Deep-sea ocean creature, the Greenland sharkPhoto credit: Dotted Yeti / Shutterstock.com
The ocean holds numerous mysteries, and even scientists can’t explain everything that happens in its depths. Devanshi Kasana, a Ph.D. candidate at the Florida International University Predator Ecology and Conservation Lab and her colleagues can personally attest to that.
Kasana has been working with the Belize Fisheries Department and a team of fishermen off the coast of Belize to tag tiger sharks as part of a research project. When they hauled in their lines, they were surprised at what they had caught because it certainly wasn’t a tiger shark.
“I knew it was something unusual and so did the fishers, who hadn’t ever seen anything quite like it in all their combined years of fishing,” Kasana said, according to Florida International University (FIU).
“It was just very surprising and confusing,” Kasana said, according to NPR. “As soon as it entered our field of vision, we saw a black figure that was getting bigger and bigger. When it came to the surface, none of the crew with all of our combined fishing experience had seen anything like that.”
Kasana texted Demian Chapman, her Ph.D. advisor and Director of Sharks & Rays Conservation Research at Mote Marine Laboratory & Aquarium in Sarasota, Florida, to share the news and a photo. After conferring with several Greenland shark experts, the final determination was that Kasana and the team had caught a Greenland shark.
Interestingly, Greenland sharks are typically found in cold, deep waters of the Arctic. So, it is believed this is the first Greenland shark found in the western Caribbean, Kasana and colleagues wrote in an article recently published in the journal Marine Biology.
An Old, Sleepy Giant
Greenland sharks are a bit of a mystery.
For starters, they are Earth’s longest-living vertebrates — living at least 250 years, but possibly more than 500 years. Researchers believe the sharks don’t even reach sexual maturity until sometime after they are 100 years old, but that’s just a theory because there is no definitive way to determine their age, according to the National Oceanic and Atmospheric Administration.
The slow-growing and slow-moving Greenland sharks are typically between eight and 14 feet long, however, they have been known to reach lengths of at least 23 feet. They weigh up to 1.5 tons, according to National Geographic.
The sharks, which are primarily scavengers eating fish, squid, carrion, and the occasional ambushed seal, are the only shark found in the Arctic Ocean year-round. They also are known to live in the North Atlantic and Russian high Arctic in waters up to 7,200 feet deepand between 28.4 and 44.6 degrees, National Geographic explained.
Why A Greenland Shark Was Found In The Caribbean
The question on everyone’s mind is: why was a shark known to live in Arctic waters found in the Caribbean? The answer, scientists have theorized, is that Greenland sharks may actually be found in oceans around the world that are deep enough.
For example, when Kasana and the fishermen found the Greenland shark, they were at Glover’s Reef Atoll, which is part of the Glover’s Reef Marine Reserve World Heritage Site off the coast of Belize. While the water along the reef is only about 25 feet deep, there is a steep slope along the edge of the atoll that drops from 1,600 feet to 9,500 feet deep, FIU explains. The water there is deep and cold enough for the Greenland shark.
“It slopes suddenly and the depth goes really deep, really fast,” Kasana said, according to NPR. “We believe the line dragged from a much shallower depth to the drop-off, which is why we ended up catching this individual.”
So, could Kasana and her colleagues discover another Greenland shark near Belize? The answer is no one really knows for sure.
“If we were to catch another individual it would be sheer luck. We don’t set our lines in a way that targets Greenland sharks,” Kasana said, according to NPR.
That said, Omar Faux, one of the fishermen in Belize, adds that “I am always excited to set my deep water line because I know there is stuff down there that we haven’t seen yet in Belize,” according to FIU.