Fear is portrayed in the story because of two reaons; the beastie and the fear of never being rescued. The boys arrive on the island and are completely shocked at the situation they were put in, and this causes fear. Also, the boys see the "beastie", and they think that they are in massive danger.

 

"…fear can't hurt you any more than a dream. There aren't any beasts to be afraid of on this island . . . Serve you right if something did get you, you useless lot of cry-babies!" 

 

The boys on the island were worring too much about things that could happen to them, that they weren't even trying to make the best of the situation. They were paranoid about everything, and did not even realize that most of the problems were only in their heads.