Hey! I've got my own copy of Hatchet right here!
Brian saw that the fish pond no longer had fish in it. He also looked at his shelter and saw that some of the wood for the wall was scattered around the beach, and his bow was jammed into a driftwood log. BUT, the main discovery was that he found the plane in the pond!
"It's the tail of the plane." - Brian, Chapter 16, Hatchet.