All this shark talk makes me just want to forget about spearfishing... hahaha J/K Thanks for all the great tips.
I'm going to try to find one of the spearfishing classes somewhere and take it.
But one more question, are you guys really seeing that many sharks when you go? What kind of sharks are you seeing and are there are certain ones you should look out for or just act the same around all of them?
It's pretty rare to see a shark unless you are spearfishing. XRay and Grouper did a test, just shooting a speargun (not at fish) and sure enough, a shark appeared. When a hook & line boat arrived at the next reef over, the shark left, and headed in the direction of the new boat. They have learned that both hook & line fishers will throw back their undersized fish, which make an easy meal for them. They have also learned that spearfishers will give up their catch if they charge them a few times.
Sharks hunt a dusk, dawn, and at night, when their superior senses give them edge over their prey. They have been doing that since before dinosaurs walked the earth, and have survived at least 5 mass extinctions with that strategy. They are not dumb and they are not mindless killers either. They won't pass up an easy or free meal, but they do not want to fight you for your fish. You are big, put off strange electrical signals (which they can detect) and blow loud, confusing bubbles from your face. You don't move like other fish, but you are apparently pretty formidable because you carry several large, dead fish in one of your appendages. You also have the ability to jump from the water and disappear completely. They don't pick fights unless they are damn sure they can win them, and they're not sure they can win fights with us yet. Bluffing on the other hand is relatively low risk, and they have learned to make a living with a bluff.
Everyone and their sister says that every shark they see is a bull shark. On this, I call Bull$4i^. I've seen nurses, sandtigers, reefs, sandbars, ONE bull, and one tiger. The tiger was a fluke, and you need to buy a lottery ticket if you see one diving around here. Bulls, sandbars, duskies, reefs, silkies, et al, are all "Requiem Sharks" and are often very difficult to tell apart. When someone sees a gray 7ft shark that doesn't have a hammer head or tiger stripes, then it magically becomes a "Bull Shark", even if it really is a reef shark or dusky. Even if you know your shark anatomy, you're going to make mistakes on id's. When I look at video we have taken spearfishing, the shark I see most is the sandbar, then what I suspect is the caribbean reef shark (even with photos and video it is difficult to tell sometimes).
I don't see any reason to change behavior based on the species of the shark*. You could have a 350 pound bull that's merely curious, or a 4' sandbar that's showing a threat posture, and trying to chase you off his reef with a few chomps. Both deserve respect. I think of them like dogs. They sense fear (at least imho) and will establish dominance if you don't establish it first. Never run from a shark. A retarded shark with two missing fins can outswim Michael Phelps, so fleeing will do you no good, and only encourages an aggressive predator.
*
If I ever see an oceanic whitetip (carcharhinus longimanus) though, my @$$ is out of the water tout suite 
