"-Look for a snout, back, tail, or flipper breaking the surface of the water. A swirl or flat spot on the water is also created by the motion of the manatee’s tail when it dives or swims.
If you see a manatee while operating a boat or personal watercraft, remain a safe distance away — 50 feet is the suggested minimum. If you want to observe the manatee, cut your motor."
manatee boat safety blog