On the acoustic backscattering by Baltic herring and sprat

Natalia Gorska; Jakub Idczak

On the acoustic backscattering by Baltic herring and sprat

Abstract

Accurate abundance estimate of Baltic clupeids, herring and sprat, is required for their
sustainable exploitation. The understanding the sound backscattering of individual fish is
important for employing the acoustical techniques, which are widely used in the estimation.
The previous studies demonstrated that the improvement of the understanding is critical for
the Baltic herring and sprat. It was the main motivation of the paper. The main objective was
understanding the difference in acoustic backscattering by herring and sprat in the Baltic
Sea. The study was based on a numerical modeling of backscattering by the individual fish.
The model input data (morphometric parameters of fish) are obtained using available X-ray
images of Baltic sprat and herring. The difference in the backscattered energy, backscattering
directivity pattern, and the body contribution into the backscattering of the total fish was
demonstrated for the considered species.