I'm not sure, but it is fun to watch. I know they get in the water, and I know the fish are real, but I question how much of the fight is real due to the amount the underwater camera shakes with each fish. Also you would think that other fishermen in the area would want to get that $2000 for a single win, and (I think) $10,000 for the biggest overall fish.
I would do it once and get a turtle the hard way lol.