A crustacean commonly called the "seven-11 crab" is on a roll, washing up in huge numbers on Windward Oahu and some South Shore beaches.
The current reproductive wave has prompted beachgoers to call and send email queries to scientists.
Many of the crabs, still in infancy, are about the size of a pea.
"This is just kind of a good year for these crabs," said Joel Martin, curator of crustaceans at the Natural History Museum of Los Angeles.
Martin said there have been similar reports of millions of crabs in the larval stage appearing on beaches in the Caribbean and that scientists don’t seem to know the cause of it.
He said the phenomenon is like a bumper crop and doesn’t indicate any kind of environmental disaster. "I don’t think it’s harmful at all," he said.
Waikiki Aquarium Director Andrew Rossiter said this year may be an exceptionally abundant year for the seven-11 crabs, also called spotted reef crabs. He said there might not be enough room on the reef, prompting many of the crabs to migrate to shore.
Rossiter said he’s received reports about the crabs appearing on Windward Oahu, including Kaaawa and Kaneohe, and also at Black Point and Diamond Head.
He said one person brought in a container Sunday with 30 to 40 crabs.
Rossiter said the native crab is at the post-larval stage and ready to settle on a reef, in a crevice, crack or rock or in the sand.
The crab, scientific name Carpilius maculatus, grows into an adult with a shell that is 6 inches across.
The seven-11 crab gets its name, evoking a lucky roll of the dice, from the seven red spots toward the top front of its shell and another four red spots on the bottom, for a total of 11.
