I don't have the definitive answer, but if I caught a fish that size I would be straining to hold it, even when standing up and using two arms. He looks calm and relaxed. I do think that a fisheye lens took the original picture. Look at the surface of the ice in the background, it appears curved, the trees tend to lean toward the edges of the picture, check the reflections in his glasses. I'm to old to understand what can be done with digital or a computer. Also the clouds tend to part towards the edges. It's been doctored.
