Estimation of krill biomass from an acoustic survey carried out in 1986, during a study of predator–prey interactions around the western end of South Georgia

An acoustic survey, designed to study the distribution of shore-breeding, marine predators and their pelagic prey, was carried out in 1986 around the western end of South Georgia. This paper describes how this acoustic data has been used to estimate krill biomass of part of the original survey area as part of an interannual study. The radiating transect design gave increased sampling intensity in the shallower part of the area, so a method of post hoc stratification has been devised to generate sub areas with more even sampling. The results highlight the importance of the shelf slope area for krill.