Credit: (Don Manalo)

An imperiled shorebird species that visits New Jersey’s Delaware Bay beaches each spring faces a new threat to its survival from a proposed change to fisheries rules, conservationists say.

The red knot, whose numbers hit a record low in 2021, would have more trouble finding the horseshoe crab eggs it eats if the Atlantic States Marine Fisheries Commission adopts new rules that conservationists say could lead to female crabs being harvested again.

The commercial fishing industry has been banned from catching female crabs since 2013 under a framework that aims to balance the harvesting of crabs for bait with the protection of shorebirds. Red knots depend on crab eggs on the bay beaches to fuel their long-distance migrations from South America.

In late January, the commission advanced a plan that would introduce new ways of estimating the bay’s crab population and lift the current ban on taking female crabs until their population reaches a certain level. Those measures, naturalists say, would increase the threat to the local population of red knots at a time when it appears to be edging closer to extinction.

No clear picture

“The current losses of adult female crabs are poorly estimated,” said Larry Niles, an independent wildlife biologist who has been working to save the red knot on New Jersey’s Delaware Bay beaches for the past 25 years. “Adding to that loss is just going to make egg densities go down and make this situation worse.”

The commission said the proposed revision to its Adaptive Resource Management framework — the tool it uses for setting annual crab-harvesting quotas for Delaware Bay states — would use new sources of data and new modeling software to set harvest levels that account for the foraging needs of shorebirds.

It estimated that about 145,000 female crabs would have been taken in 2019 if the revised framework had been in place, compared with an actual quota of zero that year. The projection indicates that the female harvest would likely restart if the changes are finalized, said Ben Levitan, an attorney with Earthjustice, an environmental law nonprofit that opposes the reforms.

“It is very likely that it would select for a resumption of the female harvest in future years,” Levitan said

But the commission insisted that the new rule would protect red knots and recognizes public demand for conserving the bird, as it said in a statement after its Horseshoe Crab Management Board approved the change on Jan. 26.

Red knot’s public profile

“The board recognizes that there is considerable public concern about the potential impact of the ARM revision on the status of the endangered red knot and is committed to fully vetting its possible use in setting harvest levels for horseshoe crabs of Delaware Bay through our public comment process,” said board chair Joe Cimino of New Jersey.

The commission, an interstate regulator, said the proposed rule changes won’t affect an understanding that there’s a link between crabs and birds.

“The conceptual model of horseshoe crab abundance influencing red knot survival and reproduction remains intact with the intent of ensuring the abundance of horseshoe crabs does not become a limiting factor in the population growth of red knots,” it said.

The commission said the new rule includes data specific to the Delaware Bay and includes other causes of crab removal including the biomedical industry, which uses blood from an unknown number of crabs to make a substance for detecting bacteria in medical products.

Last May, the population of red knot stopping over on the bay during migration plunged to 6,800, according to an annual aerial count by Niles and his associates. That was the lowest since records began in the 1980s, when the number was about 90,000, and it seemed to represent a renewed decline after several years when the population stabilized, albeit at low levels.

According to the commission, the numbers are much higher, at about 45,000, based on its own method of counting.

But Niles says the commission’s count is based on all the birds that pass through the bay rather than those that stay on the bay beaches for a couple of weeks to rest and regain weight so that they can complete their migrations to the Arctic and breed successfully.

The density of crab eggs is already only a fifth of what it was when the knot population was healthier, Niles says, and allowing the fishing industry to resume taking female crabs will make the eggs even harder for the birds to find.

Niles argued that the commission’s population estimate over-emphasizes the portion of the bird’s population that can survive by eating food other than horseshoe crab eggs. By contrast, red knots fly some 9,000 miles from the southern tip of South America every year and depend on crab eggs by the time they reach Delaware Bay. That explains why many of those birds have already been lost, he said.

Niles, who sits on the horseshoe crab panel, contended that the latest move to change the harvest rules downplays the role of dissenters like himself in the decision-making process.

Deciding without public input

“The commission has revised the model with very little outside stakeholder involvement, and because of that they have gotten this misunderstanding about the importance of Delaware Bay to birds,” he said.

The debate about how to save the red knot follows a sharp decline in its Delaware Bay population starting in the late 1990s when horseshoe crabs were overharvested. That prompted New Jersey lawmakers to ban the harvest altogether in state waters and led the commission to set catch quotas for the other three bay states — Delaware, Maryland and Virginia.

In 2015, the bird was listed by the U.S. Fish & Wildlife Service as “threatened” under the federal Endangered Species Act. Critics of the new rule change have said it could violate that law. violate its protected status

Eric Stiles, chief executive of New Jersey Audubon, urged the commission to drop the rule change in light of the latest decline in knot numbers.

“Now is not the time for the Atlantic States Marine Fisheries Commission to move forward with a proposal that would further destabilize horseshoe crab and red knot populations along Delaware Bay. Rushing such a decision could have tragic consequences for both species and the overall ecosystem of the bay,” he said.

The new rule is now subject to several more stages of review, including public hearings. But Niles said those are not likely to affect the current proposal. “They are not places where you can expect significant change,” he said.