Russian Federal Research Institute of Fisheries and Oceanography, Moscow, 107140The study has shown that by 2035 the cooling in the Northwest Pacific and Northeast Atlantic is expected. In the Northwest Pacific, a decrease in the catches of walleye pollock in the northern regions and their essential increase in the southern regions are projected. Despite the high catches of Pacific salmon in the last decade, in future the catches of this group of valuable species will decrease significantly. According to expert estimates, the reduction of total catch of walleye pollock and salmons will amount to 1 mil. tons. However, the expected cooling will be favorable for the reproduction success of chub mackerel, Japanese sardine, Sakhalin-Hokkaido herring, Bering Sea cod and Okhotsk herring. This will allow the Far East fishermen to compensate entirely the losses, provided that the fishery is reoriented to other commercial species. In the Northeast Atlantic, the expected cooling will affect negatively the reproduction success of cod, haddock, blue whiting, mackerel, herring that results in decrease in total catch by 0.5 mil. tons. However, the expected cooling will have a positive impact on capelin stock, that compensate significantly for the catch losses.

Large-scale tuna fishing with annual catch of more than 600 thousand tons is carried out in the ICCAT area. In the fishery involved 60 countries-members, and 5 countries, collaborating with ICCAT. For 10 years, there has been a steady increase in the catch of skipjack, yellowfin, spotted and mackerel tunas. Purse-seine fishing accounts for 71% of the total catch. The main commercial species are striped tuna (skipjack) and yellowfin tuna, which are ¾ of the total catch. Monitoring of the status of stocks of the most abundant tuna species is carried out on the basis of the application of analytical approach methods using data of fishery statistics and linear dimensions. The amount of recommended annual catch and allocation of quotas to ICCAT countries-members is carried out at regular sessions of ICCAT. For Russia, a member of ICCAT, the resumption of tuna fishing is very promising.

Polar Branch of Russian Federal Research Institute of Fisheries and Oceanography (PINRO), Murmansk, 183038Currently, to tune the assessment of individual stocks, in particular, of the Barents Sea cod, mathematical methods use the catch rates of some standard types of vessels. The paper presents an analysis of changes in the structure of the fishing fleet on the trawl bottom cod fishing in the Barents Sea and adjacent waters, as well as of the contribution of different vessel types to the cod fishery with bycatch for the period 2003-2018. A comparative analysis of the catch rate of different vessel types commonly used for fisheries with that one of the PST-vessels currently used as a standard type was made. It has been determined that at present it is possible to use the catch rate of NS-2 type vessels as a reference value.

The work presents the results of studies to determine the optimal average weight of juvenile pikeperch in its transfer from zooplankton nutrition to artificial feed. It was found that the pikeperch better goes to an artificial diet with an average weight of 136 mg compared to a weight of 312 and 533 mg. It shows the advantage of using mixed feeding, when during the first two weeks of the diet includes both live and artificial feed. Juveniles grown in this way are characterized by increased survival - up to 69%, against 49% in the variant of the experiment, where only artificial diets were used as feed, and the best physiological indicators close to those in wild juveniles.

In the Ob-Irtysh fisheries basin, whitefish - Coregonus muksun has traditionally been one of the main objects of fishing. In 1950-1960 years it catches averaged 3,9 thousand tonnes per year. The reduction of the main spawning grounds as a result of the deterioration of the river ecology and the high intensity of fishing in the middle of the twentieth century led to a decrease in the population of whitefish. In 1980-1990 t years here was a decrease in catches to 0,7- 1,3 thousand tons per year. In this period, catches of whitefish in the whole Ob-Irtysh basin have fallen to 10 tons, and the catch is only for research purposes and aquaculture. In Irtysh River come only a few individuals. Under these conditions, the restoration of commercial stocks of the species is possible only through artificial reproduction and reducing the impact of IUU fishing. The return of the lost places of whitefish reproduction becomes an urgent task. Modern studies have shown that to restore the population of whitefish it will take at least 20 years to move from 0,3 to 1,4 billion copies grown up to 1,5 g juvenile whitefish. Fish-breeding complex OOO «Borodino» in Omsk has repair-brood stock of whitefish in the amount of 6 thousand copies and is able to retrieve and incubate eggs, raise and hold the stocking with fry of whitefish in the Irtysh River in the volume of about 15 million copies. With the emergence of such enterprises an important task is the development of scientific recommendations for the efficiency of works on artificial reproduction. The work should be carried out on the basis of knowledge of the species biology, peculiarities of its reproduction, distribution and migration of juveniles. Fish-breeding processes for the stocking of water bodies should fully comply with the natural life cycle of whitefish. In the article on the basis of generalization of information on biology of whitefish and conditions of its dwelling recommendations on its artificial reproduction in the basin of the Irtysh River are given.

Several methods of the of the stock increment estimation based on the tanner crab daily catches dynamics are analyzed for three populations. The estimated annual increment occurs minimal if both (1) the fisheries period is divided into several seasons, (2) the vessel factor is taken into account, (3) average daily catches are calculated for each season. The deviation on the square change is recommended to be applied for the estimation of the stock change only if the square decreases. If it increases the deviation should be applied if it is proved that the new fishery aggregations appeared. Algorithm of the calculation of available stock dynamics is given. Calculation of the corrected stock assessment based on the indicator approach (trafficlight method) and taken in account the data of both sample surveys and fisheries statistics is proposed.Keywords: fisheries, catch per effort (CPUE), stock densit