Killer Robots Slash Jellyfish

Jellyfish blooms are increasingly causing problems. In Korea, the number of accidents and financial losses caused by jellyfish is estimated at 300 billion won (£1.8 m) per year. To combat the jellyfish, Korean researchers led by Professor Hyeon Myeong are using a team of robots, called JEROS (Jellyfish Elimination Robotic Swarm). These slash and grind the jellyfish, killing 900 kg an hour.

Jellyfish cause the fishing industry to lose money by breaking fishing nets. They sting swimmers. They block the seawater cooling systems of power plants. In 2009, a ten-ton Japanese trawler capsized after the three man crew tried to haul up a net loaded with jellyfish.

Scientists have proposed several reasons why jellyfish blooms are apparently becoming more common around the world’s coasts. One recent suggestion is that “ocean sprawl” may be an important driver of the global increase in jellyfish blooms. Ocean sprawl is the proliferation of artificial structures associated with shipping, aquaculture, other coastal industries and coastal protection. The theory is that the structures provide habitat for jellyfish polyps thus causing the increase in jellies.¹ Another theory is over-fishing of predators like turtles. Polluted waters – where fertiliser run-off etc causes plankton blooms – increase the food for jellyfish.

Will robots exterminating jellyfish solve any jellyfish problems? What happens to the jellyfish parts that have been cut up?

Reducing the underlying cause of the jellyfish blooms is surely more of a solution than producing billions of jellyfish bits.

The aquatic robot designed by the Korean Higher Institute of Science and Technology (KAIST) has a mountable grinding part buoyed by two cylinders that use motors to move forward and reverse, as well as rotate 360 degrees. Data from a GIS (geographic information system) map is used to specify the region for jellyfish extermination. JEROS then navigates autonomously using a GPS (Global Positioning System) receiver and an INS (inertial navigation system).

The assembly robots maintain a set formation pattern, while calculating its course to perform jellyfish extermination. The advantage of this method is that there is no need for individual control of the robots. Only the leader robot requires the calculated path, and the other robots can simply follow in a formation by exchanging their location information via wireless communication (ZigBee).

JEROS uses its propulsion speed to capture jellyfish into the grinding part on the bottom, which sucks the jellyfish toward the propeller to be exterminated.