Analyses of acoustic line-transect data from the waters around South Georgia: estimation of krill (Euphausia superba Dana) – biomass
A large-scale acoustic survey of zooplankton stocks in the waters around South Georgia was carried out during November and December 1981. The data have been analysed using various definitions of strata. The total biomass in the area of 155 786 km2 was estimated to be 1.8225 x 106 tonnes (Coefficient of Variation = 9.5%). This gives an estimate of mean density throughout the region of 11.7 tonnes km-2. Although the estimate of the mean is not sensitive to the definition of strata, the variance of the estimate is sensitive. The analyses highlight the importance of careful planning of acoustic surveys.