Genetic Identification of Brook Trout or Brook/Bull Trout Hybrids in Pataha Creek, WA

In 1998, at the time of listing under the Endangered Species Act (ESA), bull trout (Salvelinus confluentus) distribution was believed to include the Pataha Creek drainage (USFWS 2002/04, pg 8). Anecdotal information from local residents had suggested that bull trout historically existed in upper Pataha Creek, but their status was uncertain during listing and through draft recovery planning (i.e. 2001-2004). Brook trout (S. fotinalis) are known to have been introduced into Pataha Creek by the Washington Department of Game multiple times in 1951, and once in 1968. Brook trout are now well established in Pataha Creek from near Columbia Center upstream into the headwaters in the Umatilla National Forest (Mendel 1999; Schuck et al. 1988). Rainbow trout or steelhead (Oncorhynchus mykiss) also exist in this portion of Pataha Creek, as well as downstream. Washington Department of Fish and Wildlife and US Forest Service staff collaborated in an effort to capture brook trout to determine if genetic evidence could confirm a prior presence of bull trout that may have hybridized with brook trout. This information would be important for management decisions regarding ESA recovery planning and implementation.