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They’re bleeding horseshoe crabs on the Cape and some advocates are worried

Mass Audubon’s science coordinator Mark Faherty examined a horseshoe crab in Pleasant Bay in Orleans, where he has conducted research on them there for years.John Tlumacki/Globe Staff

HARWICH — Between the local dump and highway, in a nondescript building that lacks any indication of who occupies it, one of the world’s largest pharmaceutical companies recently began harvesting the milky-blue blood of an ancient creature plucked from the beaches and bays around Cape Cod.

Charles River Laboratories is one of just four companies in the United States — and now the second on the Cape — licensed to harvest the blood of horseshoe crabs for a valuable component that’s used to identify harmful bacteria during the testing of new drugs..

The Wilmington-based company’s state permit requires its staff to maintain the crabs in cool temperatures and return them to their habitat within 36 hours, but the work remains highly controversial. Tens of thousands of horseshoe crabs die every year along the East Coast as a result of such biomedical harvesting, according to the Atlantic States Marine Fisheries Commission, while studies have found that the crabs, after being bled, move more slowly, become less active, and appear to spawn less frequently.

The bleeding of crabs, combined with their use as bait and losses to their coastal habitat, has led them to be listed as “vulnerable” by the International Union for Conservation of Nature, which maintains the world’s most comprehensive list of threatened species. The group considers the crabs “endangered” in the Gulf of Maine and the Mid-Atlantic, areas that include Cape Cod, though officials in Massachusetts have cited surveys suggesting the region’s population has increased.


Charles River began harvesting the crabs’ blood here last month after a series of lawsuits and bad publicity cast a pall over similar work in South Carolina. The state permit allows the multibillion-dollar company to harvest the blood from hundreds of thousands of horseshoe crabs a year in Massachusetts. Company officials wouldn’t say how many they plan to bleed, or how much they expect to earn from the harvest.


They downplay their impact on a species that has survived for nearly 500 million years, comparing their facility to a “spa” and describing the helmet-shaped aquatic arthropods as “donating” their valuable blood before most are returned safely to the wild.

“We’re stewards of horseshoe crabs,” said Birgit Girshick, the company’s chief operating officer, who refused to let the Globe observe the Harwich operation. “We’re really proud of what we do. It’s all about patient safety.”

Stills from a corporate video show the bleeding of horseshoe crabs at the Charles River Laboratories' facility in South Carolina.Charles River Laboratories

Environmental advocates have long raised concerns about the practice, which one company has been doing for 50 years on the Cape, and worry that allowing another facility to harvest their blood could gravely endanger the horseshoe crabs. The advocates contend the mortality rate is far higher than Charles River officials or regulators say, and the mud-colored creatures’ ability to spawn can be harmed.

Diminishing the horseshoe crab population, they say, could have significant ecological consequences for a range of other species throughout the Cape’s fragile ecosystem, and beyond, including endangered shorebirds that rely on their eggs.

Advocates also note that Massachusetts, unlike other states, has few rules to protect horseshoe crabs.

“We are concerned that Massachusetts horseshoe crab populations might not be able to withstand the expected increase in harvest,” said Mark Faherty, science coordinator at Mass Audubon’s Wellfleet Bay Wildlife Sanctuary, which conducts surveys of the horseshoe crab population on Cape Cod.


Faherty and others also raised concerns about Charles River’s record in South Carolina, where they were sued two years ago for harvesting blood from crabs poached from a national wildlife refuge. This year, they were sued for storing the crabs in long-term holding ponds before being bled, depriving threatened shore birds, such as red knots, from dining on their nutrient-rich eggs.

“Anyone who cares about natural resources in Massachusetts should be alarmed by Charles River’s plans to open a bleeding facility there,” said Catherine Wannamaker, a senior attorney at the Southern Environmental Law Center, one of the groups that sued the company.

Though company officials have been secretive about the amount of crabs they bleed, Foster Jordan, the company’s senior vice president, last year acknowledged that Charles River bled up to 150,000 a year in South Carolina.

Volunteers Joanne Ingwall and her husband, Dick, counted the population of horseshoe crabs within a 5-cubic-yard area on the shore of Pleasant Bay in Orleans. John Tlumacki/Globe Staff

The growing demand for their product, as well as the backlash in South Carolina, may have led Charles River to start harvesting operations in Massachusetts, advocates say. The company uses the crabs’ blood — which is blue because of its copper content — to test more than half of the world’s injectable drugs and medical devices, such as IV bags and dialysis solutions.

“The Massachusetts population is already under pressure; Charles River will only tighten the squeeze,” said Christian Hunt, an attorney with Defenders of Wildlife, an environmental advocacy group that also sued Charles River.

State officials, however, say the population of horseshoe crabs in Massachusetts is rebounding, making it safe for the company to harvest their blood. They issued a permit to Charles River that allows the company to bleed as many as 1,000 crabs a day per licensed biomedical harvester. Company officials declined to say how many harvesters they plan to work with.


State officials also pointed to surveys done every spring for decades that show female horseshoe crabs at a near high in abundance. However, a similar state survey in the fall — which officials didn’t acknowledge until the Globe asked about it — shows the number of female crabs actually decreasing substantially over the past five years.

Others said the surveys don’t account for the historical decline of the species in the region. “Compared to [that] plenty, today’s spawning beaches are a desert,” said Deborah Cramer, author of “The Narrow Edge,” which chronicles how red knots rely on horseshoe crab eggs for food.

When asked how many total crabs they’ll allow to be bled, state officials wouldn’t provide an answer, saying such data are subject to “state and federal confidentiality laws.” Associates of Cape Cod, the other company that harvests horseshoe crab blood on the Cape, also wouldn’t release the number of crabs they bleed.

Mass Audubon’s science coordinator Mark Faherty examined a horseshoe crab in Pleasant Bay in Orleans.John Tlumacki/Globe Staff

“The division is prohibited from releasing the data,” said Troy Wall, a spokesman for state’s Executive Office of Energy and Environmental Affairs, noting the state allows some 165,000 additional crabs a year to be caught and sold for bait.

Wall added that state regulations don’t limit the number of crabs the company can bleed, because it’s a “catch and release fishery that has limited mortality.”


Since bled crabs are rarely tracked after they’re released, scientists and environmental advocates say it’s hard to know for sure how many crabs actually die, or are otherwise harmed, as a result of the bleeding, which drains large amounts of their blood.

Charles River officials told the Globe that just 4 percent of their crabs die before being returned to the wild; however, the South Carolina Department of Natural Resources has estimated more than 20 percent of female crabs die within two weeks of being bled by the company.

In its most recent stock assessment of horseshoe crabs, the Atlantic States Marine Fisheries Commission, which monitors the health of the species, estimated that 15 percent die as a result of the bleeding process. Other estimates have found nearly one-third of females die after undergoing the procedure.

Charles River officials have defended the additional pressure on the species, contending that the good from preventing the contamination of drugs outweighs the environmental impact. But there are now synthetic substitutes that rival companies say could reduce and eventually eliminate the need to rely on the crabs’ blood, which has been used for testing drugs since the 1970s.

One pharmaceutical giant that has received government permission for a synthetic alternative, Eli Lilly, has used its substitute to test COVID-19 antibody drugs.

“It is scientifically sound, a sustainable alternative to the animal-sourced testing,” said Carrie Munk, a spokeswoman for Eli Lilly, noting the synthetic version has been approved by health authorities in other countries and could eventually be manufactured in sufficient quantities to replace the crabs’ blood.

Officials at Charles River said they’re developing their own synthetic versions but it would take years before they were ready and widely adopted.

“The synthetics we’ve tested are not sensitive enough to ensure patient safety,” Girshick said. “We’re actually pushing for a synthetic ourselves, and spending a lot of money to get there.”

Until then, she said, the company will be harvesting the blood from horseshoe crabs.

A male horseshoe crab skimmed the shallow water of Pleasant Bay. John Tlumacki/Globe Staff

David Abel can be reached at Follow him @davabel.