Biomass and production of net zooplankton in the Bering Sea

• Published in: Izvestiya TINRO
• Main Author: K. M. Gorbatenko
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Transactions of the Pacific Research Institute of Fisheries and Oceanography 2021
• Subjects: биомасса; продукция; зоопланктон; копеподы; щетинкочелюстные; эвфаузииды; медузы; гиперииды; берингово море; Aquaculture. Fisheries. Angling; SH1-691; Bering Sea; Okhotsk; okhotsk sea; Берингов*; Copepods
• Online Access: https://doi.org/10.26428/1606-9919-2021-201-191-205; https://doaj.org/article/89ebfbeba066463ab2d66c2aac52cc35

Total biomass and production are evaluated for taxonomic groups of zooplankton sampled with Juday net (mesh size 0.168 mm) from the 0-200 m layer in the Bering Sea in 1986-2018. The annual mean stock of zooplankton is assessed as 245.1 . 106 t WW, or by taxonomic groups: copepods — 135.0 . 106 t (55.1 %), chaetognaths — 664.4 . 106 t (26.3 %), euphausiids — 30.8 . . 106 t (10.8 %), medusas — 7.9 . 106 t (3.2 %), and hyperiids — 7.0 . 106 t (2.9 %). The gross annual yield is estimated as 1378.6 . 106 t for copepods (P/B = 9.3), 422.5 . 106 t for chaetognaths (P/B = 6.0), 212.5 . 106 t for euphausiids (P/B = 9.0), 132.4 . 106 t for net medusas (P/B = 16.7), and 90.9 . 106 t for hyperiids (P/B = 12.3). The total annual yield of 2281.9 . 106 t, on average, was formed as a sum of 107.4 . 106 t produced in winter (P/B = 1.0), 889.6 . 106 t — in spring (P/B = 2.4), 755.2 . 106 t — in summer (P/B = 2.8), and 529.6 . 106 t — in autumn (P/B = 2.2). This annual yield was produced mostly by non-predatory zooplankton (1613.8 . 106 t), but also by predatory zooplankton (668.1 . 106 t). Mean annual P/B-ratio for the entire zooplankton in the Bering Sea was 8.5 that was in 1.4 times lower than in the Okhotsk Sea (P/B = 11.8), mainly because of predominance of less productive Copepoda species.