Scientific Anglers Anatomy of a Trout Stream with Rick Hafele by 3M. By understanding the anatomy of your favorite trout stream, you can better understand where trout hold, how they feed and how to apply that knowledge to proper selection of flies and presentation. Aquatic biologist and author, Rick Hafele, shows you how to respond as conditions change. With these proven concepts for reading the stream and proper tactics for responding to the trout, you can plan your strategy to fish any piece of water. Consistently catch more and bigger trout.