BIOLOGIYA MORYA, 2010, Vol. 36, No. 3, pp. 157-165 |
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Distribution and abundance dynamics of jellyfish in the Sea of Okhotsk Pacific Fisheries Research Center, Vladivostok 690950 E-mail: The seasonal and interannual trends in the distribution and abundance of jellyfish (Scyphozoa and Hydrozoa) in the epipelagic and mesopelagic areas of the Sea of Okhotsk during 1992-2005 were examined on the basis of trawl survey data. The area of occurrence, biomass, and numbers of scyphomedusae in the epipelagic layer were the smallest in spring; in summer and fall their abundance sharply increased and then decreased in winter. In contrast to the epipelagic, the abundance of scyphomedusae in the mesopelagic layer was significantly lower in summer than in winter and spring. This may testify to that a part of scyphomedusae winter in the mesopelagic. Hydrozoa in both the epi- and mesopelagic areas were more numerous in winter and spring. Jellyfish biomass and abundance greatly changed from year to year. Thus, in fall the biomass of scyphomedusae and hydromedusae in the epipelagic varied from 166 to 1271 and from 6 to 49 kg/km2, respectively. Key words: Scyphozoa, Hydrozoa, jellyfish, biomass, abundance, distribution, Sea of Okhotsk. |
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