This diver captured mesmerising footage of hundreds of sharks during one of their annual mass gatherings. Caroline Robertson-Brown, 50, witnessed over 100 sand tiger sharks roam the murky waters above a WW2 shipwreck located off the coast of North Carolina, USA. The shark lover now works at a trust where she spends her days doing everything she can to protect these magnificent creatures of the deep blue sea. On this particular dive, Caroline took the CEO of The Shark Trust, Paul Cox, out for his first dive in years so that he could see the amazing marine life their important work is helping to protect. Caroline, from Manchester, UK, said: “Sharks are usually thought to be solitary animals, but at certain times of the year, sand tiger sharks gather in large numbers off the Eastern coast of the USA. “We were lucky to encounter over 100 sharks on an amazing wreck dive. It is thought that sand tiger sharks have a complex social network previously thought to only exist in mammals. “These sharks are also unusual in their ability to hover in mid-water. They do this by gulping in air at the surface to make them more buoyant. They then fart to release the air! “I had no idea just how incredible the dive would be. I thought there might be 10 or 20 sharks, not 100 to 200! “We did two dives on the same wreck and just loved hanging in the water watching these incredible sharks that seem to like congregating on this wreck. “I took these images and video clips to be able to show people who will not get the chance to see such an amazing gathering of sharks just how wonderful these animals are. “Sharks have been around since before the dinosaurs. In fact, they existed before trees evolved! “The smallest shark would fit in the palm of your hand and the largest is bigger than a double-decker bus. “They live under the ice and in tropical waters. On coral reefs and in the deep blue sea. They are jawsome!”