But when the fishing boat docked in Provincetown, the fish was confiscated by federal agents. Rafael said he didn't know that tuna must be caught by rod and reel - not by a net - in order to be kept and sold. "They told me everything you have to do, but they didn't tell me that," Rafael said. The fish would have sold for almost $5,000, Rafael said. Since the fish was already dead, the government will sell the tuna, he said. He was given a warning by the agents. "I'm going to surrender all my permits. I pay all that money every year," he said. "Next time I catch [a tuna] I'm going to throw it over the side." A National Oceanic and Atmospheric Administration spokeswoman didn't immediately have a comment.