A “clustering” of great white sharks off North Carolina’s Outer Banks has grabbed the attention of shark trackers, who aren’t quite sure what’s behind it.
OCEARCH, a nonprofit that tags and tracks great whites, posted Tuesday on Facebook that four of its tagged sharks have gathered in the waters off North Carolina’s barrier islands over the past 30 days.
The group includes three males and a female, ranging in size from 9 feet 8 inches to 12 feet 7 inches, says OCEARCH. The largest weighs 1,420, says OCEARCH.
“What’s interesting is that all of the sharks… were all tagged during our Nova Scotia Expedition last fall,” said the Facebook post.
Why they’re suddenly gathering off North Carolina remains a mystery. However, one explanation could be a report issued by OCEARCH in March, which noted great white sharks are often deliberate in their prowling spots.
Researchers believe great white sharks off North Carolina are “taking advantage of all of the upwellings that occur right on the fringe of the Gulf Stream.”
“These upwellings stir up lots of nutrients and by being on the edge of the stream (and) the sharks have access to a wide range of water temperatures,” OCEARCH explained on Facebook.
Upwelling happens as winds force water away from beaches, allowing “deeper, colder, nutrient-rich water” to rise up from the ocean floor, according to the National Oceanic and Atmospheric Administration.
The result is often an area of the ocean rich in food for sharks, experts say.
“These nutrients ‘fertilize’ surface waters, meaning that these surface waters often have high biological productivity. Therefore, good fishing grounds typically are found where upwelling is common,” according to NOAA.gov.