Abstract
The two-dimensional multibeam echo integration (2DMBEI) method, which provides the user with the target strength of a fish school, was derived analytically based on the theory of three-dimensional multibeam echo integration. It was developed to establish a reliable and practical methodology of fish abundance assessment using scanning sonar for fishery use. The 2DMBEI method was implemented in the data analyzing software of a quantitative scanning sonar system. Furthermore, a sea experiment using tungsten carbide spheres simulating a fish school was conducted to validate the 2DMBEI method.
