Swarms of up to over a thousand basking sharks have been spotted along the northeastern U.S., puzzling experts who study the normally solitary species.
Aerial surveys meant to locate endangered North Atlantic right whales in recent decades have revealed massive groups of the world’s second-largest fish. Found worldwide, these slow-moving filter feeders pose no threat to humans.
As big as basking sharks are—at 32 feet long outsized only by the whale shark—the deep-sea dwellers can be tricky to track down.
And without those opportunistic sightings, “that data was hiding away,” says Leah Crowe, leader of a recent study on the phenomenon and a field biologist at the National Oceanic and Atmospheric Administration’s Northeast Fisheries Science Center. “Our goal is not to do that with our research.”
In the study, published in the Journal of Fish Biology, Crowe and colleagues documented 10 sightings of large groups of basking sharks between 1980 and 2013 along the coast of Nova Scotia to Long Island.
The researchers uncovered about 10,000 documented sightings of basking sharks in the database, and 99 percent were of groups of seven or less.
Photo: Greg Skomal/NOAA-Wikimedia Commons