An acoustic estimation of krill densities to the north of South Georgia in January 1994

Dual frequency (38 and 120 kHz) acoustic surveys were carried out in two regions along the northern coast of South Georgia from RRS lames Clark Ross during January 1994. Difference in signal strength between the two frequencies (δMVBS = MVBS 120 kHz - MVBS 38 kHz) was used to discriminate krill from other acoustic targets. A generic target strength to weight relationship was used to derive krill densities from 120 kHz signals attributed krill. At less than 1 g m-2 , mean weighted krill densities in both regions were extremely low in comparison with previously published density estimates, and provide further evidence of an extreme krill paucity around South Georgia in the 1993/4 season.