Guidelines for standardisation of hydroacoustic methods

The use of transmitted underwater sound to survey fish populations (known effectively interchangeably as hydroacoustics, echo sounding or sonar) has a long and extensive record of successful applications in the marine environment where most of its major developments have historically taken place. The very efficient transmission of sound in water, particularly when compared with that of light, makes this remote-sensing technique highly effective in most aquatic ecosystems and under many environmental conditions. As a result, it provides a valuable complement to capture-based and frequently destructive fish sampling techniques. In recent decades, technological developments, including the miniaturisation of electronic components and rapidly increasing computing power, have facilitated the production of hydroacoustic systems which can be readily deployed from small vessels on fresh waters including lakes and reservoirs.