it's definately a shark it's dorsal fin is pointed at the tip which is common amongst sharks, also if you look at it's face it's head is flat where as with dolphins it's more rounded. It is obviously a shark. look at other pictures and you'll see the resemblance!! sharks are known to migrate to warmer waters hence why the shark is in the surf, he is looking for food duh! j/p... but yes it is a shark so be careful out there!!!