Cutting a tiny traveler's ecological lifeline

Overharvesting of Delaware Bay horseshoe crabs is starving a bird that feeds there during its journey from South America to the Arctic

June 18, 2006|By CANDUS THOMPSON | CANDUS THOMPSON,SUN REPORTER

It is one of those exquisitely choreographed moments in nature: A small bird on its way from the bottom of the world to its breeding ground at the top encounters its nutritional lifeline as it lands on sandy beaches along the Delaware Bay.

Red knots arrive from South America, exhausted and emaciated. Horseshoe crabs swim from sea to shore, following their prehistoric instinct to procreate.

They get together each spring for their annual date, a two-week springtime feast and orgy that has been performed longer than humans have been recording such things.

The robin-sized bird gorges itself on the fatty eggs laid by the crab to replenish its body and stock up for the remaining leg of its flight. It needs to consume 18,000 eggs a day; a single female horseshoe crab lays 90,000 BB-sized eggs each spring.

Lately, however, red knots have been finding the cupboard bare. Commercial fishermen, in a frenzy of their own, scooped up millions of horseshoe crabs to sell to the bait industry, using pitchforks to pile the helmet-shaped creatures into pickup trucks. In 1990, the harvest was 1.2 million crabs. Eight years later, regulators stepped in to limit the harvest, but the damage was done.

The crab population plummeted. The red knot population decreased at an alarming rate. As a result, scientists and birders who used to see 100,000 red knots feeding on the Delaware Bay in the 1980s now see fewer than 15,000.

"The birdfeeder of the Delaware Bay is empty," says Perry Plumart of the American Bird Conservancy.

Eight environmental groups filed a lawsuit Tuesday in federal court in New Jersey to force the U.S. Fish and Wildlife Service to place the bird on the endangered species list. But it may be too late.

One population model suggests that the red knot could be extinct as early as 2010.

As with the force that brings the red knot and horseshoe crab together, timing is everything.

"We are up against the wall if we are to save this species," says Jason Rylander, a lawyer for Defenders of Wildlife. "And we are running out of time."

On a humid day in late May, an international group of scientists and volunteers hunker in the tall marsh grass where the ticks crawl and bite.

About 100 yards away on a sliver of beach on the Delaware Bay, 1,000 birds are feeding.

Suddenly, an explosive charge booms and echoes off the water. A tea-colored net arches skyward and falls to the sand, trapping about 100 birds beneath it.

"Run!" someone shouts, and in a blink the people in the weeds sprint to the shore. A tarp is placed over the net to quiet the birds. Then, as they roll up the net and tarp, they reach under to pull out birds. Gulls are released. The migratory birds, including 24 red knots, are placed in boxes and carried to an improvised work area behind the dunes.

Larry Niles, head of New Jersey's Endangered and Nongame Species Program, oversees the bustle, but his work force clearly knows what it is doing.

"There is no way this bay could support 100,000 birds now," he says. "We're at 15,000 birds ... That's a lot of birds by bald eagle standards, but for shorebirds, that's too low."

At the diminished level, the genetic pool is too small to sustain a hit by severe weather, disease or catastrophic loss of habitat.

New Jersey officials, alarmed by the decline of the bird, close 15 beaches during the red knot stopover period and last month imposed a two-year ban on all horseshoe crab harvests. Delaware wildlife officials lack the authority to do so; an attempt several years ago was successfully challenged in court by watermen. Maryland and Virginia - the two states nearest the Delaware Bay - have done little to protect the crabs.

In May, the regional regulatory body that sets catch quotas for creatures such as striped bass, flounder and horseshoe crabs rejected a request from conservation groups to follow New Jersey's lead. Instead, it enacted a two-year ban on the taking of female crabs. That, say red knot supporters, is not enough.

The horseshoe crab takes nine to 13 years to reach sexual maturity. Because of the massive harvest of crabs in the late 1990s, the species, although not in trouble, isn't producing enough eggs to feed the red knot. Concentrating the commercial harvest on males will not allow horseshoe crabs to rebound to levels found in the 1980s and earlier.

But the Atlantic States Marine Fisheries Commission isn't in the bird business. It is in the fishing business, and keeping commercial interests financially healthy is part of that equation.

"We keep waiting for someone to step up," says Niles. "The ASMFC undermined [New Jersey's] moratorium, and that makes it difficult for other states to act."

Ared knot is an amazing creature by any standard, but as a migratory bird it is almost unsurpassed.

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