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.

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.