What a Shorebird Can Teach Us About the Biodiversity Crisis

Throughout the animal kingdom, increasing pressures from industry are putting endangered or threatened species like the red knot at risk.

Red knots, ruddy turnstones, dunlin and semipalmated sandpipers coming through the Delaware Bay near Fortescue, New Jersey, on May 23, 2022.
Red knots, ruddy turnstones, dunlin and semipalmated sandpipers coming through the Delaware Bay near Fortescue, New Jersey, on May 23, 2022. (Aristide Economopoulos for Earthjustice)

Every year, the red knot shorebird completes one of the most epic migrations in the animal kingdom.

Red knots commonly fly from the southern tip of South America, in Tierra del Fuego, all the way to their breeding grounds in the Arctic Circle. For many thousands of red knots, this more than 9,000-mile journey includes a crucial stop in Delaware Bay, where the birds replenish with horseshoe crab eggs before completing their migrations.

Unfortunately, due largely to the overharvesting of horseshoe crabs by industry, there have not been enough eggs in recent years. As horseshoe crab numbers languish, the shorebird — which is listed as threatened under the Endangered Species Act — has suffered as well. Despite the reduced populations of horseshoe crabs and red knots, a regional fisheries commission recently weighed a proposal to lift the prohibition on killing female horseshoe crabs for use as fishing bait, which would have left the red knot with even less to eat.

But thanks to pressure from Earthjustice, our partners, and environmental advocates across the country, the commission ultimately decided not to authorize a 2023 harvest of female crabs. While we won this round, we will need to keep the pressure on for the commission to do the right thing in future years. Moreover, the existing management of horseshoe crabs in Delaware Bay has proven inadequate to sustain a reliable food source for migrating shorebirds, even without the further degradation that would have been inflicted by the new expanded harvest proposal.

A growing body of evidence indicates that many red knots are now bypassing Delaware Bay altogether, and the much-needed nourishment the region once provided, as the egg resources on the bay are no longer reliable for the birds. In 2022, researchers from the Delaware Bay Shorebird Project counted just 12,000 birds at their peak — less than half the 2019 peak of 30,000 and a fraction of the peak population of over 94,000 in 1989.

This story is not unique to the red knot. Throughout the animal kingdom, increasing pressures from industry are putting endangered species at risk. Habitat destruction is the largest driver of biodiversity loss globally. Roughly a million of the Earth’s estimated 8 million species are threatened with extinction in the coming decades. Species such as the red knot, which annually undertakes an extraordinary migration that tests the limits of their endurance, are at the leading edge of this biodiversity crisis. But if we cannot sustain the conditions that allow red knots to survive, other species will follow them on a downward spiral toward extinction as the ecosystems that sustain the web of life – including, ultimately, us – continue to unravel. Protecting the diverse range of species and the habitat on which they rely is more important than ever.

While it ultimately listened to public pressure for 2023, the Atlantic States Marine Fisheries Commission (ASMFC) advanced its proposal without transparency around the computer model upon which it is built. The public did not have the opportunity to review the full model despite requests from New Jersey Audubon, Defenders of Wildlife, and Earthjustice. The conservation groups have repeatedly raised the alarm on this proposal, since killing female crabs for use as fishing bait would only add to the problem of egg scarcity that is depleting the migratory stopover.

It is often easy for government agencies to make decisions that favor industry at the expense of a vulnerable species — and to do so without properly informing the public. As these losses continue to mount globally, we are now faced with a biodiversity crisis as epic in scale as the red knot’s migration. While the commission did not authorize a harvest of female crabs in 2023, it did approve the underlying computer model, which means that the possibility of a female harvest will arise again in future years. It is up to all of us to continue to shine a light on what this would do to both the horseshoe crab and red knot populations in Delaware Bay.

Species in our natural world are critically dependent on one another for survival. ASMFC cannot authorize a harvest of female horseshoe crabs in Delaware Bay without also harming the already threatened shorebird that has traveled halfway around the world to feast on its shores. The two are inextricably linked. It is one of the most incredible spectacles in the natural world — the spawning of hundreds of thousands of horseshoe crabs coinciding perfectly with the arrival of the red knots, providing the population the exact nourishment needed to continue their journey to the Arctic.

The Endangered Species Act entitles the threatened red knot to protections, which ASMFC must commit to upholding. Industry’s short-term interests and quests for profit must not determine whether our most vulnerable species are protected. Earthjustice and our partners will continue to use every legal tool available to protect our biodiversity, including the world-renowned Delaware Bay migratory stopover.

This blog was originally published in August 2022. It was most recently updated in November 2022.

Based in Maryland, Perry is the Public Affairs and Communications Strategist for the Rocky Mountain Office, Northern Rockies Office, and the Biodiversity Defense Program.

The Biodiversity Defense Program fights to reshape our relationship to lands, water, and wildlife everywhere by confronting the major drivers of the decline in nature, including habitat destruction and over-exploitation of wildlife.