Echo integration near the seabed

Abstract

The echo integration (EI) method has long been used for fish abundance estimations. The method is applicable to any type of fish distribution and the analysis is easy to perform by advanced software. For fish near the seabed, however, sometimes it is difficult to perform an analysis because of so-called dead zones. In this paper, the EI near the seabed is considered, reviewing past studies and introducing some new ideas such as an unsampled zone. For the consideration, close inspection of the EI theory is necessary and a section is devoted to the purpose. As an application of the EI near the seabed, a combined measurement of the volume backscattering strength of demersal fish and the surface scattering strength of the seabed is demonstrated.