Welcome to the forum! Interesting photos. It would help if you could give us a little information on them, though. Where were they taken? What kind of camera was used? Some specifics of what we're looking at. You know, things like that.
I really like the photo of the underside of the shark! What is the light above him? I'm guessing it's some sort of artificial light source, but I actually like the back-light it creates. I would like to see both fins, though- the one is cut off a bit. Overall a nice capture!