Mount Rainier National Park The glacial system on Mount Rainier is the largest single mountain system in the contiguous 48 states and consists of 26 major glaciers covering 35 square miles and creating most of 470 mapped rivers and streams that occur within the park. Streams and rivers within MORA have been altered very little by humans and represent outstanding examples of pristine aquatic ecosystems of North America. Both glacially influenced and nonglacial drainages originate on the slopes of Mount Rainier. The streamside forests represent old-growth and mature forests that were established the region before European settlement. In addition, one of the last remnants of rain forests in the Cascade Mountain Range occurs in the park. Management of these aquatic resources requires a systematic inventory of the streams and rivers and long-term monitoring to establish an ecological database. One of the least known but regionally most important components of these ecosystems are fish communities.
The present status of native fish populations in the park is not well understood due to construction of dams outside the park, and previous stocking activities. Construction of Electron Dam on the Puyallup-Mowich drainage and Alder and LaGrande Dams on the Nisqually have blocked anadromous passage to these rivers and their upstream tributaries within the park. Mud Mountain Dam on the White River also blocks fish passage, but anadromous fish (chinook, coho, and steelhead) are transported around the dam, thereby allowing access to the upper White River, West Fork of the White River, and Huckleberry Creek basins. The State of Washington has also stocked Huckleberry Creek with steelhead a short distance from the park boundary. Chinook salmon have been observed in the White River within the park. Salmon migration in the Cowlitz and Ohanapecosh Rivers are blocked by dams at Riffe Lake and Mayfield Lake. However, coho salmon are still transported around the dams.
The Carbon River is the only major drainage without man-made dams blocking fish passage. Both steelhead and coho are found in the upper Carbon River. However, the present distribution of anadromous and resident fish in these rivers within the park boundary is unknown. Fish were not native to any park lakes. Official stocking of lakes and streams began about 1918, although private, informal stockings were made prior to this time. All of the larger park streams were repeatedly stocked with native and non-native species. Stocking was halted after 1972 consistent with new NPS management policies. Non-native species introduced include brook trout (Salvelinus fontinalis), which are widely distributed; hatchery strains of rainbow trout (Oncorhynchus mykiss), and several varieties and species of cutthroat trout (Oncorhynchus clarki) including
Yellowstone and West Slope cutthroat. Reproducing populations of non-native trout still survive in at least 28 lakes in the park. Native salmonids in streams include rainbow or steelhead trout (Oncorhynchus mykiss), coastal cutthroat trout (Oncorhynchus clarki clarki), and Dolly Varden (Salvelinus malma) and/or bull trout (Salvelinus confluentus). The hatchery strains of rainbow, inland cutthroat trout and eastern brook trout were widely stocked throughout the park and may have hybridized or replaced native stocks within their historic ranges. Additionally, several native anadromous species occupied streams before the construction of dams, and may likely occur within the park today since they are transported around the dams. These species include: Coho (Silver) Salmon (Oncorhynchus kisutch): White, Carbon, North and South Puyallup, Mowich Rivers Chinook (Oncorhynchus tshawytscha): White, West Fork of the White Steelhead (Oncorhynchus mykiss): Carbon, White, Puyallup, Nisqually (documented immediately outside park boundaries).