20 years on Delaware Bay: Shorebird Need More Horseshoe Crabs



We Need More Horseshoe Crabs

The story of shorebirds on the Delaware Bay stopover this year boils down to the need for more horseshoe crabs. The population remains at only 1/3 of it’s carrying capacity, the maximum number the bay can naturally support.  There has been no sign of sustained recovery in the 15 years of a survey done by Virginia Tech and under the auspices of the Atlantic States Marine Fish Commission, the group that fell asleep at the wheel and allowing the population to be plundered.  There have been no signs of recovery for the red knot or any other shorebird whose population plummeted because of the collapse of the Delaware Bay stopover. Each year thousands of red knot leave poorly prepared for their flights to the Arctic, and we know for certain poorly prepared shorebirds either die or don’t reproduce. Finally, 2017 shows clearly that with any departure from ideal horseshoe crab spawning conditions, leaves most birds struggling to find enough eggs.  We need more crabs.


This graph from a report on the status of crabs done by Eric Hallerman and David Hata of Virginia Tech show the lack of any signs of recovery in the female horseshoe crab population of Delaware Bay since 2001


But how? Even if everyone agreed, which everyone does not, where would new crabs be found? To answer this, one must first look at the current losses.

At this time there are three main consumers of horseshoe crabs or their habitat.  The welk and eel bait industry gobbles up the lion share at a quota of more than 600,000 each year, although the actual kill has gone down over the last few years.  The medical industry bleeds over 600,000, probably kills about a third, and almost certainly diminishes reproduction of the other 400,000 because they bleed only females.  The aquaculture industry expanded their reach and area over the last two years taking more than a half mile of prime crab spawning habitat.  This too must be reckoned in the cost.



Three industries make money from horseshoe crabs. The medical industry takes lysate from the blood of crabs, raking in enormous income, none going to the conservation of the crabs or the people living in Delaware Bay.  They have the most impact because they bleed only females which have not increased in the 15 years history of regulating the bait industry. Lysate breeders refuse to make public the data on their harvest, including how many they kill.  The bait industry is more closely watched and regulated even though most restrictions have been evaded.  Largely the market for bait controls the take through legal or illegal methods.  The newest industry is oyster aquaculture.  They leased every horseshoe crab habitat on the NJ side of the Delaware Bay for metal rack aquaculture without any environmental review, sneaking the regulation into  Hurrican Sandy regulations.  The oyster aquaculture industry ruins horseshoe crab breeding habitat through industrial level ATV use on the intertidal flats used by crabs to feed and impeding crabs from easily reaching the shoreline to breed.  Agencies only require that each industry assesses their impact without accounting for all impacts together. A clever and effective way to avoid the purpose of the regulations, to recover horseshoe crabs to pre-overharvest levels.



How to Get Away with Destroying a Valuable Natural Resource

Agencies regulate each of the three industries killing crabs.  Unfortunately, they usually ask the wrong question. Instead of asking how many horseshoe crabs are needed to recover the population or the shorebird stopover, and how each industry hurts this recovery, instead, they ask how many can each business take without an impact. It like that game where you remove blocks from a structure of blocks, the loser pulling out the one that causes the structure to collapse.  In the same way, the agencies make educated guesses on the numbers of horseshoe crabs that can be safely removed.   Usually, these numbers are based on “best available science” which because of statistical uncertainty, allows the industries to force regulators to err on the high side.  Not one of them dares to add up the ecological cost of all three.  No one tries to predict when the structure will collapse.

The 2017 season on Delaware Bay points to the folly of this approach.  This year we had the unfortunate concurrence of several important influences on tidal range.  First was the new moon tide, raising water levels to a lofty peak of over 8 ft,  a rare tide indeed.  Then we had easterly winds that blew into the mouth of the bay holding the outgoing tide and assisting the incoming. The consequent coastal flooding allowed crabs to breed high on the beaches.

Then the benign winds turned deadly.  The easterlies turned westerly which piles water into breaking waves so high on the beach that they pushed crabs deep into the marsh behind the sandy beaches.  Our team, Return a Favor Volunteers and others rescued many but most would die a slow death of asphyxiation.

No Agency will take this loss of tens of thousands of horseshoe crabs into account in their assessment of impact by the industries.  It could be the block that collapses the population, but none of the other killers of crabs, the bait harvest, the lysate blood harvest, the aquaculture habitat loss will compensate for this unfortunate but natural loss.  No one is even adding them up into one loss.   This is how a natural resource is destroyed.


Thousands of horseshoe crab died because of a combination of a spring new moon tide, and easterly wind lifting waters to rarely seen high tide levels. Unfortunately for breeding horseshoe crabs, the benign easterlies suddenly shifted from the west, pushing water into breaking waves that lifted crabs over the upper beach berm and into the back marsh. With no escape, most died of slow affixation. Fortunately many volunteers of the Return a Favor Coalition braved difficult conditions to rescue many thousands of crabs. The coalition includes Wetlands Inst., Bayshore Discovery, American Littoral Society, Delaware River Keepers, Citizens United, and others. . 

The NJ Shorebird Team developed a daisy chain to rescue the nearly 5000 crabs stranded behind the dune at South Reeds Beach.  


Better Questions

Why not ask the bait industry to deduct these extraordinary natural losses from their own kill? Or force the lysate industry to stop their wholly preventable losses with better handling and less overbleeding?  Or ask the aquaculture industry to help restore habitat in compensation for the beaches no longer useful to breeding crabs?

Imagine a farmer who doesn’t replant his crops after a harvest or a forester who refuses to transplant seedlings after cutting a forest. The people killing crabs do nothing to help replenish crabs or improve their habitat.

Why not ask the larger question?  Why are those making money from the resource not required to pay the costs of offsetting the loss they cause? Imagine a farmer who doesn’t replant his crops after a harvest or a forester who refuses to transplant seedlings after cutting a forest.  The people killing crabs do nothing to help replenish crabs or improve their habitat.  Ironically the agencies don’t mind asking the economically challenged communities of Delaware Bay to pay the ultimate cost of the damage to crabs and birds. They force them into a bewildering maze of restrictive and costly regulations that obstruct even the simplest infrastructure projects like beach replenishment, sewage treatment plants or coastal bulkheading.

Why? The answer is simple political mathematics, the politician’s support industry who support the politicians.  Neither support rural communities.

The power relationship between the three industries speaks to this corrupting influence prevalent in conservation today.  If one were to rank the impacts of the three industries, first would be the medical industry’s wanton and unnecessary killing of female crabs and their insistence that all but a few compliant regulators know the truth of their damage.  The second most threatening use is the bait industry who now kill the most crabs and God knows how many go unreported.  Finally the aquaculture industry, who is permanently destroying egg laying beaches and compacting inter tidal flats.    If you look at the regulation of each, it falls the opposite way, the most regulated is the relatively small and new aquaculture industry and the well-established bait industry while the least regulated are the medical companies.

Guess who is the most powerful?


Making More Crabs

So how to make more crabs?  First we must force the medical companies to open up their bleeding process and let biologists see how many are killed from start to finish.  Then create a peer reviewed and publically visible process to gradually reduce numbers killed. Finally, create a best-management scheme that will gradually end the killing altogether.  Why kill the goose that lays the golden egg!

Second, the harvest of crabs for bait should end.  It is a waste of valuable animals important for humanity’s medical needs and other baits would suffice.  At the very least Maryland should stop pretending half their kill comes from some other horseshoe crab population ( of which there are none except Chincoteague Bay, which they protect from harvest) and reckon their full impact on the Delaware Bay population.  Then they should take part in the costly work to restore crab habitat since, in fact, they benefit the most from the harvest of both medical and bait crabs.  This irony, that the state that does the most damage, also does the least in mitigating the damage., seems to escape everyone in the regulating agencies.

Finally, the aquaculture industry must adopt practices that recognize the importance of crabs and crab spawning.  Currently, they are only being asked to mitigate impact to red knots, the agencies pretending this is a temporary impact and thus allows them to take over intertidal habitat and beach after the birds leave.  The crabs are what is important to the birds and the habitat on which they breed must be preserved or if not then replaced.  We can replace horsehose crab habitat successfully.



The American Litteral Society and Conserve Wildlife Fondation habe been very sucessful in restoring damage horseshoe crab breeding habitat. But money to restore habitat is hard to find and shold come from those making moneh on the killing of crabs.


The interested public can do more besides pressuring legislators to force better solutions.  They can take part in the rescue of crabs that are turned over naturally in high tide wave action.  The coalition of a group called ReTurn a Favor saved 73,000 crabs last year.  With the overwash tides of this year, they will no doubt save much more this year.  This practice of responding to extraordinary days should be expanded with increased funding to support those supporting the volunteers.  The state agencies could also support this effort with machines that could help the volunteers, four wheel drive trucks or front-end loaders in a key places.  Why can’t the industries who kill crabs pay for the rescue of crabs?


Horseshoe crabs naturally die in the process of spawning because the bay’s wind-driven waves upend them, leaving the stranded upside down on the low tide beach. Gulls attack them eating their gills and the eggs still lining the shell of the females. Most die before the next high tide can rescue them. The ReTurn a Favor Coalition of Bay conservation group fields teams to right them, saving 75,000 last year and very likely more this year.


The last solution is a simple one.  Estimate the total loss of crabs from natural sources, and remove them from the quota of crabs killed by the industries.  This would help force the industry to take part in conservation.

They could do much more however like creating better habitat for spawning.  In ten years this will be the best solution because by then the eggs produced would become adults.  Even in the short term, it brings crabs out of submarginal breeding habitats so they can breed in places where eggs will survive and hatch.  This will greatly increase the crab population in the long term.   One habitat solution that could work now is to survey all beaches for breaches that could lead to overwash kills.  Fixing them could be done at a reasonable cost.

But for now, we must stop the unnecessary killing of crabs and rescue those killed naturally.