It was the perfect day for cold-water diving in Halifax – at least for the time being. We were quickly learning that on the east coast of Canada, the weather can shift dramatically, transitioning from sunny blue skies to a thick fog that blankets the coastline in a matter of minutes. Knowing this, we were determined to take full advantage of that sunlight while we had it. As we made our way up the coast to our dive site, this wasn’t your typical coastal exploration; we were on a mission that had the ocean community buzzing. A Greenland shark had been spotted two hours north of the city, a sighting so rare it left divers, researchers, and locals alike equally shocked, fascinated and curious.

These sharks are elusive, mysterious, and ancient, as Professor Boris Worm, a world-renowned marine ecologist, enthusiastically explained while we drove up the Eastern Shore. Boris, who’s been based at Dalhousie University in Halifax for over 20 years, had heard about the sighting and was just as (if not more) excited than we were. It was his idea to ditch our initial plan to explore the more well-known local marine life around Halifax proper, and instead, head north to investigate this unicorn-like occurrence along the remote, wild coast of Nova Scotia’s 100 Wild Islands. 

This group of islands spans 7,000 acres of untouched coastal habitats, making it one of North America’s last great coastal wildernesses, despite the long history of settlement in the region. The islands, with their mix of rocky shorelines, wind-blown headlands, and white sand beaches, stretch over 30 kilometers along the coast, exactly where this Greenland shark had been seen.

As we drove, Boris gave us a crash course on Greenland sharks. These creatures, which live in the deep, cold waters of the Arctic, live for several centuries and are some of the most mysterious animals on the planet. Greenland sharks are thought to be slow-moving scavengers and ambush predators, feeding mostly on seal and whale carcasses that sink to the ocean floor. What’s remarkable is their competitive disadvantage compared to other marine predators. Unlike marine mammals, Greenland sharks can’t warm their blood, which makes them slower and less equipped to defend themselves or hunt actively. To add to this, most of them are blind, thanks to a parasitic copepod called Ommatokoita elongata that latches onto their eyes. In fact, most images you will find of these elusive behemoths will feature the iconic parasites dangling from their eyes. This blindness, however, doesn’t seem to impede them much, as they rely more on other senses to navigate the dark, deep waters of the Arctic Ocean.

Greenland sharks are now considered the longest-living vertebrates on earth. Boris explained that scientists have determined these sharks can live up to 500 years, far surpassing other long-lived species like the tortoise or the orange roughy, a deep-water fish known to live over 150 years. What’s even more incredible is that these sharks don’t reach sexual maturity until around 150 years of age. The discovery of their lifespan came through groundbreaking research that looked at the growth structures of their bones. Scientists discovered that some of these sharks were already mature before Canada even became a country. They were able to confirm this fact by analysing radioactive markers left by atomic bomb testing in the 1950s, which had not only spread all over the globe, even reached the depths where these sharks live at up to 7200 feet (2,200 metres). This study highlighted the amazing butterfly effect of human activity, even within the most remote marine ecosystems.

Boris also told us about his colleague, Chris Harvey-Clark, who was the first to research Greenland sharks in the Gulf of St. Lawrence, an area known for its exceptionally cold waters. In the early 2000s, Greenland sharks were found in diveable depths there, and Chris, along with his team, managed to tag a few, capturing stunning footage. However, rapid warming of the waters caused the sharks to disappear from the area by 2011, which was a concerning sign for cold-water species. That brief window was the only significant period of research on Greenland sharks in the Gulf. While Greenland sharks aren’t actively fished, due to their toxic flesh, which requires fermentation to be safely consumed, as is done in Iceland, bycatch is a major threat. Often, when these sharks are accidentally caught, they aren’t used, and their bodies go to waste. This reality contrasts with places like Iceland, where, if a Greenland shark is caught, it’s prepared and eaten as part of the country’s tradition.

As our conversation shifted back to the current shark sighting, Boris mentioned that Nova Scotia is currently experiencing something he calls “shark fever”. More people are out on the water or diving, sharing sightings, and reporting what they find in the water, creating a heightened awareness of the sharks in the region. For Greenland sharks, which are typically found in the deep, cold waters of the Arctic, showing up in shallower waters near Halifax is still highly unusual, even amidst the fever. Boris wondered whether this sighting could be related to shifting ocean temperatures, or if it was just a random occurrence. Either way, the idea that these sharks could be more present in the region than previously thought was intriguing his science-meets-conservation focused mind. 

As we neared our destination, the Eastern Shore of Nova Scotia revealed itself as a truly unique refuge. Halifax is home to one of the deepest natural harbours in North America and sits where two distinct oceanographic currents converge. To the south, warmer waters lap against granite shorelines, while the colder, bluestone-dominated northern shores are shaped by much cooler currents. As we traveled further north, the landscape shifted to vast stretches of boreal forest, one of the world’s most significant ecosystems. These forests, or taiga, stretch across Alaska, Canada, northern Europe, and Russia and are essential carbon sinks, playing a critical role in regulating our planet’s climate. Along with the cold waters, they provide a haven for a range of species, making this region biologically distinct.

But with ecological significance comes controversy. As Boris explained, the 100 Wild Islands region is on track to become a designated protected area, but not without resistance from local communities, particularly lobster fishermen. These locals fear that federal management would threaten their livelihoods, despite a compromise that allows lobster fishing to continue while limiting other fisheries. The debate isn’t necessarily about conservation, but about who controls these waters. The community has already successfully fought off open-net pen aquaculture in the area, and they prefer to manage conservation locally, rather than through federal oversight.

Pulling into a small community that is part of the 100 Wild Islands network, we heard of the local lobster fisherman who had first spotted the Greenland shark. His sighting spread quickly through the community, and thanks to connections through Boris, we were able to hear about it firsthand. Another fisherman graciously took us out on his boat to search for the shark in the same channel where it had been seen. Donning our cold-water dive gear, we were told the water was unusually cold for the time of year, which may have explained the shark’s presence. And everyone in the community seemed to rally around our expedition, trying to support us in any way they could, from prepping us for the cold and cheering us on as we got ready for cold plunges in the 7°C (44°F) ocean. The hospitality was unrivalled. 

And once down under, we were greeted by a range of marine life: from kelp forests, small white sea stars, flounder, and even curious seals. But there was no sign of the Greenland shark. On our second dive, closer to the channel where the shark had been spotted, we found only fish bones and jellyfish, though Boris did discover a large indentation in the sand, possibly the resting spot of the shark. The question remained: had the shark left the area, or was it using this shoreline as its final resting place?

After only two dives, it was clear to Boris that the effects of climate change were ever-present in this remote region. The locals we spoke to noted unusual weather patterns and colder-than-usual waters, raising the question of whether these changes were linked to the Greenland shark sighting. Boris pointed out that there’s a strong link between climate change and increased cold occurrences, which can seem counterintuitive. When we think about climate change, we often imagine a warming planet. However, rising temperatures are disrupting the polar vortex, causing cold air to shift into regions where it typically wouldn’t be. This left us wondering if the unusually cold waters around Halifax were a sign of these disruptions, or if we were simply chasing coincidences. 

But with the perfectly sunny day turning into that thick fog I had mentioned before, we knew it was time to say our goodbyes to the locals who had generously fed us, offered us warm showers, and most memorably shared their stories about life by the sea. We knew the chances of finding the Greenland shark were slim in the coming days looking at the upcoming weather forecast. But the experience had satisfied our curiosity and left us with a lot more to think about. 

During the drive back, Boris shared his long-standing passion for ocean literacy, a movement aimed at helping people understand the ocean’s vital role and our connection to it. In 2009, Boris was part of a major effort to end overfishing across North America, even traveling to Washington to meet with senators in hopes of reaching a global agreement on rebuilding fisheries. However, despite lofty promises, the campaign fell short. When Boris asked a trusted politician why this initiative didn’t succeed, he was told that the message simply hadn’t reached enough people.

That’s when Boris launched his online education platform called Ocean School. The school focuses on raising awareness about the ocean’s beauty, mysteries, and importance for the next generation. With a target of students between 5-12th grades, Boris has been able to bridge the gap between scientific research and the general public, making marine conservation more accessible and fostering a greater sense of responsibility for ocean health. Through compelling multimedia, such as AR, VR, 360-degree videos, Ocean School has been able to reach students all over the world, and many who don’t have access to the ocean as easily as those living in coastal communities. It’s also why he’s often the first to get calls when unusual ocean sightings, like that of the Greenland shark, occur. And we were quite thankful for that as we made our way back down the untouched coast. 

To our knowledge, the shark wasn’t spotted again in the weeks following our visit, and the initial buzz surrounding Greenland sharks faded along those Eastern shores. But for us, the encounter only deepened our fascination with this ancient species. The fact that these sharks have survived in the Arctic for centuries, outliving every other known vertebrate, was something we couldn’t look past. Iceland was coming up next on our expedition trail, where we’d continue our quest to understand these remarkable creatures and meet those who’ve encountered them, both alive and dead. What had started as a rare sighting had now evolved into a much larger exploration that was at the forefront of our minds.

Our expedition continues to open our eyes to the undeniable connection between climate change, and the displacement of species as their ecosystems shift around the world. Witnessing these occurrences firsthand, it’s clear that they can no longer be ignored. While the scientific community has been talking about this for decades, so many of us are only now beginning to truly grasp its effects through the natural world.

The more we travel, the more we realise that our planet is undergoing profound transformation, and species like the Greenland shark are just one part of a much larger story. While we pursue more knowledge about these elusive sharks, we’ll also be following Boris closely, as his mission to spread ocean literacy is constantly pushing us to open our eyes to what’s happening around us. Much like our own journey, his quest to foster a greater appreciation for the ocean among the public feels like it’s truly gaining momentum, with so much more to be uncovered.