In March, scientists embarked on an extraordinary search to recover a fugitive corpse. It belonged to a Greenland shark, a highly unusual discovery for beachcombers but one discovered by senior research colleague Professor Rosie Woodroffe in Cornwall, UK. When the tide came in, however, the Greenland shark slipped away, and a search team was dispatched to recover the dead animal and the intellectual insights contained within its body. They can be difficult to examine since they are secretive creatures that can live 2,600 meters (8,530 ft) underground and are the world’s longest-living vertebrates. Thankfully, it was fished out of the ocean only a few days later.
Since then, the Greenland shark has been in the care of the Cornwall Marine Pathology Team, which is part of the ZSL’s Cetacean Stranding Investigate Programme (CSIP). Pathologist James Barnett was one among them, and he recognized something was wrong with the shark’s brain. What exactly are you saying, I hear you say? Have you ever seen the brain of a Greenland shark? Let’s make a change.
“The brain was somewhat discolored and congested during the post-mortem examination, and the fluid around the brain was hazy, increasing the likelihood of infection,” Barnett stated in an email to IFLScience. The Greenland shark appeared to have contracted meningitis, an infection of the protective membranes that surround the brain and spinal cord that may be fatal in humans. If not adequately conserved, brain matter is a delicate and sensitive tissue that may swiftly disintegrate (though scientists did once find a 2,600-year-old human brain). As a result, during study, brains like this sharks are generally treated with formaldehyde to protect things from becoming too mushy.
Barnett’s team was able to cement its results with a firmer formaldehyde brain in hand. “[The infection] was later verified by histology (microscopic study of the brain),” he stated. “A Pasteurella species, a bacteria, was identified from the fluid, and it’s possible that this was the source of meningitis.” When the juvenile female shark died, she was far from her normal home and was believed to be approximately 100 years old (they may live up to 400 years). This is most likely due to meningitis, and the silt found in her stomach suggests she was still alive when she became stuck. The premature death of Earth’s longest-living vertebrate is the first time meningitis has been detected in a Greenland shark, and it’s hoped that a deeper examination of the animal’s bones will provide further information.
“The shark’s bones will be sent to the Natural History Museum in London, and other samples will be sent to cooperating researchers so that they may learn as much as they can from this unique stranding,” Barnett told IFLScience. Its skin, which may retain insights into the evolution of shark hydrodynamic flow, a toxicological screen of its liver to detect any contaminants in its system, and microplastic and nutritional study of its gastrointestinal tract are among the avenues of inquiry.
It’s also believed that stable isotope tests of its eye lens and vertebrae would reveal its genuine age. “Was it swimming about in the depths throughout the First World War?” Barnett wondered. The Sanger Institute’s Tree of Life Project will receive a few samples (frozen to -80°C/176°F) for genome sequencing, marking the project’s first Greenland shark entry. That’s a lot of knowledge from just one creature.
“The Cornwall Wildlife Trust Marine Strandings Network volunteers, as well as all those who saw and brought the corpse to shore,” stated CSIP project lead Rob Deaville. “Everyone engaged put in an outstanding effort, and it was a once-in-a-lifetime opportunity to learn more about the lives of this enigmatic and endangered deep-water shark.”
