‘Sea lice’ reported at N.J. beaches is actually jellyfish larvae, biologist says

Over the weekend, reports emerged of swimmers in Avalon and Stone Harbor complaining of itching skin, and in some instances, breaking out in rashes after ocean dips.

The culprit was pinned on “sea lice,” conjuring up images of school nurses wearing gloves while inspecting scalps for parasitic insects.

But the actual cause isn’t lice at all, but rather jellyfish larvae, according to Dr. Paul Bologna, a biology professor at Montclair State University and New Jersey’s resident jellyfish expert.

Bologna says the larvae are from thimble jellyfish, a tiny species typically found in the warm western Atlantic Ocean and the cause of seabather’s eruption, a rash caused by thimble jellyfish stings.

The condition, which is caused by barely visible larvae, appears like a speck of finely ground pepper. According to Healthwise medical staff, the rash is more common in the Caribbean and on Gulf of Mexico beaches.

The rash — “raised, hard or soft bumps, or blisters of different shapes and sizes that appear very red and may be extremely itchy” — develops from a few minutes up to 12 hours after swimming, typically under swimwear where the larvae become trapped, the guide says.

Experts say treatment includes removing swimwear as soon as possible, washing with soap and fresh water, and taking an antihistamine or applying calamine lotion.

Jeff Tittel, director of the New Jersey Sierra Club, said the larvae were likely pushed to New Jersey from Florida by Tropical Storm Isaias.

“They have already been found near Ocean City, Avalon and Stone Harbor, which means that they could spread north because of warm water and nutrients,” Tittel said in a statement. “This shows that we need to do more to both tackle stormwater runoff and leaky sewer pipes, as well as climate change.”