VARIABILITY IN BIOLOGICAL DISTRIBUTIONS AND HYDROGRAPHY FROM CONCURRENT ACOUSTIC DOPPLER CURRENT PROFILER AND SEASOAR SURVEYS

Concurrent Acoustic Doppler Current Profiler (ADCP)/SeaSoar surveys ca n provide a range of quantitative and qualitative biological data at t he same time and space scales as hydrographic data. The data resolve m esoscale variability for both biology and physics and can be displayed in real time-thereby allowing targeting of conventional sampling prog rammes. Examples from such surveys in a range of oceanic conditions an d from different oceans demonstrate the complex patterns of biological distributions, and thereby acoustic variability, which change in spac e and time in response to both biological and physical forcing. Direct comparison of data from different areas requires absolute acoustic da ta. A method for converting relative ADCP backscatter to mean volume b ackscattering strength that includes using concurrent temperature and salinity data from SeaSoar is described; the resultant data sets can b e directly compared in time and space. (C) 1996 International council for the Exploration of the Sea