Quite an interesting creature indeed. Another image from St Maarten?
Did you crop significantly? I see something that I can't explain (lack of experience kicking in here). The front part of the image and the crab looks very neat, sharp and clear. However the "read-half" of the crab looks softer, but noisy as well. I thought it might be the focus that would be on the front, but at f/11 I guess it should not be an issue.
Beside that, very nice image. I love the very small catchlight in the eye.
Thanks, folks. Yes, P-A, another St. Maarten image (I got home about an hour ago :( ). I too was wondering about that look and think it is a combination of wet shell with bright un-diffused tropical light (it was a midday picture), but I'm not sure. No, it's not a significant crop.