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 of the waters around South Georgia was carried out during November and December 1981. The data have been analysed as a survey using various definitions of strata. The total biomass in the area of 155 786 km2 was estimated to be 1.8225 x 106 t (Coefficient of Variation = 9.5%). This gives an estimate of mean density throughout the region of 11.7 t km-2. Although the estimate of the mean is not sensitive to the definition of strata, the variance of the estimate is. The analyses highlight the importance of careful planning of acoustic surveys