Spatial and Temporal Distribution of Adult Summer Steelhead in Asotin Creek, Washington Ethan Crawford and Michael Herr Washington Department of Fish & Wildlife © Joesph Tomelleri
Background BPA funded RM&E project focused on calculating VSP metrics outlined by McElhany et al Operating a juvenile trap since 2004, adult trap since Project is a product of all the efforts that preceded it; Asotin Creek Model Watershed, habitat projects (million$), etc. NMFS funded Intensively Monitored Watershed began in 2008 (EcoLogical Research, Inc.)
Study Area
The Need We needed a way to provide estimates of spatial and temporal distribution in the tributaries. -Index Redd surveys have been historically completed with LSRCP funding by Snake River Lab staff. GOAL: GOAL: To use PIT tag interrogation data to describe spatial and temporal distribution by tributary.
Methods Since 2010, all untagged wild adult steelhead captured have been PIT tagged. Data are then entered into an MS Access database. Passive observations and interrogation data then merged and dumped into the project database.
Charley Creek (CCA)
Asotin Forks (AFC)
Results We found that estimates of escapement to the tributary are similar and at the very least no worse than redd surveys. T-test: In all instances we failed to reject H 0 : Redds=Fpit
Weir Timing
Tributary Run Timing Proportion of Adults Julian Date Charley South Fork North Fork
Sex Ratio
Age Composition
Conclusions Using PIT tag observations to document spatial and temporal distribution is effective and affordable for even the smallest projects. Though utility of PIT tag observations can be limited for the same reasons that redd surveys are. PIT tag data allows us a more detailed view of the spawning population and its attributes.
Questions?