‘Sea Lice’ Attacks Prompt Warning At Florida Beaches

June 27, 2018 Last Updated: June 27, 2018

Florida lifeguards have posted a purple flag warning on a number of area beaches alerting bathers to the danger of sea lice.

The Pensacola Beach Lifeguards placed the warnings following reports of increased human contact with the tiny organisms, which are a form of microscopic jellyfish.

“What a gorgeous day out here on Pensacola beach we are flying green flags with calm surf conditions. We also have purple flags in the air due to sea lice (small jelly fish),” they wrote in a Facebook post.

Purple flags are used to alert beach-goers of the presence of dangerous aquatic life.

Stings from the tiny jellyfish can cause a red rash, with red, itchy or burning bumps that appear within four to 24 hours after exposure.

Sea lice appear to the naked eye as a “speck of finely ground pepper” floating on the surface of the water, according to the Florida Department of Health, with a size approximating that of a pinhead.

Bathing suits act like nets, trapping sea lice larvae. Pressure causes the larvae to fire nematocysts, or stinging cells.

Larva firing stinging cells after pressure from a cover slip is applied. (Florida Department of Health PDF)

When the stinging cells come into contact with human skin, people may feel a “prickling” sensation.

According to the Florida Health Department, some types of behavior on the part of swimmers can increase the risk of harm from contact with sea lice. Wearing a one-piece bathing suit or a T-shirt while swimming, and then lying on the beach or sitting in a car seat with the wet garment on could increase the severity of the reaction.

Stings from the tiny jellyfish can cause a red rash. (Florida Department of Health Sea Lice Information PDF)

Anyone exposed to sea lice and experiencing a harmful reaction is urged to consult a medical professional, according to the Florida DoH.

And if out and about on Florida beaches, the Pensacola Beach Lifeguards remind sunbathers to drink “plenty of water and apply lots of sunscreen.”