
Well, Kain pointed already out some things, I'd heavily recommend removing lots of the details in the background to make the fish stand out more. I'd also change the position and the contrast level of the boat, to sugest more depth, same for the line. THe water surface could be improved by using a form perspective and by strengthening the highlights at the fish and adding a lot of contrast to the hook, the fokus will be better.
I also think that the piece could use a lot of Antialiasing, I added here and there some sloppy AA, but it seems to be fine. It definitely needs a lot more.
And the clusters (e.g. bubbles, bg fish) need a rework to prettier forms, also those of the fish.
P.S. I read the rocks as underwater fissure and not as land/sea