Study for Biodiversity and Conservation of Kunashiri, Etorofu, Habomai and Shikotan Islands

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In 2000 and 2001, wildlife researchers from Hokkaido, Japan, and Russian wildlife experts from the Kurilsky State Nature Reserve and the Sakhalin Bureau of Fishery visited the "Four Northern Islands " (Kunashiri, Etorofu, Habomai and Shikotan) as a part of the mutual visits without visas of specialists promoted to strengthen ties between our two countries. We conducted visual surveys of the region's wildlife, mostly from boats that traveled along the coastal areas.From July 19 to 28, 2000, in southern Etorofu, Kunashiri and Shikotan, we counted 1,326 seals and six whale species ( 305 individuals ). From August 13 to 27, 2001, in Shikotan and Habomai Islands, we counted 2,950 seals,430 sea lions, 45 sea otters, 2,074 whales and 27,475 sea birds.Killer whales ( Orcinus orca ) were the most impressive of the marine mammals observed during these surveys. Observations of seven separate groups and 53 individuals were recorded. This concentration of killer whales, which are situated at the to … More p of the ocean food chain, clearly illustrates the richness of biological resources in this marine area. These marine habitats appear to be even richer than biological diversity of the Shiretoko Peninsula in Hokkaido, where killer whale sightings are rare, despite the peninsula's protected legal status and its well-preserved pristine biological habitat.The annual freezing and thawing of the sea ice creates acycle which draws nutrient-rich deep water toward the surface. This results in an abundance of both photo- and zooplankton from April to July. The plankton blooms continue through November with the flush of nutrient-rich Pacific Ocean water and the mixing of warm ( Soya ) and cold ( east Sakhalin ) ocean currents.Seeking the abundant plankton in the waters off the Four Northern Islands, school of fish migrate from subtropical zones and large schools of endemic subarctic species gather from the north. Residing permanently or migrating to prey on these fish species are seabirds, several species of whale, sea otters and six pinniped fish.The region extending from the Etorofu Strait ( Miyabe line ) to the Tsugaru Strait ( Blakiston line ) is considered a single zone in terms of biogeography. And yet, under nearly 50 years of Soviet and Russian Federation conservation policies, the Four Northern Islands continue to possess pristine habitat that have vanished from Hokkaido. Their unique biodiversity intact, the Four Northern Islands - both land and marine areas - are of great global importance. Less