How automated monitoring can improve farmed salmon welfare
Real-time recording of breathing rate, scale loss, and stress levels can give farmers better tools to ensure fish health and reduce stress factors before they develop into serious problems.
New methods that can improve the way the health and welfare of farmed salmon are monitored have been developed by researchers in Norway.
Results from the BIORELEVANCE project show that using cameras and sensors to record the fish’s physiological responses and behaviour in real time can contribute to more precise measures and better fish welfare.
“Automated monitoring of welfare indicators not only gives us better insight into the welfare of the fish, but also the opportunity to ensure more sustainable production,” said Renate Johansen, manager at fisheries and aquaculture research funder FHF which paid for the NOK 7.5 million (£550,000) project.
Mouth opening frequency
One of the most promising innovations from the project is the method for individual recognition and automatic monitoring of mouth opening frequency (MOF) in salmon – an important indicator of respiration and stress. Experiments have shown that MOF increases in response to higher temperatures, lower oxygen levels, and stress. This confirms MOF as a relevant respiratory indicator that can be used to monitor fish welfare in real time.
The use of camera technology to document MOF can provide farmers with valuable insight into how fish respond to different environmental conditions, management measures and, not least, new management methods. In particular, recording changes following stressful events could indicate the degree of welfare impact. This type of technology can also be combined with other welfare indicators to provide a holistic picture of fish health.
Scale loss
The project has investigated scale loss as a welfare indicator and found that a loss of more than 20-30% of scales can indicate reduced health. With real-time recording, farmers can gain better control and take measures earlier to reduce stress and improve fish welfare.
Given that the skin and mucous layer of salmon heal rapidly, the degree of scale loss may be more critical immediately after the scales are shed. This highlights the need for technology that can monitor scale loss in real time and assess how quickly the fish recover their skin barrier.
Stress management through brain activity
The project has also analysed stress management in salmon through brain activity. These findings provide important insights into how salmon physiology is affected by environment and handling.
“In nature, it is important not to show weaknesses as you can easily become prey for predatory fish, and the salmon will therefore try to behave normally as long as it can. This makes behavioural studies challenging. Methods like this, to document how the fish really feel, are therefore very important to build on,” said Johansen.
Strengthens sustainability
“New methods for documenting how handling and new technology affect the fish are very crucial for achieving sustainable development of the industry. If the fish are not doing well, then things are simply not going well on any level,” said Johansen.
“Securing data on fish welfare in real time will also reduce the use of experimental fish, as more data is obtained using a smaller number of fish in the development process.”
Commercially available technology such as cameras and sensors can already be used to monitor welfare indicators such as condition factor, scale loss, and wound development. By combining this data with real-time recording of behaviour, respiration, and environmental conditions, farmers can gain a more accurate picture of fish health and welfare.
Early stages
The development of real-time, individual-based welfare monitoring is still in its early stages, and challenges such as data processing capacity and connectivity issues in remote farming need to be addressed. Nevertheless, the results from BIORELEVANS show that such solutions can contribute to better fish welfare and more efficient production in aquaculture, writes FHF in an article on its website.
“This project lays an important foundation for further development of technology that ensures better fish welfare and more sustainable farming,” concluded Johansen.
Researchers taking part in the project were from the Norwegian University of Life Sciences (NMBU) and research organisations SINTEF, NIVA and Akvaplan-Niva.
