A team of shark researchers traveled to Mud Island, a remote spot off Nova Scotia, in search of a population of enormous great white sharks measuring up to 20 feet long. Their main target was Big Rose, an elusive three-ton female believed to be one of the largest great whites ever encountered in the North Atlantic.
Shark researcher Dr Neil Hammerschlag first spotted the massive predator last year and returned to find and tag her for Discovery's Shark Week special Invasion of the Mega Sharks, airing Sunday at 10pm ET. The expedition came as great white encounters between Cape Cod and Nova Scotia have reportedly surged 1,000 percent over the past decade, with researchers increasingly observing what Hammerschlag described as very large, massive great whites.
Mud Island was the last place Big Rose had been seen and is emerging as a hotspot for sharks far larger than the eight to 10 foot great whites commonly documented around North America.
The team suspended a cage beside their boat and dropped bait into the water to lure sharks close enough to identify, measure and tag. Several large sharks appeared, including three measuring more than 14 feet and a 16-foot female the team named Sweetheart, but there was no sign of the 20-foot shark they had traveled hundreds of miles to find.
Hammerschlag climbed into a small inflatable boat and moved close to the circling sharks with an air-powered veterinary gun designed to fire tracking tags into their sides. He tagged four of the animals, allowing the team to monitor their movements around the island.
The next morning, tracking data showed all four sharks had moved to the opposite side of Mud Island. Suspecting Big Rose might have followed them, the researchers relocated their equipment, but the ocean appeared empty when they arrived, and hours passed without a single fin breaking the surface.
Underwater cameras eventually showed sharks circling far beneath the boat, staying deep rather than rising to the surface. The team deployed a custom lightweight cage built to descend farther than their original equipment.
Shark Week expert and attack survivor Paul de Gelder climbed into the cage and descended 50 feet to the ocean floor, in what the program described as the first bottom-cage dive conducted at the island. A 13-foot great white appeared through the gloom, confirming the sharks were still there but staying deep.
An even larger shape then appeared beyond the cage, but poor visibility prevented de Gelder from identifying it, and he had to abandon the dive when his air supply ran low.
The team dropped a 50-pound piece of bluefin tuna into the water and waited. A large great white soon emerged from the depths, wrapped its jaws around the bait and dragged it through the water. As the shark passed the cage, researchers spotted the distinctive rose-shaped marking on her dorsal fin. It was Big Rose.
The researchers celebrated as the shark circled the vessel. Their measurements indicated she was approximately 20 feet long, six feet across and weighed roughly three tons. Experts estimated she was more than 50 years old, making her one of the oldest predators in the region as well as one of the largest.
The team dropped a second piece of tuna, hoping to draw her close enough for Hammerschlag to tag her.
But Big Rose disappeared back into the depths and did not return, so researchers were unable to track her further movements. Experts said her repeated visits to Mud Island suggested the location holds ecological significance for great white sharks.
109 sharks documented
Over the following month, Hammerschlag tagged three additional large sharks, and the team documented 109 great whites around the island, including 25 that appeared more than once. Tracking data later showed Sweetheart traveling the length of the US Eastern Seaboard, passing Florida and eventually reaching Louisiana.
Although Big Rose was never tagged, researchers said her immense width suggested she may have returned to the area to give birth. If that suspicion is correct, an undiscovered great white birthing ground could be hidden nearby, meaning the search for Big Rose may have uncovered a larger mystery in the North Atlantic.
