Echoview allows you to detect schools on single beam data, multibeam data or scanning sonar data. It will create one region for each school detected and you will be able to analyze and/or integrate the original data in those regions. Single beam and multibeam are treated very differently in Echoview.
See About 2D schools detection for detecting schools on single beam data.
See About 3D schools detection for detecting schools on multibeam or scanning sonar data.