Sharks are spending longer than ever off the coast of some popular Australian beaches, increasing the risk of interactions between the apex predators and humans. Research has found bull sharks are spending 15 more days off Sydney's coast during summer than they did 15 years ago, due to warmer water temperatures caused by climate change. The migratory sharks typically spend their winters in Queensland, chasing warming water before heading back to Sydney for some summer sun. But James Cook University experts have warned the rising water temperatures in NSW have increased the potential for human-shark encounters. With seas continuing to warm, the sharks could have a presence in southern parts of NSW on a year-long basis in the future, researcher Nicolas Lubitz said. "If this trend persists, which it...