Canadian scientists puzzled by spate of whale deaths

Some whale deaths have been attributed to collisions with ships in one of the world's busiest waterways

Canadian officials are concerned over the "catastrophic" number of right whale carcases discovered in the Gulf of St Lawrence this summer.

The Department of Fisheries says that ten examples of the endangered species have been found in the sea area between Newfoundland and Quebec, which is also the outlet of the North American Great Lakes, CTV News reports.

The sudden rise in deaths is of particular concern as there are only about 500 North Atlantic right whales left.

"This has had catastrophic ramifications on the right whale population, this number of whales being killed when we only know of three calves being born this year. It certainly indicates a rapid decline in the population," Jerry Conway of the Canadian Whale Institute told the television channel.

Blunt force trauma

Necropsies on six of the carcases indicate that three of the deaths might have been from blunt force trauma. Researcher Kim Davies told national broadcaster CBC that it's "logical to assume" that these injuries were due to collisions with shipping while the whales were still alive.

Another necropsy indicated that a fourth whale died from being tangled in fishing tackle.

However, these kind of incidents have happened before in the past, so the question is to why there's been such a sudden increase this year, Ms Davies said.

One of the reasons, according to Toronto's National Post, is that the whales have moved north in the last five years from their traditional feeding grounds in the Bay of Fundy and Roseway Basin. Climate change has been cited as to why they are chasing food to new grounds, "but there could be other factors too," Fisheries and Oceans Canada scientist Matthew Hardy says.

Economic impact

In response, the Department of Fisheries has closed one snow crab fishing zone in the southern part of the Gulf of St Lawrence, while urging shipping and fishing vessels to cut their speeds and report any whale sightings.

The government is wary that closing fishing grounds would cause economic hardship. "The snow crab industry by itself is one of our largest fisheries, and the exports are in the millions and millions," Mr Hardy told CBC.

Experts are unable to give a current number of North Atlantic right whales left at sea. Putting the population as somewhere between 475 and 525, Kim Davis told CBC that "we can't narrow it down because, for example, we just lost ten. And those are only the ten that we know about."

Researchers encounter a dead right whale in the Gulf of St Lawrence

Reporting by Alistair Coleman

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