COMPARISON OF THE BIOMASS OF ANTARCTIC KRILL, (EUPHAUSIA SUPERBA), AROUND THE SOUTH SHETLAND AND SOUTH ORKNEY ISLANDS IN THREE YEARS: 1999, 2000 AND 2008

Using a combination of techniques, we examine data from three cruises in 1999, 2000 and 2008 to calculate the biomass and demographic characteristics of Antarctic krill (Euphausia superba) surrounding the South Orkney and South Shetlands Islands. Net tow data show that length frequency distributions of krill between Elephant Island and the South Orkney Islands were similar. The similarity in length frequency distributions suggest that acoustic data collected as part of US AMLR finfish surveys may be useful in deriving biomass estimates for the South Orkney Islands in 1999. We use a simple bootstrap approach to illustrate our ideas. We re-analyze the data from 2000, including some CCAMLR data, and report on the biomass from a survey conducted in 2008. Biomass estimates in 2008 are calculated using the traditional Jolly-Hampton (1991) methodology, and represent the first estimate of biomass in this region. Together the data from these three years suggest that biomass in the South Orkney Islands is similar to the biomass in the South Shetland Islands, especially the Elephant Island region. The results are promising and suggest that where possible future data, derived from ancillary studies, can be used to better resolve the temporal trends in krill biomass in this region. Such data would benefit the future development of management strategies based on small scale units.