Warning: Box Jellyfish Invasion
Once a month, Hawaii receives a visit from alien invaders. Instead of the air, they come from the sea. They are box jellyfish, and they particularly like the beaches along Waikiki. I've always heard they arrive a week or so after the full moon. I've seen warning signs placed on beaches. I've read about their "victims" in the newspapers. This month, when an email crossed my desk announcing the pending arrival of these critters, I decided I wanted some more information. So, I went to the experts--the Waikiki Aquarium--and Karen Quinn patiently and thoroughly answered my questions.
Karen is the administrative assistant to the director of the Waikiki Aquarium. Before she joined the Aquarium, she spent six years working in Dr. Yanagihara’s laboratory at UH Manoa as a Research Associate II. In addition to animal collection, she spent most of her time trying to characterize the venom of the box jellies, bluebottle jellies, and other species.
She knows her stuff.
1. What are box jellyfish?
The Hawaiian box jellyfish or Carybdea alata are invertebrates that have cube-shaped medusae. They have potent venom that is very painful and can even cause anaphylactic shock in some individuals. They are “close cousins” to the Chironex fleckeri which is among the most venomous creature in the world.
2. How different are they from Portuguese man o’ war?
Physalia utriculus (Pacific bluebottle jellies) have floats which get carried onto windward Oahu beaches with sustained trade winds. While the box jellies are free-swimming and follow a cyclic pattern after each full moon. Box jellyfish can move more rapidly than other jellyfish.
The sting of the box jelly is generally considered worse than that of the Pacific bluebottle. That’s what most people claim anyway, but I have seen some really horrible sting marks left by the bluebottle jellies. I have not been stung by a bluebottle, so I can only say that I know from personal experience that the box jelly sting is painful and the marks it leaves behind can be seen for months. The nematocyst (stinging cells) are different between these two species. Dr. Angel Yanagihara’s lab has written papers characterizing the ultrastructure of both species:
3. If stung, how should someone treat it?
Each species of jellyfish has a suggested treatment. In my experience, I’ve heard two recommended treatments for the box jellies:
A) Hot water immersion relieves some of the sting associated with a box jelly sting (Yoshimoto and Yanagihara 2002). Twenty minute hot water immersion will inactivate many of the potent proteins (Chung and Yanagihara 2001) contained in the complex venom of the box jelly.
B) First spray or pour vinegar on the jellyfish sting site and remove any remaining tentacles with a cloth or tweezers. Vinegar temporarily deactivates the nematocysts to prevent further discharge from tentacles. Vinegar also slows the venom action but it does not permanently neutralize the toxins and only temporarily relieves some pain.
4. Why do they always pop up after the full moon?
Most researchers believe that the Hawaiian box jelly frequent certain leeward Oahu beaches 8-10 days after each full moon to spawn in shallow waters near shore coral reefs.
5. What do you think is the coolest thing about box jellyfish?
The fact that they are such strong directional swimmers that are unique in the possession of true eyes. I’ve seen footage on a television special that showed research on jellies where they would casually swim around a pole of a certain color, obviously avoid another color, and totally bump into yet another color. It would be fascinating to do studies such as this on the Hawaiian species.
6. Why does Waikiki seem to always get hit with the box jellyfish?
No one really knows. Some have speculated that they are drawn to the city lights. This theory doesn’t seem very likely since they occur overnight in other areas such as Hanauma Bay where there are no bright city lights.
However, Dr. Angel Yangihara believes that it has to do with the locations where there is a significant difference in depth that occurs in the near shore waters. She reports that each location where the box jellies occur on the leeward coast follows this pattern.
7. Do you have box jellyfish on exhibit at Waikiki Aquarium?
Our jellyfish expert at the Waikiki Aquarium, Kelley Niide, tried roughly 3 years ago and they survived for 3 weeks in our holding areas in the back. Previously, the longest held in captivity was 1 week. However, these animals have not been on exhibit on the public side.
8. How do you collect them without getting stung?
Years ago when I collected I used gloves to pick them up and later when cutting off the tentacles for processing. However, I still got stung when one wave rolled a jelly over my foot one night. Now Dr. Angel Yanagihara’s laboratory collects them using tongs. Helping them for the last two nights during the collection process, it seems like the tongs are much better system than using gloves.
You can also see additional information from the Hawaii Lifeguard Association at:
The lifeguard recommendations are based on their experiences in dealing with jellyfish stings over the years. Some of the information on the lifeguard website is slightly different from the information given in the answers above. The answers to your questions are based on research, lessons learned from fieldwork and work in the laboratory, as well as my own personal experiences.