The Last Days of the Blue-Blood Harvest

#1
Every year, more than 400,000 crabs are bled for the miraculous medical substance that flows through their bodies—now pharmaceutical companies are finally committing to an alternative that doesn't harm animals.

https://www.theatlantic.com/science/arch...er/559229/

EXCERPT: . . . Contemporary humans do not deliberately kill the horseshoe crabs—as did previous centuries of farmers catching them for fertilizer or fishermen using them as bait. Instead, they scrub the crabs clean of barnacles, fold their hinged carapaces, and stick stainless steel needles into a soft, weak spot, in order to draw blood. Horseshoe crab blood runs blue and opaque, like antifreeze mixed with milk.

And for what exactly do humans need the blood of a living fossil? A sort of witchcraft, you might say, for it literally keeps people alive. Horseshoe-crab blood is exquisitely sensitive to toxins from bacteria. It is used to test for contamination during the manufacture of anything that might go inside the human body: every shot, every IV drip, and every implanted medical device.

So reliant is the modern biomedical industry on this blood that the disappearance of horseshoe crabs would instantly cripple it. And in recent years, horseshoe crabs, particularly in Asia, have come under a number of threats: habitat loss as seawalls replace the beaches where they spawn, pollution, overfishing for use as food and bait. Horseshoe crabs bled for the biomedical use in the United States are returned to the ocean, but an estimated 50,000 also die in the process every year.

There is another way though—a way for modern medicine to make use of modern technology rather than the blood of an ancient animal. A synthetic substitute for horseshoe-crab blood has been available for 15 years. This is a story about how scientists quietly managed to outdo millions of years of evolution, and why it has taken the rest of the world so long to catch up....

MORE: https://www.theatlantic.com/science/arch...er/559229/
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#3
(May 10, 2018 03:46 PM)Magical Realist Wrote: Horseshoe crab bleeding...The crab's ok!

https://www.youtube.com/watch?v=bmte9kDMflo


Yeah, the procedure does try to keep them alive. But as the article said, an estimated 50,000 still die from it every year. It's not just horseshoe crabs, either. A calculated 20 to 40 percent of fish returned to lakes and rivers via catch and release die within days from infection of the injury, stress, or having their protective slime coat compromised by an angler's clumsy handling of them.

The different anatomy, biochemistry, and lifestyle of the crabs could obviously sport some different sensitivities than fish. But they're apparently vulnerable in their own way to catch, process, and release. The industry calls it trivial that "between 10 and 30 percent of the bled animals [...] die" from being bled. Still, better than the old unregulated days of bumping them off like Wild West buffalo.

The Blood Harvest (2014): . . . The industry says that not that many of the animals die. Between 10 and 30 percent of the bled animals, according to varying estimates, actually die. We can imagine that it's like us giving blood. The crabs get some apple juice and animal crackers and are fine soon thereafter.

But some people have noticed problems. In the regions where horseshoe crabs are harvested in large numbers for biomedical purposes—like Pleasant Bay, Massachusetts—fewer and fewer females are showing up to spawn. Perhaps the bleeding was, to use a technical term, messing them up, even if it wasn't killing them.

Researchers at the University of New Hampshire and Plymouth State University decided to test this hypothesis. They attached accelerometers to female horseshoe crabs that had been bled for our benefit.

They reported their results in a new paper in The Biological Bulletin, "Sublethal Behavioral and Physiological Effects of the Biomedical Bleeding Process on the American Horseshoe Crab, Limulus polyphemus."

The bleeding process appears to make the bled animals more lethargic, slower, and less likely to follow the tides like their counterparts do.

"The changes we observed in activity levels, movement velocity, and expression of tidal rhythms may interfere with daily L. polyphemus activities, which would be particularly pronounced during the spawning season," they write. "Spawning necessitates several energetically costly trips to the intertidal zone larger females tend to make more excursions to the intertidal zone, often making multiple trips within the same week. An activity deficit, such as that caused by biomedical bleeding, may influence either the number of those trips or their timing. In the case of the latter, females may delay spawning activity while they are recuperating, and this could reduce their spawning output."

In short: Bleeding a female horseshoe crab may make it less likely to mate, even if it doesn't kill it. (Only 18 percent of the crabs the authors tracked died.)

While the bleeding process is clearly better for the crabs than the outright harvesting that used to occur, the study shows that there's no such thing as free horseshoe crab blood.


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