From the expert
“The horseshoe crab plays a vital role in the life of anyone who has received an injectable medication. Pharmaceutical and medical-device industries use an extract of the horseshoe crab’s blood to ensure that their products — intravenous drugs, vaccines and medical devices — are free of bacterial contamination. The test using horseshoe crab blood works easily, and no other is more reliable for this purpose.” — Eric Lacy, director of MUSC’s Marine Biomedicine and Environmental Sciences Center
Charleston County Councilman Dickie Schweers’ waterfront home in McClellanville looked like a horseshoe crab graveyard last Sunday.
He plucked five dead crabs from the mud along the shoreline that day, but “it’s not uncommon for us to see dozens of dead ones,” he said.
It’s a less-than-pleasant chore.
“They really stink when they die. It’s a hassle.”
Schweers lives on Shellmore Lane, in a small neighborhood tucked in the woods, situated along a dirt road off Highway 17, just north of Buck Hall Landing on Bulls Bay.
The back of his home bumps up to the Intracoastal Waterway, where it’s not uncommon to see a variety of wildlife by land and sea — dolphins, bald eagles, a rare alligator and, yes, a few horseshoe crabs.
But dead horseshoe crabs are another thing. Schweers and other Shellmore residents have expressed concern about harvesters who cull local waters for the crabs in the name of medical research, then dump them back into the water en masse.
Most of the horseshoe crabs survive the ordeal, but a few don’t.
And lately the dead ones have been washing up in front of some homes on Shellmore Lane.
“This is not normal,” Schweers said.
Harvest by moonlight
No, what happened isn’t normal.
Horseshoe crabs are caught and released every year. They are harvested for medical research in the spring spawning season, thousands at a time picked one-by-one off sandbars during a new or full moon. The crabs are picked up at night, bled in a local lab and returned to the water later that day.
Joel Munn of Awendaw has been harvesting the crabs in Bulls Bay for 25 years, starting alongside his dad.
Early on, they were released at the Buck Hall Landing near Shellmore Lane.
After complaints the first few years, he began carrying the crabs out to the open bay and releasing them at the mouth of Graham Creek, more than two miles from the landing.
“We don’t dump in that (Shellmore) vicinity,” he said.
Starting two weeks ago, Munn’s four-boat crew picked up some 16,000 crabs over the course of six days for the year’s harvest. Each night’s catch was returned the next day.
But in spawning season, horseshoe crabs crawl to the highest intertidal zone to mate and lay eggs.
Doubtlessly, some of the returned horseshoe crabs simply carry with the spawn — the 400 million-year-old species is tough and durable, said Mel Bell, S.C. Department of Natural Resources fisheries office director.
Natural strandings occur during spawning; large numbers of apparently stranded horseshoe crabs were observed last weekend on Seabrook Island. Some mortality is expected from the catch and release and from natural strandings, and could occur side by side.
That may be what happened at Shellmore this year, when high astronomical tides coincided with the spawn.
DNR investigated the dumping report and found only about a half-dozen horseshoe crabs remaining. Even allowing for animals removed or scavenged, that’s not enough to suggest a permit violation.
“The presence of a number of dead animals does not automatically indicate any connection to the fishery,” Bell said.
Horseshoe crabs are not considered a threatened species, but they are a protected species. Harvesting them is legal in South Carolina, but it’s “extremely regulated,” said 1st Sgt. Angus MacBride of DNR.
In other states, the crabs can be harvested for whelk bait, but South Carolina restricts the harvest to catch and release for medical research.
The harvested crabs can be recaught later, so the premium is on keeping them alive, Bell said.
Their blue blood is extracted, then used on medical and pharmaceutical devices to keep off bacteria, according to the Ecological Research & Development Groups.
The state has 23 permitted horseshoe crab harvesters; Charles River Laboratories is the only local facility that holds the crabs and draws blood for research.
Multiple requests to interview researchers at Charles River Laboratories last week were denied by the company’s communications director, based in Massachusetts.
Munn said he is the only harvester he is aware of who works north of Charleston.
“I do my best to make sure we don’t jeopardize what we have going,” he said.
The harvesters “have been doing this awhile and they’re aware (of the rules). But (deaths) still happen,” said Larry DeLancey, DNR biologist.
“(The crabs) are very slow movers, so they do get stranded at low tide,” MacBride said. But horseshoe crabs are capable of waiting out of water for the next high tide. “Usually the shift of a few tides and they’re gone,” he said.
Schweers’ address isn’t the only one on Shellmore Lane where dead crabs have washed up lately.
“In past years ... it was more of a problem,” said John Chakides, who lives near Schweers along the waterway on Shellmore Lane.
Chakides said he has noticed four or five dead horseshoe crabs at a time on his property recently.
“After a few days of real hot weather ... they lay up there, they stink really bad and you have to go out in the marsh and get them and stack them up in a bucket and take them off away from here so they don’t smell so bad,” he said.
There are also some Shellmore Lane residents who say they haven’t noticed anything unusual on their property.
Local fisherman say they haven’t seen uncommon numbers of horseshoe crabs this year either.
Schweers said he isn’t sure where the harvesters are releasing the crabs, but if they are doing it correctly, he doesn’t understand how so many end up behind his house.
“If it’s medical research, I certainly support that, I just wish they wouldn’t end up so concentrated,” he said. “It’s not natural.”
Reach Lauren Sausser at 937-5598.