Almost Everything You Wanted to Know About Sea Lice, But Were Afraid to Ask What are these critters we call Sea Lice? First off, they are not lice. They are the larval form of the Thimble Jelly Fish. Thimble Jellies look like a large brown thimble that would fit on your thumb. Don't waist your time looking for the larva as they are rather small. The larva may still be present even if there are no mature Thimble Jellies to be seen. A more proper term for exposure to these larvas would be Sun Bather's Eruption (SBE). Each larva is covered by nematocyst. These are the guys that cause the SBE. When there is a change in the larva's environment, (i.e. going from salt to fresh water, drying out, feeling trapped between your skin and swimwear) the nematocysts fire. When they fire they inject a substance into your skin that causes the reaction. The reaction leaves you with itch red bumps. These are most often found in areas that were covered with swimwear. Somewhere I read but now cannot find, the source that the larva often could be found in Turtle Grass and they tend to get stirred up by careless swimmers. There is a little bit of Turtle Grass at Castaway Cay Snorkeling area; you know the shallow swim way that leads to the main area. Yep, that area where everybody stops to stand up and adjust their gear, where they can also stir the Turtle Grass and get the larva stirred up. These critters are usually found in the wider Caribbean area from March to August. The greatest chance of exposure is from April to June. I have been told that there is a pattern from South to North as the waters warm. Personally I have seen them heavy in the Bahamian out islands in May. How do you prevent or lessen your exposure? Get out of your wet swim garments immediately after you leave the water. Shower only after you are out of your swim wear. By rinsing with your swim wear on you might cause the nematocysts to fire. Before the advent of SafeSea a healthy application of sunscreen was recommended. Some folks used baby oil or even petroleum jelly. I became aware of SafeSea about three years ago. SafeSea is a sunscreen developed to help prevent exposure to sea critters that sting. (There is a disclaimer that SeaSafe has not been tested against Portuguese man-o-war and box jellyfish. These are very dangerous and I doubt if there are any volunteers to be test subjects.) It has received good reviews and can be found a dive shops. Their website is www.nidaria.com. SeaSafe maybe available at either of these outlets www.diversdirect.com or www.lifestylesdirect.com. OK too late I got those pesky bumps now what do I do? When you first see those red bumps form, a good scrubbing with soap and water with a very good strong rinse. You can also soak the affected area with white vinegar. Calamine lotion may be helpful. Topical application of hydrocortisone twice daily might lessen the reaction. They should dissipate in about 7-10 days. Make sure you wash your swimwear well and make sure it is dry before worn again. If you have a severe allergic reaction or a prolonged reaction seek medial evaluation. Hope this helps to answer your questions about Sea Lice, a misnomer for SBE. Don't let those little critters keep you from enjoying the "Big Blue Wet Thing" (the ocean).