White Sturgeon

The Kootenai River white sturgeon (Acipenser transmontanus) is 1 of 18 land-locked populations of white sturgeon known to occur in western North America. Kootenai sturgeon occur in Idaho, Montana, and British Columbia, Canada, and are restricted to approximately 167.7 River Mile (RM) of the Kootenai River extending from Kootenai Falls, Montana, located 31 RM below Libby Dam, Montana, downstream through Kootenay Lake to Corra Linn Dam at the outflow from Kootenay Lake in British Columbia. Approximately 45 percent of the species’ range is located within British Columbia. Many Kootenai sturgeon migrate within this restricted portion of the Kootenai River system to spawn in the Kootenai River, and they spend part of their life in Kootenay Lake in British Columbia. The Kootenai River originates in Kootenay National Park in British Columbia, flows south into Montana, northwest into Idaho, then north through the Kootenai Valley back into British Columbia, where it flows through Kootenay Lake and joins the Columbia River at Castlegar, British Columbia. The wild population now consists of an aging cohort of large, old fish. The population has declined from approximately 7,000 white sturgeon in the late 1970s to 760 fish in 2000. At the current mortality rate of 9 percent per year, fewer than 500 adults remained in 2005 and there may be fewer than 50 remaining by 2030. Current data indicate that population abundance declines by about half every 7.4 years. During the last 14 years of intensive monitoring (using techniques proven suitable elsewhere) only one hatching embryo has been found and no free-swimming larvae or young-of-the-year have been captured. Estimates show that annually an average of 10 juvenile sturgeon are naturally reproduced in the Kootenai River. This suggests high levels of mortality which are unlikely to sustain the historic population of Kootenai sturgeon.