Ocean Watch

A dive master I know forwarded me an e-mail question from a Florida woman who asked if Hawaii's waters have sea lice. She's highly allergic to these baby jellyfish, she writes, and since they're common in Florida, her water-sports days are over. She's considering moving to Hawaii, but not if we have sea lice.

Do we? It's a good question.

First, sea lice is a bad name for these tiny stinging jellyfish larvae, because sea lice is also the name of a salmon parasite, a crustacean of great interest to salmon farmers. Also, by calling the jellyfish lice, it encourages people to treat the stings with lice medicine, which can do more harm than good.

Besides drugstore lice treatments, Florida victims have treated the rash they got from swimming with these jellies with a variety of home remedies. Some are familiar to us, such as meat tenderizer (which doesn't work), but some are less traditional.

Among these are athlete's foot spray, spray starch, fingernail polish, undiluted bleach, ammonia, gasoline and turpentine.

The real treatments recommended by Florida researchers are over-the-counter hydrocortisone cream for the rash, and an over-the-counter oral antihistamine, such as diphenhydramine. Victims with severe symptoms should go to the nearest E.R.

In Florida, seabather's eruption, the medically accepted term for the rash, is seasonal. Most incidents occur between March and August when the jellyfish reproduce, but it can happen anytime.

The cause of all this trouble is the thimble jellyfish, a cylindrical jelly about an inch tall with 8 short tentacles hanging from its scalloped bottom.

Thimble jellyfish swim almost continuously straight up and down, usually near shore. If you swim into them, the creatures' tentacles can sting and cause a rash. But it's their offspring (the so-called sea lice) that drift around causing even more trouble.

Since thimble babies can be as small as specks of finely-ground pepper, people rarely see them. But when those larvae get inside swimming suits, people know it, because like their parents, the youngsters also have stinging tentacles.

Most jellyfish stinging cells fire under pressure (that's mechanical pressure, not stress) and thimbles are no exception. Rubbing them with a swim suit, lying on them on a surfboard, or sitting on them at the beach or in the car sets them off, and soon, a painful, itchy rash appears. Usually, this lasts about a week.

So are these little troublemakers in Hawaii?

I've not heard of the species here. However, the distribution of thimble jellyfish is worldwide in tropical and subtropical waters, and that's Hawaii. Also, the information I have about these jellyfish comes from a Monterey Bay Aquarium book called "Pacific Coast Pelagic Invertebrates."

We aren't near the coast, but jellyfish can travel in ocean currents and ships' ballast waters.

Bottom line: I don't think we have thimble jellyfish here, but we might. That's an aggravating answer to a reasonable question, but I'm not being flippant.

The oceans of the world offer no promises. Those of us who enter them must weigh the risks, and then take our chances.