I was looking at the Vice City user manuel and on p.10 it has a description of "The Beaches", and under the description is in a little print:

"Shark attacks off Vice City happen a few times a year and there are more sharks out there than you would think - best advice: stay out of the water!-"

Now my question is:

Where are these sharks?

I've been looking all over for them, to get attacked by one, and I haven't seen one shark yet!

from what I understand the only shark that appears in the game is the one from the movie studio. after you do one of the missions for the movie studio you will see it floating in the water randomly.I have seen it 2 or 3 times and it dosent do anything to your character even if you shoot it.

I saw a shark twice when I stole a boat and was fleeing from the cops. It was just randomly swimming in the water

all you have to do is get a boat,, then go to middle of the ocean, just wait for a cople of minutes and youll see a shark come out, after that feed the shark by killing your self(well there not really goin to eat you)or before you kill your self shoot it!

The shark thing is just covering the fact that your character can't swim, you die if you fall in the water.