Use of multi-frequency acoustics in studies of Antarctic zooplankton

We describe our advances in applying acoustic techniques to the study of Antarctic zooplankton. First we show how the use of three-frequency data enables us to identify a greater number of common species of macro-zooplankton than is possible when using only two frequencies. For practical reasons we are not able to utilize three frequency techniques on routine krill surveys so, secondly we illustrate how dual-frequency acoustic techniques are providing detailed information on the biomass and size of Antarctic krill