Great White in the Florida Keys

Growing up in the Florida Keys, I always try to follow the local news down there, especially since I go home to visit any chance I get. In recent news there has been three great white sitings in the last couple months. One sighting really made headlines when a shark diver down in Marathon, got back into the water out of his diving cage, to capture photos of the great white shark. Even more recently about three days ago, one of my friends who was out shark fishing for a class caught a great white shark and posted a photo of it on Instagram. The shark was about 10-12 feet long, so not very big for a great white. And it was caught about 7 miles off shore of mile marker 74, which is a little north of Marathon. Growing up I only remember truly one great white shark experience, when I was about 7 year old my mom woke me up in the middle of the night, and we went to a marina and saw a massive great white shark hanging from a crane, that a man had caught. Thinking about what we talked about the first day of class I am curious what is causing great whites to travel to the South Florida warmer waters. I am also curious to see if more and more will continue coming over the years and if so is it climate changes, or lack of food resources where they normally stay causing it?