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Sound waves reveal hungry salmon
Feed amounts to 50 percent of the costs of farming salmon. How do we know if the salmon is hungry or full?
In recent years, Norwegian aquaculture has vigorously reduced production costs and increased production efficiency, while at the same time minimized environmental impacts and ensure fish welfare.
The feeding process is a crucial factor. Currently, feed accounts for 50 percent of the total cost in fish farms. Now a new, innovative automatic feeding system based on passive acoustics systems and artificial intelligence may contribute to more sustainable fish farming.
Artificial intelligence and sound
“Our system combines different technologies, like passive acoustic sensors, IoT - Internet of Things, and machine learning to monitor and control fish behavior in the cages,” says Rosa Martínez Álvarez-Castellanos, R&D Technician at Centro Tecnológico Naval y del Mar (CTN).
The system is called SICA. It is a non-invasive, passive acoustic system comprised of two modules: Data logger and control unit.
The data logger, which is deployed in sea cages, performs the acquisition stage through the passive acoustic sensor. Data is transmitted via the wireless communication module. The control unit is placed where the feeding process is undertaken. In this project, the system was installed at the barge in SINTEF ACE facilities. Its function is to apply the machine learning algorithms to the data received and make decisions about the feeding process.
The SICA system operates autonomously, acquiring and processing the acoustic data. The technology is non-invasive and provides real-time monitoring.
In contrast to the traditional method of underwater video cameras, this system was found to detect unusual behavior of salmon more effectively during the feeding process by identifying low feed intake earlier. By improving the efficiency of the feeding process, salmon farmers can reduce environmental impacts and increase their production.
Worldwide testing
The CTN has tested the system in the Mediterranean for sea bass fish farms. These species are different from salmon, and the farming conditions are challenging. To verify that the concept works under different conditions, and in order to train the algorithms, they performed tests at the SINTEF ACE full-scale aquaculture facilities in Frøya, Norway.
This was crucial for Rosa Martínez Álvarez-Castellanos and her colleges. “We needed access to good facilities to get the best results, and especially under such harsh conditions. In particular, we were able to test our equipment under different weather conditions and with the proper feeding equipment. The results showed that our concept is working,” she says.
The facility provided access to a fish farm, boats, sensors, and assistance to set up the units at different cages. They also had fast wireless communication that helped them to test the system thoroughly. "This fast connection allowed us to expand the collaboration between CTN in Spain and the SICA system in Norway during the experiment," says Álvarez-Castellanos.
For researcher Eleni Kelasidi, this is good evidence that the aquaculture laboratory facilitates full-scale testing and research at the highest level.
"Highly qualified employees are an important reason why we are able to make it work," she says. In the future, the SINTEF ACE facilities will also be open for international researchers.
