This is a post written by Jason Freund, originally for The Scientific Fly Angler blog, which we are publishing on the Coulee Region Trout Unlimited website . Populations are incredibly complex as they are always changing - hence why we talk about population dynamics. The factors responsible for those changes are a mix of unpredictable (weather, floods, fish kills, etc.) and somewhat predictable (interactions among individuals - competition, predation, etc.). However, there ar