Steelhead Population Monitoring on Lower Yakima River Tributaries
Tim Resseguie
Yakama Nation Fisheries Management Program
Toppenish, Washington
Spawning ground surveys
Index of spawning escapement
Smolt Trap
Outmigration estimate
Timing and survival through the Yakima and Columbia rivers
Spawning Ground Surveys
Three pass surveys conducted between mid-March through the end of May
32 Miles in the Ahtanum watershed
78 Miles in the Toppenish watershed
93 Miles in the Satus watershed.
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2009 Satus Creek Spawning Survey
3 complete passes of Satus, Logy, and Dry
Creek and 2 passes of smaller tributaries
119 Redds were identified
Conditions for Redd identification were good
Satus Watershed Barriers
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Satus Creek
Main Stem Satus Creek
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Satus Creek Tributaries Redd Numbers
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Toppenish Creek
2 passes completed of Lower Toppenish mainstem, Simcoe Creek, and tributaries. Only one pass completed of the upper portion of Toppenish.
79 Redds identified
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Smolt Trap
5-foot diameter rotary screw trap
Located downstream from known spawning and rearing habitat on Satus, Toppenish, and Ahtanum Creek
Operated continuously from November through early June at each tributary
Smolt trap
Captured smolts are measured and weighed
We PIT tag a subsample of steelhead juveniles over 100 mm
PIT tagged smolts are released above the trap once a week to estimate efficiency
DNA samples
Scale samples
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Smolt Traps 2009
Toppenish Creek
–2418 Steelhead smolts captured, 1178 PIT tagged
Satus Creek
– 415 Steelhead smolts captured, 322 PIT tagged
Ahtanum Creek
– 22 Steelhead smolts captured, 17 PIT tagged
Smolt Numbers Compared with Flows in Toppenish Creek 2009
Smolt Numbers Compared with Flows in Satus Creek 2009
Toppenish steelhead out-migration timing in 2008
Toppenish Creek steelhead out-migration timing in 2005
Travel of Steelhead Smolts in Toppenish Creek between the screw trap and the Prosser PIT tag scanners
Satus Creek Out-migration timing in 2008
Out-migration Timing
Steelhead Smolt Out-migration triggered by the first significant discharge spike in late autumn or early winter.
Juveniles spend a significant amount of time overwintering in the lower section of tributaries and the Yakima River
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