Yellowstone NP is making another concerted effort to stem the tide of non-native fish within the park, called “The Native Fish Conservation Plan.” There are several sources to find out more. The Island Park News has a quick overview of what the park is doing. The park has a home page to find out more. They are currently taking public comments, and you can go to this page to add your voice. You can see the detailed letter sent from Walter Wiese, Head Guide at Parks’ Fly Shop in Gardiner, MT to get some ideas (if you need them).