The fright of a lifetime: Accidentally encountering a great white shark in Canada

Dr. Chris Harvey-Clark shares his experience coming face-to-face with one of the ocean’s top predators while scuba diving near Halifax, N.S.

  • Published Apr 07, 2023
  • Updated Apr 20
  • 1,553 words
  • 7 minutes
Great white sharks can be found in oceans across the globe, including the waters off South Africa, which is where this image was captured. (Photo: Maxwel Hohn)
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It was a sunny morning with three-metre easterly swells, which made most sites un-diveable. With me was Michael Schwinghammer, a Navy diver whom I frequently dive with. We chose to anchor by Chebucto Head near Seal Rocks over the site of the Letitia, a 1917 shipwreck because it was the only site with some protection from the weather. Although this site was less precarious, we were still slammed by swells, so we left our delicate cameras in the boat. 

At noon, I rolled into the water, closely followed by Michael. Underwater, visibility was terrible, two metres of khaki water. We descended the anchor line to a steep granite dropoff at 34m, where visibility improved. The water was warm, about 12 degrees Celsius. But after nearly 20 minutes of searching, we found no shipwreck, so we began the return swim to the anchor line.

At 12:25 p.m., I looked up the rocky slope only to see the wide tail of a big shark disappearing into the murk a few feet away. A glimpse was all I needed to recognize the tail belonged to a white shark. I turned 90 degrees to face the animal, looked up toward where it had disappeared, and began to signal Michael.

Dr. Chris Harvey-Clark has been a diver since 1976 and is the Director of Animal Care at Dalhousie University in Halifax, N.S. (Photo: Jeffrey Gallant)
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I am no stranger to shark encounters. I have been diving for the past 35 years visiting the sharkiest places while studying and filming the different species. I also teach elasmobranch biology at Dalhousie University. Over eight years in Baie Comeau Q.C., I  explored the biology of the uncharacterized Greenland shark, resulting in publications and documentaries. I have travelled the world shark diving, conquering any fears I had about these enigmatic animals. Naively, I never expected to encounter a white in home waters. Great whites are the Everest of the shark world and the sole shark species I prefer to see from inside a cage.

A few seconds after I tried signalling to Michael, the shark reappeared, this time at six metres. It had circled inshore, an excellent strategy when hunting seals. The head shape, thick body, broad peduncle, and dark to light flank all distinguished it from the smaller, azure mako and porbeagle, which also call this area home.

I knew it was a female because she had no claspers, the male reproductive organs of sharks, and she appeared to be about three and a half metres. Her mouth was open, exposing teeth, and she had no telemetry gear or tags. I watched her for 30 seconds, incredibly deliberate and menacing, radiating an overwhelming sense of close predatory scrutiny. My heart was pounding, and I focused on breathing. Part of my brain could not comprehend what I was witnessing. It was late in the season, and a white shark was watching us in Halifax Harbour. I quickly looked around but still didn’t get Michael’s attention. I began banging on my tank, head swivelling 360 degrees, something I learned diving with Greenland sharks in low visibility to keep track of any nearby animals.

Once three metres long, white sharks will switch from fish to marine mammal diet, called ‘ontogenetic shift.’ Their teeth change from pointy fish-eating teeth to serrated triangular knives suited to cutting marine mammal tissue. Nearby I had witnessed what these teeth could do. Recently, at Duncans Cove, I saw grey seals with chunks missing, slowly dying. A memorable image of chainsaw lesions plagued me as I looked into the murk, striving to catch sight of this shark.

At the three-metre experimental stage, whites begin learning to kill seals and will test-bite novel objects. Dr. Fred Whoriskey of the Ocean Tracking Network deployed yellow two metres long Slocum gliders in Maritime waters, packed with research sensors, looking nothing like a seal or fish. Recently two gliders were taken out by whites based on bite dimensions. Knowing all this, I was not panicked but scared.

Michael Schwinghammer is a navy diver that Harvey-Clark frequently dives with. (Photo: Nicolas Winkler)
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The shark appeared a third time, at the edge of visibility, nine metres away. It drifted past us again before disappearing. Michael finally saw it, pointed, head swinging to follow the shark.

Were we being stalked or merely a curiosity? Regardless, we were in a sketchy situation, far from our anchor line, facing a 23m ascent from a deep dive in bad visibility requiring a decompression stop, with a curious shark checking us out repeatedly.

We knew there were white sharks around. My telemetry receiver pinged the odd white shark a few miles away every summer. Sharks tagged by OCEARCH reported off local swimming beaches. Surfers saw big sharks at popular breaks. In 2021 in Cape Breton, a swimmer was badly bitten, likely by a white shark. Maimed seals washed up all over the place. As divers, we reassured ourselves that alien, bubble-blowing monsters like us scared white sharks.

Michael turned, hand on head in classic shark fin position, eyes bulging, inquiring – shark? He was still in disbelief mode.

The white disappeared, and we hugged the sea floor back to the ascent line. Once at the anchor, we’d go straight to the surface, no safety stop, and get out fast. Decompression injury and embolism from rapid ascent after diving could be recoverable. However, a shark bite and severed arteries, hours from medical care, less so. The vulnerable phase would be from the moment we left the bottom, silhouetted on the surface in bad visibility until we could get into the boat, and I was dreading it.

I rocketed to the surface, Michael right behind me. He got on the dive ladder and began a laborious exit, impeded by double scuba tanks. I stayed in the water, willing him to get the hell in the boat faster, and wrestled my tank off. Michael finally exited, and I began to clamber in, the lower part of my body still submerged. Those last two minutes exposed from below, anticipating the paralyzing clamp on my lower body, were the longest in my life.

An image of a white shark captured near Liverpool, Nova Scotia in October 2020. (Photo: Chris Harvey-Clark and TellTale Productions Ltd.)
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Finally, I flopped over the stern of the boat. I still could not believe we had encountered a great white. We knew they were around but rare, and we had ignored the evidence of mangled seals. Spending hours in a shark cage near Lunenburg, Nova Scotia, over three years to film fleeting seconds of a white shark had cemented my feeling they were shy of man.

The Whaler was a haven, pitching in breaking waves. I doffed my gear and helped Michael, both of us jabbering with pent-up adrenaline. I thought, how often could this possibly happen in any diver’s life? In Canada? While the episode was fresh, I recorded a summary of what had happened.

We motored to Sambro harbour, Michael calling Fleet Diving Unit Atlantic as we had completely blown our decompression stop. We wanted to ensure we were not suffering from decompression sickness. It became clear we could go to the VG Hospital for recompression treatment. We were at the dock 20 minutes later, constantly checking each other for signs of decompression sickness and happy to be alive.

On the drive back to Halifax, I had profound thoughts. I didn’t want to start a panic. On the other hand, people were diving regularly at that location; a boat load due to go out to that wreck the next day. There was no choice; this had become a public safety issue, and failing to report the incident would be negligent. I called up CBC Radio and did an interview, which became a local news story which went national that night.

A white shark tooth embedded in a glider. (Photo: Dr. Fred Whoriskey/Ocean Tracking Network)
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Discovery Channel and Shark Week have ensured humans increasingly view white sharks, not as formidable predators capable of lethal injury – not the marine equivalent of a grizzly bear, but a different, huggable kind of bear, maybe a panda. Media have gone full circle from decades-long hysteria after Spielberg’s movie Jaws to a Disney-like regard for sharks as innocuous. This trend to sympathy has been a good thing but downplays this species’ role as a mammal predator.

We have little idea how many are out there. Modelling shows a regional range from 3000 to 5000 whites is reasonable. With the return of white sharks, we may see a trophic cascade as seals are consumed, much like when another predator, the wolf, positively reasserted its effect on a well-studied ecosystem in Yellowstone Park. When wolves were reintroduced, elk declined, riverine plants and trees returned, erosion ceased, and biodiversity returned. This type of cascade could occur in the Maritimes, fueled by white shark consumption of an abundance of seals.

What the future holds in Canadian waters is guesswork, but we are sharing the coastal zone with white sharks for the foreseeable future. They are right there, 30 meters offshore in six metres of water. A few weeks before this incident, we had little trouble filming 10 whites near Lunenburg, about one shark every two and a half hours. Most were in the three metre range. With abundant food and global waters warming, white sharks are here for the long haul. 

Blame Steven Spielberg, creator of Jaws, for implanting deep-seated fear into my malleable adolescent psyche 50 years ago with that damnable, wonderful film. That guy owes sharks and several generations of scared humans a big apology.



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