No abstract

A single specimen of the northern wolffish Anarhichas denticulatus Krøyer, 1845, 393 mm in length, was documented for the first time in the Siberian Arctic (Laptev Sea, Russia). Species identification was confirmed by an integrative taxonomic approach that included examination of external morphology and DNA barcoding using the COI mtDNA gene. This species is widely distributed in the North Atlantic, but records in the Arctic Ocean are limited to the Canadian and US coasts. This record might represent a significant range extension of about 7500 km for the species and may be associated with the eastward transport of a pelagic juvenile specimen from the Northeastern Atlantic to the Laptev Sea by the North Atlantic current, consistent with the hypothesis of Atlantification of the Arctic Ocean. X-ray images of the Laptev Sea specimen and photographs showing ontogenetic variations of species’ coloration are provided for reference. The Laptev Sea specimen had a more elongated shape, longer preorbital distance, and longer pectoral, dorsal, and anal fins, as well as a larger eye and wider caudal fin compared to North Atlantic samples. The size differences are likely associated with conditions experienced as a juvenile during the pelagic stage of the lifecycle.

The aim: The aim of this work is focused on a phylogeographic analysis of the relationship between the population groups of walleye pollock Gadus chalcogrammus of the Asian part of the range.The methods: The analysis of phylogeographic analysis is based on the data of polymorphism of microsatellite markers, a fragment of the mtDNA control region (D-loop) and a fragment of the mtDNA cytochrome b gene. The newness: A comprehensive phylogeographic analysis using samples of spawning walleye pollock individuals from most of the Asian part of the range from the Sea of Japan to the northwestern Bering Sea using various genetic markers was carried out for the first time.The results: The results of the analysis of the variability of walleye pollock samples by mitochondrial markers (fragments of the cytochrome b and D-loop genes) allow us to distinguish two large population groupings within the Asian part of its range: the first one in the Sea of Okhotsk, the Sea of Japan, the waters of the Kuril Islands and southeastern Kamchatka and the second one in the Bering and Chukchi seas. Analysis of the variability of walleye pollock samples by microsatellite markers allows us to judge the absence of population groupings in the waters of the Sea of Okhotsk, the Sea of Japan, off the Kuril Islands and southeastern Kamchatka.The practical significance: When regulating pollock fishing in the Russian waters, it is necessary to establish a single total allowable catch (TAC) for each of the two superpopulations: the Sea of Okhotsk —  Sea of Japan (1) and the Bering Sea (2) combining the sizes of proposed catch for walleye pollock groups belonging to each of these superpopulations.

A new species, Lycodapus imperatorius, is described from the seamounts of the Emperor Ridge, North Pacific Ocean. The new species can be identified by its stout gill rakers, single interorbital pore, four preopercular and four mandibular pores, 95–99 vertebrae, numerous vomerine and palatine teeth, and COI mtDNA sequences. Although the new species is most similar to L. endemoscotus and L. antarcticus in morphology, the closest match to already published sequences was Lycodapus fierasfer, which is fairly different from the new species in terms of morphology. The incongruence between molecular and morphological inferences might be explained by the homoplastic nature of the morphological characteristics used for species delimitation in Lycodapus. The percent of genetic identity between the closest species of Lycodapus ranges from 95.4 to 98.6% in comparison with 99.5–100.0% between individuals of the same valid species. A key of the genus is amended to include the new species.

No abstract