Data collected during weekly annual redd surveys conducted in the Cedar River Municipal Watershed (CRW) 1996-current. Habitat Conservation Plan (HCP) bull trout redd surveys ceased after the 2011 spawning year. To continue monitoring the population, weekly surveys were reinstated by SPU in 2019. Due to staffing shortages, weekly surveys 2019 - 2022 only covered the historically most heavily used habitats, also known as the bull trout "Core Zone" (versus "non-Core Zone"). Approximately 77% of all redds observed in the CRW 2000 - 2011 would have been observed during those years using the 2019 - 2022 spatial survey extent (SPU data on file). In 2023, SPU reinstated the use of seasonal TES assistance to conduct redd surveys. Spatial and temporal coverage of surveys during 2023 were on par with historical coverage, i.e., 100% of all redds observed 2000 - 2011 would have been observed using the 2023 spatial survey extent. SPU will continue to hire at least one fish TES assistant to assist with surveys.
Information on redd location is used primarily to enable derivation of redd elevations. Redd elevation is critical to accurately represent potential impacts to the population caused by reservoir inundation of stream spawning habitat after the spawning period during fall through spring. Redd weekly timing information is critical to accurately represent whether embryos remain in the gravel and are vulnerable to impacts of reservoir inundation as the reservoir is refilled starting in early spring.