This an amazing piece of photography showing great sills and technique of the artist. The timing is perfect; sunset, sea and dolphin all in one, captured in an extremely symbolic manner.
The sky to sea ratio has been matched beautifully and the water on the right side with the glare matches perfectly as though its reflecting the motion of the dolphin.
The only minus I could see it that the sky could have had a few clouds visible to give it a sort of texture that showing up like a simple gradient. The dolphin could also have been highlighted a bit more.