Target strength of Antarctic krill

In-situ measurements of individual krill target strength are presented (modal value = -69db). Net samples obtained immediately before the experiment indicate that the animals were reproductively mature and averaged 47.44mm in length. Results agree well with recent predictions of acoustic target strength based on extrapolations of other field experiments using the bent cylinder model of sound scattering by elongated zooplankters. The modal value of the measurements is 6.7dB lower than that predicted by the BIOMASS equation for 47.44mm krill.