Two dead great white sharks found stranded in Maritimes in ‘very unusual’ weeks: researcher

“In my lifetime…there have been less than five great white sharks that I’ve heard of getting stranded anywhere in (North America)”

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FREDERICTON — The discovery of two dead great white sharks stranded in Atlantic Canada in less than two weeks is a mystery to researchers.

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Fred Whoriskey, executive director of Dalhousie University’s Ocean Tracking Network, called the stranding of two of the ocean’s top predators abnormal.

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“In my lifetime – and it’s been many years – there have been less than five great white sharks that I’ve heard of stranded anywhere in the North American region,” he said. said in an interview. “So this is a very unusual event.”

The Marine Animal Response Society said in an Oct. 21 social media post that a great white shark was found dead in Kouchibouguac National Park in New Brunswick the previous weekend. The organization studies marine animals and assists in rescues and surveys.

The 3.4 meter mature male was found on the beach and samples were taken to help study the species.

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Whoriskey, who is not involved in autopsiing the animals, said a second great white found dead Wednesday in North Sydney, Nova Scotia, was a minor.

The great white shark is endangered under the federal Species at Risk Act. There is no estimate of population size in Atlantic waters, according to the Federal Department of the Environment website. There have been around 100 records of white sharks spotted off the Atlantic coast since 1874, although sightings are increasing, with more than 40 since 2009, the website added.

The death of two sharks in such a short time could be a sign that the numbers of these animals are increasing, Whoriskey said. Most sharks seen in Canadian waters are usually juveniles, which is one indicator of a growing population.

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“It could very well be that we expect to see things like natural mortalities more frequently, because, whether we like it or not, things go wrong in biology.”

Whoriskey said white sharks have no predators in Atlantic Canadian waters. “So we are probably looking for natural causes for these two animals. Which is kind of an interesting phenomenon.

The images of the sharks, he said, do not suggest they were killed by a collision with a ship or a rope entanglement. The animals could have died from a virus or bacteria, which could be studied during the autopsy process, he said. But it’s not simple because scientists don’t have a good idea of ​​the types of diseases white sharks suffer from.

“If we don’t know what we’re looking for, we don’t yet have a probe to detect it. It may be a pathogenic organism that has not yet been identified by science. So that could be quite intriguing,” Whoriskey said.

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Boris Worm, professor of marine conservation biology at Dalhousie University, said great whites are found as far away as Newfoundland. They are typically found in Canadian waters in late summer and fall, he said, “probably hunting some prey species in our area, such as mackerel.”

The biggest risk to the species, Worm said, is humans.

With fishing trawlers, a hunting shark might not notice the trawl and get caught, which could lead to its death, he said.

And longline fishing casts baited lines with hundreds of hooks. Sharks with their remarkable olfactory senses can sense this from a distance and are attracted to it, he said.

“These fisheries usually have a large bycatch of sharks,” he said. “They didn’t bring white sharks on board often because the white sharks would bite through the line if they got caught and escaped. But they have occasionally been reported in longline fisheries.

This report from The Canadian Press was first published on October 28, 2022.

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