Researchers in Norway test how comfortable salmon in a commercial fish farm being monitored by underwater robots instead of human divers
- A team of scientists in Norway observed 188,000 salmon in a sea cage fish farm
- They sent a smaller and larger robot into the water to observe the salmon
- The fish appeared to be more comfortable with the smaller robot, indicated by how closely they swam to it and how slowly they beat their tails while near it
Researchers in Norway are testing how salmon in a commercial fish farm might react to being regularly monitored by an underwater robots.
While fish farms are typically uneventful environments, they still require oversight to ensure the captive fish are safe and healthy, a task most commercial fish farms assign to a human diver.
Maarja Kruusmaa and a team of researchers at the Norwegian University of Science and Technology wanted to test how fish would respond to being watched over by robots instead of people.
Researchers in Norway used two different underwater drones as monitors in a salmon fish farm to see how comfortable fish were around robot interlopers
‘The happier the fish are, the healthier the fish are, the better they eat, the better they grow, the less parasites they have and the less they get sick,’ Kruusmaa told New Scientist.
The team used two different underwater robots to test whether the fish would react differently based on the size and propulsion method.
One robot, a boxy jet-ski-sized machine called Argus Mini, was propelled by thrusters.
A smaller robot, called U-CAT was the size of a small dog and propelled itself with four fin-like flaps.
The team recorded the reaction of the salmon to the two different robots, specifically looking to see how close the fish would get to each, and how frequently they beat their tails while nearby, an indication of anxiety.
They used a smaller robot, called U-CAT, that was propelled by four mechanical flippers and a larger thurster powered robot called Agus Mini, that was propelled by thrusters
They also recorded footage of the fish moving around the sea cage with a human diver and then with no observer of any kind, human or robot.
The fish seemed to be most comfortable with the smaller U-CAT robot than either the human diver or the Argus Mini.
The fish beat their tails slightly faster around the U-CAT, but slower than they did with either the Argus Mini or the human diver.
The tail beating was slowest when the fish were alone.
The first were most comfortable with the smaller robot, U-CAT (far right), as indicated by how closely they swam toward it and how much less quickly the fish beat their tails compared to when they were around the larger Argus Mini
The findings suggest fish are most disturbed by the size of the person or thing they’re forced to swim with
The findings suggest that while fish seem to prefer not having any outside observers, they tend to be most comfortable with smaller ones, regardless of whether machine or human.
‘Size matters,’ says Kruusmaa.
‘You can make a very complicated robot that’s extremely quiet and has a smiley face and speaks fish language, but that would be hugely costly and the fish don’t seem to care.’