Visualization of fish movement and size estimation of the fish by using broadband split-beam echo sounder

It is important information to measure fish movement, swimming direction, and target strength of the fish for species identification by using active acoustics. Broadband quantitative echo sounders have been developed in the world. Broadband system can measure single echo traces from individual fish with high range resolution. Single echo traces with high range resolution give us much more information of fish movements than by using conventional narrow band quantitative echo sounders. This paper presents the results of our in situ measurements.