Scientists have been left baffled by the increasing number of dead great white sharks with enlarged brains that are washing up on beaches across North America.
The marine mystery is causing alarm among the scientific community in Canada and the United States who are yet to discover what is causing the inflammation.
Before August 2023, the Canadian Wildlife Health Cooperative (CWHC), which studies wildlife health issues, had not come across a dead white shark in 30 years.
But when one did wash up on Prince Edward Island with no signs of injury it puzzled experts before they eventually found meningoencephalitis, an inflammation of brain tissues that eventually disrupts normal cognitive functions, to be the cause of death.
After this a further four great white sharks have washed up on beaches across Canada’s Atlantic coast and similar phenomenon has been noted in the United States – with the first being recorded in July 2022 off the coast of Massachusetts.
Concerningly, most of the fish, which are famed for their strong immune systems, were all found to be suffering from the same brain inflammation.
Speaking to the New York Times, Dr Megan Jones – a veterinary pathologist and regional director of the CWHC – said cases of bacterial infections cause brain inflammation have been recorded in the past.
However, these infections were easy to identify and she is now part of a group of scientist determined to discover whether the species is now facing a new unknown threat.
A dead great white shark washed ashore on Nauset Beach, Massachusetts, in October 2024. Scientists have been left baffled by the increasing number of dead great white sharks with enlarged brains that are washing up on beaches across North America
Concerningly, most of the sharks, which are famed for their strong immune systems, were all found to be suffering from the same brain inflammation raising concerns the species could be facing an unknown threat
Dr Jones said: ‘Three of these five seem to have the same potentially infectious disease affecting their brain.’
‘We need to know more about what that is.’
She added that if a shark’s brain is squeezed it may no longer be able to feed or could lose its way and get stuck in shallow water becoming beached.
Other scientists such as Tonya Wimmer, executive director of the Canada-based Marine Animal Response Society, have speculated that the rising number of dead sharks could be the natural result of population increase.
With more sharks dying simply because there are more of them in the ocean.
Factors such as climate change has led the waters of the Atlantic to become more warm pushing the predators more north.
Similarly their primary prey, seals have also seen their population recover providing an abundance of food.
Compared other marine wildlife, such as whales and dolphins, there is still a lot of unknowns about sharks and research into them remains underfunded.
On top of this, great white sharks are largely misunderstood as a species.
Thanks to blockbuster hits such as Jaws and Deep Blue Sea, the marine animal has been painted as a seaborne villain which will attack any person who swims in to its path.
However, in reality deliberate shark attacks on humans are extremely rare.
Instead it is mankind that pose more of a threat to great whites with commercial fisheries being a key threat.
Globally the species is now listed as vulnerable with the number of great whites steadily decreasing with an estimated 5,0000 to 3,500 left in the wild.
