A recent article from The Newark Star Ledger offers news that 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 evidence 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 conservation 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.
PHOTO COURTESY OF BILL HUBICK.
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 semipalmated 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."
-Dan
