Horseshoe crab shells mysteriously dot beach

A wildlife officials says it might simply be that the sea creatures are molting their protective coverings.

By JON WILSON

© St. Petersburg Times, published December 29, 1999

TREASURE ISLAND -- A string of horseshoe crab shells along parts of the beach has raised eyebrows and generated questions for the past few days.

But so far, officials who monitor aquatic life say there's no evidence that something is killing the hard-shelled creatures with the long, sharp tails.

The horseshoe crabs -- so named because of their shape -- simply may be shedding their shells, said Scott Willis, spokesman for the Florida Fish and Wildlife Conservation Commission.

When the animals molt, they essentially walk out of their shell, leaving it behind. What appear to be legs also are part of the old external skeleton. Horseshoe crabs have no particular molting season, but can do so year-round.

"We're dealing with a fish kill down in the Fort Myers area, but we haven't had any calls in the past few days about horseshoe crabs," Willis said, though he wouldn't rule out the possibility of a kill.

"I hate to speculate," he said.

Red tide, an efficient killer of fish, isn't as hard on horseshoe crabs, Willis said.

"It can (kill them), but they're pretty low on the totem pole. They're pretty tolerant," he said.

The commission typically will look into possible kills if they receive several calls from a given area on the Fish Kill Hotline. (Call 800-636-0511. A recorded message asks for the kill's location, species and numbers.)

The shells started washing up last week, said Tom Seberig, who manages the pool bar at the Island Inn, 9980 Gulf Blvd.

"I've never seen that many. That's all (people) are talking about," Seberig said.

Tuesday morning, there weren't any directly behind the Island Inn. But a thin line of yellowish-brown shells stretched for 100 yards on either side of the hotel's beachfront.

They lay on sand just above the high tide mark, the biggest ones 6 to 7 inches long, not counting the tail.

Those are considered medium-sized, Willis said. The biggest horseshoe crabs might grow to 10-12 inches and molt several times during their life.

There is nothing toxic about them or their shells, but barefoot strollers should take care not to step on the sharp tail, Willis said.

Neighborhood Times received at least one call from someone complaining that the crab shells were sending up a stench, but there was no odor late Tuesday morning. Seberig said he had not noticed one during the week.

Gulls, always on the lookout to scavenge a morsel, were ignoring the shells.

"If those were just molts, there is very little meat in them," Willis said. "It might be an indication that it's not a kill. But it's an awfully hard outer shell. And being cold out, the birds might not be feeding as actively."

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