Adding to the threats faced by horseshoe crabs, a controversial pharmaceutical company has just begun harvesting their blue blood on Cape Cod.

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

Charles River began harvesting blood crabs here last month after a series of court case and bad publicity cast a veil over similar work in South Carolina. The state permit allows the multi-billion dollar business to harvest the blood of hundreds of thousands of horseshoe crabs a year in Massachusetts. Company officials did not say how much they expected to bleed, or how much they hoped to earn from the harvest.

They play down their impact on a species that has survived for nearly 500 million years, likening their facility to a ‘spa’ and describing the helmet-shaped aquatic environment arthropods as “donating” their precious blood before most are safely returned to the wild.

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

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

Conservationists have long been concerned about the practice, which a company has practiced for 50 years in Cape Town, and fear that allowing another facility to harvest their blood could seriously endanger the horseshoe crabs. Lawyers argue death rate is far higher than Charles River officials or regulators say, and the spawn ability of mud-colored creatures may be affected.

Declines in the horseshoe crab population, they say, could have significant ecological consequences for a range of other species in the fragile Cape ecosystem, and beyond, including endangered shorebirds who depend 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 may 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 population surveys. horseshoe crabs on Cape Cod.

Faherty and others have also raised concerns about the Charles River case in South Carolina, where they were sued two years ago for drawing blood from poached crabs in a national wildlife refuge. This year they were prosecuted for storing the crabs in long-term holding ponds before being bled, depriving endangered shorebirds, such as red knots, of feeding on their nutrient-rich eggs.

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

Although company officials have kept the amount of crabs they bleed a secret, Foster Jordan, the company’s senior vice president, admitted last year that Charles River was bleeding up to 150,000 per year in South Carolina.

Volunteers Joanne Ingwall and her husband, Dick, counted the horseshoe crab population in a 5 cubic meter 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, supporters say. The company uses the crabs’ blood – which is blue due to 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 people of Massachusetts are already under pressure; Charles River will only add to the pressure,” said Christian Hunt, an attorney with Defenders of Wildlife, an environmental advocacy group that has also sued Charles River.

State officials, however, say the horseshoe crab population in Massachusetts is rebounding, allowing the company to safely harvest their blood. They issued a license to Charles River that allows the company to bleed up to 1,000 crabs per day per licensed biomedical fisherman. Company officials declined to say how many harvesters they planned to work with.

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

Others said the surveys did not account for the historical decline of the species in the area. “Compared to [that] a lot, spawning beaches today are a wasteland,” said Deborah Cramer, author of “The Narrow Edge,” which chronicles how red knots depend on horseshoe crab eggs for food.

When asked how many crabs in total they would allow to be bled, state officials did not provide an answer, saying such data is subject to “federal and state privacy laws.” Cape Cod Associates, the other company that harvests horseshoe crab blood in the Cape, would also not disclose the number of crabs they bleed.

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

“The division is prohibited from disclosing the data,” said Troy Wall, spokesman for the state’s Executive Office of Energy and Environmental Affairs, noting that the state allows the capture and sale of anything. 165,000 additional crabs per year as 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.”

Because bled crabs are rarely tracked after they are released, scientists and conservationists say it’s hard to know for sure how many crabs actually die or are otherwise injured as a result of the bleeding, which drains a large amount of their blood.

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

In its most recent inventory valuation 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 found almost a third of women die after undergoing the procedure.

Charles River officials have defended the added pressure on the species, saying the good of preventing drug contamination outweighs the environmental impact. But there are now synthetic substitutes that rival companies say could reduce and possibly eliminate the need to rely on crab blood, which has been used to test drugs since the 1970s.

A pharmaceutical giant that has received government clearance for a synthetic alternative, Eli Lilly, has used its surrogate to test for COVID-19 antibodies.

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

Charles River officials said they were developing their own synthetic versions, but it would take years before they were ready and widely adopted.

“The synthetics we tested are not sensitive enough to ensure patient safety,” Girshick said. “We are pushing for a synthetic ourselves and spending a lot of money to make it happen.”

Until then, she said, the company will harvest the blood of horseshoe crabs.

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

David Abel can be contacted at [email protected] Follow him on Twitter @davabel.