Here in Hawaii we are blessed with being able to dive year round in warm ocean waters. One of the drawbacks to living on an island in these warm waters is that we share the waters with the box jellyfish.
Box jellyfish are drawn to the South and Leeward facing shores of the islands 7-12 days after a full moon. Days 8, 9, and 10 after a full moon are the most likely days to spot box jellies near the shore, however they may be found offshore at any time.
Box jellyfish are a class of cnidarians (jellyfish) called Cubozoa. Some of which are considered to have one of the most deadly stings in the world. Their sting carries venom that attacks not only the skin, but also the central nervous system and the heart.
Box jellyfish get their name from the box-like shape of their bodies. Multiple tentacles drop from each corner of their box-shaped bell, yielding an average of about 300,000 stinging cells, called nematocysts on each box jellyfish.
Although many of the over 50 species of Box Jellyfish are highly poisonous, and a few are considered to be extremely deadly the species that we generally encounter here in Hawaii are smaller and less toxic than their Australian cousins. That does not mean that the species here in Hawaiian waters are not able to kill you, they still have the ability to cause severe allergic reactions in people who are especially sensitive to their toxin which could result in pulmonary (heart) and/or respiratory failure.
The average size for a box jellyfish in Hawaiian waters is about 1 to 4 inches tall with tentacles reaching up to about 2 feet long. Their bodies are clear making them nearly transparent and difficult to see in the water.
A typical box jellyfish encounter leaves the diver with red, painful, swollen, whip-like stripes where the nematocysts on the tentacles of the jelly came in contact with the divers bare skin. The pain can be severe and will generally last a couple of days, however there are a few things that you can do to lessen the pain.
To treat a Box Jellyfish sting follow these simple steps:
- Immediately flush the affected area with vinegar to remove any unfired nematocysts from the skin. Contrary to what is taught in folklore, local practice, and even some papers on sting treatment, DO NOT use fresh water, urine, ammonia,meat tenderizer, sodium bicarbonate, boric acid, lemon juice, fresh water, steroid cream, alcohol, cold packs, papaya, hydrogen peroxide, or anything else other than vinegar to flush the affected area as it may cause the remaining nematocysts to fire injecting more toxin and could also lead to infection. There is absolutely no scientific evidence to suggest that any of these home remedies will disable further stinging and venom discharge.
- Using a gloved hand, stick, or other such tool, pick off any remaining pieces of tentacle from the skin.
- Immediately flush the affected area with vinegar once again.
- Once the area has been flushed clean with vinegar, soak the affected area in water as hot as you can stand (at least 115°F) for about 15 to 20 minutes. If the affected area cannot be submersed in hot water a hot compress can also be used.
- Apply an ice pack to relieve pain.
- Immediate medical attention may be necessary as the stings may induce anaphylactic shock.
For expected arrival dates of the box jellyfish to the island of Oahu, check our convenient forecast calendar.