Delaware Bay Red Knot Shorebird Numbers Remain Historically Low Despite Modest Increase

The Delaware Bay Shorebird Venture, which has assessed shorebird numbers within the area for 26 years, discovered that the threatened pink knot shorebird’s numbers remained at traditionally low ranges in 2022. The pink knots modestly elevated from 6,800 in 2021 to over 12,000 this yr, however that quantity is lower than half the 2019 peak depend of 30,000 and a fraction of the height inhabitants of over 94,000 in 1989.  

“The explanation for this eyes wide-open destruction of probably the most necessary pure options within the U.S. shouldn’t be difficult,” stated Larry Niles, wildlife and habitat-restoration biologist and lead researcher for the Delaware Bay venture in a current weblog submit. “Merely put, the businesses permit the killing of too many crabs leaving solely sufficient to spawn when sea circumstances are good, after which blame the lower than good circumstances for the collapse of the stopover. If crabs have been allowed to recuperate to historic numbers, birds would have abundance in any circumstances.” 

Delaware Bay is a crucial resting level for many pink knots as they full their epic migration from as far south as Tierra del Fuego to their breeding grounds within the Arctic Circle. Purple knots depend on horseshoe crab eggs to replenish and renourish earlier than ending their journeys, however as a result of overharvesting of crabs in current a long time each egg availability and pink knot numbers have suffered. In 2015, pink knots have been listed as “threatened” underneath the Endangered Species Act. 

The Atlantic States Marine Fisheries Fee (ASMFC) superior a proposal earlier this yr that poses a major risk to each horseshoe crabs and pink knots. The proposal, superior by the physique’s Horseshoe Crab Administration Board in January, would virtually actually lead to renewed killing — or “harvesting” — of feminine crabs to be used as fishing bait, reversing a longstanding prohibition. New Jersey Audubon, Defenders of Wildlife, and Earthjustice have warned that the proposal threatens to trigger a violation of the Endangered Species Act by additional depleting the horseshoe crab eggs that pink knots rely on. ASMFC may make a last resolution on the proposal as quickly as October and set new horseshoe crab bait harvest quotas for the 2023 fishing yr at the moment.  

“The ASMFC’s horseshoe crab administration coverage during the last twenty years has adversely affected the whole near-shore tidal ecosystem of Delaware Bay,” stated David Mizrahi, vice chairman of analysis and monitoring for New Jersey Audubon. “Shorebirds arriving from South America to feed as they put together to proceed their journey to the Arctic to breed, forage fish, and the younger of a number of sportfish like weakfish and striped bass all rely on horseshoe crab eggs in abundance, which has been missing during the last 20 years.”

“With pink knot numbers in Delaware Bay remaining at traditionally low ranges, ASMFC’s proposal is a big threat to the birds’ survival and restoration,” stated Ben Levitan, senior lawyer for Earthjustice’s Biodiversity Protection Program. “ASMFC ought to be restoring horseshoe crabs and pink knots in Delaware Bay, not making the scenario worse.” 

Horseshoe crab egg density in Delaware Bay was roughly 7,000 eggs per sq. meter in Could 2022, nicely beneath the ten,000 egg per sq. meter density seen lately. Within the Nineteen Nineties, earlier than the overharvesting of horseshoe crabs, eggs reached practically 50,000 per sq. meter. Researchers from the Delaware Bay Shorebird Venture have concluded that the overharvesting of horseshoe crabs has instantly impacted pink knot shorebird numbers within the area.  

“The easy truth is that pink knots are ravenous to demise,” stated Christian Hunt, Southeast consultant at Defenders of Wildlife. “With extinction now an actual chance, the choice to additional scale back protections in Delaware Bay is meaningless. The ASMFC must reverse course earlier than the pink knot passes the purpose of no return.”  

As horseshoe crab numbers languish in Delaware Bay, satellite tv for pc transmitters have proven birds bypassing the area as a stopover altogether, though options don’t present a enough meals provide. With a spottier distribution of horseshoe crabs and shorter spawning durations that final only some days throughout lunar tides, moderately than weeks, egg assets on the bay are now not dependable to the birds.  

See pictures of pink knots and horseshoe crabs in Delaware Bay.