Water Resources Research Act Program

Details for Project ID 2008OR103B

The Influence of Sediment Deposition on the Emergence Success of Juvenile Salmonids

Institute: Oregon
Year Established: 2008 Start Date: 2008-03-01 End Date: 2011-02-28
Total Federal Funds: $24,348 Total Non-Federal Funds: $63,068

Principal Investigators: Stephen Lancaster

Project Summary: The deposition of both coarse and fine sediment may pose a great risk to the survival of gravel spawning fish. Land use practices and wildfires, particularly preceding large storms, can be associated with large influxes of sediment to stream channels. While several studies have investigated the direct effects of fine sediment on the habitat and physiology of salmonids, the effects of coarse sediment deposition have not been established. A critical uncertainty in predicting the effects of accelerated erosion is quantifying the critical depth of sediment that can be penetrated by juvenile fish emerging from subsurface incubation habitat. The objective of this study is to quantify how the depth and composition of fill affects the emergence success of juvenile salmonids. Our approach uses experimental channels at the Oregon Hatchery Research Center to vary the depth and composition of sediment overlying incubating eggs in a series of two experiments. We hypothesize that increases in coarse sediment depth will result in a linear decrease in survival by entrapping juvenile salmonids in the subsurface environment. We further hypothesize that fine sediment will exponentially decrease the depth at which mortality occurs. The combined effects of fill depth and composition on egg survival and juvenile fish emergence will be analyzed with regression analysis. The resulting regression equation can then be used to infer survival rates from field-based measurements of fill depths and fine sediment concentration, thereby providing a predictive tool that can be used for monitoring and assessment. Without the information gained from this study, the biological implications of sediment deposition will remain uncertain and management targets will continue to lack a scientific basis. The proposed research addresses a key uncertainty in predicting the effects of increased sediment loads on fish survival, which is of broad concern through the Pacific Northwest region. The effect of sediment deposition on salmonid habitat also addresses two focus areas important for water resource management identified by the Institute for Water and Watersheds five year report; specifically research that can inform management decisions for the protection of forested streams and identifies the ecological implications of the deterioration and loss of aquatic and riparian habitat. Identification of the impacts of sediment deposition during the period of egg incubation will allow more informed forest and stream management decisions. Research products will include a peer-reviewed research paper published in a national or international journal, and presentations at local workshops with land managers and scientists. Students will also gain from training and participation in the proposed study. Researchers involved in the study will actively engage in outreach to the general public and school children through tours of the experimental facility.