On feeding of deep-sea crabs on the continental slope of northwestern Kamchatka

Mean index of gastrointestinal tract fullness for golden king crab Lithodes aequispinus is 15.5 ‱. Detritus occurs in 40.5 % of the cases, so it is a common food for this crab, Polychaeta, Ophiuroidea and Decapoda are 33.2 %, 32.1 % and 15.4 % of its ration, respectively, whereas Mollusca are only 11.5 % of the ration weight, despite of frequent occurrence. Triangle tanner crab Chionoecetes angulatus has the mean index of fullness 20.9 ‱, Polychaeta and Mollusca are two main components of its ration (31.4 % and 27.3 %, respectively) and Decapoda and Pisces are the secondary components (13.9 % and 12.2 %); detritus occurs in 11.2 % of the cases. Cannibalism is observed incidentally for the latter species

Results of multidisciplinary survey in the Laptev Sea in August-September, 2015

Data on oceanographic conditions and species composition of plankton, benthic and demersal fish and invertebrates are presented, obtained in the complex survey over the external shelf of the Laptev Sea in August-September 2015. The zooplankton abundance was low, with only local increases up to 400 mg/m3. Species diversity of fish and nekton invertebrates in the bottom trawl catches was low, too: 26 fish species and 2 species of cephalopods. Mean biomass of fish was estimated as 4.3 t/km2 (in total 132. 103 t within the surveyed area of 30,500 km2). All fish species were distributed sparse. Arctic cod was the most abundant and occurred over the whole surveyed area, with large-sized fish dominating at the bottom and medium-sized (9-15 cm) fish - in the pelagic layer, other commercial species were greenland halibut and deepwater redfish caught on the continental slope. Bottom invertebrates in trawl catches were presented by 6 species of shrimp and 12 taxonomic groups of different rank, with predominance of starfish, brittle stars and sponges; gastropods were represented by 11 species, with Neptunea heros dominating by mass (42 %). Macrobenthos in samples of the bottom sampler was presented by 20 taxonomic groups, with predominance of polychaetes, bivalves and sipunculoids

Results of complex surveys in the East Siberian Sea in August 2015

Data on oceanographic conditions, composition of plankton communities, benthic and demersal fish and invertebrates in the southern East Siberian Sea are presented by results of the complex survey conducted in August 2015, The bottom trawl survey assessed 10 species of fish and 3 species of jellyfish with total biomass 1900 t. Arctic cod Boreogadus saida dominated absolutely in the benthic ichthyocenose (60.6 % of the total biomass). Besides, 3 species of shrimps, 1 crab species, 4 species of gastropods, and 6 other taxonomic groups of macrobenthos including starfish and isopods were found in trawl catches, with the average biomass of macrobenthos 41.7 kg/km2. In the bottom samples of macrobenthos, 12 taxonomic groups were presented, with predominance of bivalves, polychaetes, isopods, and amphipods (summary 95 % of the total biomass)