Известия ТИНРО (Sep 2015)
Generalized assessments of composition, quantitative distribution and biomass of benthic macrofauna on the shelf and slope in the North-West Pacific
Abstract
Quantitative information on the bottom macrofauna of the continental shelf and slope down to the depth 2025 m is generalized for the Far East of Russia and the adjacent waters of North Korea and Japan (in total 32,700 bottom trawls obtained in 224 expeditions over the area about 2 million km2 in 1977-2010). The total mean biomass of macrofauna is estimated as 38.64 million tons including 21.8 · 106 t of fish and cyclostomes and 16.9 · 106 t of invertebrates: 22.5 · 106 t in the Okhotsk Sea, 8.2 · 106 t in the Bering Sea, 3.7 · 106 t in the Pacific waters of Kamchatka, 2.8 · 106 t in the Pacific waters of Kuril Islands, and 1.4 · 106 t in the Japan Sea. The Okhotsk and Bering Seas have the higher biomass mainly because of their vast areas, but the density of macrofauna is ranked in other order: the Pacific waters of Kamchatka (64.5 t/km2, without jellyfishes - 18.7 t/km2) - Pacific waters of Kuril Islands (27.1 t/km2) - Bering Sea (24.5 t/km2) - Okhotsk Sea (16.5 t/km2) - Japan Sea (11.7 t/km2). The total biomass of fish and cephalopods at the sea bottom is the following: 13.8 · 106 t in the Okhotsk Sea, 4.6 · 106 t in the Bering Sea, 2.7 · 106 t in the Pacific waters of Kuril Islands, 1.4 · 106 t in the Pacific waters of Kamchatka, and 0.9 · 106 t in the Japan Sea, and their density is: 26.5 t/km2 in the Pacific waters of Kuril Islands, 23.6 t/km2 in the Pacific waters of Kamchatka, 13.9 /km2 in the Bering Sea, 10.1 t/km2 in the Okhotsk Sea, and 7.4 t/km2 in the Japan Sea. The areas with narrow shelves and sharp slopes, steep and patchy relief, are usually denser populated. However, the Japan Sea has the lowest biomass and density of benthic macrofauna, possibly because of lower productivity.
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