Researchers from the Norwegian University of Science and Technology have found that robotic turtles can monitor farmed fish and their cages without disturbing the fish. The team used a robot called U-CAT, which was originally used for archeological studies of shipwrecks on the seafloor.
A sea cage holds 200,000 farmed salmon. If the cages are damaged the fish could escape and interbreed with wild salmon. Monitoring fish health and the state of the cage is done with divers or underwater vehicles. But these methods are intrusive and can disrupt or stress the fish and limits the number of times the cage can be inspected.
The team found that a robotic turtle swimming around the cage and filming the equipment is able to do a gentle and efficient inspection job. Fish were only a little scared or stressed by the robot turtle. The fish swam calmly and fairly close to the robot without spooking.
Interestingly, the crucial characteristics of the robot were its size and speed, but he color and motor noise hardly mattered. The small size and slow movements were the most important to making the robot less disturbing to the fish. The robot’s resemblance to an ocean organism was not important. This means that any small slow-moving robot can be used to monitor fish cages.
Robotics can provide fish breeders with online updates and monitoring life in a sea cage. The robots can be connected to various measuring instruments and sensors for continuous monitoring without interruption. This could contribute to quicker responses, greater predictability, better fish welfare and lower mortality.
A paper on this research was published in Royal Society Open Science.