Jellyfish shredding robots take sting out of sorting catch of day
AN UNDERWATER robot has been built to seek out and kill soaring numbers of jellyfish.
Populations of the invertebrates are increasing at a rapid rate in some parts of the world, including Japan and with sightings in British waters becoming more common, which poses a risk to the fishing industry as they get caught in nets and spoil catches.
Engineers have built a 3ft-long, autonomous prototype and tested it in a lab, finding it to be highly efficient at seeking and destroying jellyfish.
Future experiments will deploy it in the wild to see if it is able to locate and exterminate live populations.
A team of researchers from Hiroshima Institute of Technology set out to create a “jellyfish extermination device” that would “suck and crush” them before ejecting the fragments back into the ocean.
“In this experiment, a jellyfish extermination device was mounted on [an] autonomous underwater vehicle, and a crushing experiment was conducted using a jellyfish sample, which is made of water and gelatin,” the researchers wrote in the Journal of Japan Society for Design Engineering.
“It was confirmed that a jellyfish sample with a diameter of about 7cm (2.7in) and a height of about 11cm (4.3in) could be crushed to small pieces…during less than about eight seconds.”
The theory is that a robot can be carried by ships and deployed in the water, where on-board ultrasonic sensors and AI technology can identify a jellyfish target, then a large hose would suck the creature into the vehicle and jets of pressurised water and a turbine shred it into pieces.
Engineers are confident a version of the robot will be used in the oceans by 2024 and they say it can operate at depths of more than 160ft for up to three hours before returning automatically to its mother ship.
Early versions, such as the first-of-itskind prototype, will target moon jellyfish, which can grow up to 12in in diameter, and if the prototype proves to be effective, larger robots could be deployed that use the same techniques to go after much bigger species, such as Nomura’s jellyfish, which can grow to 6ft and weigh 440lb.
“The robot will help to reduce the burden on fishermen, who have to manually remove jellyfish caught in their nets”, Prof Ahn Jong-hyun, the team’s co-leader, told the Yomiuri newspaper. “In the future, we want to develop a robot that can exterminate giant Nomura’s jellyfish.”
Fisheries estimate that jellyfish cost the Japanese industry more than £60million a year, with thousands of reports of damage to fishing equipment every year.
Jellyfish blooms, which are linked to warmer waters and climate change, are also becoming more common in British waters.
Prof Martin Attrill, a marine ecologist from Plymouth, wrote in The Conversation last year that there were large numbers of lion’s mane jellyfish off the Scottish coast.
“This stunningly beautiful animal can be one of the biggest jellyfish in the world,” he said.
“The largest specimen recorded had a diameter of over 2m (6.5ft) and tentacles trailing back nearly 37m (121ft) from the main body, making it probably the longest animal in the world.”