Researchers are puzzled by the discovery of two deceased great white sharks that washed ashore in Atlantic Canada in less than two weeks.
The beaching of two of the ocean’s top predators was deemed abnormal by Fred Whoriskey, executive director of the Ocean Tracking Network at Dalhousie University.
“In the course of my lifetime — and that’s a lot of years — there have been fewer than five white sharks that I have heard of beaching anywhere in the North American area,” he said in an interview.
So, this is a really exceptional occurrence.
In a post on social media on October 21, the Marine Animal Response Society reported that a great white shark had been discovered dead the previous weekend in Kouchibouguac National Park in New Brunswick. The group assists with rescues and investigations while also conducting research on marine wildlife.
On the shore, an adult male measuring 3. 4 metres tall was discovered, and samples were taken to aid in the research of the species.
A second great white found dead in North Sydney, New South Wales, on Wednesday was a youngster, according to Whoriskey, who is not engaged in the animals’ necropsies.
The federal Species at Risk Act declares the great white shark to be endangered. The federal Environment Department’s website states that there are no estimates of the population size in Atlantic seas.
White shark sightings off the Atlantic coast have been documented about 100 times since 1874, but there have been more than 40 sightings since 2009, according to the website.
Two sharks dying in such a short period of time would indicate that there are more of these creatures, according to Whoriskey. One sign of an increasing population is that the majority of sharks observed in Canadian waters are young adults.
“Things go wrong in biology, like it or not, so it’s very possible that we would expect to see things like natural mortalities more frequently.”
According to Whoriskey, there are no predators for white sharks in the waters around Atlantic Canada. We are therefore likely investigating natural explanations for each of these species. It is a somewhat fascinating phenomenon.
According to him, the sharks’ pictures do not indicate that they perished due to a ship impact or rope entanglement.
He suggested that the necropsy procedure may be used to investigate if a virus or bacteria caused the animals’ deaths. However, that is not simple because researchers are unsure of the diseases that affect white sharks.
“We don’t currently have a probe to pick it up if we don’t know what we’re searching for. It might be a pathogenic organism that science hasn’t yet managed to name. Therefore, that would be somewhat intriguing,” Whoriskey added.
Great whites can be seen all the way up to Newfoundland, according to Boris Worm, a Dalhousie University professor of marine conservation biology. He remarked that they often spend the late summer and early fall in Canadian waters, “possibly driving some prey species into our area, such mackerel. ”
Humans provide the biggest threat to the species, according to Worm.
He explained that with fishing trawlers, a shark on the prowl can miss the trawl net and become entangled, which could result in its demise.
Longline fisheries also deploy baited lines equipped with a huge number of hooks. Sharks are drawn to it because they can smell it from a distance thanks to their extraordinary sense of smell, he claimed.
According to him, there are often many sharks caught as bycatch in these fisheries. White sharks were rarely brought onboard because they would bite through the line if they got trapped and tried to get away. However, there have been sporadic reports of them in longline fisheries.
The Canadian Press first released this article on October 28, 2022.
It is “extremely rare” that two great white sharks have died off the Maritimes in recent weeks.
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