A couple of our "fishermen" threw a few slabs of skipjack (used for cut-bait) to the sharks. The sharks checked them out and ignored them. Some other idiot threw a beer can overboard and one of the sharks immediately ate it.
These fish respond to electrical stimuli as well as scent and vibrations in the water. They can literally "feel" a food fish using his swimming muscles.
This means that there are a LOT of things that can happen in the water that can make them think you are the entree for their next meal.
Not all of these sharks have read up on exactly how they are supposed to act (they don't get the "Discovery Channel") so don't be surprised when they do something you didn't expect.
If you want to play with a shark, just think about which of the two is more likely to end up in an ambulance.
You play with sharks with a 45/70 and Garrett ammo... What that diver is doing is insane.