Titia, This is a "spiny lobster" sometimes called crayfish found in the warm waters of Florida and the Carribean. I prefer the "Maine lobster" a called water lobster which 2 big claws when it comes to eating.... However I'd rather dive where the spiny lobster resides....
Wow...intimidating subject. How deep underwater was this? In a perfect world, the scene would be more brightly illuminated, but I understand the severe lighting difficulties inherent in underwater photography.
There seems to be almost a 'polarized' effect all around the subject, but never on the subject itself. Is this a post-exposure modification, a digital artifact (result of compression or something?), or something else that I've never heard of before?