Crabby trysts on the beach

Wildlife officials survey the ancient mating ritual of the horseshoe crab.

June 12, 2005|By Rona Kobell | Rona Kobell,SUN STAFF

BOWERS BEACH, Del. - In the pitch-black night of a deserted beach, J.R. Futcher shines her flashlight on the unsuspecting lovers.

She's interrupting a private moment. But the horseshoe crabs appear not to notice. Several helmet-headed males cluster around one plump female, forming a mating circle that's kicking up quite a froth of sand. Futcher lays a one-meter-square plastic grid atop the crabs, does a quick head count and repeats the process.

"Twelve males, one female!" Futcher calls out.

The annual mating dance of the horseshoe - a prehistoric creature that is more spider than crab - has again arrived on the shores of the First State, where it has perplexed and fascinated scientists for decades.

Every year, between May and June, millions of horseshoe crabs crawl from the ocean to the Delaware Bay at late-night high tide, searching out the opposite sex. The larger females lay their pearly-green eggs in the sand, and the attending males release sperm to fertilize those eggs.

Then, when day breaks, thousands of shorebirds arrive, emaciated and exhausted from their journey from South America. They have come to feast on the protein-rich eggs, fattening themselves up for the next leg of their trip to the Canadian arctic.

However, the ancient ritual has come under strain in recent years. There appear to be fewer horseshoes since fishermen have begun using them for bait. And possibly as a result, avian enthusiasts have noticed a decline in the shorebird populations, particularly the beloved red knot.

Although horseshoe crabs are a species older than dinosaurs and have been coming to Delaware Bay for more than a thousand years, wildlife officials realized they didn't know much about their spawning habits or their numbers. They wanted to determine how much the population has dropped, and whether there was a link between the declining birds and a smaller egg supply.

So, the beach spawning survey was born. For the past decade, twelve times a year, during the full and new moon cycles, volunteers like Futcher comb the Delaware Bay beaches, plopping down their lightweight grid squares every 10 paces to count the numbers of crabs. Bowers Beach, a fishing community south of Dover, is deserted on the night of the new moon, with only the three surveyors walking along the sand.

Katy O'Connell, who runs education programs for the nearby Delaware National Estuarine Research Reserve, leads the way in her waist-high waders. She and Futcher move at a rapid clip, knowing the tide will turn within an hour or so. By night's end, they will have walked half a mile and laid down their grids 100 times.

Futcher and O'Connell call out their counts to Julie Lamborn, O'Connell's 18-year-old sister, who records them on her clipboard chart. Some grids have nothing; some have as many as five females and 30 males, many encrusted in barnacles.

O'Connell calls the surplus males "satellites"; they're still able to fertilize some eggs if they can wedge themselves into the party.

"There are a lot of males plying around off the coast, waiting for a place to be," she said. "It's like happy hour at the bar."

Though the May part of the season was slow and cold, June has so far been a happening month. Thanks to little wave action and warm water, O'Connell and her volunteers have seen abundant spawning activity at the three Delaware beaches they have surveyed.

She'll have to wait several weeks for the U.S. Geological Survey to tabulate the results, but O'Connell says initial findings show a relatively stable horseshoe crab population.

The initial results this year have done little to quell the debate over whether to restrict the harvesting of horseshoe crabs - a fight pitting the interests of commercial fishermen against bird enthusiasts.

Despite their impressive longevity, horseshoe crabs have not been beloved creatures. In the early 20th century, they were used for pig feed. In the late 1980s, the pharmaceutical industry began extracting their blue blood to test medical devices.

In the 1990s, conch and eel fishermen discovered that horseshoes - particularly pregnant females - were an excellent and free source of bait. For a time, fishermen pulled pickup trucks and trailers up to the beach and loaded up on the crabs.

Worry over the fate of the migratory shorebirds prompted Delaware and New Jersey - the states with the largest horseshoe populations - to regulate horseshoe harvests.

Currently, the two states allow fishermen to remove 150,000 crabs a season from the bay. Delaware had to wait longer to enforce the law than officials would have liked because it lost a court battle against commercial fishermen who opposed the limits.

John Hughes, secretary of the Delaware Department of Natural Resources and Environmental Control, wishes he had more data to support more regulation.

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