卷 44, 编号 7 (2018)

A complex bottom trawl survey (430 stations) was conducted over all of the shelf and continental slope (within a depth range of 10–750 m) in the Russian waters of the Sea of Japan from April 1 to July 8, 2015. A total of 211 taxa of invertebrates were recorded from trawl catches. The most widely represented of them were starfish (36), shrimps (32), gastropods (27), bivalves (23), brachyuran and anomuran crabs (11), polychaetes (11), coral polyps (10), and sponges (10). The total recorded biomass of macrozoobenthos in benthic biotopes of the northern Sea of Japan reached 1 572 500 t (136 600 t in Peter the Great Bay, 341 500 t in the Southern Primorye area, 686 000 t in the northern Primorye area, and 408 400 t in the Western Sakhalin subzone), which is higher than the mean long-term level. The total stock of commercial invertebrates was estimated at 630 000 t. Its largest portion (265 200 t, or 42.1%) was concentrated in the northern Primorye area (western Tatar Strait). The mean specific biomass of the trawl macrozoobenthos constituted 13.5 ± 1.1 g/m² (including 6.3 ± 0.5 g/m² of commercial benthic species). The most abundant groups were brittle stars (372 200 t), brachyuran crabs (231 600 t), anomuran crabs (48 700 t), shrimps (226 900 t), sponges (182 900 t), sea lilies (167 500 t), starfish (77 200 t), sea urchins (59 000 t), and bivalves (49 500 t). The vertical distribution of the total benthos and its commercial portion was characterized by maxima in the upper shelf (10–50 m) and within a depth range of 300–400 m. In the northwestern Sea of Japan, 18 biocenotic complexes of trawl macrozoobenthos were identified. The largest areas were occupied by the group of the sedentary seston-feeding sea lily Heliometra glacialis (biomass 5.5 g/m², depth range of 104–692 m, 131 stations), the group of the polyphagous snow crab Chionoecetes opilio (4.4 g/m², 27–552 m, 71 stations), the group of the mobile seston-feeding basket star Gorgonocephalus eucnemis (6.6 g/m², 58–372 m, 40 stations), and the group of the polyphagous pale yellow sea urchin Strongylocentrotus pallidus (4.7 g/m², 17–351 m, 40 stations).

An analysis of variations in the abundance of pink salmon on Iturup Island and in four areas of the eastern Sakhalin Island coast in 2007–2016 has shown that year-classes of this species become weaker if they are exposed to the effect of typhoons during their embryonic development in rivers (spawning nests) or juvenile feeding in coastal waters (soon after their downstream migration from rivers). The size of the pink salmon runs to these waters in 2017 completely fits the relationships identified for the previous year. These results indicate the decisive role of extreme environmental factors in the formation of the abundance of pink salmon.

As reported in the 1930s, the level of the forage base in Lake Khanka could provide from 2600 to 17 000 t of fish. The low fish capacity of the lake was explained mainly by a high abundance of small non-commercial species. For the purpose of increasing the fish capacity, a proposal was made in 1961 to introduce the Pike-Perch into Lake Khanka. This fish was expected to provide 200–300 tons extra fish product a year and also increase the proportion of valuable fish species in the lake by “destroying harmful rough fish” within 10–12 years. The introduction of pike-perch into Lake Khanka was carried out in 1970–1978. An analysis of data on the current status of the pike-perch population in the lake shows that this species has formed a stable self-reproducing population, whose biomass is now comparable to the level of the native common predatory fishes (80–100 t). In preying mainly on the sharpbelly (genus Hemiculter) and other abundant rough fish, it does not compete with other predators. Nevertheless, the pike-perch provides 20 t of marketable product a year, being rated as the second or third most commercially valuable fish species in catches from the lake.

Communities of epiphytic diatoms develop seasonally. On macroalgae, they reach the highest density in the middle of summer and decline to a minimum value in winter. This discrete pattern makes it possible to use the tool of difference (recurrent) equations for testing the concept of density regulation on the interannual dynamics of the number of epiphytic diatoms. The properties of the obtained multi-step recurrent models for the interannual dynamics of the number of diatoms in the epiphyton of the macroalga Ulva lactuca Linnaeus collected from three areas of coastal waters in Peter the Great Bay, Sea of Japan (Amur Bay, Ussuri Bay, and Stark Strait), are considered. The proposed multi-step recurrent models do not contradict the primary data of observations. Each of the obtained descriptions for different water areas is characterized by its specific pattern of dynamics. The reproductive capacity of epiphytic diatom community is the lowest in the Stark Strait; the highest reproductive capacity is observed in Amur Bay. According to the models, the epiphytic diatom communities in different parts of Peter the Great Bay exhibit generally complex, pseudochaotic, dynamics of their number.