Error estimation in the acoustic target strength measurement of Antarctic krill

Hydroacoustic techniques have a major role to play in living marine resource estimation and monitoring, as illustrated in the BIOMASS (Biological Investigations of Marine Antarctic Systems and Stocks) program. Quantitative assessment of krill stocks calls for accurately determining the relationship between acoustic backscatter and organism parameters such as length and mass. This relationship is commonly expressed as the target strength of an individual organism. This paper presents a review of experimental measurements and signal processing techniques carried out over the last four years in Australian and Antarctica, with a detailed analysis of the errors and uncertainties associated with the measurement process. The results are compared with those of workers from other countries and have contributed to a significant change in the krill target strength vs. length relationship used by the international CCAMLR (Commission on the Conservation of Antarctic Marine Living Resources) Organization.