Species richness and taxonomic composition of trawl macrofauna of the North Pacific and its adjacent seas.

A checklist is presented of animal species obtained in 68,903 trawl tows during 459 research surveys performed by the Pacific Research Fisheries Center (TINRO-Center) over an area measuring nearly 25 million km2 in the Chukchi and Bering seas, Sea of Okhotsk, Sea of Japan and North Pacific Ocean in 1977-2014 at depths of 5 to 2,200 m. The checklist comprises 949 fish species, 588 invertebrate species, and four cyclostome species (some specimens were identified only to genus or family level). For each species details are given on the type of trawl (benthic and/or pelagic) and basins where the species was found. Comprehensiveness of data, taxonomic composition of catches, dependence of species richness on the survey area, sample size, and habitat, are considered. Ratios of various taxonomic groups of trawl macrofauna in pelagic and benthic zones and in different basins are analysed. Basins are compared based on species composition.

DNA barcoding for squids of the family Gonatidae (Cephalopoda: Teuthida) from the boreal North Pacific.

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.