An exploratory analysis of
climate impacts on Washington
steelhead productivity
Nate Mantua
University of Washington
Climate Impacts Group
Pacific States Marine Fisheries Commission Pacific Coast
Steelhead Meeting
March 7-9, 2006 Fort Worden, WA
Analysis
 Compare steelhead environment for
“best” and “worst”productivity
periods from select populations
 Use daily streamflow, ocean
temperatures, and upwelling
indices during key periods of
steelhead lifecycle
Data
 WDFW steelhead data
 Estimate recruits-per-spawner (R/S) indices
from WDFW run-reconstructions by assuming a
fixed age-structure
 Hatchery smolt-to-adult return rates (SARs)
 Environmental data
 Daily streamflow from USGS gages
 Sea surface temperatures: time series from
select locations + maps from ship-buoysatellite data
 Annual spring transition dates
Populations discussed in this
talk
Skagit R. wild WSH
Quileute R.
wild WSH
Green R.
hatchery WSH
Wenatchee R.
Wild SSH
Yakima R.
Wild SSH
Chehalis R. WSH
(hatchery and wild)
Kalama R. WSH
(hatchery and wild)
Wenatchee R. SSH
run-size and R/S
 The Wenatchee R.
summer steelhead
declined
dramatically in the
1960s-70s,
rebounded in early
1980s, down in the
1990s, and sharply
increased in 19992001
Standardized anomalies
Wenatchee R. water year flow
anomalies: (1971-2000 averages)
Population and
productivity trends
for Yakima R. are
similar to those for
Wenatchee R.
 What’s driving these
fluctuations?
 Was it the ocean?
Streamflow? Both?
Neither?
Annual Run-Sizes
Annual R/S
Age .0 (post-smolt) cpue
(from Burgner et al 1992, INPFC)
3rd year
Nearshore SSTs during
Wenatchee summerrun ages 3 and 4
 There is a weak
tendency for 1st
spring/summer SSTs to
be warm during best
S/R years, and cool
during the worst S/R
years
 This is also true in 1st
and 2nd winter at sea
Smolt migration
4th year
Seasonal temperature and all-ages
steelhead distribution patterns
(after Burgner et al 1992, INPFC)
April-May-June
July-August-September
January-February-March
October-November-December
Spring/Summer smolt-year SST and
Wenatchee R. SSH R/S extremes
1980
1981
1982
1984
1998
1971
1972
1987
1989
1991
fall/winter smolt-year SST and
Wenatchee R. SSH R/S extremes
80-81
81-82
82-83
84-85
98-99
71-72
72-73
87-88
89-90
91-92
SW WA hatchery
steelhead SARs
 Kalama and Chehalis R.
hatchery winter-run
SARs are similar
 warm spring-summer
SSTs have no high
values
 latest spring transition
dates have low SAR
rates
April 1st
Spring/Summer smolt-year SST
and Chehalis hatchery SAR
extremes
1983
1984
2000
2001
2002
1982
1989
1993
1996
1997
Green R.
Hatchery SARs
 Green R. hatchery
winter-run SARs show a
prolonged downward
slide
 tendency for the
warmest spring-summer
SSTs to have only low
values
 Weak tendency for late
spring transition dates
to have low values
April 1st
Quileute R.
wild winterruns
 Peak run-sizes from
1995-2001, lows
from 1994-2003
 R/S highest from
1991-94 during
period of relatively
low escapements
3rd year
Nearshore SSTs
during Quileute
winter-run ages 3
and 4
There is a weak tendency for
1st spring/summer SSTs to be
warm during best S/R years,
and cool during the worst S/R
years
This is also true in 2nd summer
at sea
Smolt migration
4th year
Skagit R. wild
winter-runs
 Peak run-sizes from
1985-1990, lows from
1978-1981 and 19911998
 R/S highest from 197884 during period of
relatively low
escapements
1st year
2nd year
3rd year
4th year
Skagit winter-run age
0-2 streamflow and
age 2-4 nearshore
SSTs
weak tendency for high summer
flows in emergence year of high
R/S year, and high winter flows
for low R/S years
weak tendency for SSTs to be
warm during best S/R years
Smolt migration
Preliminary summary
 To date, this exploratory analysis finds no
prominent patterns of environmental links
with productivity
 confounded with density dependence related to
varying escapements?
 Weak tendencies for high wild fish
productivity (and low hatchery fish
SARs) with warm spring-summer SST during
smolt migration year
 There are many more exploration and
analysis opportunities with these data!
acknowledgements
 thanks to the many WDFW and Tribal staff who
have conducted spawner surveys over the past 30
years so that this rich run-reconstruction data set
exists
 Bill Gill from WDFW provided run-reconstruction
data sets and advice
 Curt Kraemer provided Green River hatchery SARs
 Nick Gayeski for providing Skagit R. runreconstruction data
 Funding for this research has been provided by
NOAA’s Regional Integrated Sciences and
Assessments program as part of NOAA’s Climate
Office
Catch per angler day as an index of
abundance for BC wild steelhead
Queen Charlotte Is.
West Coast VI
East Coast VI
Lower Mainland
• regional patterns suggest common environmental influences
• yearly changes in CpAD modestly correlated with yearly changes in
coastal upwelling (summer) and downwelling (winter) winds 2 year prior
to catch data (typical year of smolt migration) …
Smith and Ward, 2000, CJFAS
Smolt-to-adult (marine) survival:
Keough River, Vancouver Island
Smith and Ward 2000, CJFAS
spring/summer SST during BC’s
good 80s and poor 60s-70s
Low CpAD era: 1966-79
High CpAD era: 1981-89
A weak tendency for higher CpAD when
spring/summer SSTs near average.