You can't really determine size from that particular picture since you have no reference. A large fish held out from the body of a person with the camera fairly close will look huge.
Here's an example below from a website that sponsors fishing trips with a humorous but honest disclaimer from one of the sponsors:
"It's a BIG fish, but not THAT big! Sean Tennis is goofing with the camera by holding his fish really really really close to the camera to make it look larger. However, it is still a BIG pargo in his hands."