Deep-sea sharks kept showing up between Denmark, Sweden and Norway — and now scientists may know why

A new study has discovered that the Skagerrak — a cold stretch of sea between Denmark, Norway, and Sweden — is quickly growing to become an important place for young Greenland sharks. As reported by Discover Wildlife, the research was featured in the journal Ecology and Evolution and shared an interesting discovery about one of the most mysterious aquatic creatures and their new favorite 'hotspot'. 

The Greenland sharks are also referred to as gurry shark or grey shark and can live up to 500 years, grow as long as 21 feet, and are some of the slowest animals in the ocean. Until now, scientists had assumed their natural habitat to be the Arctic and North Atlantic, but the latest research changes that idea. Researchers looked at the data from 1,610 Greenland sharks across the North Atlantic and found that the Skagerrak had the most young sharks, measuring between 3 to 6.5 feet long. These are considered 'teenage sharks'. 

With a surge of Greenland sharks in Skagerrak, marine biologist and associate professor from the Natural History Museum of Denmark, Peter Rask Møller, shared, "We consider the deepest areas of the Skagerrak to be a potentially important feeding ground for ‘teenage Greenland sharks." They opined that the area is rich in fish, marine mammals, and even dead animals, which makes it perfect for the sharks to grow.

The study also stated that the newborn sharks, usually just about 1 foot long, are probably born near the Mid-Atlantic Ridge, south of Iceland, instead of the Arctic. These deep areas are quiet and free from fishing, which makes them a safe place for the pups. Lead author of the study, Julius Nielsen, opines, "Future targeted studies will most likely confirm that the Greenland shark gives birth to its many pups in undisturbed parts of the deep sea near the Mid-Atlantic Ridge in deep waters, where there is little activity from commercial fisheries." Historically, sharks have suffered a bad reputation, although the National Ocean Service confirms that they rarely ever attack human beings if left unprovoked. Swimming away in a hurry often makes humans resemble flocks of fishes fleeing the hunter, which makes these sharks dive right into them. Maintaining a cool head and behaving normally while maintaining eye contact usually sees deep-divers return to the surface unscathed. 

For a long time, scientists knew very little about their biology because these sharks live so deep and are rarely seen. Their natural habitat was stated to be Greenland, Iceland, Norway and the Barents Sea, Canada, and the newly identified nursery area, Skagerrak Strait. What makes the Greenland sharks so special and their study so important is that they are considered one of the longest-living vertebrates on Earth. The study is also crucial as Greenland sharks are listed as 'Vulnerable' on the IUCN Red List (the inventory of the extinction risk of biological species and global conservation status). “This study provides new insights into the life history of the Greenland shark, which will aid the development of targeted conservation measures,” share the authors.