Sawyer is wearing a short sleeve blue t-shirt when he jumps into the water after the relay race at the end of the movie. Once underwater, the shirt has long black sleeves. This indicates a passage of time.
When the news channel shows Winter, there is footage of the dolphin being lifted into the truck at the beach. At the beginning, when the dolphin was first rescued, there were only the rescuers and the boy, but one of the rescuers did have a camera and was filming the events.