I love it! The composition is really nice, it makes the whole picture so easy to look at. I love the lighting!! I agree with Headwax about the difference in color temp though. The sky and the sand look so warm but the dolphins look like are being lit by a much whiter light. I'm not sure what could have made the colors look better but I didn't really notice it 'till Headwax pointed it out anyway, so it still looks really good.
The only thing that stands out for me is the shadow on the dolphins should be darker. I think this is more a personal preference that a technical thing, but the shadow on the grass in the sand seems pretty dark and is facing the camera because there is so much backlighting with the sun so low, it seems there should be more shadow facing the camera on the dolphins. But like I said, that's just a personal preference.
You've done a great oceanscape that two dolphins jumped into and became the stars of! The water looks great, the dolphins are having a blast, the grass in the foreground ties the whole picture together with the sun in the background...I love it! Great job!
SirBonovox
*edit*
Let me correct my previous statement. The shadows on the dolphins ARE dark enough, I just thought the shadows should cover more of the dolphin's body. But again, just a personal preference.
The more I look at this scene the more I like it. You can see the warm colors reflecting in the water, that helps the scene a lot. Again, great job.