The Newark Star Ledger


Turns out the red knot is not alone in its plight

Sunday, February 01, 2009

BY BRIAN T. MURRAY

Star-Ledger Staff

Tiny and easily overlooked among the hordes of more spectacular shorebirds
streaming up and down the Atlantic Coast, the semipalmated sandpiper is
suddenly standing out in the fragile ecological ballet that unfolds annually
at the Delaware Bay.

The little brown bird, named because of its partially webbed feet, is
providing new insight into the link scientists have drawn between the
plummeting population of the more celebrated red knot sandpiper and
dwindling number of horseshoe crab eggs on the New Jersey and Delaware
shores.

A team of five researchers with New Jersey Audubon and a Dutch scientist,
wrapping up a month of field work last week in the South American wintering
grounds of the semipalmated sandpiper, announced that they have found evi
dence the species also is in serious decline -- and likely for the same
reason as the red knots.

In the 1980s, about 2 million semipalmated were counted by researchers on
the 4,000-mile coastline of Suriname and neighboring French Guiana, where
scientists say 85 percent of the world's population of the bird winters
annually. Last month, only 400,000 of the birds were found in aerial surveys
by the New Jersey Audubon expe dition.

"We had already found a 50 percent decline over 15 years by 2006. Now, this
is a 70 to 80 percent decline since the survey in the 1980s. I think it's
alarming," said David Mizrahi, the team leader.

The problem, he said, appears to be in the Delaware Bay -- also the
controversial source of the red knot's troubles.

The area has been called the East Coast's Serengeti because of the natural
marvel that unfolds each spring. For eons, most of the Atlantic Coast
population of horseshoe crabs have arrived at the bay to lay the eggs of a
new generation.

In turn, millions of shorebirds migrating from southern wintering grounds
land to feast on those eggs -- a crucial meal as they continue their trek to
northern breeding grounds.

"About 80 percent of the world's population of red knots go through the
Delaware Bay on their return north. About 60 percent of the world's
population of semipal mated sandpipers come through at the same time,"
Mizrahi said.

"There just doesn't seem to be a major change down in the wintering areas of
either the red knot or the semipalmated sandpiper to ex plain a decline in
either species. The Arctic breeding grounds of the red knot also have not
changed ... But what we do know is that there have been changes in the
stopover area both birds share in North America," he said.

New Jersey and Canadian biologists have insisted for years that a decline in
horseshoe crab eggs in the Delaware Bay is causing the decline in red knots,
which fly 10,000 miles from wintering grounds as far south as Tierra del
Fuego. Where the birds once found 50,000 eggs per square meter, there are
now 20,000.

Biologists also have concluded the red knots are arriving in Arctic breeding
grounds too underweight to mate.

Last year, they said the entire Western Hemisphere's population of red knots
was between 18,000 and 33,000 birds -- down from 100,000 to 150,000 about 20
years ago. Preliminary reports this year show slightly lower counts.

The data drove New Jersey officials to impose a moratorium last spring on
harvesting the crabs by fisherman who use them as bait in a lucrative conch
and eel industry. But New Jersey is the only East Coast state to impose a
ban, and it remains contentious.

"It really gets down to the fact that the focus has been on the harvest of
horseshoe crabs because it's an easy target. But the conserva tion issues
really need to be considered in a larger context," said Greg DiDomenico,
executive director of the Garden State Seafood Association. "Why point to
one group's im pact, when there are so many other possibilities? To some
extent their research has been a conclusion in search of a study."

No one disputes over-harvesting dramatically reduced crab numbers by the
1990s. But they re bounded after federal and state restrictions on
fishermen's hauls were imposed in 1996, and last year the fishermen pointed
to a study showing 20 million crabs in the Delaware Bay area.

Delaware still permits crab harvesting, limiting hauls to male crabs and a
maximum of 100,000 annually. The same restriction was recommended last year
by a majority on the Atlantic States Marine Fisheries Commission, a group of
15 states, including New Jersey, formed to coordinate conservation and
management of Atlantic Coast fisheries.

Fish companies have condemned New Jersey's ban, which put 39 local
harvesters out of business. The red knot's plight, they insist, may have
more to do with the bird's natural inability to compete for survival.

Enter the semipalmated sandpiper.

"The semipalmated sandpipers cement the underpinning that something more is
in play here than just a problem isolated to the red knots," said Eric
Stiles of the New Jersey Audubon expedition. "The semipalmated sandpipers
don't winter in the same area as the red knot or breed in the same areas.
They only share this one stopover area, the Delaware Bay, and they, too, are
in decline."

The research team spent three weeks capturing 2,500 semipal mated
sandpipers, taking blood and tissue samples and fitting them with
identifying legbands. The data will be used in monitoring the semipalmated
this spring as they return to the Delaware Bay.

"But in order to nail this all down, we must ultimately get to the breeding
grounds as well to confirm that the problem is in the North American
stopover," Mizrahi said. "We're following the model our colleagues in Canada
and the New Jersey Division of Fish and Wildlife have already used on the
red knots."