I think it's just a matter of fish getting startled. Case in point: I know a guy that was paddling a canoe in Florida with a friend. Not sure where but I thought he said Okeechobee. Anyway they were playing around and the other guy was pounding the bottom of the canoe like a drum beat. Suddenly a largemouth rocketed out of the water and into the canoe!

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.