The relationship of Snake River stream-type Chinook survival rates to in-river, ocean and

climate conditions

Howard Schaller, USFWS *Charlie Petrosky, IDFG

NPCC Science/Policy Workshop - September 12, 2007

0

20000

40000

60000

80000

100000

120000

1960 1970 1980 1990 2000

YearS

alm

on

an

d S

tee

lhe

ad

Steelhead

Spring/Summer

Fall

Sockeye

Coho

IHR-62

JDA-68LMO-69

LGO-70

LGR-75

Snake River Salmon and steelhead declined since completion of hydrosystem

Snake River spring/summer Chinook Smolt-to-Adult Return Rates (SAR)

0%

1%

2%

3%

4%

5%

6%

7%

1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Migration year

Pre

ha

rve

st

SA

R

run reconstruction adult recruits

CSS

NPCC objective 2%

NPCC objective 6%

Survival declines for stream-type Chinook were in the Smolt-to-adult life stage

mean

bad futureclimate/ ocean

good futureclimate/ ocean

hydro delayed mort

ocean regimedelayed mort

hydro delayed mort

ocean regimedelayed mort

Stock viabilitydelayed mort

Stock viabilitydelayed mort

median

Is there evidence linking estuary and early-ocean mortality to the migration experience

through the hydrosystem?

THE Critical Uncertainty that differentiated risk levels

amongst options in the 2000 Biological Opinion

(Peters and Marmorek 2001; Karieva et al. 2000; Wilson 2003)

Different passage routes over, through, or around dams

Submersible traveling screen

Collection channel

(3) Turbine

Forebay

Tailrace

(1) Spillway

Reservoir

(2) Juvenile Bypass Systems

Gatewell

Transport via barge and truck: • Bypass facility stress• Can not separate species• Disease exposure• Change estuary arrival timing

Inriver migrants also face challenges from the altered migration route

Hydrosystem effects on Smolt to Adult Survival Rates (SARs)

•Mortality within the hydrosystem (measurable)•Mortality in Estuary/Early Ocean life stages

Transported

• Measurable (relative)

– survive ~½ as well as in-river migrants in ocean (D ~ 0.5)

In-river migrants:

• Fish condition

– injury, stress, bioenergetics

• Delayed migration

– bioenergetic costs

– physiological state vs. arrival timing

– miss optimal environmental conditions

• Mostly indirect inferences

Berggren et al. (2006); Budy et al. (2002)

Multiple Analytical Methods for

mortality inferences

1.Compare Spawner-Recruit residuals upriver vs. downriver populations

2.Multi-stock S-R models differential and common mortality estimates between upriver &

downriver populations

3.Compare SARs PIT tags, upriver vs. downriver populations

4.Multiple regression upriver populations only vs. migration & ocean conditions

Snake River ESUDownriver populations

Spatial/temporal comparisons Spawner-Recruit models using downriver populations

-5

-4

-3

-2

-1

0

1

2

1950 1960 1970 1980 1990 2000

Brood year

Res

idu

als

Downriver populations

Schaller et al. (1999); Deriso et al. (2001);Schaller and Petrosky (2007)

Snake R. survive ¼ to 1/3 as well as downriver since dams

Common annual mortality patterns between upriver & downriver populations

Common year effects correlate with good and poor ocean conditions

Spawner-recruit analyses

Snake River populations

Snake River ESUDownriver populations

PIT tag SAR comparisons wild Snake and John Day stream-type Chinook, 2000-2004

Comparative Survival Study: CSS 10-year Report (2007)

PIT tag studies:

Downriver SARs are 3-4X Snake SARs

Snake River SARs generally < 2 to 6% SAR

Snake vs. John Day wild stream-type Chinook (PIT tags)

0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

14.0%

1999 2000 2001 2002 2003 2004 2005

Migration year

SA

R (

1st

dam

to

BO

N)

Snake

John Day

NPCC 2-6% SAR

CSS 10-year Report (2007)

Differential mortality

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

1970 1975 1980 1985 1990 1995 2000 2005

Migration year

Dif

fere

nti

al m

ort

alit

y

Spawner-recruit

PIT tags

Snake River survival 1/3 to ¼ survival of John Day populations

CSS 10-year Report (2007) ; Schaller and Petrosky (2007)

Spawner-Recruit analysis vs SAR comparisons:estimated difference in mortality Snake vs. downriverestimated difference in mortality Snake vs. downriver

Multiple Regression for Snake River alone1st year ocean survival (s3 in Zabel et al. 2006)

Environmental variables: migration corridor & oceanModel selection criteria: AIC and BIC

Bonneville Dam

Freshwater

Ocean

Directsurvival

transportedFish St,ds

Smolt to Adult Return rates

Recruits/Spawner

Smolts-per-spawnerEggs

Estuary

Direct survival through

Dams Si,ds

Hatcheries and Tributary habitat

s3 - Ist year estuary/ocean survival: (climate, estuary and plume conditions, and Delayed hydro mortality)

Harvest

Upper Dam

Si,e/o = Se/o*(1-Li)

MainstemHydro

Direct adult survival through Dams Su

Water Travel Time: Lewiston to Bonneville Dampre-dam ~2 days;

current ~ 19 days (10-40 days)

1938 (BON), 1953 (MCN), 1957 (TDD), 1961 (IHR), 1968 (JDA), 1969 (LMN), 1970 (LGS), 1975 (LGR)

0

5

10

15

20

25

30

35

40

45

1929 1939 1949 1959 1969 1979 1989 1999

Wat

er T

rave

l Tim

e (d

ays)

Coastal Upwelling Process

•Pacific Decadal Oscillation

• Interdecadal climate variability in the North Pacific – (Sea Surface Temperature)

•Coastal Upwelling Index• based upon Ekman's

theory of mass transport due to wind stress - 45oN – (productivity)

“Good Ocean”• Cool phase PDO• April Upwelling • Oct Downwelling

Expected change in 1st year ocean survival vs. WTT, Sept. PDO & Apr. Upwelling

Response to WTT - similar to results using upriver/downriver populations

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 5 10 15 20 25 30 35 40

Water Travel Time

S3

- fi

rst

year

oce

an s

urv

ival

average PDO & Upwellgood ocean SepPDO = -1; AprUp = 40poor ocean SepPDO = 1; AprUp = -40

Current WTT

Pre-dam. WTT

Best fit (adj. R2=0.71), simplest model (best BIC)

Survival Patterns for Snake Populations

• Multiple Regression Analysis: WTT was a variable that consistently explained patterns in various survival metrics

• These measures of survival were best described by WTT during smolt migration and ocean/climatic variables– Stream-type Chinook S3

– Stream-type Chinook SARs

– Stream-type Chinook R/S

– Steelhead S3

– Steelhead SARs

0.0

0.5

1.0

1.5

2.0

2.5

0 5 10 15 20 25 30 35 40

Water Travel Time

Ch

an

ge

in R

/S

average ocean (PDO = Upwell =0)

good ocean SepPDO = -1; AprUp = 40

poor ocean SepPDO = 1; AprUp = -40

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0 5 10 15 20 25 30 35 40

Water Travel Time

SA

R

average PDO & Upwell

good ocean SepPDO = -1; OctUp = -50

poor ocean SepPDO = 1; OctUp = 25

Summary• Upriver/downriver

population performance indicates the hydrosystem is a key factor influencing early ocean mortality

• Analyses of only Snake River populations - a significant component of early ocean survival is related to impacts of the dams – Magnitude of

hydrosystem related early ocean mortality ~ similar to other methods

Snake River stream-type Chinook

0%

20%

40%

60%

80%

100%

S3 (1st year ocean) Spawner/Recuit

Hyd

ro r

elat

ed o

cean

mor

talit

y

Conclusions • Multiple lines of

evidence indicate mortality in the early ocean life stage is related to cumulative impacts of the hydropower system

• Recovery efforts need to address these cumulative impacts