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Great White Lydia hanging out in Newfoundland

Every time I meet my doctor, she asks me the same question: Did you swim with sharks this summer? Usually, I reply: Are you looking for new patients? And we continue talking about those six great white sharks that hung out in Nova Scotia’s waters earlier this year. She is a surgeon, of course.

There are more great white sharks showing up in Canadian waters than previously thought. We know this because of tags that have been attached to shark fins by scientists tracking their movements and collecting other information about life as a shark.

Great white shark (Carcharodon carcharias)

Great white shark (Carcharodon carcharias) © Wildlife Pictures / Jêrome Mallefet / WWF-Canon

Lydia is the name of yet another great white. She has been roaming Newfoundland’s south coast (only 20-30 km off Placentia Bay) for the past several days. My best guess is that the teenage shark from Florida has been riding the Gulf Stream northward looking for snacks. At a moderate length of about 4 meters, Lydia has presumably changed from a fish- to a red-meat diet.

The menu is set: “seal en masse”. Seals have become plentiful in the Canadian Atlantic and are often blamed for the demise of cod. Now the story has a new twist: sharks are coming in to feed and are snacking on seals in a truly ecosystem-based manner. Their voracious appetites keep food species in check. As top predators, white sharks have never been overly abundant, but they are widespread in the coastal waters of all the major oceans.

Scientists have determined that great whites in Canada’s Atlantic are an endangered species and the federal government has protected them under its Species at Risk Act. Protecting great whites is a smart move not only because they are endangered as a species but also because they are major agents controlling the structure of open water ecosystems.

There is also a pocket book argument for saving sharks. Sharks are worth more in the world’s oceans than they are on restaurant menus according to a recent University of British Columbia study. Currently, shark ecotourism brings in $314 million annually worldwide, and this sector is expected to continue growing. That figure is projected to double to over $700 million per year within the next 20 years. In comparison, the landed market value of shark fisheries around the globe is $630 million per year, but has been declining over the past 10 to 15 years.

Worldwide, about 1 million sharks are killed by humans each year. The documented shark comeback is a reason for optimism. I am a SCUBA addict but have not yet dived with a great white. And if I ever were to encounter a great white during a dive I’d probably stay motionless at the bottom and hide in a kelp bed (unlike my colleague Jarrett Corke).

WWF's Bettina Saier swims with a whale shark.

WWF’s Bettina Saier swims with a whale shark.