Acoustic density estimation of dense fish shoals

TL;DR

This paper presents a novel acoustic method for estimating the density of dense fish shoals by analyzing multiple scattering effects and using volumetric scans, overcoming limitations of traditional techniques.

Contribution

It introduces a combined approach utilizing multiple scattering analysis and volumetric scanning to estimate fish density in dense shoals, which was previously challenging.

Findings

Successful observation of multiple scattering and coherent backscattering effects.

Ability to isolate individual fish from dense shoals for target strength estimation.

Effective density estimation in dense fish shoals using combined acoustic methods.

Abstract

Multiple scattering of acoustic waves offers a noninvasive method for density estimation of a dense shoal of fish where traditional techniques such as echo-counting or echo-integration fail. Through acoustic experiments with a multi-beam sonar system in open sea cages, multiple scattering of sound in a fish shoal, and in particular the coherent backscattering effect, can be observed and interpreted quantitatively. Furthermore, a volumetric scan of the fish shoal allows isolation of a few individual fish from which target strength estimations are possible. The combination of those two methods allows for fish density estimation in the challenging case of dense shoals.