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    Results of an acoustic investigation of Antarctic krill, Euphausia superba, biomass-density in the Elephant Island area in January/February 2001

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    Número de documento:
    M.A. Thomasson (Sweden), J.H. Emery (USA), J. Rademan (South Africa), R.P. Hewitt (USA) and B.I. Bergström (Sweden)
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    Results from an acoustic krill survey in the Elephant Island Area carried out Jan 27th to Feb 4th 2001 are presented. Data were collected with a SIMRAD EK60 Scientific Echo Sounder installed on the R/V “Polarstern”. The collected acoustic data were post-stratified in three strata based on demographic results obtained by net sampling. Data files from the 38 kHz and 120 kHz recordings were prepared and processed according to protocols used for the CCAMLR 2000 Synoptic Survey. An average biomass density of 15.32 g/m2 and a standing stock (B0) of 1.7 million tonnes were estimated for the entire area. The highest density was found in the southernmost stratum and lowest density in the northernmost stratum. The estimated average agrees well with estimates made by the U.S. AMLR program from two surveys (15.6 g/m2 and 12.8 g/m2 respectively) performed the same field season in partly the same area, and with the estimate based on RMT-8 net sampling carried out during the “Polarstern “ expedition (13.04 g/m2). The biomass density presented here is also higher than the long-term running mean from net samples for the Elephant Island area (13.9 g/m2, 1977- 2001).