Non-native Species Impacts on Native Salmonids in the Columbia River Basin

Including Recommendations for Evaluating the Use of Non-Native Fish Species in Resident Fish Substitution Projects

July 15, 2008  |  document ISAB 2008-4

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In 2007, the ISAB’s partners — the Council, NOAA Fisheries, and the Columbia River Indian Tribes — approved the ISAB to evaluate the state of knowledge of the impact of both intentional and unintentional introductions of non-native aquatic species on native salmonids in the Columbia River Basin. The ISAB found that the potential impacts and risks to native salmonids and other native fishes from non-native species are significant, with most subbasins in the Columbia River Basin already dominated by non-native fish species. Because of these impacts, the ISAB recommends that the Council and the Fish and Wildlife agencies in the Basin elevate the issue of non-native species effects to a priority equivalent to that of habitat loss and degradation, climate change, and human population growth and development.

The report is intended to help the Council:

1. develop guidelines for implementing the Fish and Wildlife Program to minimize future impacts from non-native species and
2. frame scientific guidance and propose criteria for deciding the limitations and appropriate use of non-native fishes to mitigate hydrosystem losses through resident fish substitution.

Sep 5 correction: The ISAB removed an incorrect statement from our July 15, 2008 report, in the last paragraph on page 35 continuing on the top of page 36, that lake trout were first introduced into McDonald Lake in Glacier National Park and then spread to Flathead Lake. In fact, Spencer et al. (1991) documented that lake trout were introduced into Flathead Lake in 1905 and first appeared in McDonald Lake in 1959 (Fredenberg 2002). To support this change, we added the following reference to our report: Fredenberg, Wade. 2002. Further evidence that lake trout displace bull trout in mountain lakes. Intermountain Journal of Science, Vol. 8, No. 3: 143-152.

The ISAB thanks Wade Fredenberg of the US Fish and Wildlife Service, Kalispell, Montana, for catching the error in our report."

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