The recent spate of attacks — seven since June in North Carolina alone — has little to do with the shark population off American coastlines. Shark attack, George Burgess says, "is driven by the number of humans in the water more than the number of sharks." Carol Buchanan/iStockphoto hide caption

itoggle caption Carol Buchanan/iStockphoto

Surfer Alexis Gazzo (left) is helping train specialized lifeguards who will survey the waters around popular beaches in Reunion for sharks. Shark attacks have gone up sharply along the coast of the Indian Ocean island, with seven people killed in recent years. Emma Jacobs for NPR hide caption

itoggle caption Emma Jacobs for NPR

The antenna trailing off the diver's foot is there to ward off sharks by creating an electromagnetic field that sharks are sensitive to. Unlike fish snagged with the diver's spear gun, sharks warded off by the Shark Shield remain unharmed. Courtesy of Shark Shield hide caption

itoggle caption Courtesy of Shark Shield