Species structure of pelagic ichthyocenes in Russian waters of Far Eastern seas and the Pacific Ocean in 1980–2009

Abstract

Based on the results of pelagic trawl catches in 1980-2009 a general list of ichthyofauna in Russian waters of the Far Eastern seas and the Pacific Ocean comprise 450 species, among which 114 species are iden tified in the Sea of Japan, 258 species in the Sea of Okhotsk, 170 species in the Bering Sea, and 319 species in the Russian waters of the Pacific Ocean. The species composition of the ichthyofauna was classified according to taxonomical, biotopical, and zoogeographical status of the species. The Simson' index of dom inance varies in a narrow range from 1.58 to 2.66, and the Pielou's evenness index has low values: 0.17 (Sea of Japan and Sea of Okhotsk), 0.19 (Russian waters of the Pacific Ocean), and 0.27 (Bering Sea). Values of the indexes are confirmed by the conclusion about the dominance of one or two to three species in the sur veyed ichthyocenoses made according to the analysis of profiles of rank curves. The highest species diversity (Margalef's index) is observed in Russian waters of the Pacific Ocean and the lowest diversity is in the Sea of Japan. When comparing qualitative and quantitative composition of ichthyofauna in respect to regions, the lowest index of diversity is found for the fauna in the Sea of Japan. The dynamics of biomass (tons/km 2 ) of all components of pelagic ichthyocenoses is observed according to the periods of years and their species structure is determined. The average long term density of pelagic fauna concentrations in the area under survey con stitute 16.8 tons/km 2 and its total resources are 70-80 million tons.

The Aleutians and Beyond: Distribution, Size Composition, and Catch Dynamics of the Aleutian Skate Bathyraja aleutica across the North Pacific

“…The Aleutian skate Bathyraja aleutica (Gilbert, 1896) is widespread across the North Pacific Ocean, and it plays an important role in ecosystems [ 20 ]. It is a boreal species inhabiting the Okhotsk and Bering Seas, waters off the eastern Kamchatka, Japan, Kuril, and Aleutian Islands, as well as the Gulf of Alaska and along the American and Canadian Pacific coast down to California [ 12 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. The information available from the literature on the distribution and biology of this species is not sufficient to understand its life history cycle, and it has so far been scattered and fragmentary [ 4 , 5 , 6 , 8 , 18 , 20 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , ...…”

Mesopredatory fishes from the subtropical upwelling region off NW-Africa characterised by their parasite fauna

“…Another fish species found in the same tropical upwelling region is the black snake mackerel Nealotus tripes , Johnson 1865 (Gempylidae). N. tripes can be found in mesopelagic habitats at depths to 600 m ( Nakamura & Parin, 1993 ), with a global distribution in tropical and temperate waters ( Strasburg, 1964 ; Yatsu et al, 2005 ; Tanaka, Mohri & Yamada, 2007 ; Mafalda Jr, Souza & Weiss, 2009 ; De Forest & Drazen, 2009 ; Wienerroither et al, 2009 ; Ivanov & Sukhanov, 2015 ). As a nyctoepipelagic species, it roams mesopelagic regions at daytime and migrates to the surface at night (e.g., Boehlert, Watson & Sun, 1992 ; Yatsu et al, 2005 ).…”