the second cluster had only "smooth" saddle patches. The differences between the clusters were statistically significant. Thus, the killer whales from the seas of the Russian Far East comprise at least two reproductively isolated clusters with stable ecological and morphological differences, that is, two different ecotypes - fish-eating and mammal-eating. Different ecotypes of killer whales should be managed separately during accounts, monitoring, evaluation of human impact and estimating the number of animals allowed to capture from natural populations.