A Greenland shark, or a hybrid between the Greenland shark and Pacific sleeper shark, was captured over the insular slope at Glover’s Reef, a coral atoll in Belize.
Devanshi Kasana, a Ph.D. candidate in the Florida International University (FIU) Predator Ecology and Conservation lab, was working with local Belizean fishers to tag tiger sharks when the surprise discovery was made.
While the exact species could not be confirmed, it is most likely a Greenland shark (Somniosus microcephalus) or a hybrid between the Greenland shark and the Pacific sleeper shark (Somniosus pacificus). This is the first record of a sleeper shark in the western Caribbean region and further supports the hypothesis that these sharks, best known from polar and subpolar latitudes, occur at depth in tropical regions.
“At first, I was sure it was something else, like a six-gill shark that is well known from deep waters off coral reefs,” Kasana said. “I knew it was something unusual and so did the fishers, who hadn’t seen anything quite like it in all their combined years of fishing.”
Greenland sharks remain somewhat of an enigma to science. Because little is known about them, that means nothing can be definitively ruled out about the species. Greenland sharks could possibly be trolling the depths of the ocean all across the world.
The waters where Kasana and the fishermen found the shark certainly get deep. Glover’s Reef Atoll — part of the Glover’s Reef Marine Reserve World Heritage Site, a marine protected area (MPA) — sits on top of a limestone platform, forming a lagoon surrounded by a coral reef. Along the edges of the atoll, there’s a steep slope that drops from 1,600ft to 9,500ft deep, which means there is cold water needed for a Greenland shark to thrive.