Even After Listing, Red Knots Continue to Face Serious Threats in Delaware Bay

With the listing of the Red Knot as “threatened” under the Federal Endangered Species Act in January 2015, many in the conservation community thought the days of battling to protect the Delaware Bay, its horseshoe crabs and the migratory shorebirds that stop to eat their eggs en route to breeding grounds was over. Unfortunately, new developments threaten to undermine all of the successful conservation work N.J. Audubon and others have fought to achieve in the Delaware Bay.
The new threat comes by way of oyster aquaculture development, not the traditional method of offshore growing, but a new method called “rack and bag” aquaculture, which requires structures to be placed in the intertidal zone. Unfortunately, oysters in Delaware Bay are subject to a type of parasitic worm called Polydura that encases them in mud. Without routine power washing, the oysters die before they are market size. Power washing is usually done daily, and requires intensive activity and access by ATVs within the intertidal zone. This can cause chronic disturbance that excludes shorebirds from aquaculture areas. ATV activity could compact the intertidal sediments, adversely affecting intertidal invertebrates, like clams, that horseshoe crabs feed upon during the spawning season. Finally, the rack and bag structures could diminish access by horseshoe crabs as they move to and from spawning beaches.
From a conservation perspective, it all boils down to “location, location, location.” With mapping and historical information, N.J. Audubon and a consortium of conservation organizations and scientists have identified the most important areas in Delaware Bay for Red Knots, and have strongly advised against any aquaculture in these areas. Some of the areas in question were restored after Hurricane Sandy, specifically to benefit spawning horseshoe crabs and migratory shorebirds with investments in excess of $5 million.
However, New Jersey Department of Environmental Protection (NJDEP) is allowing development of this industry to take place outside the legislatively-established Aquaculture Development Zone, which was designated to avoid critical habitat for shorebirds.
Additionally, NJDEP has also decided to allow two leaseholders to remain and conduct intensive aquaculture in the most sensitive foraging areas for Red Knot, which could ultimately have an adverse effect on their survival. Although some of their aquaculture activities have been limited, (for example, number of maintenance days), the two leaseholders are being allowed to stay in this sensitive area and continue activities. N.J. Audubon and its partners strongly advocated against this position.
N.J. Audubon supports responsible oyster aquaculture and believes that there can be a robust and thriving industry in the Delaware Bayshore at the same time as we protect the most critical shorebird habitat. In fact, many dozens of leases are held in areas less critical to Red Knots and other shorebirds. We have been working with partners and through a variety of methods including engagement with other scientists, outreach to the U.S. Fish and Wildlife Service (USFWS), extensive discussions with the NJDEP, outreach to legislators, working through the Endangered and Non-Game Species Advisory Council and more to support this reasonable compromise. We will continue to actively work to protect the Red Knot, horseshoe crabs and habitats that are vital to them. Many thanks to all our members who support the critical work we do to protect the Delaware Bay and its wildlife.
This article is published with permission of the N.J. Audubon Society.