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Coho salmon spawning preference in artificial stream channels at the Oregon Hatchery Research Center. Leanne Weiss Advisor: Desiree Tullos. wildernessclassroom.com/.../coho%20salmon.jpg. What factors impact where salmon spawn?. Common descriptors of spawning habitat:. Gravel size
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Coho salmon spawning preference in artificial stream channels at the Oregon Hatchery Research Center Leanne Weiss Advisor: Desiree Tullos wildernessclassroom.com/.../coho%20salmon.jpg
What factors impact where salmon spawn? Common descriptors of spawning habitat: Gravel size Water depth Velocity
What other factors impact where salmon spawn? Hyporheic zone • “subsurface region of a stream where the groundwater and stream water interact” (Arntzen, Geist and Dresel 2006). How do Hyporheic processes effect fish and their choice of spawning habitat? Upwelling areas of groundwater discharge into stream water Downwelling areas of stream water discharge into groundwater
Consider known spawning and non-spawning sites and the following variables: Upwelling/Downwelling Subsurface velocity Substrate size Dissolved oxygen
How do you measure upwelling/downwelling? Vertical Hydraulic Gradient • where difference between water level in the piezometers and water level in the stream: • [water level inside piezometers] – [water level outside piezometers] • And depth of stream bed to the bottom of the piezometer: • [top of piezometer to center of opening] – [top of piezometers to gravel surface] From Dahm et al. 2006
Other measurements taken Subsurface Velocity Slug tracer test Enter in a known concentration of NaCl and measure conductivity Substrate Size Sieve samples Cumulative particle distribution (surface/subsurface)
Most literature shows upwelling or downwelling to be the most important factor in spawning location Possible reasons my data did not show this • Artificial channels • Constant flow • Bedload is not moving • Habitat is not restructured
Why should we care? ESA “critical habitat” Better ways to create artificial habitat
Thanks… • Desiree Tullos, David Noakes, OHRC, Ryan Couture, Joseph O’Neil, Nicole Czarnomski, Arianna Lambie, John Best, Cara Walter, Donna Viss, Sherri Johnston, Julia Jones, Kari O’Connell, Jorge Ramirez, Jennifer Hill Works Cited inPresentation Arntzen, E.V., Geist, D.R., Dresel, P.E. 2006. Effects of fluctuating river flow on groundwater/surface water mixing in the hyporheic zone of a regulated, large cobble red river. River Res. Applic. 22:937-946. Dahm, C.N, Valett, H.M., Baxter, C.V. 2006. Chapter 6: Hyporeheic Zones. In Hauer, F.R., Lamberti, G.A. (eds.), 2006 Methods in Stream Ecology (pp 119-144). Oxford UK: Elsevier.