For five nerve-wracking minutes, Chris Harvey-Clark knew what it was to be hunted.
The聽veteran聽diver聽and a friend were swimming through waters just outside聽the mouth of聽Halifax Harbour, hoping to see some of the torpedo rays he studies while also taking in the wreck of HMS Letitia, a WW 1 hospital ship.
As the pair headed back to their descent line and were about to slowly聽ascend聽to聽the boat,聽Dr.聽Harvey-Clark saw the silhouette of an animal he knew instantly to be a聽great聽white shark.聽The water was so clear at 23 metres down that he could easily make out the shark鈥檚 distinctive counter shading, snout and huge tail. He could also聽see that it was about three metres long and likely an older juvenile 鈥斅爉eaning, it could be overly inquisitive and less discerning when deciding what to chomp into.
Sharks at the three-metre stage are just making the transition from fish to mammal as their main diet source. Fred Whoriskey, executive director of the Ocean Tracking Network (OTN) at Dal and Dr. Harvey-Clark鈥檚 partner in the torpedo ray research, has had two Slocum gliders 鈥� eight-foot autonomous aluminum research instrument platforms 鈥� attacked and damaged by probable white sharks in waters off Nova Scotia.
鈥淎t that age, they鈥檙e testing everything out so those are the sharks I fear the most,鈥� Dr. Harvey-Clark, Dalhousie鈥檚 veterinarian聽and director of animal care,聽said after his underwater encounter聽at around noon聽last Tuesday.
鈥淚t鈥檚 one thing to have a shark do a drive-by and check you out once, but if the shark comes back repeatedly that鈥檚 a predatory investigation going on and you don鈥檛 want to be at the bitter end of that.
鈥淭hat is the feeling of being hunted and it鈥檚 not a good feeling.鈥�
'A scary scene'
Dr. Harvey-Clark, who also teaches Dal鈥檚 summer shark course, was positioned below the shark聽on a rocky slope聽and about eight metres away聽from聽the animal聽on its first pass. He started banging on his tank聽with his light聽to alert his friend, who was looking in a different direction. Moments later, the shark made a second pass approximately six metres away 鈥� close enough for Dr. Harvey-Clark to lock eyes with it.
鈥淚 decided it was time to get the hell out of there,鈥� he says with a chuckle. 鈥淚t was all murked out and that鈥檚 a very dangerous place to be.鈥�
At that point, Dr. Harvey-Clark鈥檚 diving partner saw the shark silhouetted dramatically about 11 metres away from them as it passed for third time and they decided to get back to their ascent line as quickly as possible.
The two would normally do a decompression stop on the way up to their boat to allow the body to expel dissolved gases in the blood and prevent sickness. But they decided to forego the safety measure since they feared the shark was monitoring them and they聽would have trouble seeing much of anything as they moved through the final nine metres of water that was churned by very rough seas, with two-and-a-half metre visibility.
For Dr. Harvey-Clark, that was the most stressful period聽as he considered all of the聽odds stacking up聽against them.
鈥淭he visibility聽was so bad you couldn鈥檛 see the end of your fins, you鈥檙e in murky water,聽we were right around the corner from聽where there are seals with a foraging shark nearby and no ability to fend it off so that is about the worst it gets,鈥� he says.
鈥淚鈥檝e been in the water with every kind of shark,聽but this is a scary shark and a scary scene.鈥�
Warmer waters
The pair made it safely back on board their boat, unleashed some colourful expressions and then monitored themselves for decompression sickness. Luckily, neither suffered any effects from their rapid ascent.
Dr. Harvey-Clark also notified聽local dive shops that regularly take recreational divers out to nearby sites of the shark鈥檚 presence in the area.
He also noted that the water temperature seemed higher than normal for this time of year, registering聽12聽C聽at 33.5 metres feet below and聽8 C聽at 91 metres.聽It also seemed odd to Dr. Harvey-Clark that they would encounter a great white at that time of day, since they typically forage either early in the morning or late afternoon. He also thought they would be gone from the area by now and moving south as part of their usual migration.
鈥淭he water鈥檚 still warm聽and the sharks are still here,鈥� he said, noting that聽this could be聽the first verified聽white shark聽sighting by divers in the North聽Atlantic.
He says there also seem to be more sharks in the region, adding that over three days he recorded聽22 encounters聽with great whites聽off Lunenburg last summer while filming a documentary. A seal was also found in early October with a large chunk聽taken out of its back聽near聽Duncan鈥檚 Cove, and later washed up dead.
Dr. Whoriskey said it鈥檚 not that unusual to see great whites this time of year,聽but water聽temperatures聽may聽be affecting their behaviour.
鈥淥ur records of sharks electronically tagged by OTN partners are showing that in recent years the whites are around聽Nova Scotia聽into early December, with our peak number of detections in October聽and November,鈥� he said.聽鈥淪o,聽this聽may not聽be聽that unusual. The warmer temperatures a bit later into the season may be making them more active and increasing encounter probabilities, however.鈥�
鈥淭here is also the possibility that Chris smells particularly tasty!鈥澛�