Underwater video shot on Thursday shows what researchers say is a rarely-seen 30-foot whale shark swimming off the northern coast of Oahu near Kāneʻohe Bay.
Footage shows the shark feeding on schools of nehu, or Hawaiian anchovy, in the pristine blue water.
"While all the small nehu were being drawn to the surface from all the predators, the whale shark was coming in and using its massive mouth to come up to the surface, open it, and then the suction would cause all the fish to funnel into its huge mouth," said Mark Royer, shark researcher with the Hawaii Institute of Marine Biology with the University of Hawaii at Manoa.
Royer saw the whale shark while he and fellow HIMB researchers were returning from conducting fieldwork. They spotted what they believed to be a bait ball, or a tightly-packed spherical formation of small fish, as they were pursued by predators below.
Royer dove in to investigate further and was surprised to find that one of those predators was a whale shark.
"The whale shark is the world's largest fish, and though it is known to be in Hawaiian waters, it is rarely seen," the University of Hawaii said in a press release about the sighting.
Royer added that the video also captures a large aggregation of small and large predators, including mackerel scad, mackerel tuna, skipjack tuna, sandbar sharks and seabirds, who were also feeding on the nehu.
The University of Hawaii added that whale sharks are known to approach boats standing idle in the water. They encourage people to be mindful and respectful of the animals by letting them approach and not aggressively approach and disturb them.
Whale sharks can grow up to 40 feet and can weigh up to 40 tons, according to NOAA. The large animals mostly eat small organisms, such as nehu, which they strain from the water as they swim with their wide, meter-long mouths and specialized teeth.
Original article source: Watch: ‘Rarely seen’ 30-foot whale shark spotted near popular bay in Hawaii