Title: Ping it back – On the use of active acoustics for ecological monitoring
Abstract: Active acoustics or fisheries acoustics is now the most common tool when it comes to monitoring pelagic animals globally and has been called upon as the staff of Moses or the most promising tool when it comes to ecosystem monitoring. Active acoustics allows monitoring of large areas in a relatively short period of time. Sound at one or multiple discrete frequencies or nowadays through a sweep over a range of frequencies is emitted into the water. On its path through the water column, every object with a density different from the surrounding medium will reflect sound back to the sound source location. Measuring this echo allows the identification of the nature and quantification of the amount of the reflecting source, with a certain level of uncertainty, provided the characteristic backscattering properties of the target are known. Here I will provide a gentle introduction into the world of active acoustics and illustrate the use of the technology in the context of ecological studies or how it can help us gain novel insights into the structure of marine ecosystems at a high spatio-temporal resolution.