Title: Historical Review
1Historical Review
2Two Management Approaches Spill for Fish Passage
- Planning dates
- Percent passage dates
3Planning Date Advantage
- Certainty in planning and implementing hydro
system operations - Eliminates controversy and conflict regarding
spill management - Implemented within present data collection
systems
4Planning Date Disadvantage
- Late migrating stocks receive less spill
protection - Does not adjust to variability in passage
distribution and timing - Does not incorporate travel time
5Advantage of Fixed Percent Passage
- Potential to extend protection to later migrating
stocks which extend beyond the present planning
dates - Potential economic benefit if percent passage
date occurs prior to the present planning date
6Disadvantage of Percent Passage Date
- Uncertainty in planning, difficult to predict
- Present data collection system does not support
this management approach - Using run-at-large weights protection to hatchery
releases - Present mark groups do not support this
management approach
7Present Sampling and Marking Do Not Support the
Percent Passage Approach
- Mark groups do not represent the entire passage
distribution - Marking constraints
- Sampling constraints
8Cont.
- Requires more extensive marking of specific
stocks to fully represent the migration - May require later end date of sampling
- Additional PIT tag marking required of index
groups
9Using Run-at-large, Weights Protection to
Hatchery Releases
- Run-at-large dates are determined by large
production releases upstream of the project - Protection of upstream origin or weaker stocks
is diminished at downstream sites
10The Historic Data1985-2003
- Run-at-large
- Timing and distribution data is highly influenced
by large hatchery releases - Present marking and monitoring does not allow the
differentiation between hatchery and wild stocks
in the run-at-large - Percentiles based upon the run-at-large timing do
not accurately represent the wild passage
distribution
11Spring Migrants
- For wild PIT tagged yearling chinook from the
Salmon and Clearwater basins, the 10 year average
95 detection date occurred after the June 20
planned end of spring spill in the lower Snake
River. - For Salmon River stocks in 6 out of the 10 years
analyzed (1994-2003), 7 to 16 occurred after
June 20. - For Clearwater wild yearling chinook in 9 of 10
years, 6 to 23 of detections occurred after
June 20.
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14Summer Migrants Snake RiverRun-at-large
- The 1991-2003 average 95 passage date at Lower
Granite was Sept. 3 - The 1991-2003 average cumulative passage index
that occurred after August 31 at Ice Harbor was
11.6 - The 95 passage date at Ice Harbor occurred after
August 31 in 9 of 13 years (based on Lower
Granite plus travel time)
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17Marked Snake Basin Subyearlings
- In 7 of 13 years (1991-2003) greater than 5 of
passage occurred at Ice Harbor after August 31,
August 15 at Lower Granite Dam. - Marked subyearling chinook may not represent the
wild run at large. In 5 of the 8 years of data
(1991-1998) marked fish showed a much earlier
passage date.
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19Lower Columbia Summer Migrants
- The 95 passage date of the summer migration at
McNary is largely influenced by the present
hatchery release schedules for Ringold and Priest
Rapids (Aug. 6 19) - For the 1995-2001 wild Hanford reach groups which
are PIT tagged in early June, 95 passage occurs
on July 26. There is no tag data for the middle
and late portion of this population.
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21Mid-Columbia Summer Migrants
- Unclipped subyearling chinook at Rock Island from
1997-2003 average 95 passage date at McNary is
Sept. 16 - In 3 of 7 years of data 95 passage occurred at
MCN (7-21) and BON (10-27) after August 31
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23Percentage of annual PIT tag detections occurring
in August at McNary Dam for subyearling chinook
originating in the Snake R. and Mid-Columbia R.
basins
Year Snake River Basin Snake River Basin Snake River Basin Mid-columbia River Basin Mid-columbia River Basin Mid-columbia River Basin Mid-columbia River Basin
Year ClearwaterRiver () Snake River () Tucannon River () Yakima River () Hanford Reach () Rock Island Dam () Wells Hatchery ()
1998 28.6 18.7 1.2 3.3 0.0 53.1 1.8
1999 (0 fish) 42.3 No tags 30.7 2.4 64.9 14.1
2000 (0 fish) 8.8 6.9 2.9 16.3 64.0 20.3
2001 (0 fish) 33.4 33.3 0.0 17.2 71.7 37.7
2002 (0 fish) 12.7 2.0 No tags No tags 57.2 5.1
2003 (3 fish) 12.5 No tags No tags 0.0 28.6 1.0
24Percentage of Subyearling Wild Chinook Migrants
Observed at John Day Dam During August
Year Yakima River Hanford Reach
1998 19.6 2.3
1999 20.0 9.2
2000 20.8 44.7
2001 4.5 66.7
25General Impressions
- Significant modifications are required to
sampling programs to facilitate the percent
passage management approach. - Expansion of mark groups are required for all
species to support the percent passage approach.
26Cont.
- On average 95 passage date for subyearling
chinook at Lower Granite Dam extends past the
planning date. - By terminating spill at Ice Harbor on August 31,
only the passage distribution through August 15
at Lower Granite is provided spill protection.
27Cont.
- On average wild Mid-Columbia stocks extend beyond
the planning date at McNary Dam.