Sonar image. Artist's impression of the sort of data that will emerge from the 'Fish-TV' project. Fish-TV was designed by Dr Jules Jaffe at the Scripps Institution of Oceanography. It is an ultrasound sonar device which will be able to detect zooplankton and higher marine life in a volume of several cubic metres of sea. The sonar output is linked to a computer-based interpolation system, which will be able to provide a display such as that seen here, with the data renewed once per second. This will allow in situ studies of marine fauna populations in a non-intrusive manner. The black and white sonar image has been tinted blue.