This is the first of a two-part report explaining how vessel strikes happen, why they’re increasing and what’s being done to stop them. Read part two here.

In the last month, eight North Atlantic right whales have been found dead in Canada’s Gulf of St. Lawrence, including two members of the critically endangered species this past week.

Canadian authorities say work to determine these new whales' cause of death is ongoing.

Whatever the cause of these latest deaths, researchers worry collisions with ships are increasingly to blame.

When struck by a ship, these whales often experience extraordinary trauma.

“There are a number of cases of where whales that either had half of their tail cut off, or their entire tail cut off completely,” says Sarah Sharp, a veterinarian with the International Fund for Animal Welfare (IFAW). “That would make it so that whale basically could not swim, could not get to the surface, could not take a breath.”

In studying necropsy reports of right whales dating back to the 1970s, Sharp has seen whales who’ve died from punctured chest cavities, broken spinal columns, and fractured skulls.

In the last two years alone, 20 North Atlantic right whales have been found dead in Canadian waters. Of the 11 that could be necropsied and studied, seven were found to have died as a result of vessel strikes.

Challenges of Piloting a Vessel

Michael Burns, an academic director at Bourne's Mass Maritime Academy, where student mariners are taught to avoid whales using simulation exercises, says there are a number of reasons why a ship might collide with these whales.

“Ships don't have brakes. We can do things to slow us down as quickly as we can, but even so, it can sometimes take, under the best circumstances, two or three ship lengths, or in some cases maybe even miles for a ship to slow down,” Burns says.

Also, he says, whales don’t show up on most electronic charts or radar screens because they’re too close to the surface, so mariners have to rely on sight alone. At night, especially, it’s extremely difficult to spot dark animals in dark waters.

Plus, it’s difficult to react to these whales when they are seen.

“All of this wildlife experiences ship collisions for the same reasons that we end up hitting deer on highways, which is that we don't control where wildlife goes,” said Sean Brillant, a senior conservation biologist with the Canadian Wildlife Federation. “We can only control where we go. And as a result there seems to be inevitably some conflict.”

Brillant says that conflict is in part because whales don’t seem to be getting out of the way of ships.

“Why don't they dodge? Nobody really knows. The likely answer is that they've never had to dodge anything in their evolutionary history. They've never [been] taught to dodge anything and in order to learn from a bad experience you need to survive,” he says. “Very few of them survive from these types of collisions.”

With that in mind, it falls to humans to take actions to keep them safe.

“The best thing we can do is try and figure out where they're going to be and make sure we manage our activities around them in a way that doesn't inadvertently drive them to extinction, which is what we're kind of facing right now,” Brillant said.

But limited visibility for mariners and lack of control over where whales go are nothing new, so why are vessel strike deaths increasing now?

The answer lies in where North Atlantic right whales are and how that’s changing, and that’s where climate change comes in.