Further analysis of target strength measurements of Antarctic krill at 38 and 120 kHz: comparison with deformed cylinder model and inference of orientation distribution

Data collected during the krill target strength experiment [J. Acoust. Soc. Am. 87, 16-24( 1990)] are examined in the light of a recent zooplankton scattering model where the elongatedanimals are modeled as deformed finite cylinders [J. Acoust. Soc. Am. 86, 691-705 (1989)].Exercise of the model under assumption of an orientation distribution allows absolutepredictions of target strength to be made at each frequency. By requiring that the differencebetween predicted and measured target strengths be a minimum in a least-squares sense, it ispossible to infer the orientation distribution. This useful biological quantity was not obtainablein the previous analysis which involved the sphere scattering model.