Environmental Assessment of Culvert Fish Passage using Environmental DNA

WSDOT is correcting hundreds of fish passage barriers in compliance with a U.S. District Court injunction. Culvert injunction implementation also requires post-project monitoring. WSDOT contracts with Washington Department of Fish and Wildlife (WDFW) for biological monitoring to detect salmon and steelhead presence at WSDOT fish passage sites. Current methods for assessing fish use upstream of corrected barriers requires biologists walking the stream looking for evidence of salmon. The new method using eDNA enables the detection of species by taking water samples and analyzing the DNA which is constantly shed by organisms in the environment. This looks to be a more efficient and reliable method especially for detecting species present at low levels or those which are difficult to observe. The use of eDNA would also allow for the detection of rare or endangered species, or others of management interest which could aid in project analysis or prioritization. The proposed project will develop and routinize sensitive and cost-effective methods for endangered species assessments and post-project monitoring. Utilizing eDNA methods from water samples, the detection of salmonid species, ESA listed species, invasive species and other species of conservation interest will be undertaken as a continuation of a project already underway between UW and WSDOT at fish passage restoration sites in Skagit county on state roadways. Sampling protocols will be developed for three target species, along with guidelines for data interpretation. The protocols will be applicable for other species besides the three chosen for this proposal.