Juvenile Salmonid Use of Thermal Refuges in the Klamath River FY2014

During this project, the Yurok Tribal Fisheries Program conducted snorkel surveys on a weekly basis at five different tributary confluence areas on the lower Klamath River between river kilometer (rkm) 26 and rkm 80. We also used these funds to monitor adult salmonids (Chinook and steelhead) that were using thermal refugia in the Klamath River. These observations are extremely important in regards to disease outbreaks in adult salmonids, especially Ich. We were able to observe large congregations of adult Chinook and steelhead at the Blue Creek thermal refugia. These groups of fish can lead to disease outbreaks and our observations are used by water managers to make decisions regarding river conditions. Data analysis is currently being conducted on all aspects of this study. We were unable to conduct a PIT tagging study during the 2015 field season (we did conduct the PIT tagging pilot study in the 2016 field season). The PIT tagging aspect of this study was not carried out due to the projects lead field biologist unexpectedly separating from the Yurok Tribal Fisheries Program just before the start of the field season. We were unable to find a suitable replacement until after the window of opportunity for this study had passed.

The goal of this project is to continue the long-term monitoring of cold water refuge areas in the mainstem Klamath River, and also to begin to answer questions about exposure to disease-bearing water in the mainstem Klamath by juvenile Chinook and coho salmon and steelhead. (1) Capture and PIT tag numerous juvenile salmonids within or close to various thermal refuges. (2) Install PIT tag listening stations at various thermal refuges. (3) Detect these tagged fish as they enter and exit various thermal refuges. (4) Compare results to river conditions. This project will enable the Yurok Tribe to participate in the development of scientific information that will be used to affect water management on two important tributaries to the Klamath River; the Shasta and Scott Rivers. Outcomes and Benefits: Ascertain the length of time juvenile salmonids are holding in thermal refuges; establish how these tagged fish interact with the river while holding in the thermal refuges; gain a better understanding of the migrational timing between different thermal refuges; determine any relationships between study results and river conditions.