Novel Acoustic Techniques for Assessing Fish Schooling in the Context of an Operational Ocean Observatory

摘要

The goal of this work is to develop new methods for observing large spatial scales in oceanic ecosystems. In particular, this report focuses on the development and use of a new type of mid-frequency, multi-beam sonar for making long-range backscatter images of fish aggregations in shallow water with the aid of the ocean acoustic waveguide. Fish aggregation is important during spawning, predation, and feeding, yet the quantitative analyses of gregarious movements and behaviors remain relatively rare. Measurements of fish aggregations are often difficult, particularly in pelagic environments. In terms of the forward sonar problem, widespread fish aggregations will appear as interfering reverberation, while schools and shoals may appear as false targets or may screen other targets, degrading sonar system performance.