Their monthly invasion into Waikiki tracks with the full moon. (So they’re out there)

The monthly box jellyfish invasion into Waikiki tracks with the full moon.
Published: Jul. 13, 2022 at 4:37 PM HST|Updated: Jul. 21, 2022 at 1:01 PM HST
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HONOLULU (HawaiiNewsNow) - There’s was a full moon last week, which means Hawaii’s monthly box jellyfish invasion is upon us.

They’re practically invisible, but have been called one of the biggest threats to beachgoers.

And a recent UH-Manoa study, based on more than a decade of research, has helped answer longstanding questions about where Hawaii’s species of box jellyfish come from and their unique relationship with the lunar cycle.

According to the team of researchers, the jellies take a one-way trip to the beach from deeper environments to spawn and die around eight to 12 days after the full moon, and just before the new moon — a particularly dark period of the lunar phase.

“If you could see an underwater Ziploc bag, that’s about how hard it is to see the box jellyfish, all you can really see are the slight pink tentacles,” said Dr. Angel Yanagihara, lead researcher of the study.

She started studying box jellyfish more than two decades ago after being stung herself in 1997.

“These are serious animals and if you are stung in thin skin, especially around the neck, or the inner aspects of the arm, or women and children who have thinner skin, the dose of venom that they are exposed to can be sufficient that you don’t just develop a sight rash and pain, but global symptoms throughout the whole body.”

Those symptoms can include stomach cramping, sweating, anxiety, elevated blood pressure, a racing heart and intense, burning pain.

Yanagihara says box jellyfish are a normal participant in the food web, but the highest number of them in Hawaii are found in the population off Oahu’s most famous beach ― Waikiki.

Why? Yanagihara said there are a few reasons.

For one, animals that would keep the jellies in check, like sea turtles and grazing fish, have been depleted in the area. There are also other human-related influences, like runoff, fertilizer and offshore artificial reefs that may aid the increasing number of the species.

The monthly invasions of jellies into the crowded Waikiki coastline mean stings are almost inevitable.

“We warn them there’s dangerous box jellies out here and we get told all the time, ‘oh, we’ll watch out for them, we’ll be okay,’” Yanagihara said.

She added the 10th day after the full moon usually has the highest prevalence of the jellies close to shore, especially in the mornings.

“If there is big surf offshore, they get beat up and the tentacles are still out there in the surf zone. So it’s better to maybe swim in a swimming pool during this window of time.”

Yanagihara said there hasn’t been concrete evidence of deaths due to box jellyfish in Hawaii but noted notoriously fatal, larger species of box jellyfish — like in the Philippines, where children are their no. 1 victim.

But some beachgoers aren’t going to let the jellies win.

Eight years ago, Dr. Rick Hall gathered up a group of volunteers from his church and started collecting jellyfish that had washed up onshore.

Every month, you can find them sporting metal trash pickers and meticulously pacing the Waikiki shoreline at sunrise.

“People come up being stung and they don’t know what to do,” Hall said, mentioning his group picked up over 3,000 jellyfish in one day during their June rotation.

So what to do if you’re stung by a box jellyfish?

Yanagihara says the well-known resort of rubbing sand onto the skin may only worsen the sting.

Instead, you should douse the area in vinegar as the acid has a unique property to stop the venomous “ticking time bomb” capsules from firing further, she said. Then soak the area in hot, bath temperature water for 45 minutes to inactivate the venom deep inside the skin.

Yanagihara has also developed a remedy called “Sting No More” after being approached by the U.S. military about “career ending” stings on combat divers. It is now available to the public and works in two parts, with a spray followed by a cream that Yanagihara says acts “faster and better” than the hot water tactic.

Yanagihara’s research doesn’t end in Hawaii.

She’s investigating box jellyfish worldwide, including species that are much more dangerous than those found in Hawaii.

Some of those species’ stings can lead to scarring and even death.

“We’re actively engaged in providing this technology as a humanitarian donation to the Philippines, as well as developing a dissolvable wafer version of that and IV therapeutics based upon this technology,” Yanagihara said.

“Current objectives are to really address the health burden in the most heavily impacted area in the Indo-Pacific, the Philippines, also Indonesia and Thailand to a lesser degree.”

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