acousticTS - Physics-Based Models for Acoustic Target Strength

Acoustic target strength (TS) represents the intensity of an echo returning from an individual scatterer such as bubbles, fish, or zooplankton. TS can be used to convert integrated or volumetric backscatter collected from fisheries acoustic surveys into units of number density (e.g. animals per m^3), abundance (e.g. number of animals), and biomass (e.g. kg). This parameter can also be used to aid in classifying backscatter, such as separating likely echoes of large predatory fish (e.g. adult cod) from smaller prey (e.g. shrimp). One way to estimate TS is to use physics-based models to calculate theoretical TS that comprise exact and approximate solutions as well as analytical approaches. The models provided can help provide TS estimates over broad statistical distributions of model parameters. Applications are described by Lucca et al. (2023) <doi:10.1121/10.0022459>, with fisheries-acoustics principles from Simmonds and MacLennan (2005) <doi:10.1002/9780470995303>.