I personally believe in the "life of the fish" method of measurement. Let's say that three years ago, you caught a 12 inch trout. And that a trout might grow three or four inches a year. Then it's only natural, in the life of that fish, that it could now be a 20 inch trout. So "I caught a trout that is 20 inches long" might well be a true statement. Just sayin'.