Beach Biters : Tiny, Carnivorous Crustaceans Invade Shores of Newport


An unusually large number of small, bloodsucking, flesh-nibbling creatures have invaded the waters around Balboa Island and the peninsula.

“They can be pretty nasty when they get going,” said Richard Brusca, curator of crustaceans at the San Diego Natural History Museum. “They’re somewhere between a wolf pack and a pack of mosquitoes. They’re like mini-sharks.”

Although beach-goers have occasionally reported painful attacks by them over the past decade or so, this is the first year that Excirolana chiltoni-- also called marine pill bugs for their relation to the common garden insect--have arrived so early and in such numbers.


Their favorite food is fish, but the pests aren’t picky about what they eat, as 2-year-old Crystal Johnston recently found out.

The little girl was splashing in the water near the Balboa Pavilion when her father heard her crying.

The tiny crustaceans “were climbing up in her diapers,” said Craig Johnston, 36, who has spent summers at Newport Beach all his life. “They drew some blood. It happened so fast.”

Living in sand near the water’s edge, the tiny flesh-eaters are about a quarter of an inch long and have a pair of saw-toothed mandibles designed to cut quickly and cleanly into skin. After making an incision, they suck their victim’s blood for about 30 seconds before dropping off.

The water-borne vampires pose no serious danger to humans, but people who have suffered the bites say they sting.

“I was trolling for them, and they swarmed around me,” said Monica Mazur, who is investigating recent complaints about the creatures for the county’s environmental health department. “They felt like little pinpricks all over my ankles and feet.”


Health officials said they have had five reports of attacks by the bugs in the past 10 years, including one last August, but never this early in the summer season.

“This is pretty unusual,” said Larry Honeybourne, who oversees beach water quality for the county.

Marine biology experts said that evidence suggests there may be an unusually large population this year of the crustaceans, which move up and down the coast of California in huge packs of tens of thousands that cover several square miles.

“From the evidence at hand, they seem to be more abundant at this time than previously,” said Bill Newman, a professor of biological oceanography at the Scripps Institution of Oceanography at UC San Diego.

Brusca said it is difficult to explain the population boom, although it could be caused by a glut of food in Newport Bay or by a normal surge in the life cycle of the creature.

In any case, those using bay beaches should prepare for a summer of painful bites, according to Brusca.


“They have a propensity for finding the thin-skin parts of your body, between your toes and fingers, the backs of your knees, on your crotch,” said Brusca, who discovered a related species on a Mexican beach gnawing on his 2-year-old daughter’s bottom. He promptly named it after her.

Veterans of the beach, though, say the bugs are more an annoyance than anything else.

Scott Durre, who was going windsurfing in the bay Thursday, said he has little fear of the bugs, whose bites he has often endured during his 15 years in the area.

“It’s like little, tiny pinches all over you,” said Durre, 43, an independent contractor. “It doesn’t hurt; it’s just irritating.”

Brusca gives the pests somewhat more credit, noting their ability to clean a minnow of its flesh in two to three hours.

Marine Pill Bug at a Glance Latin name: Excirolana chiltoni Relatives: Cousin of the pill bug common to Orange County gardens Habitat: Japan through the Aleutian Islands and down to the coast of Southern California Location: Lives in sand near the water’s edge Life cycle: Two to three years Worldwide population: Several million Common mistake: Sometimes incorrectly called a sea louse or fish louse Bug Bites Has been known to hinder forensic pathologists in Japan since it often devours all or parts of corpses of drowning victims. A closely related Caribbean cousin, twice as large, often drives swimmers from the water with painful bites. Ichthyologists use the meat-eater to clean specimens of their flesh and leave intact skeletons. When high tide covers nest, it turns predatory, biting chunks of flesh from anything that moves. When tide ebbs, it becomes a scavenger, seeking dead crabs or fish to eat. Moves with ocean currents in packs that contain tens of thousands of individuals and are several square miles in area. Unusual among crustaceans, the female gives birth to live young after a two-month gestation. They stay within the pack into which they were born. Sources: Richard Brusca, curator of crustaceans, San Diego Natural History Museum; Bill Newman, professor of biological oceanography, Scripps Institution of Oceanography, UC San Diego; “Intertidal Invertebrates of California,” by Morris, Abbott and Haderlie