The photo was taken very early in the morning and there was still just a little of the sunrise colors in the air. Now, you'll laugh about this, the colors on the water was oil (probably diesel fuel from the fishing boats). I noticed it when I got to a place where I could get a little more light from the sky to reflect off of it. It was a bit like a rainbow, in that it's hard to capture the subtle colors with a camera.
Great observation!