Recent bioacoustics observations in the NW Indian Ocean

To understand the way the marine ecosystem works, we must be able to resolve and sample appropriate scales of variability with interdisciplinary sampling systems collecting relevant data concurrently at the same time and space scales. Acoustics offers a way of obtaining a variety of quantitative biological data both remotely and non-intrusively. Our research has focussed on the use of bioacoustics as an aid to understanding the ecology of oceanic plankton and micronekton. We have worked in three areas: a) to couple together bioacoustics and other environmental data so that these various data are taken concurrently at the same time and space scales. b) to assess biomass/bioacoustic relationships to improve the quantitative assessments from acoustic systems. c) to widen the application of coupled acoustic/environmental sampling by developing a wide frequency range sonar capable of giving quantitative data over a wide range of target sizes. We have made some progress in all three areas and illustrate these with data taken from two cruises to the NW Indian Ocean