The Horseshoe Crab Restoration Initiative
Was formed to protect, steadily increase and sustain horseshoe crab populations in Southern New England
Photo Credit: Paul R. Bartholomew, used with permission
Rhode Island Oceanographic’s Horseshoe Crab Restoration Initiative (HCRI) is a project that has far-reaching implications. The horseshoe crab populations of southern New England (and elsewhere around the world) are very much endangered having undergone serious declines over the past twenty-five years. The scientific data collected over this time relates the declines to over-harvesting of horseshoe crabs for use as whelk and eel bait and for their coveted blue blood, which is used by the pharmaceutical industry. Declines in horseshoe crab populations have also been linked to the loss of critical horseshoe crab breeding and nursery habitats, pollution, and the effects of global warming.
The amazing and biomedically important properties of the blood of the horseshoe crab are highly valuable to the health and well-being of humanity. One component of the blood - known as LAL - is used by pharmaceutical companies to insure that the vaccines and medications that people take are free of harmful toxins and bacteria. As the demands for new medications and vaccines continues to increase the demand for LAL. This greatly increases the need to reverse this rapid decline in horseshoe crab populations and to begin to protect, steadily increase, and sustain horseshoe crab populations worldwide. In addition to LAL, scientists are continuing to study the blue blood of horseshoe crabs in order to determine if it has other biomedically-important compounds. However, if the declining trend in horseshoe crab populations is not reversed in this decade this important and mysterious creature - whose fossil lineage extends back over 400 million years - may become extinct.
HCRI is also very concerned about the damage already inflicted on the greater ecosystem in which the horseshoe crab is a major part of. Horseshoe crab eggs are a major source of food for trans-Arctic migratory shorebirds and play a large and important role in these birds’ ability to thrive and migrate. As horseshoe crab populations have dwindled, so have the populations of these birds, including the endangered Red Knot. Horseshoe crab eggs and young also serve as food for a number of marine invertebrate and vertebrate animals. Declines in horseshoe crab populations may seriously impact other species living within their ecosystems.
HCRI is executing a plan to rapidly and efficiently restore the population of horseshoe crabs along the Rhode Island Coastline over the next 3-5 years through an aggressive aquaculture and protected areas plan that will put an estimated 1 million horseshoe crabs back into the population in just a decade. We believe this population level will be able to be sufficient to fortify the long term survival of RI horseshoe crabs and rebalance the great ecosystem in which the horseshoe crab plays a major role in.
At ~ 450 million years old, the horseshoe crab is among the oldest living species on earth. Classified as a “living fossil” these mysterious and majestic creatures pre-date the dinosaurs by hundreds of millions of years yet they have somehow eluded extinction. Over the last 100 years or so, horseshoe crabs have proven to be critically important not only of coastal marine ecosystems but also to human health!
Horseshoe Crab Fossil, Yale Peabody Museum Collection. Photo Credit: Timothy Fadek (Used with Permission)
Horseshoe crabs eggs are eaten by transarctic migratory shorebirds, like the endangered red knot. Every spring these birds arrive along the Atlantic coast and feed upon the densely caloric horseshoe crab eggs, providing them with the nutrition needed for their long flight to the Arctic. Unfortunately, many coastal areas where horseshoe crabs once nested have been lost to overdevelopment, climate change impacts, and pollution.
Photo Credit: Paul R. Bartholomew (Used with Permission)
The American eel and whelk fisheries depend on horseshoe crabs for bait. In fact, bait harvest of horseshoe crabs has ranged from 500,000 to over 2.5 million over the last 25 years. The value of both fisheries is increasing which puts more demand on the horseshoe crab bait industry.
(Graph taken from the Atlantic States Marine Fisheries Commission 2019 Horseshoe Crab Benchmark Stock Assessment and Peer Review Report)
The blue blood of the horseshoe crab is an extremely complex and valuable resource. It contains unique antiviral and antibacterial properties which cannot easily be recreated in a lab. To get the blood, horseshoe crabs are collected, brought to specialized facilities, and bled. This has been going on for over 50 years and the demand continues to increase - especially with the development of the COVID-19 vaccines and therapeutics worldwide.
Photo Credit: Timothy Fadek (Used with Permission)
Scientists still study the amazing blood of the horseshoe crab in order to unlock its many medically-important secrets.
The problem, however, is horseshoe crab populations are decreasing and time is running out to save them. The fishing industry, the medical industry and coastal development have mounted a challenge that even the horseshoe crab, after existing for over 400 million years, may not be able to conquer. The populations of the four living horseshoe crabs across the globe are severely challenged and the once largest populations on the planet in the Northeastern United States are now endangered.
Adult Horseshoe Crab and trail .Photo Credit: M C Cuomo (used with Permission)
What can be done to save the species?
The Horseshoe Crab Restoration Initiative - Rhode Island Oceanographic’s inaugural initiative - is moving swiftly to protect and foster a restoration of the horseshoe crab population and its ecosystems before it’s too late.
How do we balance the needs of the industries that rely on horseshoe crabs, coastal development, and human health with the need to conserve the horseshoe crab and the organisms that rely on it for generations to come? This question requires answers and the mission of the Horseshoe Crab Restoration Initiative is to provide these answers, raise public awareness, and develop and implement creative measures to restore the horseshoe crab populations of the greater Northeastern coastal waters of the United States.
Working with the scientific and academic communities, industry partners, legislators, government agencies, and the general public, the HCRI is actively engaged in horseshoe crab husbandry, aquaculture, and research, identification and preservation of critical horseshoe crab habitats, development and testing of effective artificial baits for use in the whelk and eel fisheries, and creating educational materials for use in both traditional and non-traditional settings.
How can you help?
Become a supporter of RIO and HCRI.
Together we can help horseshoe crabs and all those that rely on them thrive!
Horseshoe crabs moving onshore during spring breeding. Photo Credit: M. C. Cuomo (Used with Permission)
Active HCRI Projects
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Horseshoe Crab Aquaculture
Successfully breeding horseshoe crabs and raising larvae and juveniles to supplement natural stocks (Photo Credit: Paul R. Bartholomew,. Used with Permission)
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Protecting Critical Horseshoe Crab Habitats
Identifying critical horseshoe crab habitats and working to pass legislation to protect these sites. (Photo Credit: Paul R. Bartholomew. Used with Permission)
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Making Horseshoe Crab Industries Sustainable
Working to develop sustainable and novel practices for horseshoe crab-dependent businesses and industries (Photo Credit: Melissa Devine, The Secret Life of Whelks, RI Sea Grant)
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Education and Outreach
Creating Horseshoe Crab-based learning content for PreK-University students and the general public (Photo Credit: TImothy Fadek, Used with Permission)
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Horseshoe Crab Research
Supporting research into nutrition, genetics, biochemistry, ecology, paleoecology, and conservation of the horseshoe crab (Photo Credit: M.C. Cuomo, Used with Permission)
Horseshoe Crab Aquaculture
Photo Credit: M C Cuomo (Used with Permission)
Horseshoe Crab Breeding
In partnership with Limulus Ranch, LLC and the University of Rhode Island’s Graduate School of Oceanography, the HCRI is supporting the establishment of a horseshoe crab breeding and aquaculture facility. This facility is dedicated to insuring the successful captive breeding of adult Rhode Island horseshoe crabs and the culture of hatchlings through the first two years of life. Two year old horseshoe crabs will be released back into the coastal waters of Rhode Island in order to augment the natural populations.
Breeding pair of Horseshoe Crabs in Captivity, (Photo Credit: M. C. Cuomo. Used with Permission)
Horseshoe Crab Aquaculture
In partnership with Limulus Ranch, LLC, HCRI is supporting a horseshoe crab hatchery and grow-out facility. Using only sustainable designs and natural products, horseshoe crab larvae and hatchlings are being reared through the age of two when they are then transferred back into local coastal waters.
Three year old horseshoe crab raised in the lab. (Photo Credit: Timothy Fadek, Used with Permission)
Molt series of horseshoe crabs (Photo Credit: M.C.Cuomo, Used with Permission)
Two and four year old lab-raised Limulus (Photo Credit: Timothy Fadek, Used with Permission)
One year old lab-raised Limulus swimming (Photo Credit: Ernst , Used with Permission)
Early stage Limulus juveniles (Photo Credit: Paul R. Bartholomew, Used with Permission)
LImulus juveniles (Photo Credit: Paul R. Bartholomew, Used with Permission)
Two year old lab-reared horseshoe crab (Photo Credit: M.C. Cuomo, Used with Permission)
Close-up of one year old lab-reared Limulus (Photo Credit: Paul R. Bartholomew, Used with Permission)
One year old lab-reared Limulus walking in sediments (Photo Credit: M.C. Cuomo, Used with Permission)
Student intern counting larval horseshoe crabs (Photo Credit: M.C. Cuomo, Used with Permission)
Third post-hatch horseshoe crabs (Photo Credit: Paul R. Bartholomew, Used with Permission)
Protecting Critical Horseshoe Crab Habitats
Horseshoe crabs come ashore on the beaches of Rhode Island in Late Spring - Early Summer. Protecting these breeding beaches, as well as the environments where the juvenile horseshoe crabs live, is central to increasing the numbers of horseshoe crabs in the waters of Rhode Island.
Napatree Point Conservation Area, Photo Credit: Paul R. Bartholomew
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The HCRI, working with the RI DEM, is presently mapping both historical and present-day horseshoe crab breeding beaches in order to understand how much critical habitat has been lost over the past 60 years.
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Working with the RI DEM and Conservation Organizations, the HCRI will support efforts to identify and map important juvenile horseshoe crab habitats along the Rhode Island coast
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HCRI is working with federal, state, and municipal governments, scientists, and the public to establish protected areas for horseshoe crab populations in RI
Making Horseshoe Crab Industries More Sustainable
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Photo Credit: Charlene Sharpe
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The Bait Fishery
HCRI, in partnership with the scientific community, the artificial bait industry and the horseshoe crab fishing community, is supporting the development and testing of artificial baits for the whelk and eel fisheries. Such bait will reduce and, ultimately eliminate, the need to use horseshoe crabs as bait. (Photo Credit: Thomas F. Angell, RI DEM, Used with Permission)
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The Bleeding Industry
At present, the standard bleeding protocols for horseshoe crabs in the LAL industry is to simply drain the blood from a horseshoe crab until it stops bleeding. The HCRI wants to change that and supports the development of scientifically sound and measured bleeding of individual horseshoe crabs. Such practices will reduce the mortality and other detrimental effects of bleeding upon horseshoe crabs. (Photo Credit: Timothy Fadek Used with Permission)
Education and Outreach
Change starts with Awareness and Awareness starts with Education.
The HCRI is committed to increasing understanding of and appreciation
for the amazing horseshoe crab and the important roles it plays in both
human and ecosystem health.
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RIO, working in partnership with local schools and school districts, seeks to develop age-appropriate hands-on science content based on the horseshoe crab that will be made available for educators in Pre-K-12 settings.
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RIO, working in partnership with URI and other RI institutions of higher learning, seeks to support college interns and graduate student working on specific research projects tied to the horseshoe crab populations of Rhode Island and consistent with the HCRI’s mission..
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RIO, working with local conservation groups and government partners, will prepare and disseminate information and activities that can be used to raise awareness of the importance of the horseshoe crab in Rhode Island.
The Horseshoe Crab hatchery and rearing facility. Photo Credit: M.C. Cuomo, Used with Permission
Horseshoe Crab Research
The HCRI is supporting basic research on the Rhode Island horseshoe crab populations. Working with state and federal agencies, academic and industry partners, and conservation organizations, HCRI is committed to: gaining insights into the ecology, genetics, developmental biology, biood biochemistry, evolution, and environmental geochemistry of RI horseshoe crab populations relative to populations throughout the greater New England and Mid-Atlantic states.
Photo Credit: Paul .R. Bartholomew, Used with Permission
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Genetics
HCRI seeks to understand the genetic relationship among horseshoe crab populations throughout Rhode Island and the greater New England and Mid-Atlantic States regions. (Photo Credit: Paul R. Bartholomew, Used with Permission)
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Habitat Geochemistry
HCRI seeks to understand the geochemical factors that influence breeding beach selection and juvenile habitat selection by horseshoe crabs along the RI shoreline. (Photo Credit: M.C. Cuomo, Used with Permission)
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Blood Biochemistry
HCRI seeks to more fully understand the relationship between growth stage, nutrition, and the composition of Horseshoe Crab blood, particularly Limulus Amoebocyte Lysate. (Photo Credit: Timothy Fadek, Used with Permission)
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Paleoecology
HCRI seeks to more fully understand the paleoecological history of Horseshoe Crabs in order to better understand how these amazing animals have survived for ~ 450 million years. (Photo Credit: M.C. Cuomo, Used with Permission)
The Story of the Blue Blood
Horseshoe crab blood is different than human blood. The protein that transports oxygen in human blood is hemoglobin - it contains iron, which is what gives human blood its red color. Horseshoe crab blood is blue as you can see in the photograph. The protein that carries oxygen in horseshoe crab blood is hemocyanin and contains copper, rather than iron, and is blue in color, as a result. The blue blood cells that transport oxygen are called cyanocytes.
Just like human blood, the blood of horseshoe crabs contain more than simply oxygen-carrying cells. The disease-fighting cells of the horseshoe crab are called amoebocytes. These special cells release a substance called coagulogen whenever a crab is wounded.
Coagulogen causes the blood to clot when it encounters a wound or a bacterial toxin and stops it from spreading in the horseshoe crab. In the late 1950’s-early 1960’s, Dr. Frederick Bang and Dr. Jack Levin realized that coagulogen could be used biomedically to detect bacterial infections in humans, including meningitis. They developed the extremely sensitive Limulus Amoebocyte Lysate (LAL) test which, at present, remains the world-wide standard for testing for the presence of harmful bacteria in humans and in the manufacturing of all pharmaceuticals and biologics as well as in anything that will ultimately be implanted in humans and other organisms.
Horseshoe crab blood is also used in to diagnose a variety of fungal infections in humans and is being investigated for other medical applications including the development of novel anti-cancer and anti-HIV drugs.
Most recently, LAL has been used by in the development and production of the majority of the world’s vaccines against COVID-19 and its variants. So…if you have received a vaccine recently, you might want to thank a horseshoe crab.
COVID-19 Vaccines. Photo Credit: Dado Ruvik, taken May 2, 2021, Reuters)
How is LAL made?
Horseshoe crabs are captured and blood is collected from them and centrifuged, which concentrates the amoebocytes
Water is added to the amoebocyte concentrate which causes them to rupture, releasing the coagulation proteins (“the lysate”)
Over 600,000 North American horseshoe crabs are captured and bled to meet the annual LAL demand; the Asian species are also captured and bled
At present, LAL is the standard screening test for bacterial contamination worldwide – over 80 million tests are performed each year.
The number of horseshoe crabs needed to meet the worldwide demand for LAL over the coming decades is expected to continue to increase despite the recent creation of a synthetic alternative to LAL.