almost this exact same thing happened to a co-worker of mine. him and a group were diving on a shipwreck off the SC coast. only when they hit the water did they realize that a group of 10-12 tiger sharks had chosen this shipwreck as a breeding ground or a meeting place. he said one of them was about 12 foot and one was about 15 foot and the rest were 6 foot and smaller. he said as soon as they hit the water, the sharks immediately started circling them and the 12 footer starting getting closer and closer until one of them finally hit it with one of those sharkgun things and killed it. when the shark was hit and started bleeding, all the other sharks attacked it and the divers made tracks back to the boat.
now, about midway through this video, you can see the shark is within 10 feet of the guy's s-pear and is clearly circling him. I'm no expert, but I'd say if a tiger shark is circling you within 10 feet, you better do whatever you need to live. like Big Arn said, a tiger shark will eat ANYTHING and are known to be pretty aggresive. I don't buy that whole "we're in their environment" thing. on land, we're in the environment of bears, lions, and alligators. and I'd imagine that if you were being closed in on by a bear or lion and had the means to defend yourself, you'd probably do it.
