Zooplankton biomass and abundance of Antarctic krill Euphausia superba DANA in Indian Ocean sector of the southern ocean

Abstract

Zooplankton sampling was carried out during the first six Indian Scientific Expeditions to Antarctica (1981-1987) to estimate krill abundance in the Indian sector of the Southern Ocean (between 35 to 70 degrees S and 10 to 52 degrees E). This study aims to understand the distribution of biomass of zooplankton, especially the krill, using the data collectEd. by net sampling techniques. Total zooplankton biomass for all the sampling station ranged from 9 to 684 ml/1000 super(3) (x:143.34 + or - 138.61 SD; n = 150). Biomass data groupEd. by 5 degrees latitude interval shows the presence of higher biomass (x:191 ml/1000 m super(3); n = 31) in the Antarctic divergence region (between 60 to 65 degrees S). Euphausiid Euphausia superba DANA formed a considerable component of biomass and together with eggs and larvae represented over 60% (n = 39) of mean total zooplankton-biomass in the coastal ice region. The values for population density and biomass of adult-size krill varied between 0 to 4320 individuals and 6 to 305 ml/1000 m super(3), respectively