You might want to think twice about that week at the beach this summer. Last year saw a skyrocketing number of shark attacks worldwide—and the risk factors could continue for the foreseeable future. According to the University of Florida’s International Shark Attack File annual report, there were 79 attacks in 2010, up 25 percent from 63 in 2009. The U.S. saw 36 of them, the most in the world, while surfers were the victims of more than half the strikes worldwide. It was "hugely unusual by shark-attack standards," said file director and shark expert George Burgess. He said higher water temperatures, tied to rising global temperatures, and divers feeding reef fish and sharks could be behind the increase. The good news? Only six of the attacks were fatal, and incidents in Florida, at 13, fell to their lowest level since 2004.