Bay & Environment: Knot to worry - time to quit horseshoe-ing around? - Bay & Environment is The Sun’s blog devoted to news about Maryland’s environment

In dry bureaucratic language, the federal government has acknowledged what bird-watchers have been saying for some time - the globetrotting shorebirds known as red knots are in trouble because the mid-Atlantic horseshoe crabs on which they depend are also in trouble. Both need protecting, activists say, but they say federal and state action to date has been inadequate.

In its annual review of plants and animals that may need federal protection, the U.S. Fish and Wildlife Service reports that red knots are dwindling, most likely because their primary food source - eggs laid on Delaware Bay beaches by spawning horseshoe crabs - are likewise reduced. The report was published in the Federal Register on Wednesday.

The numbers of red knots counted on the Delaware Bay's beaches by biologists and dedicated bird-watchers have plummeted from around 95,000 in the 1980s and '90s to less than 14,000 lately. These birds make one of the longest migrations of any in the animal kingdom, flying from the coast of Chile and Argentina in winter to their breeding grounds in the Canadian Arctic, and back. They stop off on the mid-Atlantic coast, primarily around Delware Bay, in May and June to replenish their energy by feasting on eggs laid by horseshoe crabs that have crawled up from the depths to mate.

The helmet-shaped horseshoe crabs, dubbed "living fossils" because of their prehistoric lineage, have been harvested for years by fishermen for use as bait. Efforts to protect the slow-moving crabs have been mixed. New Jersey banned harvesting them, and Delaware tried a two-year ban, only to have it overturned in court last year. The state responded by restricting the harvest to males only.

Under those and less restrictive catch limits set by the Altantic States Marine Fisheries Commission, the harvest of horseshoes in New Jersey and Delaware has declined substantially since the late '90s, but the federal report says it's unknown whether the crab population will rebuild or how long it might take to increase the production of eggs, since the slow-moving creatures take eight to 10 years to reach maturity.

Though concerned birders have filed petitions three times over the past four years to protect the red knot under the Endangered Species Act, the federal government has declined to nominate the species for listing.

Darin Schroeder of the American Bird Conservancy says wildlife activists will continue to press for action from the fish and wildlife service, which in this week's report rated the red knot as more threatened than previously. In the meantime he's urging more protective measures from the states, particularly Maryland.

"Obviously, what we're hoping for is a moratorium (on harvesting horseshoe crabs)," Schroeder said. "But short of a moratorium, any action that would substantially increase the number of female crabs on the beaches would be beneficial."

To those who wonder why Maryland should do more to limit catch of horseshoe crabs in its waters when the birds are feeding primarily on eggs laid in Delaware Bay, Schroeder notes that studies have suggested that the crabs range up and down the Atlantic coast. So those seen in Maryland at times may wind up laying eggs on the Delaware shore.

Maryland's Department of Natural Resources held a public meeting this year to discuss what else it might do about horseshoe crabs, Schroeder noted.

"So we're hoping that Maryland will once again see this assessment by the U.S. Fish and Wildlife Serivce and it will spur them to take some immediate steps of their own," he said.

UPDATE: State natural resources officials say they are considering furrther action soon, though they downplayed how much help Maryland catch restrictions alone would be for the Delaware Bay's horseshoe crabs, or for the troubled red knots.

The state acted nearly a decade ago to curtail its commercial horseshoe crab harvest, reducing it by 72 percent from its peak in the 1990s, said Mike Luisi, of DNR's Fisheries Service.

The state capped landings at 172,000 crabs a year, Luisi said, and out of concern for the abundance of egg-laying females, fishermen have agreed to voluntarily balance their catch, with roughly equal numbers of males and females. The number of egg-laying females should be showing some real gains in the next year or two, he suggested, since it takes up to a decade for young crabs to reach reproducing age - roughly the amount of time the catch restrictions have been in place.

Still, the state's catch limit is the third highest among mid-Atlantic states, and wildlife activists have pressed for further restrictions or even a moratorium, like New Jersey's. Assistant Secretary Frank W. Dawson said state officials are weighing options now and may propose something in time for the spring spawning season.

"There's quite a constituency out there of folks that bleieve that greater conservation measures need to be taken," Dawson said. "We certainly don't take their concerns lightly."

But he and Luisi cautioned that even a statewide moratorium on catching horseshoe crabs may not do that much to help the red knots. Scientists estimate that the Delaware Bay crab population, of which Maryland's are a part, contains nearly 11 million females. So a ban on further harvest in Maryland would spare at best 100,000 females a year. There may be other problems the birds face, such as habitat losses.

But with the red knots continuing to lose ground and scientists unsure what it will take to reverse their decline, Luisi acknowledged, "every little bit may help."

(Horseshoe crab photo by Jerry Jackson of the Baltimore Sun)