If you are swimming alone you get an option to "Watch Shark" which usually leads to a warm wetsuit and a battle with the shark where you take some damage. "Examine Shark" has only happened to me when I was swimming with a merman/mermaid. Result is STILL a battle with the shark but you usually wind up winning with no damage taken. Anyway that has been my experience with it. You get a message that ends with , "Way to go, Champ!" lol Merfolk don't get attacked by sharks and if you are swimming with them you can have a friendly conversation where you "Talk about sharks" but I'm not sure if this would prevent the attack.