биота российских вод японского моря - Materials of Alexey Shipunov

Habitat and breeding. E. pacifica is an epi- to mesopelagic species, in the Seaof Japan inhabiting depths to 1000 m (Vinogradov, 1968). Diurnal vertical migrationsare observed in euphausiids 8 mm long and larger. In the cold-water regions of the seaassemblages are densest at depths of 200–300 m in the daytime and from the surfaceto 150 m at night. In the warm-water regions assemblages are densest at depths from300 to 400 m in the daytime. Considerable density of assemblages is registered todepths of 600–650 m. Young euphausiids with body length up to 7–8 mm remain inthe upper 100-m layer day and night.From February to April E. pacifica breeds, and the phenological wave of nearsurfaceassemblages of pre-breeding and breeding krill moves from the southwesternpart of Honshu Island northward to Hokkaido. Euphausiids gather in assemblages at anear-surface temperature of 6–7 °C and disseminate when temperature reaches 16 °C(Komaki, 1967). This is the main period of intensive inshore krill fishery in Japan. Inthe eastern region of the sea the phenological wave starts in February and moves fromsouth to north. Breeding begins in the northern half of the Tatar Strait only in July,when water warms up to 13–14 °C, it is most intensive in August-September and endsin mid-October (Pogodin, 1981, 1990). There are almost no data on E. pacifica breedingin the coastal waters of Primorye. One of the authors (B.M. Borisov) found theeggs of E. pacifica in Amursky Bay (Peter the Great Bay) on November 17, 2004. Accordingto A.G. Pogodin’s data (1982) the diameter of E. pacifica egg capsules rangefrom 425 to 625 µm, and according to B.M. Borisov’s unpublished data the diameteris 370 to 530 µm (at the diameter of egg capsules equal to 530 µm, the diameter of anembryo was 340 µm).The diet of these euphausiids includes wide range of objects; their preference isfor meso- and microzooplankton, whereas phytoplankton and detritus are consumedrarer.ReferencesAdrianov, A.V. & O.G. Kussakin. 1998. A chek-list of the biota of Peter the Great Bayof the Sea of Japan. Vladivostok: Dalnauka. 350 p. (In Russian).Afanasiev, N.N. 1985. Macroplankton of the northern Sea of Okhotsk: Avtoref. Diss…Kand. Biol. Nauk. Moscow: IOAN SSSR. 25 p. (In Russian).Araki, M. 1971. [Ecology of the Euphausiid distribution in the Sea of Japan and SurugaBay. The manuscript of dissertation (In Japanese). 66 p., 55 figs.]Baker, A. de C., Brinton, B.P., & E. Brinton. 1990. A practical guide to the Euphausiidsof the world. London: British natural history museum. 96 p.Boden, B.P., Johnson, M.W., & E. Brinton. 1955. The Euphausiacea (Crustacea) of theNorth Pacific // Bull. Scripps Inst. Oceanogr. V. 6(8). P. 287–400.Brandt, F. 1851. Krebse // Middendorff A.Th.v., Reise in den äussersten Norden undOsten Sibiriens während der Jahre 1843 und 1844. V. 2, Zool. (1). S. 79–148.Dolganova, N.T. 2000. The composition, seasonal and interannual dynamics of theplankton of the northwestern Sea of Japan: Avtoref. Diss… Kand. Biol. Nauk.Vladivostok: TINRO-tsentr. 23 p.Endo, Y. & Y. Komaki. 1979. Larval stages of euphausiids with descriptions of thoseof Thysanoessa longipes Brandt // Bull. Jap. Sea reg. Fish. Res. Lab. V. 30.P. 97–110.87