Data of 8 surveys conducted by Pacific Fish. Res. Center (TINRO) in the Pacific waters at Kuril Islands in 2004-2012 are summarized to consider forage base and food relationships of nekton and plankton and to estimate consumption of forage resourced by nekton. The total stock of zooplankton and micronekton in the epipelagic layer changed from 62 to 158 million tons over the shelf and slope of the surveyed area and from 41 to 75 million tons in its deep-water part. Mezopelagic fishes, squids, pacific salmons, and subtropical fishes were the main consumers of these forage resources in summer. The portion of zooplankton stock consumed annually by nekton was relatively low: 4.2-9.3 % for shelf and slope areas (data for 2004, 2007, and 2011) and 4.5-15.6 % for the deep-waters (data for 2004, 2007, 2009, and 2011), without significant year-to-year changes in the diet composition and feeding intensity of nekton. There is concluded that zooplankton and micronekton of the studied area serve successively the food needs of its consumers and carrying capacity of the epipelagic layer in the Pacific waters at Kuril Islands is quite substantial.
Trophic links between nekton and plankton are analyzed using the data collected in trawl surveys conducted by Pacific Fish. Res. Center (TINRO) in the Pacific waters at Kuril Islands and East Kamchatka in June-July of 2004-2016 and in the central and western parts of the Subarctic Front zone and adjacent subarctic waters in February-April of 2009-2011. Spatial, seasonal and interannual dynamics of nekton communities are detected, as well as changes in their composition and abundance. The most significant changes were caused by mass migrations of subtropical species, as in summer of 2014-2016. In these cases, new components were involved in the food web and energy flows between the low and upper trophic levels were changed, in the first place concerning to copepods, then to euphausiids, amphipods, and small-sized nekton prey. There were no such significant interannual changes in the energy flows in winter. The estimates of daily and seasonal energy flows between low and upper trophic levels, as well as the consumption rate of forage resources indicate no excess of allowable grazing pressure upon forage resources in the upper pelagic layer of the surveyed areas.
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