Calapooia Chinook Environmental DNA Monitoring

Spring Chinook in the Calapooia River once numbered as many as 9,500 adults and were listed under the federal ESA in 2005. To make the most effective use of future monitoring funds and enable instream restoration targeted at the reach-scale, the CWC sought to address these information gaps regarding UWR spring Chinook in the Calapooia River with eDNA monitoring. The Calapooia Watershed Councils (CWC) proposed environmental DNA (eDNA) monitoring collected water samples on the mainstem Calapooia River and Sodom Ditch, from its confluence with the Willamette River in Albany to the end of anadromy on USFS property at RM 72.9, to determine the presence or absence of the Threatened Upper Willamette River (UWR) Chinook. The eDNA monitoring completed is the first evidence of Upper Willamette River Chinook in the Calapooia since 2015 and provides new evidence of their presence to support conservation efforts for the ESA-listed population. The results of this project informed the selection of instream habitat restoration sites and out-planting locations, depicted the spatial distribution of spring Chinook in the Calapooia River, and provided insights for future monitoring.

Once completed, the results of the Calapooia Watershed Councils environmental DNA monitoring will update the current understanding of Chinook distributions in the watershed by producing a map of negative and positive detections of Chinook DNA, along with the quantity of DNA detected at each sampling location. By comparing DNA quantities between sampling locations, managers can identify areas with relatively more or fewer fish throughout the sampling area. The map of detections will enable the prioritization of important Chinook habitat in the mainstem Calapooia at the reach-scale (~1.0 kilometer reaches). Fisheries biologists and restoration professionals would, therefore, be equipped with the knowledge of where future instream restoration would be most effective. In addition to highlighting key Chinook habitat, the map of Chinook DNA detections will provide a baseline for future surveys aimed at documenting Chinook in the Calapooia (e.g. where to sample in the future) decreasing the cost and increasing the success of these future efforts.

Another benefit of the eDNA monitoring will be the ability to ground truth the results of water quality monitoring conducted in the headwaters for the presence of ESA listed UWR Chinook. The CWC is currently monitoring stream temperatures (Wild Winter Steelhead; OWEB 218-3045-16036) during the summer months (May-Oct) to evaluate water quality limitations for salmonid survival and productivity in the upper Calapooia River. By comparing reaches with suitable water temperatures for salmonid survival and positive detections for UWR Chinook DNA, the CWC and fisheries managers will be provided with a greater understanding of habitat limitations facing UWR Chinook in the Calapooia River.

A major benefit of this proposed eDNA monitoring is the ability to run a portion of the sample (i.e. filter) for a target species, such as UWR Chinook, and archive the remaining portion of the sample for future investigations. The initial cost of $102 to run a sample is reduced for subsequent sample analysis to $42. Thus, this robust sampling effort will provide opportunities to answer future, and unforeseen, questions about the aquatic community of the Calapooia River. Species of particular interest for future investigations include Ludwigia spp. , freshwater mussels, Oregon Chub, and Pacific lamprey.