Preliminary characterization of underwater noise from a salmon farm in northern Patagonia

Chile's salmon aquaculture industry (the world's second largest) has expanded rapidly, with limited evaluation of its environmental impacts. To quantify underwater noise, continuous recordings were collected over five days at a salmon farm in northern Patagonia (Quemchi, Chile), providing empirical data from an understudied region. Sound pressure levels (20 Hz-10 kHz) were analyzed in one-third octave bands using an autonomous recorder. Noise levels were higher during daytime, indicating farm operations dominated the acoustic environment under daylight. Loud-noise events (the noisiest 10% of minutes) were examined at 63 Hz, 125 Hz, and 5000 Hz. No temporal pattern emerged, likely reflecting the limited monitoring period, although episodes of elevated acoustic disturbance were observed. Given the rapid expansion of salmon aquaculture in Northern Patagonia, these preliminary findings provide baseline information and highlight the need to incorporate acoustic monitoring into conservation and management frameworks for this vulnerable marine ecosystem.