Keeping Jellyfish In Check
One jellyfish alone can't cause much damage, but Myung Hyun, a professor of Civil and Environmental Engineering at KAIST, said that jellyfish attacks are costing South Korea nearly $2.8 million dollars a year in damage. In an effort to minimize the damage that jellyfish are causing, he and his colleagues created JEROS, short for Jellyfish Elimination RObotic Swarm.
The robots are equipped with cameras and GPS to navigate toward the jellyfish. Once they find a large bloom, the robot sucks them up with a submerged net that funnels them through a quickly spinning propeller, pulverizing the creatures into small fragments. The robot chewed through "400 kilograms per hour," according to KAIST.
"If you consider that one jelly fish weighs about five kilograms, it's probably not doing very much," said Monty Graham, a professor of marine science at the University of Southern Mississippi. "One robot would take care of 80 jellyfish, but a swarm along the regional coast line can be tens if not hundreds of millions of jellyfish."
Rather than viewing the jellyfish as a species that just recently started to thrive, Graham said that they may have always been doing this and ecologists never noticed. "We've historically ignored jellies as being an important part of the coastal ecosystem," he said. "It seems like a jellyfish bloom happens out of the blue and the world has gone to heck, but we really just don't have a long-term perspective."
However, recent human activity may also be contributing to the rise of jellyfish. "Too many nutrients from agriculture are brought to the ocean via runoff," said Graham. "That promotes certain types of algae growth that make the water hypoxic, or under-oxygenated. The jellies seem to be able to tolerate these environments better than fish or crustaceans."
Regardless how the jellyfish boom got started, Graham sees it as an issue that needs to be addressed, though through an ecological perspective than an engineering one. "It's signaling a problem in the ecosystem," he said. "If you deal with those issues, you're going to have a secondary impact and might improve the ecosystem's health."