Sandy Point: Getting Back to Sharing the Shore

 

by Beth Sullivan

American Oystercatchers 
Photo credit: Rick Newton

There is so much going on right now. There is so much beauty at this moment in time. Such life and rejuvenation, birth and growth, freedom and the ability to breathe more openly and hopefully.   I am quite sure that this spring seems extra special because of the year we have all been through.   We have holed up, curled in and in many cases, kept our heads down.   It is time now to grow outward and explore and remind ourselves how lucky we all are.

Nature has provided solace and sustenance for so many of us over the last year and a half.   It is time now to look at where we have been and see how we can restore and support some of our natural areas. To give back a bit.   As stewards we have begun getting back onto the preserves and working as teams, to maintain and monitor.  Over the summer we will make the rounds and I will report on what is happening.

Sandy Point: One Island, Two States

The first update is about Sandy Point Island: Avalonia’s gem of a wildlife refuge in Little Narragansett
Bay, between Stonington and Napatree Point in Rhode Island.  The history of the island and Avalonia’s ownership can be found in earlier blogs and on our website.  Its primary purpose is as a nature preserve.  It is acres and miles of shifting sand and beach grasses and shrubs. The island itself has shifted dramatically over the decades, a fact which can be seen easily on a series of aerial maps and Google Earth.   But even with the movements of the land over time, the island has remained a historical nesting and refuge area for a wide variety of very special species.

If you find a tagged horseshoe crab,
take a photo and report it
Photo Credit: Beth Sullivan

The most ancient of these species is the horseshoe crab: Limulus polyphemus.  These relics of the dinosaur era return to the same areas of sand at the edges of the oceans around the world, somehow following some magnetic compass in their own bodies, to come ashore during the full and new moons of May and June at the high tides, to mate and lay their eggs.  For almost a decade, Avalonia volunteers made multiple trips each season, usually at night and by kayak, out to the island to count and tag the horseshoe crabs. This was part of Project Limulus, a study conducted by Sacred Heart University. The tagging part of the project is completed, different parts of the study continue, and the crabs continue to return to the sandy island each late spring into summer.  If you find a tagged horseshoe crab, take a photo of the information on the tag, and report it on the website link below.   

https://www.sacredheart.edu/academics/colleges--schools/college-of-arts--sciences/departments/biology/project-limulus/

 

Piping Plovers
Photo Credit: Rick Newton

The island is also an important nesting site for several threatened or endangered species of birds.  Piping plovers, American oystercatchers and least terns make their homes and raise their young on this strip of sandy island.   All these species make very simple scrape nests on the sand, amid the pebbles and shells on the beach. They are very vulnerable to all kinds of dangers. High storm tides can wash the nests away, there are predators that target the eggs and the young, including the gulls that also nest there, and crows.   Sadly, some of the worst disruption is human caused.    The island is much loved by many people for its beauty, beaches, and wildlife.   But people and wildlife do not always mix well.   Our simple presence near a nest can cause a parent to abandon the nest or eggs.  People can inadvertently step on, or land their boat on, a nest or eggs.    When the chicks hatch, they can run but they cannot fly so they must get to the water’s edge to feed by finding their way through whatever obstacles there may be on the shore. On busy summer weekends, that can be people, blankets, chairs, kids and coolers.  Dogs are not allowed on the island at all, even on leash, because their mere presence terrorizes the birds.

They have a narrow window of time, when they nest, incubate their eggs then have the young wandering around like toddlers; vulnerable to all sorts of dangers and hard to control!

Signage is provided for all visitors
Photo credit: Beth Sullivan

The US Fish and Wildlife Service has provided an amazing partnership with Avalonia to monitor the
wildlife, provide fencing to help remind visitors to avoid nesting sites, create educational signage and offer trained biologists to be on the island to teach visitors about the importance of the habitat.   For permits and passes which are required, please visit https://rhodeislandpermits.recaccess.com/

We are at the Solstice.  The longest days of the most lovely of seasons. We all want to enjoy our new freedom to get back out in nature with our friends. Please remember that wildlife on all our preserves, needs to be protected. At Sandy Point the protection is critical to the survival of 3 species. Please help us, and the wildlife, by observing the guidelines and looking out for and enjoying the other beings that use the island.

 

USFWS biologists monitor the nesting sites
and roped off areas.
Photo credit: Rick Newton

All creatures seem to be drawn to the 
gentle, shifting shoreline of Sandy Point.
Photo credit: Beth Sullivan

When young shorebirds need to run to the
water, they can encounter many obstacles.
Photo credit: Beth Sullivan

 

 

The Horseshoe crab, a living fossil

By Rick Newton

On the list of the Nature Conservancy’s top migrations is that of the horseshoe crab (Limulus polyphemus). It is truly a wonder to experience. Horseshoe crabs are called a living fossil; they have been around for over 350 million years virtually unchanged. It is not really a crab as it is associated more closely with spiders and scorpions. Worldwide there are four species of horseshoe crabs but only one in the United States on the east coast.

In late spring and early summer, mainly around the times of full and new moons and on the hide tide cycle, horseshoe crabs migrate from their wintering grounds to local beaches to lay their eggs. The female crab, usually with a male crab grasping on to the female’s shell with a pair of modified legs resembling boxing gloves, buries herself into the sand laying a cluster of around 4,000 eggs. Over several nights the female may lay as many as 100,000 eggs. About a month later, the eggs will hatch, and tiny horseshoe crabs will spend the first few years of life on tidal flats and marshes.

Horseshoe crabs molt many times before reaching maturity. 

Because horseshoe crabs have a hard shell they must molt to grow. They will molt around six times in the first year and up to eighteen times before reaching sexual maturity. Once the crabs reach sexual maturity, which takes about nine or ten years, the molting stops. When the male crab completes its final molt, the front claws take the shape of boxing gloves that he uses to grab on to the female for spawning. A horseshoe crab's lifespan is believed to be 20 – 30 years.

Horseshoe crab bodies are composed of three parts: prosoma (head), opisthosoma (central area), and telson (tail). Horseshoe crabs cannot hurt you. Many people think the tail is some kind of stinger, but it is mainly for allowing crabs to flip themselves over should they get turned upside down. Horseshoe crabs have ten eyes, and much of the research on human vision has been accomplished using horseshoe crabs. Horseshoe crabs have book gills to get oxygen from the water and can live on land for up to four days if they get stranded. Their food consists of razor clams, soft-shelled clams, and marine worms.

Horseshoe crabs are important for a few reasons. First, shorebirds migrate from South America to the Artic. Most need to stop and rest and feed on their travels north to their summer breeding grounds. Their migration coincides with horseshoe crab spawning. Eggs that are exposed to air by wave or boat wake action or by the digging action of other crabs, quickly dry out and won’t hatch. But these eggs are the primary food source for the migrating birds allowing them to double their body weight in less than two weeks.

Not just a fossil

Second, horseshoe crab blood plays a vital role in human medicine. Their copper-based blood, which turns blue when exposed to oxygen, contains blood cells called amoebocytes. A testing reagent called LimulusAmoebocyte Lysate (LAL) is derived from the amoebocytes of the horseshoe crab. The LAL is used to test the sterility of vaccines, drugs, and other medical devices. However, recent biomedical developments have shown that a synthetic compound may be an alternative to using horseshoe crab blood, thus saving hundreds of thousands of crabs from being bled. You can learn more here.

Horseshoe crabs have few natural predators except for seagulls or raccoons that may feed on an overturned crab. Major threats are from harvesters (who sell crabs as bait for conch, whelk and eel), human disturbance, and loss of habitat due to beach development or shoreline modifications as communities harden the shoreline to deal with rising sea levels.

Avalonia’s Sandy Point Nature Preserve is one of the primary spawning areas for horseshoe crabs with hundreds of crabs coming to the beach on peak cycles. Volunteers from Avalonia, Mystic Aquarium, and others support Project Limulus (Sacred Heart University & USFWS) in southeastern Connecticut. These volunteers are citizen scientists counting, measuring, and tagging horseshoe crabs during the early spring and summer.

Be a citizen scientist

Anyone can help by just walking the beaches and looking for tagged crabs. If you see a tag on a dead crab, remove the tag and report the tag number, date, time and location to the number on the tag, or provide this information via the internet at: http://www.fws.gov/crabtag/ If you see a tag on a live crab, just write down the tag number and report it as above, leaving the tag on the crab. If you see any crab upside down, just flip it over by grasping it by the side of the shell (not the tail).

If you see a flipped Horseshoe crab on the beach.

Give it a hand and turn it over by its shell.

Tagged horseshoe crabs – Groton / Stonington area – 2009 to 2017

Note: some of the decline in tagged crabs is due to budget reductions to the USFWS with fewer tags being distributed. In general, however, volunteers are seeing fewer crabs each year.

You can read more about Horseshoe crabs in   The Underwater Secrets of Horseshoe Crabs, here.

photographs by Rick Newton

Horseshoe crab season 2017

By Beth Sullivan

There are some things you can rely on, events that happen at a certain time, under certain conditions, every single year. Some for hundreds or thousands and even millions of years.

One such occurrence is the arrival of the Horseshoe crabs along the sandy shores here, in the places we humans now call home. For millions of years, these ancient species have been pulled by the tides and phases of the moon, to seek mates and find their way to the safe coastal areas for spawning.

Certainly the shoreline has changed over that time. Sandy beaches have eroded, disappeared, and reappeared in new areas. Barrier beaches have been washed away, and islands have moved, literally. And new islands and sandbars have appeared in shallows along the edge of the sea. But what has not changed is the cycling of the moon, its constant pulling on the waters of the Earth, and the effect it has on the Horseshoe crabs which, as a species, has remained almost unchanged for many millions of years.

Gently sloping beaches and low surf areas are ideal for Horseshoe Crab nests.

Sandy Point has drifted over centuries, but continues to offer sanding nesting areas for Horseshoe Crabs

So, when we head out to Sandy Point and other local beaches to find and tag the Horseshoe crabs, we always anticipate that some things will not have changed.

Unusual year

This year was just an odd year for lots of reasons. The weather did not cooperate around the times of the full moon and new moon in May. Those are the times when the tides are most extreme and best for nesting crabs. It is not just that we humans don’t like going out in windy wet weather, but the crabs do not like it either. They do not like to come ashore when the surf is rough. A lot of freshwater-rain runoff into their favored nesting sites will also keep them away. So May really was a wash-out. I don’t know where they went, but they were not at all the places I expected them to be.

Too much surf can flip a crab or pair of crabs and expose them to predation.

The early full moon in June really wasn’t much better for conditions, but we paddled out to Sandy Point and cruised along the shore. In past years, the north side of the island would have been the most desirable stretch of sandy beach for nesting. We found a few pairs along that north shore, and a few more down toward the extreme eastern tip. But it was discouraging. We tagged about 15 that night, certainly not close to the dozens or hundreds of only a few years ago.

Each crab is assessed for size, condition, and gender. The tags are placed with a peg, into their shell, the carapace, in an area that will not impede their functioning. We make notations about certain physical characteristics including injuries or damage to shell, and also note all the “baggage” they carry: hitch-hikers that are mollusks of varying species and seaweeds. The tags bear a number that can then be tracked when they are recovered at a later date. When we look for crabs, we always note the “recaptures” and document their condition and tag number. It reveals interesting data.

Finding an old tag helps provide data on longevity and and travel patterns.

Once more we tried with the new moon phase at the end of June. Technically this should be the real high point. We have, in the past, counted over 1000 crabs jostling for space in the sand, jostling for mates, and jostling off competitors. But not this year.

End of June excitement

Three of us paddled out to the island. A bit of a wind and rolling waves made it interesting, but on the north side it was calm and quiet. We got caught in a sudden downpour but were rewarded by a spectacular rainbow and beautiful sunset. We noted more pairs of crabs, making their way to shore. Large females followed closely by their smaller mates.

The crabs often carry a lot of marine baggage. 

Tagged crabs are inspected closely for damage and condition. 

We were only allotted 50 tags for the whole season out on Sandy Point, and we used them up by the time we got to the eastern tip. And then the action started. Around the tip and out to the south side where the surf was a little rougher, we began to count more and more crabs. Singles, pairs, triples and even a few quads-one female with multiple males. We found several with older tags, and later investigation showed that some of them had been tagged more than three years ago, a couple right there on the island.

As we walked we counted: more than 100 more crabs, all participating in that ancient ritual, on that particular night. It was a far cry from that year of more than 1000. Something has changed. But for a smaller population, the moon still pulls them to this island. And something pulls us out to share in that ritual.

The adventure provides rainbows, sunsets and moon rise views.

Whatever pulls the crabs to Sandy Point, pulls us as well.

Photographs by Mike Charnetski, Rick Newton, and Beth Sullivan.

Moonlight

By Beth Sullivan

What is it about moonlight that tugs at tides and hearts and horseshoe crabs?

The full moon has pulled at the Earth’s waters since the beginning of time. Creatures living in the ocean most certainly have responded and adapted to those tugs. People living near the sea are finely tuned into the changes in the tides. They know without consulting charts and apps when the tides will be full and what phase the moon is in.

Sunset from the island. Photograph by Mark Hibbard.

This past weekend the moon and sun and tides were in a unique situation, coming together in a way that doesn’t happen often. Monday was the Summer Solstice, the longest day of the year. As the sun set beautifully in the West, a turn of the head revealed the huge Full Strawberry Moon rising in the East, within minutes. The tide was rising to full, and the Horseshoe crabs were following their ancient instincts to seek sandy shallows to mate and lay eggs.

All efforts are made to tag and measure the crabs while they remain close together. Photograph by Mark Hibbard.

A few of us were lucky enough to be out during this cycle and appreciate the beauty and mystery of the ritual that has gone on for millions of years. As long as there has been a spit of sand that is Napatree Point, which gave birth to Sandy Point, the crabs have sought out this protected place.

Project Limulus

In an effort to understand the life cycles, needs and drastic decline of the horseshoe crab population, Project Limulus has been studying these creatures by supporting teams which scout the shoreline along Long Island Sound to observe, count and tag the crabs. Volunteers are taught to measure and assess the condition of each crab encountered. Tags are to be placed in a specific area on the shell. On this night we were treated to a motorized ride out to the eastern end of the island. We usually paddle out, which certainly is fun, but this was a luxury. It was calm and beautiful.

Usually there is the greatest “action” on the protected north shore of Sandy Point. The crabs seem to seek out the quieter waters and gently sloping beach to make their nests. There were not many to be found. We did however get to observe two Piping Plovers which have protected exclosures over their nests. We also were met by the loud cries of several families of American Oystercatchers which are having a great success out there this year.

The Oystercatchers greeted us with lots of noise. Photograph by Rick Newton.

The Piping Plivers still struggle to nest successfully on Sandy Point. Photograph by Victoria Limi.

At the far east end, we were beginning to be discouraged, all that walking and effort for virtually no crabs. However, as we rounded the point and headed along the south shore, the current increased; there was more wave action, and hundreds of crabs.

Horseshoe Crabs on the beach

As far as we could see down the beach there were mounds at the waterline, each indicating a nesting pair. As we walked toward the first, we could see even more off shore, some already dug into the sand, in a couple of feet of water, others moving toward shore. There were many “piles” with one large female surrounded by as many as 4 smaller males, jockeying for the best positions.

Larger females are often joined by several smaller males as she digs a nest. Photograph by Tom Frohnapfelw.

The males usually try to connect with a female farther off shore and they will land together so that as she digs into a nest in the sand, he will be in the best position to fertilize her eggs as she lays them.

On this night, the crabs didn't seem to mind the waves. Photograph by Rick Newton.

We only had 100 tags to use. We used them all in a relatively short time, and there were still more crabs coming into the shore. We were tired; it takes a bit of muscle to manage the crabs, tools and equipment while bending into the water. It was getting late, and the tide was turning. We left the rest of them to nest in peace.

Moonlight gave us a bright glow to make our way back in the night.

The Strawberry moon rose over Watch Hill. Photograph by Ingrid Fedderson.

Sunset, Full moon and the tides tug on more than just the horseshoe crabs.

A Season of Changes on Sandy Point

By Beth Sullivan

It seems like summer just began. We were just waiting for the Plovers and Horseshoe crabs to arrive on Sandy Point. And now they are ready to leave!

It was an interesting season on Sandy Point. It was the first summer that the US Fish & Wildlife Service (USFWS) was formally able to become the keepers of the lovely Island. As a transition year the COMO continued to issue permits but no longer supplied stewards to collect daily fees and do periodic patrols. Instead, this year we had dedicated, environmentally educated, interns and stewards out on the island as time and funding allowed. Instead of merely collecting fees, they informed people about their purpose and presence.

USFWS has erected informational kiosks for to explain our goals for conservation.

Education is often the very best way to get cooperation. When they encountered a violation, a dog on the shore for example, these stewards were able to give a real reason WHY a dog is such danger to the nesting birds (real or perceived predator). They spent many hours early in the season putting up roping to delineate where the nesting birds had set up housekeeping. But the stewards, this year, could also explain WHY the protected area needed to go all the way down to the water. (Young birds need access to water’s edge for feeding before they can fly). Visitors who understand this may be more willing to set their umbrellas and blankets away from these areas.

We can all learn to share the island with the species that need our protection.

The pebbles, shells, and sand are all the birds need to build their nests.

Kiosks explain the rules

The USFWS also erected two informational kiosks with photos and graphics to illustrate our combined efforts for conservation on the island. Now if only everyone would read them. On several occasions we were out monitoring, only to find people set up with campfires and their dogs, right under the signs!

According to Ryan Kleinert, the USFWS Biologist leading the team out there, the State-listed American Oystercatchers did very well. We had 8 pairs arrive early, get down to business and fledged 13 chicks. The Piping Plovers had a harder time. Ten pairs arrived on the island, but their efforts were greatly impacted by Gulls that chose to move into their nesting areas and aggressively take over, and crows that were predators on eggs and young. Those 10 pairs attempted 14 nests, and only 1 Piping Plover chick survived to fledge. Next year the stewards will try a new tactic to protect nests and deter the predators.

American Oystercatchers forage along the beach. Photograph by Rick Newton.

The Piping Plovers were challenged this year by Gulls and Crows. Photograph by Victoria Limi, Plover Intern 2013 USFWS.

Horseshoe crabs tagged again

We tagged Horseshoe crabs again this year. The Project Limulus Study group had fewer tags to hand out; we only had 200 to use. We did tag that number, and we could have done more, but there were nowhere near as many Horseshoe crabs out there as in earlier years -another change. We did count recaptures, those that had tags on them from previous efforts. One female crab we encountered nesting was originally tagged in 2009! Reporting those tag numbers is still important data for collection.

The tagged Horseshoe crabs provide important data on the range and travels of the species. Photograph by Rick Newton.

While this was a year to educate, we can expect that there will be more enforcement of the rules next year. Wouldn’t it be wonderful if everyone who enjoys the island, was willing to take a bit more responsibility to obey the rules, think about the species that depend on this place for their survival and act as stewards as well?

There's no better place to be at sunset.

Even those Horseshoe crabs recognize Sandy Point as special place, to call home and are now further protected by new stewards from the Fish and Wildlife Service. Let’s hope all the rest of the visitors to our Island can offer the same protections to all the species that call it home.

Photographs by Beth Sullivan unless otherwise indicated.

A Mid Summer Report from Sandy Point

By Beth Sullivan

Sandy Point is Avalonia’s lovely little gem of an island, situated East of Stonington Point, South of Barn Island and North of Napatree Point. It is a spot treasured by many for the sandy beach, clear cool water, and peaceful surroundings, but also as a premier wildlife preserve. Situated partly in CT and mostly in RI, it poses a unique set of issues for stewardship and preservation.

Oystercathers nest on Sandy Point.

Sandy Point. One island, two states.

Shorebirds flock to Sandy Point

The real Sandy Point season begins with the arrival of the shorebirds. Some just stop over on their way farther north. Others, like the Piping Plovers and the American Oystercatchers, arrive to make their homes here. These birds are federally protected ,and this little island is known as one of the most successful breeding areas for the Oystercatchers. Unfortunately the gulls, especially the Black Backed Gulls, present some real difficulties with competition and predation. The US Fish & Wildlife Service has had a keen interest in the island for protection of the shorebirds here. Their stewards arrive on the island when the birds do, note where they are setting up their nests, and will place signs and roping around large areas to deter people from walking through and disturbing birds or destroying nests. Avalonia has an agreement with the Stonington COMO which issues passes for usage of the private island. This helps fund their stewards who go out several times a week to help monitor the beach, look for violations of the simple rules, and to educate the public about the significance of the nature preserve. Not everyone appreciates the efforts to protect the birds. Sadly, the stewards are often harassed. Some visitors to the island will deliberately flaunt their disrespect for the rules, let dogs run loose, and set up within the roped areas. How sad that in this day of enhanced understanding about the environment and our increased roles as defenders and protectors, some people just refuse to be compliant, or to care.

These signs help protect the nesting birds.

Piping Plovers

Horseshoe Crabs in decline?

Another wave of wildlife arrives in May. During the new moon and full moon high tide cycles, the ancient species of Horseshoe Crabs arrive offshore and prepare to make the island their breeding grounds. Last year we reported on several nights of adventure on the island, when teams of us paddled out and spent hours counting and tagging the crabs. Look here, and here and see a video here. We tagged nearly a thousand crabs in the area over last year's late spring and early summer, reporting our data back to the scientists at Project Limulus at Sacred Heart University. This year we have been discouraged. We are all trying to make excuses and wonder why there have been so few Horseshoe crabs , not only at Sandy Point, but also at local beaches and Bluff Point. We had far fewer tags available to us this year, and we actually had a hard time coming up with enough crabs to use them on. Admittedly we had several nights of bad weather, with storms or rain and wind that made the kayak trip impossible. We spent one long night out there in late June; we walked from one end to the other and back again, and we found only 137 new crabs plus about 20 that had been tagged in previous years. Where are they all? Are they nesting elsewhere? Did we miss a big night? Or are we experiencing a terrible population crash? Scientists from DEEP and Project Limulus are all concerned. We continue to make trips out and count. It is not as exciting as last year.

Please report any tagged crabs you may see.

Black-backed Gulls are a serious threat to the Horseshoe Crab.

Horseshoe Crab with a visible tag.

So the birds have had a decent year, with good numbers of Oystercatchers fledged. Piping Plovers are about average with other years. Horseshoe crab numbers are way down, and human numbers remain high. We are grateful for all those visitors to the island that enjoy and respect the nature there, who offer their own efforts at stewardship to encourage understanding by others. We thank those who make reports, pick up trash, and help with public education. Every eye and helping hand counts!

A breach for nature and people too.

Let’s see what the second half of the summer brings.

Photographs by Rick Newton.

Tagging the Horseshoe Crab

We have had two previous posts on Avalonia eTrails about tagging the horseshoe crabs that make their way to Sandy Point to spawn (here, and here). Now you can see the action yourself. The tags enable researchers with Project Limulus to study the ecology of Long Island Sound horseshoe crabs by tracking their movements. Nature videographer Gerry Krausse recorded a group of taggers at the end of June. He produced this short video documenting the evening:

(Direct link to video is here)

Digging deep to study the Horseshoe Crab

Over the past months, you may have followed discussions about our efforts to count and tag horseshoe crabs on several area beaches and Avalonia’s Sandy Point Island.

On Wednesday, July 17, Avalonia volunteer taggers Binti Ackley and Beth Sullivan were joined by Professors Jennifer Mattei and Mark Beekey, and four students from Sacred Heart University to do further studies of the population on the Island. Thanks to Avalonia member and Pine Point science teacher Jon Mitchell we were transported, gear and all, back and forth, and he joined the group.

The Sacred Heart team has been studying all aspects of Horseshoe Crab biology: life spans, migration routes, mating studies, habitat quality, nesting and hatching studies as well as all stages in between. A great deal of information has been amassed over the last decade and they continue to compile and add to the data base.

On this morning, we arrived at the beach at low tide, giving us the greatest expanse of beach where we expected to find nest depressions, as well as mud flats and small pools where we might find newly hatched juveniles. Horseshoe crab nests are mostly dug during the high tide and at night. This morning there were dozens of depressions along the high tide line indicating nesting activity over the last week. We gently scraped away layers of sand until we uncovered the clusters of eggs. Newly deposited eggs are glistening grey/blue, not much bigger than grains of sand, and are somewhat clumped together.

Horseshoe crab eggs  look like small pearls mixed in the sand.

As the eggs mature, they appear to become more beige or peach colored, and the ones that were closest to hatching were nearly translucent and the minute crab could be seen, at times, moving inside the egg. Samples of eggs were taken from dozens of different nests along the shore. They will be evaluated for numerous things. Some will be checked for heavy metals, including lead. This is often found in habitats near where hunting has occurred and the lead shot becomes absorbed into the sand area and into the eggs. They will also evaluate for the caloric content of the eggs to see the quality of the “food supply” inside of the egg, usually measured in the fat content, and may indicate health or viability.

Another interesting aspect of examining the nests was the presence of an entire community of organisms that live within the nest. The organisms are dependent on the eggs, the spawning fluid or milt, the sugar based material that holds the eggs together, and the bacteria that develop within the nest. There were worms, isopods, amphipods and even beetles that spend their life cycle within horse shoe crab nests. Many nests had deep holes poked into them and footprints all around from numerous bird species, notably sandpipers and oystercatchers that probe for the nutritious eggs. 

Examining a nest for eggs. Note the bird foot prints surrounding the area. 

In the mudflat pools we were shown how to really pick out the newly hatched, juvenile crabs, that were so small they were easily mistaken for tiny bits of gravel. The very smallest were probably hatched within the last weeks.

Newly hatched horseshoe crabs.

We also found juvenile crabs that ranged up to two inches across that were probably the young of last year. These burrow to forage in the mudflats and may be found by their trails in the sand. There were also weighed, measured and categorized. 

A one year old juvenile.

Underside of a juvenile.

We also scouted for adult crabs, though they were hard to find because of the time in the moon cycle as well as the tide levels. We did find at least five and they were weighed, measured and photographed, and samples taken from each to assess health and heavy metals in their blood.

This Horseshoe crab was tagged at least three years ago.

Taking samples from an adult horseshoe crab.

Documenting a tagged visitor to Sandy Point.

The scientist team checked soil samples, plant material, other invertebrates, small fishes and snails that share the habitat with the crabs.

It was pretty amazing to explore the web of life and interdependency to be discovered along a special stretch of sandy beach.

We are excited to have a connection with the Sacred Heart team and look forward to sharing their data and learning more about a special inhabitant of our Avalonia Island.

Written and photographed by Beth Sullivan.

Find out more about Project Limulus.