



The situation makes a nice vivid modern example of the "tragedy of the commons," in which private actors driven by their own incentives overuse a common resource until everyone suffers as a result.



The cost of crab blood has been quoted as high as $14,000 per quart. Their distinctive blue blood is used to detect dangerous Gram-negative bacteria such as E. coli in injectable drugs such as insulin, implantable medical devices such as knee replacements, and hospital instruments such as scalpels and IVs. Components of this crab blood have a unique and invaluable talent for finding infection, and that has driven up an insatiable demand. ... There are currently no quotas on how many crabs one can bleed because biomedical laboratories drain only a third of the crab's blood, then put them back into the water, alive. But no one really knows what happens to the crabs once they're slipped back into the sea. Do they survive? Are they ever the same? ... While industry experts say the $14,000-a-quart estimate is high—the figure is more likely the price tag for the coveted amoebocytes that are extracted from the blood—it is testament to how precious LAL [Limulus Amoebocyte Lysatehas] become. To make enough of it for LAL testing, the biomedical industry now bleeds about 500,000 crabs a year. Global pharmaceutical markets are expected to grow as much as 8 percent over the next year. ...

The International Union for Conservation of Nature, which sets global standards for species extinction, created a horseshoe crab subcommittee in 2012 to monitor the issue. The group decided last year that the American horseshoe crab is "vulnerable" to extinction ... "Vulnerable" is just one notch below "endangered," after all. Furthermore, the report said crab populations could fall 30 percent over the next 40 years. (This risk varies by region. While populations are increasing in the Southeast and stable in the Delaware Bay, spawning in the Gulf of Maine is no longer happening at some historic locations and the population continues to decline in New England, largely because of overharvesting.) ... The Atlantic States Marine Fisheries Commission (ASMFC), which manages the fishery resources along the Atlantic coast, has harvest quotas in place on bait fishermen who use horseshoe crabs to catch eels and conch. But not for biomedical laboratories. They can take as many crabs as they like, and that harvest continues to grow. The number of crabs harvested by the U.S. biomedical industry jumped from an estimated 200,000 to 250,000 in the 1990s to more than 610,000 crabs in 2012, according to the ASMFC's latest stock assessment report. ...



The same story plays out across the Pacific Ocean. The horseshoe crab native to Asia, called Tachypleus, produces a different but equally useful version of LAL called Tachypleus Amoebocyte Lysate, or TAL. But horseshoe crabs are already disappearing from beaches in China, Japan, Singapore, Taiwan, and Hong Kong, places where they once thrived. ...



If the species were to dwindle, it wouldn't just be an issue for conservationists but for everyone, as LAL is currently the only substance able to detect gamma-negative bacteria in the health field. As one conservationist put it, "Every man, woman, and child and domestic animal on this planet that uses medical services is connected to the horseshoe crab." My ignorance of horseshoe crab physiology and ecology is deep and profound, so maybe the environmental concerns here will turn out to be overblown. Also, in this age of genetics and biotechnology, it seems implausible to me that scientists can't eventually find a substitute for the blood of horseshoe crabs! But as long as the blood of horseshoe crabs remains relatively cheap, spending money for research on substitutes doesn't look profitable. Here's a sampling of Chesler's argument, but the article itself is very much worth reading:My ignorance of horseshoe crab physiology and ecology is deep and profound, so maybe the environmental concerns here will turn out to be overblown. Also, in this age of genetics and biotechnology, it seems implausible to me that scientists can't eventually find a substitute for the blood of horseshoe crabs! But as long as the blood of horseshoe crabs remains relatively cheap, spending money for research on substitutes doesn't look profitable.

When global demand for a natural product that reproduces only slowly skyrockets, it can be an extinction or near-extinction event. A classic example is how global demand for buffalo hide nearly wiped out the North American bison . Caren Chesler reports an in-progress story about " The Blood of the Horseshoe Crab" in Popular Mechanics (April 13, 2017). The subtitle of the story reads: "Horseshoe crab blood is an irreplaceable medical marvel—and so biomedical companies are bleeding 500,000 every year. Can this creature that's been around since the dinosaurs be saved?"