Acoustic monitoring of underwater sounds to optimize aquaculture operations

Aquaculture has been the fastest-growing food sector globally for decades. It is practiced in various forms, from pond farming and land-based facilities with large tanks to vast net cages in open seas. However, aquaculture still faces significant challenges in sustainability, environmental compatibility, animal welfare, and health. Automation and digitalization of processes are crucial to addressing these issues. A key component is the continuous monitoring of both the fish and the technical aquaculture facilities, allowing for quick and efficient interventions when deviations occur. Automated and digitized processes based on sensors are gradually complementing and replacing manual handling by trained personnel.

Acoustic monitoring for fish populations

Traditional visual sensors (camera-based) often struggle to monitor fish effectively due to varying light conditions and water turbidity, making it difficult to assess health status, satiation levels, or potential stressors. Our technology addresses this by recording underwater sounds in aquaculture environments using hydrophones. These signals are then analyzed through statistical signal processing and AI models, resulting in software-based action recommendations (Passive Acoustic Monitoring, PAM). Initially, we identify suitable acoustic signal properties that can model fish behavior (e.g., fin movements and water displacement for activity, sucking and swallowing noises for feeding). Using a comprehensive reference dataset that includes both the acoustic data and specific, manually recorded characteristics of the fish population (number, size/weight, health status, stocking density, activity level, and tank conditions), we train an AI model. This model can then assign specific fish behaviors to individual acoustic events in real-time (Acoustic Event Detection, AED).

Our methodology leverages our expertise in audio signal processing and acoustic event detection and classification, now applied to the innovative field of underwater monitoring in aquaculture. Fraunhofer IDMT utilizes the excellent resources of the Fraunhofer Society and collaborates with Fraunhofer IMTE, which contributes excellent expertise and infrastructure in aquaculture and fish health to this interdisciplinary technology.