A fisheries regulator advanced a plan that conservationists say poses a new threat to the survival of the red knot, a protected shore bird that visits Delaware beaches on its migration each spring, and last year dropped to a record-low number.
A panel at the Atlantic States Marine Fisheries Commission in late January approved reforms to a plan that regulates the harvest of horseshoe crabs, an iconic Delaware Bay species whose eggs provide essential food for the red knots and other shorebirds on their long-distance migrations.
If finally implemented, the plan would allow new methods of counting horseshoe crabs in the bay. It would also incorporate local data to a model that is not always specific to Delaware Bay, and it would add more sources of crab removal including mortality from catches by the biomedical industry, which takes unknown numbers of crabs from the bay.
Conservationists say the reforms would overestimate the crab population and allow the commercial fishing industry to resume its catch of female crabs, whose harvest has been banned since 2013 in an effort to boost egg production and feed the shorebirds.
“The Commission should prioritize the food supply for red knots, which are listed as threatened under the Endangered Species Act."Earthjustice attorney Ben Levitan
The vote by the Horseshoe Crab Management Board is “deeply disappointing,” said Ben Levitan, an attorney for Earthjustice, an environmental law nonprofit that opposes the change.
“The Commission should prioritize the food supply for red knots, which are listed as threatened under the Endangered Species Act,” he said. “The proposal would likely lead to a resumption of killing female horseshoe crabs for fishing bait, which would imperil the food supply upon which red knots depend.”
Earthjustice called the proposals “the most dramatic weakening of protections” in the history of the commission’s management of the horseshoe crab harvest.
In May last year, only 6,800 knots stopped off on both the Delaware and New Jersey sides of the bay, the lowest number since records began in the 1980s, according to an aerial count by naturalists. The sudden drop renewed concern that the bird’s rufa subspecies is headed for extinction despite more than a quarter-century of efforts to save it.
Once steady at around 90,000, the population plunged starting in the late 1990s because of the over-harvesting of horseshoe crabs for commercial fishery bait and farm fertilizer. The harvest was then banned in New Jersey and limited in Delaware, Maryland and Virginia by catch quotas set by the commission. Those measures appeared to stabilize the population for most of the last decade but it has now resumed its decline to dangerously low levels, naturalists say.
Any further decline in the bird’s population could affect the Sussex County preserve of Mispillion Harbor, a migration “hotspot” where scientists and volunteers, some from overseas, come each spring to study and watch a renowned natural spectacle. Shorebirds there include the red knot, which weighs less than 5 ounces and migrates up to 18,000 miles a year, one of the longest migrations in the avian world.
Critics say the rule change might violate the Endangered Species Act, under which the bird was listed as “threatened” in 2015.
“We are committed to ensuring that red knots are effectively conserved and recovered as required by the Endangered Species Act, and that the Delaware Bay ecosystem is not further impaired,” Levitan said. He urged the commission’s board to reject the proposed revisions.=
A decision to resume the harvest of female crabs would make it even harder for the birds to find the food they need to complete their migration and to breed successfully in Arctic Canada, conservationists say.
“This is a setback,” said Larry Niles, an independent wildlife biologist who has monitored the red knot on the New Jersey side of the bay for the last 25 years, and made the latest count.
Niles argues that the aerial count showing the new decline is the most accurate gauge of the bird’s status because it shows the number that are stopping off on the Delaware Bay to feed and regain weight after flights that for some of the birds start as far away as Tierra del Fuego on the southern tip of South America.
Crab numbers in the bay have not increased in recent years, Niles argues, and if the commission allows the fishing industry to resume its catch of females, that will make crab eggs even harder for the birds to find. He estimates that the density of eggs on the beaches is now about a fifth of what it was before the over-harvest of horseshoe crabs in the late 1990s.
For their part, commission scientists count all the birds that pass through the bay during the migration season whether or not they stop off – a number that they estimate at around 45,000 between 2011 and 2020. The commission said red knot numbers were “fairly stable” during that period and that annual survival estimates were “consistently high”. Conservationists say the commission’s method risks double-counting.
Niles argues that the commission’s count is not an accurate gauge of the population because it includes birds that don’t stop on the bay beaches because they can’t find food. Those individuals, a majority, are less likely to breed successfully or even to survive the remainder of their arduous migration, he says.
Meanwhile, crab numbers were stable in the decade to 2013 and have recently been increasing, the commission said. In 2019, it estimated there were 21.9 million male crabs and 9.4 females in the Delaware Bay region.
The regulator says the proposed revision to its Adaptive Resource Management (ARM) framework recognizes the importance of crab eggs to the knot, and the high public profile of the fight to save it.
“The board recognizes that there is considerable public concern about the potential impact of the ARM revision on the status of the red knot and is committed to fully vetting its possible use in setting harvest levels for horseshoe crabs of Delaware Bay-origin through our public comment process,” said Joe Cimino, chair of the horseshoe crab board, in a statement.
Despite conservationists’ worries, the commission argued that the proposed revision doesn’t change its recognition that the birds depend on crabs to survive and thrive.
“While additional data and model improvements are used in the ARM revision, 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 proposed rule change will now be evaluated by another commission panel consisting of state and federal representatives. If approved, the measure will then go out for public comment, and then be presented for a final evaluation. Any final changes to fishing quotas resulting from the reform would be effective in 2023.
