Oleg Katugin

Biochemical genetic variation in the highly abundant squid species from the North Pacific Ocean was examined in relation to their intraspecific differentiation and population structure. A large amount of data collected over a period of approximately 15 yrs was analyzed using protein electrophoresis as a basic research tool. In total, approximately 750 individuals of Ommastrephes bartramii (LeSueur, 1821), 300 individuals of Todarodes pacificus Steenstrup, 1880, and 5800 individuals of Berryteuthis magister (Berry, 1913) were covered by the approach. A geographic pattern of population genetic variability was observed in O. bartramii, with major genetic differentiation attributable to inconsistency in allele frequency distribution and in levels of genetic variation between the squid from the western and eastern parts of the species broad range in the North Pacific Ocean. In T. pacificus from the Japan Sea, significant intraspecific genetic differentiation was largely due to allele fre...

A fragment of cytochrome c oxidase I was used to assess whether species of the squid family Gonatidae from the North Pacific could be identified using DNA barcoding approach. Pairwise intra- and interspecific p-distances were assessed, and systematic relationships among species were estimated by NJ analysis. Examined species formed well-differentiated species-specific clades on the neighbor-joining and Bayesian trees. Multiple taxa formed clades supported by both tree topologies and species hypothesis-free ABGD method. Species morphologically identified as Gonatus tinro and Gonatopsis okutanii demonstrated intraspecific level of molecular genetic divergence (0.2-0.3%) indicating that they are conspecific. Genetic differences between the G. berryi clade and a squid morphologically close to that species may indicate a new cryptic species. High levels (>6.2%) of genetic differentiation within B. borealis suggested the existence of two cryptic species. This study confirms the usefulness of DNA barcoding for identifying species as well as discovering cryptic diversity in the gonatid squids, and indicates the need for further deeper insights into the phylogeny of the Gonatidae.

Abstract. The horizontal, vertical, and seasonal distribution patterns; size structure; maturity; feeding activity; and life cycle of the deep-water pelagic gonatid squid Gonatopsis octopedatus Sasaki, 1920 are described based on data collected during 25 research cruises in the Sea of Okhotsk and northwestern Pacific Ocean. This species was rather common in the Sea of Okhotsk and occurred occasionally in the Pacific Ocean. It was distributed mainly beyond the continental shelf between 0 and 1300 m depth. The largest aggregations of squid occurred in the deep southern basin in the Sea of Okhotsk. The highest abundance was observed in summer, when small young squid dominated the catches. In autumn and winter, growing squid descended down to the mesopelagic zone, where adult and maturing squid dominated the catches. Dorsal mantle lengths ranged from 28 mm (early juveniles) to 163 mm (mature adults). Analyses of seasonal changes in size structure, sexual maturity, and vertical distribut...

ABSTRACT Genetic variability of the highly valuable gadid species, walleye pollock, Theragra chalcogramma (Pallas 1811), from five spatially separated northwestern Bering Sea areas (Ozernoi Bay, Olutorskyi Bay, Koryak shelf, Navarin Genetic variability of the highly valuable gadid species, walleye pollock, Theragra chalcogramma (Pallas 1811), from five spatially separated northwestern Bering Sea areas (Ozernoi Bay, Olutorskyi Bay, Koryak shelf, Navarin region, and Anadyr Gulf) was investigated. Haplotype diversity within the samples ranged from 0.8788±0.0393 to 0.9436±0.0162. region, and Anadyr Gulf) was investigated. Haplotype diversity within the samples ranged from 0.8788±0.0393 to 0.9436±0.0162. Nucleotide diversity within the samples ranged from 0.0108 to 0.0127. Nucleotide diversity among the regional collections Nucleotide diversity within the samples ranged from 0.0108 to 0.0127. Nucleotide diversity among the regional collections ranged from 0% to 0.18%. Walleye pollock from the Anadyr Gulf appeared genetically separate from the other four samples in ranged from 0% to 0.18%. Walleye pollock from the Anadyr Gulf appeared genetically separate from the other four samples in a clustering of genetic distances. Total heterogeneity among all five samples was significant, while there was no heterogeneity a clustering of genetic distances. Total heterogeneity among all five samples was significant, while there was no heterogeneity among the four samples excluding that from the Anadyr Gulf. Pair-wise comparisons using tests for heterogeneity and Fst supported the dendrogram of genetic distances in that only the collection from the Anadyr Gulf was significantly different among the four samples excluding that from the Anadyr Gulf. Pair-wise comparisons using tests for heterogeneity and Fst supported the dendrogram of genetic distances in that only the collection from the Anadyr Gulf was significantly different from the others. The observed pattern of genetic differentiation among walleye pollock from the northwestern Bering Sea presumably from the others. The observed pattern of genetic differentiation among walleye pollock from the northwestern Bering Sea presumably emerged as a result of a population of the species subdividing in the northernmost part of its geographic range, though furtherged as a result of a population of the species subdividing in the northernmost part of its geographic range, though further analysis is needed to verify this supposition. analysis is needed to verify this supposition.