Four indices of prey availability are calculated from surveys conducted in the vicinity of the Seal Island CEMP site during the austral summers of 1990 to 1996. The indices are measures of average prey density, depth, distance from Seal Island, and persistence over time. Acoustic data from two AMLR surveys each year were subsampled to include the foraging range of predators breeding at Seal Island. Indices derived from these data indicate that although average prey density varied by a factor of almost five between 1990 and 1996, prey were consistently distributed along the edge of the shelf break north of Elephant Island, and between 25 and l00 m depth. Indices of average prey density agree with demographic indices of krill abundance derived from net samples. Indices of persistence over time reflect the relative biomass of juvenile krill near Seal Island during the first survey of each year as compared to the biomass of post-spawning adults near Seal Island during the second survey of each year. It is hoped that these indices may be useful in modelling krill predator breeding success as a function of prey availability.