[For more about the
horseshoe crab, see the interview with Anthony Totah
Jr.]
Treading
Water
For millions of years, horseshoe
crabs have climbed Delaware Bay shores in a mating ritual
as cryptic as it is beautiful. But with new threats from
biological labs, the fishing industry, and Mother Nature,
the new laws designed to protect the creatures are
drawing controversy.
By Curtis Rist
Photographs by Clay and Patricia Sutton
Pictured at right:
Horseshoe crabs mating on the shores of Delaware Bay.
Each May, along the desolate beaches
on Delaware Bay, a battalion of primordial creatures
emerges from the surf. They can be recognized by a tiny
ridge of their tails poking up through the waters, then
by a helmet-shaped body as they glide to shore. These are
the unmistakable profiles of the horseshoe crab. The
females arrive first, then an hour later the males, who
dance on the beach in an annual mating frenzy that peaks
with the extreme tides under a full or new moon.
 Even more spectacular is the arrival of the
crabs' predators--a total of eleven species of migrating
shorebirds, including ruddy turnstones, sanderlings,
dunlins, and what is believed to be the world's entire
population of red knots--which flock by the millions to
this tiny way station on their journey from wintering
grounds in South America to their own breeding grounds in
the Arctic tundra. Pausing for the three-week-long
horseshoe crab mating season, they fatten up on the
pinhead-sized eggs, which lie by the billion in grayish
globs on the beach. "It's a noisy festival of
digging and eating, with birds biting one another, and
flying in the air with incredible precision, like the
Blue Angels," says Joan Walsh, chief biologist with
the Cape May Bird Observatory. "It rivals the
wildebeest and the caribou migrations as one of the
natural world's great spectacles."
The scene has been repeated for millions of
years, though the crabs themselves have been making the
ritual egg-laying stop for at least 200 million years,
since the dawn of the age of dinosaurs. But, sadly, it is
now imperiled, some experts say. Horseshoe crabs, which
spend most of their lives buried in mud and have never
attracted much attention, have suddenly found themselves
in demand by commercial fishermen. And new regulations
devised to protect the creatures have yielded some
unexpected problems.
Although inedible to humans, horseshoe crabs,
when halved or quartered with a band saw, prove
irresistible to local eel and lightning whelks (also
known as conch), which are prized as food in Asia,
Europe, and the Caribbean. To satisfy the demand for
jellied eel in Germany and conch creole in the Dominican
Republic, fishermen have been hauling the horseshoe crabs
from the waters to use as traps in record numbers--in
some cases, directly off the beaches beneath the beaks of
the migrating shorebirds. Some environmentalists and
researchers fear that this escalating harvest, which
began in 1991, could jeopardize the horseshoe crab colony
in Delaware Bay, the largest such conglomeration on
Earth. "The numbers are down," says Bob
Loveland, an associate professor of biology at Rutgers
Univer-sity, who has studied the crabs since 1984, and
concedes that the actual size of the population remains a
mystery. Still, he says, "Just about everyone has
documented a tremendous diminution."
To be sure, horseshoe crabs have known trouble
before. Beginning in the last century, they were scooped
up in huge numbers--no one can say exactly how many--and
ground into fertilizer for crops, a practice that did not
stop until the middle of this century, with the advent of
petroleum-based fertilizers. Unlike some marine
creatures, such as blue crabs, horseshoe crabs have a
very long maturation period: A female crab cannot even
lay eggs until she reaches nine or ten, and has a life
expectancy of about sixteen years. As a result, the
population drastically fell during the fertili- zer
craze, and the recovery was painfully slow.
To address this controversy, the state passed
regulations last year that largely banned horseshoe
crabbing during May, the peak mating month. But those
regulations are generating their own measure of dispute.
Fishermen--some of whom had begun driving to the edge of
egg-laying spots such as Reeds Beach and tossing into
their tractor trailers thousands of crabs with a loud
thud of chitinous shell--claim the restrictions are
cutting into their profits. And they doubt, in some cases
justifiably so, data showing the decline of the crab
population.
Complicating matters further, the crabs are
not just in demand by the birds and the fishermen, but by
biological laboratories that "bleed"
them--literally milk a portion of their blood--to produce
a clotting agent used worldwide to test many
pharmaceuticals for bacterial contamination. In a process
regulated by the federal Food and Drug Administration,
some 200,000 crabs are taken each year by three New
Jersey laboratories, and although the crabs are later
released, up to 10 percent die.
The demand for the horseshoe crabs by both
birds and humans is ironic, considering the species--an
arthropod more closely related to the spider than the
blue crab--evolved its ability to lay eggs on the sand as
a way of avoiding predators in the sea. One of only three
species of horseshoe crabs in the world (the other two,
in Asia, are rare or endangered), the Atlantic horseshoe
crab can be found only on the East coast from Florida to
Maine. With their two sets of eyes, one below and one
above their shells, and their unusual blood which turns
blue when exposed to air, they've long been a curiosity
to beachcombers. And the crabs are even an enigma in the
prehistoric record: "There's actually not a single
fossil of the New Jersey species. Not a single
fossil," says Loveland, because they disintegrate so
quickly.
T he largest horseshoe crab population now
lives in Delaware Bay, and is posing yet another riddle:
How many of them are there, and how--if at all--can they
be protected? So far, the efforts to find out have been
maddening. "The organism is cryptic," says
Robert Munson, a fisherman from Money Island in
Cumberland County, who also catches horseshoe crabs.
"It spends most of its time buried in the mud,
eating young clams or juvenile oysters, anything that it
can crunch open. So if you go out looking for it, most of
the time you don't find them." In the face of doubt,
absolute protection is a nice idea, but it runs headlong
into the problems of the commercial fishermen. The
regulations have made things difficult for fishermen,
such as Munson, a retired biological oceanographer from
the University of Washington. For the last fifteen years,
he has plied the waters of Delaware Bay in a 25-foot dory
while setting gill nets to catch menhaden (members of the
herring family, which are turned into fish oil and fish
meal). In the spring, the horseshoe crabs become
entangled in his nets, and for the last six years,
instead of freeing them and setting them loose, he has
sold them as bait. With the regulations--which he
reluctantly helped approve as a member of the state's
Horseshoe Crab Advisory Committee to the state's Marine
Fisheries Council--he has had to stop. "I'm not
allowed to keep them" during the month of May, he
says, adding that he now throws them overboard. He might
catch 100 crabs in a day, he says, worth about $50 on the
bait market. "And," Munson says, "no one
likes to throw $50 bills away, that I know of."
Yet while the regulations have eliminated the
social clash between birdwatchers and crab fishermen on
the beaches, the overall effect has been unexpected. The
price doubled from about 50 cents for a prized female
crab to $1 during the May prohibition--not much of an
incentive to stop fishing for them, even with potential
fines ranging from $100 to $1,000. "If you're taking
a truck and hauling away 10,000 crabs, you're talking a
pretty good chunk of change," says Loveland. Perhaps
as a result, the reported harvest actually rose last
year, from 325,000 to more than 600,000.
Peter Himchak, a supervising biologist at the
Marine Fisheries Bureau of the Division of Fish Game and
Wildlife Management at Nacote Creek, in Atlantic County,
says the data simply aren't good enough to speculate
about the effects of the commercial fishing industry on
the horseshoe crab population. Bird-watchers and
conservation groups cry out for protection; fishermen
clamor for their rights. In the absence of proof, Himchak
is sure of only one fact: "It has turned out to be a
very controversial thing," he says.
The ultimate future of the horseshoe crab may
lie outside the realm of regulation altogether. Loveland
has documented what he believes is another impact on the
species' future: A rising sea is wiping out crucial
habitat. Already, the southern part of New Jersey is
slowly subsiding, he says. And the ocean, too, appears to
be rising as global warming continues. "It could be
the beginning of a new geologic cycle, or a result of the
ground sinking because we're taking too much groundwater
out for wells," says Loveland. Whatever the cause,
the effect is clear: Inch by inch, the shoreline is being
inundated. "As that happens, sand is removed, and
that provides less habitat for crabs to spawn," he
says. "We're looking at the degradation of beaches
from the Cape May Canal at Higby's Beach all the way up
to Sea Breeze."
With the full moon this month, the horseshoe
crabs will clatter again to the beaches and lay their
eggs in whatever sand they find--oblivious to the forces
shaping their fate.
Copyright
© 1997, Micromedia Affiliates
[For more
about the horseshoe crab, see the interview
with Anthony Totah Jr.]
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