Ambient noise
Ambient noise is usually not a limiting factor to the performance of sonars and echo sounders.
The ambient noise may be split up as follows:
•  Sea noise: Air bubbles, seismic disturbances, waves, boundary turbulence, etc.
•  Biological noise: Fish, mammals
•  Man made noise: Other vessels, interference
•  Precipitation noise: Heavy rain or hail
In some areas, where many vessels operate together, the engine and propeller noise from other vessels may be disturbing. Interference from hydroacoustic instruments located in other vessels may also be a limiting factor. The sea noise depends on the weather conditions. In bad weather the sea noise can be quite high due to the waves.