The article presents the results of underwater video observation of conical crab pot in vivo. The behavior of the king crab in the zone of action of conical crab pot is analyzed. Using the video recording method, it was possible to accurately determine the ratio of individuals that entered the pot to the total number of individuals that appeared, to track the movement of crabs depending on the change in current. Based on the data obtained, the behavioral algorithms of individuals are described. It was shown that the location of the bait and the design features of the pot affect the catch efficiency. In order to entry into the pot it was necessary to make 2.91 attempts on average. In 93.8% of cases, the appearance and entry of a pot against the current was recorded. The average crab appearance rate was 24.5 ind./h, and the entry rate into the pot was7.9 ind./h. In search of bait, the crab mainly moves in small segments of 2-3 meters, developing a speed of0.11 to 0.38 m/s, an average of 0.21 m/s, with subsequent stops to identify the direction of the smell source. A new method is proposed for estimating the density of individuals of the red king crab in the study area based on the speed of catching the pot. The derived formulas for calculating the density make it possible to standardize the data and use the catches of pots with different time intervals of being under water. The table is proposed for the transition of the pot catch to the population density of the red king crab.

New data on diet composition of schoolmaster squid Berryteuthis magister in the Western Bering Sea presented in this article. A list of feeding objects of this species sufficiently expanded, mainly by cephalopods and teleost fishes. New data confirm previous reports on opportunistic feeding strategy of schoolmaster squid. Two kinds of feeding tactics of schoolmaster squid in relation to feeding different objects is shown: schoolmaster squid behaves like a grazed predator in relation to mas abundant macroplanctonic Euphausiidae. Feeding activity in relation to other feeding objects decreases in this case. From another hand, it implements feeding strategy of ambushing predator in relation to all another feeding objects, without any significant feeding preferences. Changes in diet composition related with changes of predatory apparatus of schoolmaster squid, such as tentacles autotomy of adult specimens, is shown. The proportion of Euphausiidae and shrimps decreased significantly in schoolmaster squid diet after tentacles autotomy. Evidences of hypothesis of tentacles autotomy as a protecting mechanism against juvenile specimens of schoolmaster squid cannibalism from side of adult specimens not confirmed.

Despite the importance of lampreys g. Lethenteron in Kamchatka peninsula’s rivers, full-scale studies have been conducted only in two rivers - Utholok and Kol so far. In other reservoirs lampreys have been either studied poorly or not studied at all. In particular, their taxonomic status, morphological and biological features, intraspecies and interspecies relations, their general role in ecosystems have not been precisely defined. Therefore, there is a quite scarce information on spread of lampreys in Kamchatka peninsula’s reservoirs. The main difficulty of obtaining such scientific data is that the collection of material necessary for research and monitoring is a significant challenge, as lampreys are secretive most of the time and die after spawning. In addition, Kamchatka peninsula’s reservoirs are often located in inaccessible places. This paper presents materials on spread of lampreys on Kamchatka peninsula for the subsequent analysis of their biological characteristics in this region. The used material was taken from personal research and published literature.

In 2004-2018, there were significant fluctuations number of population of blue whiting (Micromesistius poutassou) in the North-East Atlantic. Since the early 2000s, large-scale changes in the hydrological regime were observed on the water area of the blue whiting. The results of research of blue whiting performed in June-October 2004-2018 on russian fishing vessels were used in the work. The results of international trawl-acoustic surveys carried out in May-September on the waters of the Norwegian and Barents Seas were also analyzed. The distribution of blue whiting due to the features of hydrobiological conditions in the areas of feeding and the dynamic of length-age structure of population of fish has been studied. It was noted that in the area of international trawl-acoustic surveys and russian fisheries the distribution of the main concentration of blue whiting and the inter-annual length-age dynamic of structure were similar. It is shown that during the period of fluctuations of stock the extent of migrations and density of the main schools of blue whiting changed. Changes of distribution of feeding schools of blue whiting in 2004-2018 were related both to features of hydrobiological conditions on the water area of the Norwegian Sea and to the dynamics of the length-age composition of fish. The distribution of blue whiting in the western areas of the Barents Sea was related to the features of the hydrological regime in this water area.

Investigated the pacific sardine Sardinops melanostictus, caught on August 25-26, 2018 in the area of Shikotan Island. The total length of the fish varied from 16.0 to 26.0 cm, and the weight - from 42 to 223 g, while the length and weight of the females - on average, 20.9 cm and 120.6 g were significantly greater than the length and weight of males - 19.6 cm and 95.2 g. The number of males and females in the studied sample (210 specimens) was 54.8% and 45.2%. The oldest generation of germ cells in the ovaries of all fish was composed of previtellogenic oocytes with a diameter of up to 100-110 microns in the smallest and up to 120-130 microns in the largest individuals. Given the size of the fish, we believe that all the studied individuals were sexually mature, and the state of the oocytes indicated that at the time of fixation they were as distant from the spawning as the past and the upcoming. In the largest oocytes of almost all fish, lipid inclusions were present, which are not evidence of cortical nuclei stage ore fat stage oocytes, but may be associated with a high content of subcutaneous and abdominal fat. Its share, according to literature, by the end of August is the maximum.

A histological analysis of the testes, whose tissue samples were taken from fresh corpses of 18 sea otter aged from one month to two years in the period of their mass death on Bering Island in 1991-1995, was carried out. Testes were fixed in liquids of Shtiva, Buena. The material was embedded in paraffin. Sections 4-5µm thick were stained with hematoxylin-eosin, Heidengain’s azan, according to the method of trichrome and tetrachrome-CHIC. Morphometric characteristics were used as indicators of the development of spermatogenic epithelium: using a screw eyepiece micrometer, the diameter of the seminiferous tubules, the diameter of the nuclei of spermatogenic cells were measured, the area of the nuclei of sustentocytes and interstitial endocrinocytes was determined, and the number of stenttocytes in a single cross section of the seed canal was determined. Studies have revealed active spermatogenesis in the testicles of sea otter at the age of two years. In these sea otters, the diameter of the seminiferous tubules reaches a maximum; the convoluted seminiferous tubules contain all spermatogenic cells, including spermatozoa. Sustentocytes and interstitial endocrinocytes are characterized by signs of high functional activity.

Contamination of water, bottom sediments and the roach Rutilus heckelii by heavy metals (copper, zinc, lead, cadmium, mercury), arsenic, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) has been studied in the Sea of Azov over the period 1982-2018, and the results obtained are presented. Nowadays, the concentrations of heavy metals, arsenic, OCPs and PCBs in the water and bottom sediments of the Sea of Azov are observed to decrease vs. the years of the highest pollution (1982-1995). In 1982-2007 in some water samples, the concentrations of copper, mercury, OCPs and PCBs exceeded the maximum permissible concentrations for fishery reservoirs. For several years the lead and cadmium concentrations were also higher than their average values for the corresponding type of bottom sediments. Until 1992, of the heavy metals in question, there was observed an excess of maximum permissible concentrations only for lead in the roach liver, eggs and roe. Of the PCB congeners evaluated in the water, bottom sediments and roach, persistent and dangerous penta- and hexachlorobiphenyls were identified, among which dioxin-like congeners were also found. The differences are shown in the bioaccumulation of pollutants by roach.

Fishes in Subarctic lakes are highly demanding to the water quality and pollution results in organism response that allows to use it as a test objects reflecting state of water quality. Ichthyopathologies cause transformations of population and ichthyofauna under anthropogenic impact. The development of Kola Peninsula resulted in pollution of water bodies with wastewater from mining enterprises containing heavy metals, surfactants, petroleum products, sulfates and others. Lake Bolshoi Vud’yavr that is located in the center part of the Khibiny mountain massif and can be considered as a man-made technogenic water area under multifactorial chronic pollution for decades. Ichthyofauna of the lake in the 1930’s, consisted of 6 species: brown trout, аrctic char, whitefish, grayling, burbot, nine-spined stickleback. The sewage resulted in almost complete disappearance of fish in the lake, excepting Arctic char, which currently dominates the ichthyofauna. Water quality assessment was carried out on the basis of histological analysis and revealed changes in the gills, liver and kidneys, indicating metabolic disorders, weakened immunity, the development of functional disorders and the mobilization of compensatory mechanisms. Most of the morphological changes should be regarded as the long-term consequences of chronic sublethal exposure to toxicants, which can cause a reduction in life expectancy, early maturation or infertility. However, a number of histopathologies testify to acute reaction of fish organism and make it possible to assume that there are sporadic local discharges of pollutants.

To identify the seasonal dynamics of aquatic biological resources (ABR) catch in the Russian waters of the Bering Sea, the perennial data from 2003-2015 were analyzed. In January-April, the removal of marine fish from annual resources amounts to only 4.9%, crabs - 4.2%, shellfish - 0.2%. With the onset of the warm period of the year, the production of fish and invertebrates is activated: from May to December, 95.8% of crab resources are developed, from May to November - 100.0% of shrimps, from May to August - 99.2% of salmons, July-December - 91,2% of marine fish, in August-November - 97.9% of shellfish. The seasonality of catch of crabs and shrimps is largely influenced by their physiological state (mass shedding), and shellfish activity of population groups affects the fishery of shellfish. The conjugation of seasonal catch of cods (pollock, cod, saffron cod) and flounders (flounders) fish with sculpins and greenlings, which are caught by by-catch in the course of the trawl-snurrevod fishery, is noted. The same dependence in seasonality of catch is observed with the prevailing production of cods (pollock, cod) and flounders (halibuts) fish with grenadiers, rockfishes and skates, caught by the fleet by bottom longline fishery and trawls as accompanying species. The catch of smelt fishes, which are mastered during coastal fishery, which has the character of a specialized one, is timed to February-March, May-June and October-December. Salmonids are harvested mainly in June-August, with the exception of loaches, some of which fall in the fall and beginning of winter. Large- scale trawl fishery for pollock contributes to the fishing and feeding of herring in July-September, however, the formation of dense wintering aggregations of the latter leads to the organization of its specialized trawl fishery. The research results provide an opportunity to increase the annual catch of ABR and increase the efficiency of the use of the resource base of this water area.

It provides an overview of the cultivation of artemia in the retrospective and the current aspect in the world and in Russia. The analysis of literature data shows that the artemia cultivation develops in three main directions: obtaining nauplius by the method of incubation of cysts; extensive cultivation of basin and pond methods; intensive cultivation in open and closed water systems. It is shown that the most acceptable type of aquaculture in the conditions of Western Siberia is the introduction of naupliius into natural salt water bodies during the period of biomass decline in the local artemia population and the production of additional cysts. Intensive cultivation of artemia in open and closed water supply systems involves the cultivation of crustaceans with high density in special tanks (basins) with increased water exchange and feeding artificial feed. The basic principles for the production of artemia in temporary salt farms, as well as the main components in the organization of cultivation are presented. In addition to the development of scientific biological and technological foundations of artemia aquaculture, it is indicated that improvement of the regulatory legal regulation of this field of activity is necessary. In particular it required changes and additions to a number of regulatory legal acts in the field of aquaculture. Attention is drawn to the need to develop preventive measures to control the activities of enterprises in the aquaculture of artemia in Russia.

Larvae obtained from eggs and later juveniles of pure species of Kaluga Huso dauricus and Amur sturgeon Acipenser schrenckii and reciprocal hybrids between them: K×AS and AS×K, were grown in RAS during the year. The studies were conducted in the 2018-2019 in the tanks modules of the RAS of the FSBSI «VNIRO». Compared to the parent species, the AS×K hybrid has a higher survival rate, but is inferior to the K×AS hybrid in terms of growth rate. Kaluga had the highest growth rate, with the lowest survival rate. Kaluga had the lowest feed coefficients at all stages of cultivation, and Amur sturgeon had the highest. The values of the feed coefficients of the hybrids were intermediate relative to the maternal species, and the feed coefficient for the K×AS hybrid was lower than for the AS×K hybrid. Long-term cultivation of Amur sturgeons without sorting leads to a significant increase in the different sizes of juveniles, and of Kaluga, to an increase in cannibalism. The terms of anatomical and cytological differentiation of the sex of the Amur basin’s sturgeon and their hybrids were established as a result of histological studies. An analysis of the morphological and physiological state of the yearlings allowed us to determine the optimal conditions for their cultivation and the normal passage of gametogenesis in RAS. The use of RAS confirmed the fundamental possibility, as well as the prospect of growing sturgeons of the Amur basin and their hybrids in any region of Russia.

The studуwas carried out in Federal Selection and Genetic Center of Fish Breeding in 2016-2017 (Ropsha, Leningrad region). Females and males of rainbow trout of mutant golden color at the age of 2+ were kept in different light and temperature conditions for 9 months before their maturation. Females and males were compared in weight and body size, and reproductive features. An individual assessment of females for embryo survival was carried out. The significant effect of water temperature on the growth rate of fish, the maturation of females, fecundity and the size of eggs was revealed. It was found that intensity of the body golden color and the carotenoid pigmentation of the eggs depends on the light. Moreover, females that were kept at low water temperature and low illumination intensity for a year were characterized by the lowest survival rates of embryos. Thus the intensity of illumination and optimization of the temperature regime in the development of biotechnology for breeding of rainbow trout of golden color should be taken into account.

Trawl survey was performed in the Bering and Okhotsk seas in the autumn period of 2019. The abundance and biomass of Pacific salmons in the period of their post-catadromous migrations from the rivers` mouths to the feeding area. Data on spatial distribution, density, biological state of other mass fish species in the northwestern Pacific were obtained. Research vessels “Professor Kaganovsky” and “TINRO” performed this survey together. The pink salmon accumulations in the Bering Sea were surveyed fully and estimated at 154 million fish. In the Sea of Okhotsk, the northern part of pink salmon accumulations remained partly surveyed and estimated at 554 million fish. The total quantity of pink salmon is estimated not to exceed 1 billion individuals.

Oceanographic, planktonic, trawl and acoustic surveys were conducted in the Chukchi Sea in August 2019 at the research vessel “Professor Levanidov”. The hydrological and hydrochemical regime was formed under the influence of the spread of Pacific waters coming through the Bering Strait; East Siberian desalinated waters - from the west along the coast and to the north of Wrangel island; and waters of Arctic origin. North of 73°30N, waters of Atlantic origin with characteristic temperatures higher 0 °C and salinity over 34.5‰ were observed at the depths mainly from 180 m to the bottom, which were clearly traced in the distribution of bottom temperature, salinity and hydrochemical characteristics. The oxygen saturation of water in the surface layer within the entire studied area exceeded 100%, the maximum values - in the pycnocline layer (158%). The processes of photosynthesis were limited by mineral nitrogen, the onset of summer was evidenced by its minimum in the surface layer. Mesoplankton biomass was high with predomination of chaetognaths and copepods, euphausiids were second in rank; in the southern part of the sea biomass was twice as high as in the north. In the northern part, there was an intense phytoplankton bloom, a large number of nauplias and copepodites of the early stages of development, which formed a spring complex. In the southern part, low concentrations of phytoplankton observed, copepods were represented by older age groups, which is typical for the spring-summer period. The catch was dominated by the Tanner crab, accounting for about 50%. Sea stars and the brittle stars were of secondary importance, with polychaetes, sponges and gastropods to a lesser extent. 44 species of fish were found in the catches, and representatives of the families Cottidae, Zoarcidae, Liparidae, Gadidae, Pleuronectidae, and Agonidae dominated. The biomass of large walleye pollock was 890 thousand tons, that of polar cod 117 thousand tons, and Bering flounder 42 thousand tons. According to acoustic data, the abundance and biomass of pollock within the survey area was 242 million inds. and 398 thousand tons, polar cod - 9349 million inds. and 206 thousand tons, respectively. The daily ration of a large pollock varied from 3.4% to 4.7%, and that of polar cod from 2.5 to 9.4% for a different-sized fish. Of the marine mammals, the grey whale was most often found near the Bering Strait, while walruses and polar bears were observed in the northern part of the sea.