Характеристика нектонных и планктонных сообществ в верхней эпипелагиали западной части Берингова моря и океанических вод Камчатки летом 2003 г.

• Main Authors: Глебов, И., Свиридов, В., Очеретянный, М., Ефимкин, А., Слабинский, А., Басюк, Е.
• Format: Text
• Language: unknown
• Published: Федеральное государственное унитарное предприятие «Тихоокеанский научно-исследовательский рыбохозяйственный центр» 2004
• Subjects: Anadyr; Anadyr’; Atka; Bering Sea; Bering Strait; Navarin; Pacific; Sockeye; Anadyr'; Kamchatka; Pseudocalanus minutus; Subarctic; Берингов*; КАМЧАТК*; Copepods
• Online Access: http://cyberleninka.ru/article/n/harakteristika-nektonnyh-i-planktonnyh-soobschestv-v-verhney-epipelagiali-zapadnoy-chasti-beringova-morya-i-okeanicheskih-vod-kamchatki; http://cyberleninka.ru/article_covers/12551242.png

Рассмотрены особенности океанологической обстановки, результаты исследований нектонных и планктонных сообществ в верхней эпипелагиали западной части Берингова моря и океанических водах Камчатки в июлеавгусте 2003 г. Летом 2003 г. прослеживалась усиленная адвекция океанических вод и значительное повышение температурного фона на поверхности моря по сравнению со среднемноголетним уровнем. Валовый запас зоопланктона в западной части Берингова моря и океанических водах Камчатки в слое 500 м оценен в 60,8 млн т. После сокращения запасов массовых видов рыб (сельдь и минтай) нектонное сообщество эпипелагиали западной части моря стабилизировалось на относительно низком уровне биомассы (1,28 млн т). В составе верхнеэпипелагического нектона значительно возросла доля (65,6 %) тихоокеанских лососей, из которых выделяется кета (45,4 %). Наиболее характерной особенностью распределения лососей в 2003 г. явилось их глубокое проникновение в районы северного шельфа. Oceanographic conditions and nekton and plankton communities are considered in the upper epipelagic layer of the western Bering Sea and adjacent Pacific waters in JulyAugust of 2003. An unusually strong warming of surface mixed layer of Bering Sea was observed in summer 2003 because of intensive advection of warm oceanic waters and calm weather. The oceanic Subarctic waters entered the Sea through the Near Strait and influenced on its southwestern deep-water part. The other warm stream, Central Bering Sea Current was traced in the eastern Bering Sea as far as the Bering Strait. As the result of strong warming, a well-defined warm (up to 12 oC) upper mixed layer was observed. Its thickness reached 2025 m in the northern part of the surveyed area, and its temperature was 24 °С higher than climatic values. Total biomass of zooplankton in the upper 500 m layer was estimated as 48.6 million tons in the western Bering Sea, and 12.2 million tons in the oceanic waters off Kamchatka. The large-size fraction dominated (6086 %) in plankton community, and copepods and sagittas dominated in the large-size fraction. The percentage of small-size fraction was insignificant: 513 % the copepods Oithona similis and Pseudocalanus newmani dominated in this fraction. Medium-size fraction of zooplankton was insignificant, too: 726 % in the shallow northern part of the Sea and 518 % in the deep-water southern part, with the copepods Pseudocalanus minutus, P. newmani, and Metridia pacifica predominance. Epipelagic nekton community of the western Bering Sea showed a stabilization at the relatively low level of biomass (1.28 million tons). Its structure was polydominant, where small-size pelagic and mesopelagic species dominated by numbers, whereas large-size pelagic and megaplankton species dominated by biomass. The fish fauna was represented by 55 species (51 species within Bering Sea), and cephalopods by 8 species. The fish species included both permanent and temporary inhabitants of the upper epipelagic layer and mesopelagic migrants from the lower strata. The share of Pacific salmons (chum, chinook, and sockeye) in the total biomass was very high: 65.6 %, with 45.4 % of chum salmon; that is significantly higher than in 1980-s. So high abundance of the salmons in the northwestern Bering Sea in 2003 was a result of their active migration from the U.S. waters and wide distribution over the northern shelf because of strong inflow of the warm Navarin Current into the Anadyr Bay. The biomass of Atka mackerel was high, as well, and the biomass of mesopelagic fish species (as northern smoothtongue) was close to that in 1990-s.