Acoustic environment of aquaculture net-pens varies with feeding status of Atlantic salmon (Salmo salar)

Continuous data on the condition of fish is necessary to monitor, control and document biological processes in fish farms in real-time, yet acquiring it from a large net-pen environment is challenging. Tools to rapidly detect change in the entire net-pen population are lacking. Automated passive acoustic monitoring is emerging as an effective monitoring tool in wildlife monitoring but has not before been tested in an aquaculture setting. Here, we explore the possibilities for passive acoustic monitoring in an aquaculture perspective. We investigated whether the soundscape of a net-pen could infer information on the condition of the whole net-pen population. In three cases, conducted at two different fish farms, we tested whether Atlantic salmon (Salmo salar) influence the soundscape of the net-pen. We provide evidence that Atlantic salmon alter the acoustic environment when compared to an empty net-pen. We observe from a 24-h recording that the acoustic fingerprint of the net-pen varies over time and mirrors the feeding status of the fish. Our results demonstrate the potential for passive acoustic monitoring in fish farms and provide a new direction for data-driven management in aquaculture to improve fish welfare and operational feeding routines.