On the basis of research and literary data the current state of Zeisko-Bureinsky populations of kaluga Acipenser dauricus and amur sturgeon Acipenser schrenckii is described. It is shown that these populations have an extremely low abundance because of overfishing. The following measures are suggested to increase these species abundance: to reduce kaluga and amur sturgeon catches in the Middle and Upper Amur river and to build a new hatchery in Blagoveshchensk city.
According to trawling surveys of 1991-2011, it is revealed that the threaded sculpin abundance’s variations have poorly expressed cyclic character. The highest level of the stock was observed in the beginning of 90th years. Last years the species is on the abundance reduction. Trade mortality shouldn't exceed 30 % of the commercial stock.
Key words: threaded sculpin, size, age, dynamics, abundance, stock, Peter the Great bay.
THE BERING SEA POLLOCK (THERAGRA CHALCOGRAMMA) STOCK ASSESSMENT, AND IT’S FISHERIES IN THE NORTHERN BERING SEA IN EARLY 2010-S.
Pollock biomass and abundance in the Bering Sea recovered to an average levelin 2010 as result of incoming of some abundant year classes – in 2006, 2008 and 2009. Biomass estimated in 6,2 mln. t, and abundance – in 18.35x109 in 2010, in comparison with 2009 it’s higher on 87. 8,3% and 42,4% consequently. Distribution of postspawning and immature pollock in summer-autumn period into northwestern Bering Sea and Russian EEZ increased in 2010-2011.
Key words: pollock, Bering Sea, abundance, biomass, stock assessment, seasonal migrations, recruitment, fisheries.
VARIATIONS OF REPRODUCTION EFFICIENCY OF PINK SALMON ONCORHYNCHUS GORBUSCHA AND CHUM SALMON ONCORHINCHUS KETA AT SPAWNING GROUNDS OF SAKHALIN ISLAND RIVERS