Analysis of the contemporary geographic distributions of mtDNA haplotypic diversity of sockeye salmon (Oncorhynchus nerka Walbaum) on the Asian part of its range and consideration of possible scenarios for microevolution of the species were performed. In total, 172 specimens of sockeye salmon from different rivers of Kamchatka, Chukotka, north coast of the Sea of Okhotsk, and from the Kuril Islands were analyzed using the entire mtDNA control region (1,010 bp) sequencing. After multiple alignments of the sequences 16 polymorphic sites were identified. Most of substitutions were detected in the first and the last thirds of the D‐loop sequence, as well as one insertion was registered in the poly‐T region. Two mass haplotypes (Hap_1_10T and Hap_2_13T) were revealed; they were present in most samples and differed by three substitutions and two indels. All the sequence variants were distributed among two haplogroups in compliance with the mass haplotypes. The star‐shaped topology of the MST‐tree points to a rapid increase in the diversity of groups, indicating a rapid expansion of the species after its number reducing in the past. The diversity of the first haplogroup was higher, but its main fraction fell on the samples from the middle reach of Kamchatka River, which seems to be a refugium during the Late Pleistocene glaciation. Presence of both haplogroups in most populations in approximately equal proportions indicates that the entire Asian part of the sockeye salmon range is a zone of secondary contact. We hypothesize that Hap_2_13T had more ancient origin and the Hap_1_10T was formed somewhat later, apparently in Asia, because almost all transitional forms between the haplogroups were found in Iturup Island populations.

Изучено генетическое разнообразие популяций нерки Oncorhynchus nerka (Walbaum) из рек Восточной Камчатки и материкового побережья Охотского моря с использованием данных об изменчивости гена цитохрома b (cytb) мтДНК. Проведена оценка значимости различий по нуклеотидным заменам и по частотам гаплотипов между парами исследованных популяций. Выявлены различия между неркой из разных регионов (североохотоморского и беринговоморского), а также между изученными локальностями из одного региона. В то же время показано, что доля межпопуляционной генетической изменчивости относительно умеренная (12,67%), что свидетельствует об относительно небольшом времени дивергенции популяций. Модель распределения частот попарных нуклеотидных различий, полученная для популяций из исследованной части ареала вида, позволяет предположить, что локальности нерки образовались в результате слияния генетически отдаленных, конспецифичных популяций. Возможно, в истории вида происходило разделение его ареала, что способствовало образованию двух генетически независимых (на протяжении многих поколений) линий.

No abstract

Hydrological regime and morphodynamics of the outlet part of the Kamchatka River, dynamics of mixing zone, patterns of juvenile Pacific salmon distribution and migration in the coastal waters of Kamchatsky Gulf in the zone of operating trap nets were analyzed on the results of complex field works prowided in summer period in 2018–2019; fishing and specifics of sockeye salmon spawning run in the river was described. In the course of analyzing the entire complex of available long-term data, an assessment of the likely impact of some key factors on the dynamics of anadromous migration of sockeye salmon in the Kamchatka River was made; biological statistics of spawners and current state of reproduction of this stock was demonstrated. It is found, that natural environmental factors, neither abiotic nor biotic (including fish health as population internal factor), could not cause disturbance of sockeye salmon spawning run dynamics in the Kamchatka River in recent years. Smoller body size and physiological imperfection of the spawners before the anadromous migration due to effects of high number of pink salmon in recent years are suggested to be the most likely cause of spawning run delay in late sockeye salmon morph. Regime of commercial use of the stock and general increasing pressure on the spawning stock by coastal fisheries are demonstrated to be the strongest outer factors to affect modern state of the resources and sockeye salmon population structure in the Kamchatka River, causing permanent escapement deficiency on spawning grounds in the river basin (first of all in the late morph), and also infact lead to disballance between different subpopulation groups in the composition of the stock. Recommendations in order to provide recovery and sustainable level of the Kamchatka River sockeye salmon stock are given in the perspective of more efficient commercial use of the stock next several years; highlights for further researches are outlined.

Gmo-С86) в выборках минтая из Охотского моря. Показано, что наиболее дифференцирующими для охотоморского минтая являются локусы Gmo-C86 и Gma106. Выявлен высокий уровень генетической изменчивости особей в пределах исследованных выборок. Кластеризация выборок носит случайный характер. Корреляции между количественными оценками генетических различий выборок F st и географическими расстояниями между местами взятия проб не обнаружено. По результатам проведенного исследования не подтвердилась гипотеза о том, что нерестовым районам соответствуют отдельные популяции.