Trivia: When Gollum is catching a fish in the river, Andy Serkis had to act out the scene first, so the computer animators has something to work with. However, when they got to the river, it had been snowing and the whole river had turned to ice. The crew had four hours to defrost the river and get rid of the snow so the scene could be shot. They managed to do it, but Serkis still had to perform the scene in near-freezing water with so many thermal suits, etc, that he could hardly move.