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May 19, 2018
NEWSLETTER OF THE PARTNERSHIP FOR THE DELAWARE ESTUARY: A NATIONAL ESTUARY PROGRAM
V O L U M E 1 6 T I S S U E 3 T S P R I N G 2 0 0 6
very summer, while vacationingwith my family at the Jerseyshore, a lone horseshoe crabseems to make an appearanceon the beach. The arrival of this
visitor is always announced by childrenscreaming What is that thing? andDont touch it because it bites. Much tothe chagrin of my own kids, I always wel-come the opportunity to scoop up these
lonely horseshoe crabs, dispel all themyths surrounding them, and to share alltheir wonders.
When I think about what sets apart theDelaware Estuary from other estuariesacross the country, and even around theworld, it is undoubtedly its population ofspawning horseshoe crabs the largest
By Kathy Klein, Executive Director, Partnership for the Delaware Estuary
Unfortunately, the management issues surrounding horseshoe crabs are not exactly blackand white.
Coast Days Page 15Celebrating coastal marine environments inNew Jersey, Pennsylvania and Delaware
3 Species SpecificThe Horseshoe Crab: Not Just AnotherPretty Face
4 Estuary BasicsUnderstanding Horseshoe Crab SpawningActivity
6 PerspectivesThe Uncertain Fate of Delaware BayShorebirds
8 TidingsProtecting Horseshoe Crab and HumanHealth
10 Making WavesCommunities Create Horseshoe CrabSanctuaries
12 News You Can UsePlan2Fund: A Development Directors NewBest Friend
For Teachers: Steamboat ExploresDelaware River History and Ecology
13 Estuary TriviaHave You Hugged a Horseshoe CrabToday?
14 Estuary Events
In this Issue
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Meetings of the Estuarys Implementation Teams and Advisory Committees occur on a regular basis and are open to the public. Formeeting dates and times, please contact the individuals listed below:
Estuary Implementation CommitteeKathy Klein, Executive Director (Chair)(800) 445-4935, ext. [email protected]
Monitoring Advisory CommitteeEdward Santoro, Monitoring Coordinator(609) 883-9500, ext. [email protected]
Toxic Advisory CommitteeThomas Fikslin, Branch Head(609) 883-9500, ext. [email protected]
Polychlorinated BiphenylsImplementation Advisory CommitteePamela Bush, esq. (609) 883-9500, ext. [email protected]
Fish Consumption Advisory TeamThomas Fikslin, Branch Head(609) 883-9500, ext. [email protected]
Science CoordinationDanielle Kreeger, Estuary Science Director(800) 445-4935, ext. [email protected]
Habitat Restoration CoordinationKellie Westervelt, Restoration Director(800) 445-4935, ext. [email protected]
Delaware Estuary EducationNetworkLisa Wool, Program Director(800) 445-4935, ext. [email protected]
MEETINGS CONTACT LIST
on Earth. This truly amazing animal, which is more closelyrelated to spiders and scorpions than to crustaceans, hasbeen around for over 250 million years. It is mind bog-gling to think how this gentle creature has evolved tosuccessfully survive, especially when you consider allthe other species that have disappeared over thesame period of time.
The best time of year to get up-close and personal with ahorseshoe crab in the Delaware Bay is during the hightides of May and June. This is especially true near the newand full moons, when daily tides are at the highest. This iswhen adult horseshoe crabs journey from the depths of theAtlantic Ocean to Delaware Bay beaches to spawn.
At the same time that horseshoe crabs are coming ashore to laytheir eggs, hundreds of thousands of shorebirds are travelingnorthward from South American en route to their summer breed-ing grounds in the Arctic. Along the way, red knots, dunlins,
ruddy turnstones, sanderlings, semi-
of birds, stop off in the Delaware Bayto feast upon horseshoe crab eggs.Each bird literally eats thousands ofeggs each day during its brief visit toour neck of the woods. These eggs
provide the energy these shorebirdsneed to complete their migration to the
The population of horseshoe crabs in the bay,their relationship with migrating shorebirds, and their
value to both the fishing and pharmaceutical indus-tries has, in recent years, resulted in an ongoingdebate on how this living resource should be man-aged. I invite you to read through this issue ofEstuary News to learn about this amazing creaturespast, present, and future, and to uncover some of its
mysteries. I guarantee that thenext time you see a horseshoecrab, you too will feel someaffection toward this green, hard-shelled warrior of the sea.
Signature Species continued from page 1
The best time of year to get up-close and personalwith a horseshoe crab in the Delaware Bay is duringthe high tides of May and June.
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palmated sandpipers, and other species
3E S T U A RY N E W S T S P R I N G 2 0 0 6
e all have a love-haterelationship with thepharmaceutical industry.We love the drugs that
save our lives but hate those bills at thepharmacy. Few of us realize, however, thatthe safety and purity of this industrys prod-ucts are dependent upon the lowly horse-shoe crab. Even fewer know that our forefa-thers learned from Native Americans thatthe horseshoe crab was the original slowrelease fertilizer. American Indians, likesome Asian cultures, also ate the largearthropod, and for decades, farmersthroughout the Delmarva Peninsula caughtand fed the crabs to their chickens andpigs. In fact, millions wereharvested for suchuses up until thelate 1800s.
Whilehorseshoecrabs have beenvalued and used for onepurpose or another fordecades, it has onlybeen relatively recentlythat scientists have rec-ognized their ecologi-cal importance.Horseshoe crabs are now referred to as akeystone species, or one that holds thekey to success for other bay species, like
juvenile fishes or visiting shorebirds. In addi-tion, the use of the crabs blood supports amulti-billion dollar, international pharmaceu-tical industry that we all depend on for ourquality of life or even life itself but I amgetting ahead of the story.
The horseshoe crab is revered for its manydistinctive features. For example, it has 10eyes, two of which are located on theunderside of the crab and are possiblyused for orientation while traveling throughthe water. To propel itself, the crab alsouses its branchial "legs," or book gills,which resemble the book lungs of primitive
arachnids. These function similarto the gills of a fish and
allow the crab to"breathe." Its six
pairs of ambu-latory legsalso allow itwalk acrossthe seafloor as itfeeds on var-
ious bottom-dwelling inver-
tebrates, suchas clams, poly-
chaete worms andsmall crustaceans.
These unique charac-teristics may have con-tributed to the animalgroups survival of a
mass extinction in the Permian Period thatkilled half of all wildlife, including thedinosaurs, and 95 percent of all marine
species. Since that time, numerous post-Paleozoic life forms have learned todepend on the horseshoe crab and itseggs to survive. These include: shorebirds,finfish, sea turtles, snails, oysters and manymore.
It All Starts With a Green EggAdult horseshoe crabs come ashore in thegreatest numbers during May and June tobury thousands of little green eggs onDelaware Bay beaches. The best placesfor observing this phenomenon in Delawareare Pickering, Bigstone and SlaughterBeaches, and in New Jersey, the beachesat Norburys Landing and Villas, as well asat the South Cape Shore Lab belonging toRutgers. Their numbers peak on the highesttides, or the tides of new and full moons,and they prefer the night tides, when preda-tory shorebirds are resting. Each female,along with a male hooked on, digs aseries of nests while laying several thou-sand eggs. These are then fertilized bymale horseshoe crabs.
The eggs are deposited five to seveninches deep in the sand and hatch weekslater. The precocious larvae both swim andcrawl for their first few weeks before settlingdown for a benthic life, plowing through thesand and mud while searching for wormsand clams. Like all arthropods, they mustmolt shells. Each young crab grows fromthree-sixteenths of an inch to more than nineinches for males and 12 inches for females,molting some 17 times over the 10 years orso it takes to reach sexual maturity. It isthought that horseshoe crabs live 20 years
By William Hall, Marine Education Specialist, University of Delaware Sea Grant
Horseshoe crabs have been harvest-ed for uses ranging from fertilizer tomedical testing, the latter of whichhas resulted in several Nobel Prizes.
THE HORSESHOE CRAB:
Not Just Another Pretty Face
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ate on a May evening, withthe moon nearly full, I stoodon the beach at Ted HarveyWildlife Area east of Dover,
Delaware, and listened to the hollowknocks of horseshoe crabs jostling forposition on the high tide. A stiff westerlywind did not bother the thousands ofcrabs because it was pushing wavesaway from the shore.
Watching this phenomenon, I could nothelp but wonder what w