Winter zooplankton biomass and population structure of calanoid copepods in the Bering Sea basin
2001
Ozaki, K. (Hokkaido Univ., Hakodate (Japan). Faculty of Fisheries) | Takeuchi, T. | Shiga, N. | Mito, K.
The zooplankton biomass, species composition of calanoid copepods and population structure of dominant calanoid species were investigated using samples collected by vertical hauls from 500-m depth in the Bering Sea basin during winter 1993. Zooplankton biomass ranged from 13.9 to 57.9gwwm sup(-2) (mean=32.5g wwm sup(-2) ) and was at the same level as summer biomass from 0-80-m depth. Calanoid copepods comprised 75% of the total biomass. Zooplanktonic and calanoid biomasses were lower at the eastern edge of the Bering Sea basin. A total of 34 calanoid species were identified. The dominant species in both numerical abundance and biomass were Eucalanus bungii, Neocalanus cristatus, N. flemingeri and Metridia pacifica. Developmental stages were mainly copepodite 4 (C4) to C6 (adult) for E. bungii, C1 and C5 for N. cristatus, C4 and adult for N. flemingeri, and C5 and adult for M. pacifica. Some of these stages are also known to be deep-dwelling, overwintering stages in the subarctic Pacific.
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