Greenland sharks (Somniosus microcephalus) are a native species of the cold waters of the North Atlantic and the Arctic, living at great depths, having been found more than two thousand metres below the surface.
It is believed to be the longest-living vertebrate in the world, but little is known about how it actually lives, and how it reproduces. But a new scientific investigation has lifted a bit of the veil of mystery surrounding what is one of the planet’s largest carnivorous sharks.
In a article published in the journal Ecology and Evolution, a group of researchers suggests that the Skagerrak Strait, between Denmark, Finland and Sweden, may be a “nursery” for Greenland sharks, explaining that this area has the highest proportion of juveniles, between 90 centimetres and two metres in length. This species can reach five metres from the tip of the snout to the tip of the tail.
“We consider that the deeper areas of the Skagerrak may be an important feeding zone for ‘adolescent Greenland sharks’, and, in fact, the study is the first to systematically examine the occurrence of Greenland sharks in Skagerrak,” says in a press release Peter Rask Møller, marine biologist at the Natural History Museum of Denmark and one of the authors of the article.
The work also notes that it is unlikely that females give birth in waters around Canada, Greenland, Iceland, Norway and Russia, since “in pregnant females no newborn pups have ever been recorded in any of these areas,” states the scientist.
The team believes that it is in the deep waters of areas with little human disturbance, such as traffic from commercial fishing vessels, that the mothers have their offspring.
Greenland sharks are a species vulnerable to extinction, according to the IUCN Red List classification, and face serious threats to their survival, notably bycatch in fishing gear.
Therefore, scientists are convinced that deepening knowledge about the life of these prehistoric-looking animals, which can live for hundreds of years, is essential to drive efforts to protect them.
“The study is a breath of fresh air in the Greenland shark history across the North Atlantic,” stresses Peter Rask Møller, since, among other things, it “provides an understanding of how Denmark’s deepest marine areas also play a role in the species’ life history.”
However, more research is needed to learn more about how this cryptic species moves, lives and reproduces, and which parts of the ocean it frequents most.
