Carmela Cuomo thought she had the secret within reach, hidden in a shallow black tank at the NOAA marine fisheries laboratory in Milford, Conn. The horseshoe crabs she had plucked from New Haven Harbor in 2000 trundled about their springtime ritual, digging pits in the sand, laying their eggs and fertilizing them. She was trying to understand what formula of light, food and chemistry induced these 500-million-year-old creatures to breed. But the next year, before she could figure it out, the crabs stopped mating, and the secret eluded her.

Cuomo, an environmental scientist at the University of New Haven, continued to search for the answer for 10 years, in the tanks at Milford, at labs at her university, and in a set of aquariums in her own basement. Now, finally, she has begun to unlock the mystery.

Having the answer would have major practical implications. No one, except by accident, has been able to get horseshoe crabs to mate in captivity. If scientists could figure out how to breed them, the ability might take pressure off the wild populations along the U.S. Atlantic coast and in East Asia. The pharmaceutical and medical products industries value the armored arthropods because a clotting extract from their blood is the world standard for detecting deadly gram-negative bacteria. Their eggs are also a vital food source for migrating shorebirds. And a huge fishing industry uses them for bait.

When Cuomo’s crabs failed to mate in 2001, she fiddled with mimicking the tides, altered the angle of her artificial beaches, and changed their food. Each year she shifted her parameters, but nothing worked. Then, in 2007, at an international conference on horseshoe crabs, Cuomo heard an elderly Japanese researcher talk about raising crabs in mud taken from the beach where the eggs were laid. Cuomo realized what had been missing from her breeding experiment: natal sand. The one year she had managed to get her crabs to breed, unlike any other year, she had taken both the crabs and the sand for her tanks from the same spot. She tried again, and the crabs canoodled—not only in the traditional late spring season, but ongoing into October. She has repeated the process, with the same success.

Now, driven by her innate curiosity, Cuomo is moving on to other aspects of the mystery: What’s in the sand that matters? How do the crabs sense it? And can she help save a species?

This article was originally published with the title Crab Love Nest.

5 Comments

1. 1. jasjr7273 11:31 AM 3/24/11

   Way to go Carmela!

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2. 2. ego99 11:39 AM 3/28/11

   Interesting violation of the anti-plagiarism rules in a scientific magazine.
   And I quote: "...in 2007, at an international conference on horseshoe crabs, Cuomo heard an elderly Japanese researcher talk about raising crabs in mud taken from the beach..."
   I guess some researchers merit no name recognition?
   Does this disrespectful anonymity apply only to Japanese researchers?
   Roger M.

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3. 3. V.E.LovesScience 10:36 PM 4/21/11

   Good point Roger....

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4. 4. ccuomo in reply to ego99 10:27 PM 5/15/12

   Dear Roger,
   As a scientist who has actually been plagiarized I need to clarify a few points. First, I had already gotten the crabs to breed in captivity twice before I heard the elderly Japanese gentleman refer to the larval crabs that he was rearing in mud - and I had, by that time, isolated the fact that natal sand had a major impact on their breeding. In fact, I was presenting this information at the same conference as the elderly Japanese researcher - his comments at the conference pertained to the rearing of one larval crab to adulthood and he concluded that the main necessary ingredient for raising them from larvae to adults was simply "love". He was not breeding adult crabs - he was raising larval crabs with school children. Hearing his comments about the larval crabs simply confirmed my already developed hypothesis about what was working in my experiments. I hope this clarifies things.
   C. Cuomo

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5. 5. timtak 10:01 PM 2/24/13

   All the same, it would be nice to hear the Japanese researchers name together with his research.
   
   I have heard that there is a horseshoe crab expert near me in Yamaguchi, southern Japan, one of the few places on the mainland where there are still lots of crabs. He raises crabs with school children. I wonder if it is the same guy.

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