Hot topics in fish acoustics (active)

Abstract

It is important to quantify the spatial distribution of fish in their natural environment (ocean, lake, and river) and how the distribution evolves in time for a variety of applications including (1) management of fish stocks to maintain a sustainable source of food and (2) to improve our understanding of the ecosystem (such as how climate change impacts fish) through quantifying predator–prey relationships and other behavior. Active fish acoustics provides an attractive complement to nets given the great distances sound travels in the water and its ability to rapidly survey a large region at high resolution. This method involves studying distributions of fish in the water through analyzing their echoes through various means. While this field has enjoyed development for decades, there remain a number of “hot topics” receiving attention from researchers today. These include: (1) broadband acoustics as an emerging tool for advanced classification of, and discrimination between, species, (2) multi-beam imaging systems used to classify fish schools by size and shape, (3) long-range (km to 10's km) detection of fish, and (4) using transmission loss to classify fish on one-way propagation paths. Recent advances in these and other topics will be presented.