Jellyfish are wreaking havoc on tourist destinations

Jellyfish blooms are on the rise and taking over the ocean, experts say. They may not look scary, but they pose a serious threat to regions that are just now entering their tourism seasons.

A horde of jellyfish forced the shutdown of a nuclear power plant in Sweden earlier this month after they clogged the filtration system. Fishing boats in Japan have been capsized by refrigerator-sized Nomura jellyfish becoming caught in nets. And just last week, swarms of poisonous box jellyfish – which have historically been limited to Southeast Asia and Australia – stung nearly 200 people along Florida’s Daytona Beach.

“That’s never happened before,” said Angel Yanagihara, a professor in tropical medicine at the University of Hawaii.

Jellyfish are the most deadly marine organism in the world, with few predators. While there are species of jellyfish that don’t sting humans, a sting from certain varieties of box jellyfish can cause death within minutes.

“There’ve been more deaths due to jellyfish in the last 30 years than from sharks,” said Yanagihara. That’s a number that’s sharply on the rise.

With 20-40 people dying yearly from box jellyfish stings in the Philippines and an average of one death annually in Australia, the headlines could be enough to discourage tourists from heading to the beaches – especially since the casualties are a “recent phenomenon,” said Yanagihara. Fifty years ago, there simply weren’t that number of deaths being reported in Southeast Asia, she said.

As northern Australia enters the peak of its box jellyfish season, which runs from October to May, public health officials are issuing warnings for swimmers. Approximately 40 people each year, many of them tourists who are unaware of the dangers, are treated in northern Australia for life-threatening jellyfish stings.

While the deadly varieties of box jellyfish have historically been limited to Australia and Southeast Asia, the less poisonous (though still incredibly painful) species of box jellyfish can be found in the thousands off of Waikiki Beach at night and are now turning up in places like Florida and India.

The most terrifying of the 60 varieties of box jellyfish is commonly known as the Irukandji jellyfish (scientific name: Carukia barnesi). It’s less than a centimeter large and its sting doesn’t leave a mark. Yet after being stung, victims can suffer vomiting, back pain, or even brain hemorrhaging and heart failure. Irukandji jellyfish are also on the move. They’ve historically been only found off northern Australia, but a National Geographic documentary found them in the waters off Japan and Florida.

Victims of box jellyfish bites can also suffer from something known as Irukandji syndrome, with death possible 12-48 hours after a sting. Studies have found that the number of Irukandji deaths and injuries is likely vastly underreported, because the sting isn’t noticed or the injuries are attributed to something else.

There is debate among scientists over the increasing number of jellyfish sting reports, since what we could be seeing is simply an increase in reporting and documentation rather than an increase in the number of jellyfish. There’s also little known about what is happening in the deep ocean away from coastal areas. But, there’s little debate that there has been increased attention to the dangers of jellyfish.

Biologist Lisa-Ann Gershwin chronicled the rise of the creature this year in her book, “Stung! On Jellyfish Blooms and the Future of the Ocean.” All the concern is enough to make a traveler stay out of the water permanently – exactly what beach communities that rely on tourism don’t want. Those beaches are now taking steps to stop jellyfish from attacking and driving away swimmers.

“Beaches in places around the world put up nets to block jellies from some swimming areas,” said Jennifer Purcell, a jellyfish researcher with Western Washington University.

This summer, the beaches along the Mediterranean found their season ending abruptly when swarms of wall-to-wall jellyfish attacked the coasts. While the jellyfish in the Mediterranean are largely non-lethal, the stings can still be incredibly painful and irritating. Nearly 150,000 tourists were treated for jellyfish stings in the region.

For next year’s tourist season, the Med Jelly Risk project will install nets along a number of beaches in Northern Italy, said Purcell. And, many heavily jellyfish-trafficked beaches have instituted jellyfish warning flags, in addition to the general warning flags.

Scientists along Israel’s Mediterranean coast are also experimenting with underwater sounds – like dog whistles – to scare off jellyfish.

Also, tourists can use tracking resources like Jellyfish Watch to know where jellyfish have been seen recently. Because tools to study and count the creatures are still being developed, this kind of crowd-sourcing approach can be helpful.

Yanagihara has also developed a cream that can be worn to inhibit jellyfish stings and serve as a treatment for the stings. Diana Nyad, the high-profile swimmer who recently completed the swim from Cuba to Florida, used customized versions of the creams and gels to get through a sea of box jellyfish with only minor stings to the lips, a challenging area to protect, said Yanagihara.

“We’re working fast and furiously to get those things to the market,” she said.

Some researchers are also looking at how to make jellyfish more palatable, so that we can simply eat our way out of this epidemic.

Or, if a future where a scourge of jellyfish overruns the ocean doesn’t sound crazy enough, there may be something even crazier to stop it: terminator robots.

Jellyfish have cost South Korea nearly $300 million a year in lost tourism and shutdown reactors, prompting the Korea Advanced Institute of Science and Technology to develop a jellyfish-shredding robot known as JEROS (Jellyfish Elimination Robotic Swam). The robots float on the top of the water, detect jellyfish and then suck them into a net and shred them with a propeller. Gruesome? Yes. But, also effective.

In less than an hour, 880 pounds of jellyfish were destroyed in a test. The team is working on a new version that can destroy 2,000 pounds of jellyfish in the same amount of time and is trying to develop a way to deal with the lethal variety of jellyfish.

The only problem is that this approach may actually be very short-sighted, said Yanagihara. When the jellyfish are shredded they release all their reproductive material, making it likely that there’ll be a larger number of jellyfish in the next generation.

When Yanagihara was stung by a box jellyfish in the late 1990s off of Hawaii, she had never heard about the dangers before. But, she learned about them quickly. “It felt like thousands of burning needles in my neck and arms and ankles,” she said. She was even more surprised when she made it back to shore and was treated in an ambulance with vinegar, saran wrap and meat tenderizer. “It seemed more like a BBQ than a medical treatment,” she said.

That prompted her to begin research on a treatment for the venom and to do field work on jellyfish, so the jellypocalypse doesn’t hurt other swimmers.