Mountain Lake Non-Native Fish Eradication Pretreatment Planning Reconnaissance Surveys of Kettling, Skymo, and Sourdough Lakes at North Cascades National Park Service Complex, Washington: 2010 Data Summary by National Park Service (Paperback / softback, 2013)
Ninety- three naturally fishless mountain lakes found in the park complex have been stocked with n-native trout, and currently 33 of these lakes contain naturally reproducing populations. These self-sustaining fish populations have the ability to overpopulate with multiple age classes, effectively dominating many trophic levels and consuming excessive amounts of their prey base. In addition, n-native trout are dispersing downstream from lakes and competing or hybridizing with native fish.