Hawaii Box Jellyfish

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Learn how, when, and where these stinging animals swarm the Hawaiian waters and how to treat a sting.

• General: Educational • General: Guide • General: Health / Wellness / Spirituality

Guide Series: Hawaii Dangers
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Box Jellyfish are a common problem in Hawaii, but usually only impact the island of Oahu, and usually only a few days out of each month. In fact, they normally only come to shore around the 9th, 10th, and 11th day after the last full moon. View our box jellyfish calendar to see their predicted arrival dates.

Because of that, it's usually easily to predict their arrival times though they can come early and / or stay later and even come at other times. But those days are the most common.

During those times, they are most commonly found on the southern shores of Oahu though we've seen them in many other places as well. Even west facing shores as far north as Keawa'ula Beach (Yokohama Beach). A lot just depends on the currents and the strength of the wave action pushing them towards the island.

Jellyfish don't really swim around, they sort of go with the current and those that we usually see are very clear and around 3-4 inches tall and 1-2 wide. Because they are very clear they often look like small plastic bags or plastic cling wrap, especially when they wash ashore.

What Does A Sting Feel Like?

The part of the animal that stings are the tentacles that hang at the bottom of the jellyfish, these are usually around 5-10 inches long on the jellies that we see here. Just one of these brushing against you can mean a very painful sting. It's likely to hurt a lot more than a bee sting as the amount of cellular rupture is more than 10,000 times higher than a bee sting. The venom is also said to be more like snake venom in that it causes cellular destruction.

What Should I Do If I Get Stung?

We are not doctors and this is not medical advice but the common logic that we've heard and read is that if you are stung you need to peel the tentacle off of you (use tweezers, a stick, but not a bare hand unless you want to be stung again). Then flush the area with a lot of white vinegar and use heat for the pain.

Immersing the stung area in hot water is often said to help. Resist the urge to pee on anyone this happens to unless you're going with the idea that laughter is the best medicine. Otherwise, stick with the vinegar.

Using cold water, ice, or cold packs is said to not be a good idea and can cause more stinging cells to discharge. Ice packs may feel good but only temporarily slow the venom and once the area warms again the venom can continue doing its thing on you at which point you may be alone and away from help.

We've hear that pain relief sprays that contain any alcohols should not be used as they can cause a large discharge of stinging cells and make things worse.

If you experience difficulty in breathing or are otherwise concerned you should seek immediate medical attention. If there is a lifeguard at the beach talk with them right away. Better safe than sorry since the stings can cause anaphylactic shock.

You'll even need to be careful just walking on the sand during these times when the box jellies swarm because the currents will wash them up on the sand and they are very difficult to see. Some will remain alive for a while but even when dead their tentacles can still sting you if you touched one or stepped on one.

While they can be difficult to spot, if you look down and watch where you walk it should be fairly easy as long as you go slowly. Once you see one and get a feel for their look it's easy to spot them. When we find them we usually use a stick and scoop them into the trash so nobody steps on them.

We've included some pictures to give you a rough idea of what you are looking for but these creatures are hard to photograph on sand since they blend in so well. Look closely and you'll spot them in our pictures. We've also included a photo showing how hundreds can swarm the shore in rare cases (these were all taken at Ko Olina Lagoon 2 (Honu Lagoon)).