The 10 Essential Understandings about Upper Columbia River

Spring Chinook Salmon

Todd Pearsons and Peter Graf

Grant County Public Utility District

7/20/2017

Parkhurst

Overview

1. 10 essential understandings

2. 6 important knowledge gaps

3. 3 management recommendations

1. Three main characteristics of UC spring Chinook abundance (1, 1850-1935)• “Their runs, however had been virtually decimated during the past

thirty or forty years largely through the construction of impassable mill and power dams and by numerous unscreened irrigation diversions.” (Fish and Hanavan 1948)

1. Three main characteristics of UC spring Chinook abundance (2-1935-present)

1. Likely dramatic decrease between 1850 and 1935 (HH) 2. Dramatic increase since 1935 largely the result of hatcheries (GCFMP)3. NOR have generally declined since escapement was measured in 1960 and remain low (ESA -1999)

1. Three main characteristics of UC spring Chinook abundance (3-1999-present)

Recovery Goal

2. Loss of local adaptation

• Barriers, genetic mixing, and abundance bottlenecks• All spring Chinook passing Rock Island Dam and intended for natural

production were transported to Nason Creek between 1939 and 1943

• “The original plan for the Grand Coulee Fish-Maintenance Project was to compress the salmon runs then utilizing some 1,140 miles of the upper Columbia River and tributaries into a stream length of approximately 677 miles.” (Fish and Hanavan 1948)

• “The relocation of fish runs occasioned by the construction of Grand Coulee Dam was an experimental operation on a vast scale.” (Fish and Hanavan1948)

Parkhurst

3. Long history and influence of hatcheries

• GCFMP hatchery composit and outplanting BY1940-

• Every major spawning population has received SPC stocking (refuges)

• Current PUD hatcheries have a high standard of care, recalculation 10

• Supplementation mechanics are working as planned but may be decreasing NORs (BACI)

4. Evidence of density-dependence during freshwater spawning/rearing (abundance, size)

0

40,000

80,000

120,000

160,000

200,000

0 500 1,000 1,500 2,000

Nu

mb

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f P

arr

Number of Spawners

Chiwawa Spring ChinookSmooth Hockey Stick

K = 113,801

Adj r2 = 0.809

5.Ocean conditions are correlated with interannual variation in abundance

6.Long migration distance decreases survival

• Juveniles - “research under present conditions (e.g., Skalski 1998; Muir et al. 2001; S. G. Smith et al. 2002) indicated that while travel rate depends on flow, survival seems to be an almost constant function of distance; the farther the fish have to go, the less likely they are to survive the trip.” (Quinn 2005, p 227)

• Adults - early run timing disproportionately exposes adults to predators and harvesters

7. Cold water and perhaps low food limits juvenile growth and likely increases migration mortality• One of the coldest

regions in the country

• Water temperature can limit scope for growth

• Food may be low because of low nutrients (carcasses)

• Small size decreases migration survival (Wenatchee 93 mm, Tucannon 106 mm, Yakima 125 mm)

8. Protected, changed, and hostile habitats

• Much public land - Physical habitat in many areas is excellent

• Historic changes in physical habitat, beaver and salmon carcass abundance

• Unusual habitats – large area of the Methow River goes dry annually, two spawning aggregates migrate through Lake Wenatchee

9. Many handling events contribute to mortality

Handling Activities (n=20)• Electrofish in Nason Creek

• Screw trap in Nason Creek (2)

• Screw trap in Wenatchee River (2)

• Juvenile trap at Rock Island Dam

• Gate well net at Wanapum Dam (2)

• Gate well net at Priest Rapids Dam (2)

• Juvenile trap at McNary Dam

• Juvenile trap at Bonneville Dam

• Catch and release angling of adult below Bonneville Dam

• Catch and tag below Bonneville Dam for survival study

• Adult trap at Bonneville Dam

• Caught in gill net in Zone 6 and then escapes

• Sampling at Dryden Dam

• Conservation fishery in Wenatchee River

• Sampled RRS/brood collection/management at Tumwater Dam

• Sampled at Chiwawa weir for brood collection

Hypothetical Mortality Scenario (41%)• Total mortality = direct mortality +

indirect mortality + cumulative handling mortality

• Total mortality for 10, 20% of population, 2% mortality sampling events = 4% + 20% + 5% = 29%

• Total mortality for 1, 100% of population, 2% mortality sampling event = 2% + 10% = 12%

• Grand total mortality = 29% + 12% = 41%

10. Improvements to hydro, hatcheries, and habitat, have not been fully evaluated yet• Hydro - GPUD juvenile bypasses - Wanapum 2008, Priest 2014

• Hatchery recalculation 2013

• Habitat enhancements - riparian vegetation, side-channel reconnections

Some important gaps in knowledge

1. Influence of historic actions on productivity (e.g., GCFMP)

2. Cause of NOR limitation associated with hatcheries (BACI, density-dependence, domestication, spawning distribution, inbasinreferences)

3. Mainstem survival in the absence of dams

4. Limitations on growth/survival from cold temperatures and nutrients

5. Effects of multiple handling events on survival

6. Influence of recent management actions on survival

Management recommendations

Revise hatchery expectations and resize conservation hatchery programs

Assign balanced number and distribution of refuge and reference streams

Focus attention on fixable limits - nutrients, adult loss, compounded handling/delay