Last month, a Greenland shark (Somniosus microcephalus) washed ashore on a beach in Cornwall, England. Now, experts have confirmed the shark died from a brain infection called meningitis. It is the first recorded case of disease-related death in the rare species, reports Mike Snyder for USA Today.
Greenland sharks have rounded snouts and small fins. They are usually found in cold, deep-water habitats in the Arctic and North Atlantic Oceans about 2,200 meters (7,200 feet) below the surface. Little is known about the elusive species and the sharks rarely encounter humans. The shark's death in Cornwall could help experts learn about the species.
The 13-foot-long female shark was found stranded on March 13. At an estimated 100 years old, she is still considered a juvenile because Greenland sharks can live up to 400 years old. Damage on its fin and a slit on the shark's stomach suggested that it was stranded on the beach and died soon after flailing about and swallowing sand, reports Joe Pinkstone for the Telegraph.
After a tide swept the shark's body back out to sea, a recreational boating company recovered the shark's body on March 15, where it was then taken for examination, reports Laura Geggel for Live Science. A necropsy was performed by pathologists at the Cornwall Marine Pathology Team.
"During the post-mortem examination, the brain did look slightly discoloured and congested, and the fluid around the brain was cloudy, raising the possibility of infection," explains pathologist James Barnett of the Cornwall Marine Pathology Team in a statement. The team plans to publish a forthcoming scientific paper with details of their post-mortem investigation.
In a microscopic examination of the brain, pathologists found a genus of bacteria called Pasteurella in the collected fluid. The rod-shaped bacteria can cause various severe diseases in domesticated animals, some mild infections in humans, and may have been the cause of meningitis in the shark. The brain infection likely caused the shark a fair amount of confusion, which may be why the shark left its usual depths for shallow waters, per the Telegraph.
"Discovering that this shark had meningitis is likely a world's first, but the significance of this in terms of any wider stressors is unknown. Ultimately, like most marine life, deep-sea species such as Greenland sharks may also be impacted by human pressures on the ocean, but there is not enough evidence at this stage to make any connections," says Rob Deaville, the Zoological Society of London's project lead for the Cetacean Stranding Investigation Programme (CSIP), in a statement.
CSIP investigates all cetaceans, marine turtles, sharks, and whales stranded around the UK's coastline. Over 12,000 stranded cetaceans and about 3,500 necropsies have been recorded since the program's establishment in 1990. The collected data provides one of the most extensive datasets of mortality and stranding in these species.