Sable Island: A special slice of the Atlantic

Text and photos by Caroline Branan

I have had the special privilege of visiting Ocracoke Island annually with my family and we still continue to do so. With ease, I grew to love the island, so different from where we live in Chapel Hill. Ocracoke inspires people in many ways, from getting married on the beach, to spending countless hours fishing in all kinds of weather or taking that perfect sunset photograph.

My Ocracoke inspiration led me to learn about nature and find ways to understand and improve the environment, specifically our vast oceans. This led me to North Carolina State University where I graduated in 2022 with a B.S in marine sciences and a B.S in biology with a minor in music performance. Currently, I am in a master’s program at Texas Tech University studying biology.

Soon after graduating from NC State, I had the opportunity to co-write an article with Peter Vankevich, Released balloons: the scourge of the beach and seas.

To illustrate that this is a global problem, Sable Island was included. Similar in many ways to Ocracoke, it is a crescent-shaped island, roughly 25 miles in length located 180 miles off the coast of Nova Scotia. One of the many deflated balloons that ended up there was marked with a school name from Ohio and the date March 31. It appeared on that island three days later.

At the time of co-writing that article, I had no idea that I would have the incredibly special opportunity to spend six weeks, from Dec. 30 to Feb. 9, on that island and will return to study grey seal pup development for my master’s thesis. I didn’t even connect the dots until I started the school year. It’s incredibly fascinating how Ocracoke connects you to important people and places that shape your future, which people refer to as “the Ocracoke effect.” The connections you make on this island can shape your life trajectory, leading to your growing appreciation of Ocracoke.

My master’s thesis focuses on investigating the effects of iron on grey seal pup development, and the animals we work with are the grey seals on Sable Island. The grey seal pups need lots of oxygen in their blood and muscle to dive in search of food to survive. Their levels drop during development and slowly rise after they wean off their mother’s milk. However, it takes time for their stores to rise up to mature levels and often pups are still lacking oxygen stores when they go off to forage, meaning weaker diving abilities. Iron is a key micronutrient needed to form the proteins that oxygen binds to, specifically hemoglobin and myoglobin. A pup’s early iron levels depend solely on intake from their mother’s milk. So, I’m investigating whether iron limitations stem from the mother’s milk or from pup internal physiology using iron supplementation techniques.

All our research procedures and interactions are approved by our National Marine Fisheries Service (NMFS) permit number 25794, and our utmost priority is to interact with the seals as little as needed. I hope my research will lead to more questions about seal physiology and conservation efforts across pinniped species.

Since very few people can actually visit Sable Island, here are some details written within the context of comparing and contrasting Sable with Ocracoke.

Sable Island has a romantic image as home to hundreds of free-roaming horses, has the world’s largest breeding colony of grey seals, and an amazing list of bird species, many blown far off-course. Its unique assortment of flora and fauna is a huge draw for both research and tourism.

Since 2011, Sable is a National Park Reserve, managed by Parks Canada — their version of our National Park Service. It has a small year-round Parks staff team and no permanent residents.

Due in part to limited housing, only a few researchers can be on the island at a given time.

Those tourists with the money can make day visits only, no camping. Requests to visit must be made in advance. To make it even more of a challenge, it is not uncommon to get all the way there and be denied access by boat or small aircraft due to bad weather, especially fog, high winds and dangerous waters.

This sandbar has been known as Sable Island, or Isle de Sable, since 1601, with “sable” meaning sand in French. So, when I say sandbar, I’m not minimizing Sable’s beauty and impact; I refer to the literal translation and topography.

Like offshore of the Outer Banks, Sable Island is also known as the “Graveyard of the Atlantic” due to the enormous number of shipwrecks that have occurred starting in the late 16th century. Over 350 documented shipwrecks have occurred around Sable Island, with the first being a sailing ship, the “HMS Delight,” in 1583. These shipwrecked vessels pale in comparison to today’s large ships and many were small fishing boats, but they still held crews who perished in these swirling waters.

Because of the seemingly constant winds and swirling overwash, it is not unusual that long-buried vessels will resurface due to shifting sands and then be buried again.

Many factors make it treacherous to navigate around the island, including storms, high winds, fog and strong currents.

There are three main currents that meet very close to Sable Island: the Labrador Current, the Gulf Stream and the Belle Isle Current. These currents also create dense fog over the island especially from late spring into summer, heavily obscuring it from the view of oncoming ships.

Due to the proximity of the three currents, lots of marine debris washes up onto the island. Parks Canada and the Sable Island Institute are partnering on a Beach Monitoring program and analyzing it to help understand the level of ocean pollution. One study showed that 92 percent of this debris is plastic.

Hurricanes and tropical storms that impact the Outer Banks often creep their way up the Atlantic Ocean towards the island. Hurricane Dorian, which caused massive devastation to Ocracoke’s village, struck Sable as a Category 2 storm.

With so many shipwrecks and rumors of plunderers on the island, in 1801 the government of Nova Scotia established a series of lifesaving stations and a permanent staffed station that would benefit shipwrecked individuals and save many future lives.

Today, there are far fewer shipwrecks due to advanced navigation systems such as GPS, radar and sonar as well as better weather forecasts and communications.

Much like our own Ocracoke, Sable Island is a vital habitat for flora and fauna.

Although not native, both islands have had their own population of horses that had different origins. In the 1700s, horses and other livestock were introduced to Sable Island as a cheaper way to graze and start cultivating a civilization. Left to roam freely, they became feral and adapted to the island’s harsh conditions, surviving major storms by sheltering in the island’s hollows and between its high dunes.

Whereas the human population was never high, mostly fewer than 25 people, the horse population has thrived primarily because of the island’s abundant year-round marram grass as their primary food source, which also serves as a sand anchor. Despite the island’s narrow width–a little over a mile–these long-maned shaggy horses are aided by freshwater springs which are present throughout the middle of the island.

The current horse population is estimated to be about 475 individuals. An ongoing debate dating back more than 50 years between ecologists, government officials and animal lovers over what to do with the herd continues today: Should they manage their numbers, remove them or leave them entirely alone?

Contrasting with the Sable Island population, the famous Ocracoke horses, often referred to as ponies, were thought to have started from horses that had swam ashore from Spanish shipwrecks during the 16th and 17th centuries. But the National Park Service that commissioned an in-depth study which has recently dispelled much of the folklore about them. The horses today come from a mix of breeds.

Rather than grazing around the island freely, Ocracoke’s horses, about 11 in number, are well cared for and penned in to at the island’s center to avoid being struck by passing vehicles along NC 12.

Sable Island is a botanist’s paradise with nearly 200 plant species (not all native) that include six orchids and plentiful cranberries. However, there are no trees except for one small pine tree planted in the 1950s. Attempts to combat erosion by massive plantings were unsuccessful. Trees are not suitable for Sable’s extreme weather and poor soil conditions.

Both islands have a variety of migratory and native bird species. More than 350 species have been recorded on Sable Island and the checklist of Birds of the Outer Banks has approximately 400 species, although many on that list have been observed on Ocracoke.

If there is one bird that connects the two islands, it is the Ipswich Sparrow which almost exclusively breeds on Sable Island and winters along the narrow Atlantic coastal dunes down to Georgia.

The Ipswich sparrow is a subspecies of the Savannah Sparrow with a larger build and lighter plumage. It faces conservation issues related to winter habitat depletion. The Ipswich Sparrow Demography Project operates in both the United States and Canada. It focuses on banding sparrows with unique transmitters to identify them and track their conservation status. Be on the lookout for them the next time you walk along the dunes in the wintertime. The Project loves to get photo documentation.

My favorite part about my time on Sable Island was watching the large numbers of grey seals that haul out onto land during the winter breeding season.

During the cold winter months, around half a million grey seals come out of the water and allot their energy to breeding and raising pups.

Pregnant females will haul out and give birth to their pups a couple of days after settling. Then they nurse their pup for about 15 to 18 days, pumping them full of milk and nutrients, causing the pups to triple in size.

After another couple of weeks on land, the pups make their way towards the water and start their adventure into the deep blue unknown.

While grey seals currently dominate the island, there is a small population of harbor seals that breed during the summertime. In years past, harp, hooded and ringed seals have all been spotted on this small island. These seals are more comfortable breeding on pack ice. So, their breeding grounds move further north each year.

The grey seal population has been monitored by Canada’s Department of Fisheries and Oceans (DFO) since the 1960s when Sable Island and the Gulf of St. Lawrence hit an all-time low of 2,300 and 5,000 animals, respectively, due to excessive commercial harvesting. By implementing strict harvesting rules and monitoring, the total population has reached 424,000 animals across all Canadian breeding regions (as of 2017) and are officially deemed “not at risk.”

The grey seal team within Canada DFO goes to the island every year to monitor how often marked grey seals return to Sable Island for the breeding season. Some of these female seals have been returning to the island for over 30 years. Alongside this long-term population study, they put satellite tags on grey seal pups and track their horizontal movement across the Scotian Shelf and the rest of the Atlantic Ocean. Many pups die within their first year due to limited prey resources and predation from sharks. Watching their population on and off the island is crucial to understanding how they survive.

So, what was it like to spend six weeks on Sable during the winter season? Well, similarly to Ocracoke–there is almost always wind blowing. While most days were cloudy, the sun would peek out every so often, providing some extra warmth for us scientists working outside. Snow flurries would hit us at least once a week, however, snow didn’t stick around for too long on the cold but unfrozen sand. On those precious clear nights, we would brave the cold and take in the array of constellations. It was a beautiful sight to see amidst the howling winds.

My family and I have joked that Sable Island is just a “glorified sandbar” due to its topography and little human activity. In reality, this sandbar deserves all the glory and more.

The island offers an unfathomable measure of solitude amidst a vast ocean, providing you with an incredible amount of introspection. Being on the island reminds you how beautiful and pure nature can be.

There are not many parts of the world where much of the area is untouched. So, if you ever get the chance to visit this slice of the Atlantic, take it in and savor it.