Steelhead and Snow Linkages to Climate Change ?

Recruitment Curves Fact or Fiction?

Clues from Residuals

Possible Candidates PDO PDO PNI PNI Stream flow Stream flow Others Others

Mountain Snowfall A guess based on my experiences A guess based on my experiences Good skiing years = good fishing years Good skiing years = good fishing years

Data Sites for Snow Index Crater Lake Mount Rainier

Which Measurement? Seasonal Maximum Snow Depths Mt Rainier Crater Lake

Snow Depth Index and Residuals Snow Index

Evaluation of Crater Lk & Mt Rainier Snow Index (CRSI) Spawner-Recruit time series for 26 populations of Oregon steelhead Spawner-Recruit time series for 26 populations of Oregon steelhead Evaluated 4 environmental indices as variables Evaluated 4 environmental indices as variables CRSI CRSI CRF CRF nsPDO nsPDO nPNI nPNI Attempted fit of B-H function w/ and w/o environmental variable Attempted fit of B-H function w/ and w/o environmental variable Comparison Comparison Was model statistically significant ? Was model statistically significant ? Which model had lowest AICc score ? Which model had lowest AICc score ?

Four Environmental Indices The Last 80 Years

Fitting Recruitment Curves Overview Predictor Variable 1 Spawners Predictor Variable 2 Environmental Index Response Variable Recruits

Fitting Recruitment Curves Timing / Lags Predictor Variable 1 Spawners Predictor Variable 2 Environmental Index Response Variable Recruits

Which Models Significant?

AICc “Best Model” Frequency CRSI CRF nsPDO nPNI 19 Populations 5 Populations

The Not So Cool Part Decreased Snow = Fewer Steelhead

Mountain Snow Levels are in Decline (from 1950 to present) Source: Mote et al. 2003

Air Temperature is the Story (Willamette Valley 7-yr Running Avg) CRSI AirTemp

Temperature Increase to Continue Source: IPCC (2007)

Driven by Anthropogenic Factors Source: IPCC (2007)

Climate Change is Here “The West’s snow resources are already declining as the climate warms ” - Mote et al. (2003)

What Does this Mean for Steelhead ? Smaller Populations Smaller Populations Higher Risk of Extinction Higher Risk of Extinction How Much Higher ? How Much Higher ?

Attempt to Quantify Extinction Risk Snow trends as proxy for climate change effect Snow trends as proxy for climate change effect Forecast extinction risks with PVA Forecast extinction risks with PVA Tested three CRSI scenarios Tested three CRSI scenarios Slight decline (8% per 100 yrs) Slight decline (8% per 100 yrs) Moderate decline (15% per 100 yrs) Moderate decline (15% per 100 yrs) Large decline (34% per 100 yrs) Large decline (34% per 100 yrs)

PVA Model Add Spawners Recruits Adjusted Recruits CRSI

Slight Decline in CRSI Prob Extinct < 0.05 to 0.25 Prob Extinct < 0.05 Prob Extinct < 0.25 to 0.50 Prob Extinct < 0.50 to 0.80 Prob Extinct > 0.80

Moderate Decline in CRSI Prob Extinct < 0.05 to 0.25 Prob Extinct < 0.05 Prob Extinct < 0.25 to 0.50 Prob Extinct < 0.50 to 0.80 Prob Extinct > 0.80

Large Decline in CRSI Prob Extinct < 0.05 to 0.25 Prob Extinct < 0.05 Prob Extinct < 0.25 to 0.50 Prob Extinct < 0.50 to 0.80 Prob Extinct > 0.80

Grim Predictions At least 50% of populations At least 50% of populations vulnerable to extinction vulnerable to extinction

Implication for Fish Managers Crafting a Response Extreme Response #1 Extreme Response #2

A More Measured Response Accept that steelhead are in a evolutionary race against a rapidly changing environment Accept that steelhead are in a evolutionary race against a rapidly changing environment Losing the race = extinction Losing the race = extinction Management response should be: Management response should be: 1. Eliminate impediments to natural process of genetic adaptation 2. Support regional, national, and international actions to lessen and slow the impact of climate change

Natural Evolutionary Processes Part 1 – Get all Pieces in Full Play Enable full expression of species diversity Enable full expression of species diversity Functional populations across species range Functional populations across species range Function distribution across diverse habitats within a population’s range Function distribution across diverse habitats within a population’s range Resident life history strategy Resident life history strategy Repeat spawner life history strategy Repeat spawner life history strategy Older age smolts Older age smolts Maximize abundance of wild spawners to help retain genetic diversity Maximize abundance of wild spawners to help retain genetic diversity

Natural Evolutionary Processes Part 2 – Don’t put Adaptive Gains at Risk Limit use of hatchery fish Limit use of hatchery fish Genetic (regardless of broodstock origin) Genetic (regardless of broodstock origin) Ecological Ecological Expect phenotypic changes that depart from the historical condition, for example Expect phenotypic changes that depart from the historical condition, for example More resident fish More resident fish Smaller fish Smaller fish Different out-migration timing Different out-migration timing Different return timing Different return timing Do not try to counteract these changes Do not try to counteract these changes

Natural Evolutionary Processes Part 3 – Change Definition of Success Steelhead management paradigm shift Steelhead management paradigm shift Old – Abundance, productivity, and fishery utilization goals Old – Abundance, productivity, and fishery utilization goals New - Facilitation of rapid evolutionary change New - Facilitation of rapid evolutionary change Evidence of population response will be much slower and more difficult to detect Evidence of population response will be much slower and more difficult to detect Determination if management strategy is a success will not occur in our lifetimes. Determination if management strategy is a success will not occur in our lifetimes.

Summary Mountain snowpack is linked to climatic factors that effect steelhead survival and recruitment Mountain snowpack is linked to climatic factors that effect steelhead survival and recruitment Climate change will greatly increase the vulnerability of steelhead populations to extinction Climate change will greatly increase the vulnerability of steelhead populations to extinction Facilitating the evolutionary process of population adaptation to climate change should be the primary focus of steelhead management in the future Facilitating the evolutionary process of population adaptation to climate change should be the primary focus of steelhead management in the future

Questions ?

36 populations of steelhead, coho, and spring chinook

Preview Demonstrate an association between variations in mountain snowpack and steelhead recruitment performance Demonstrate an association between variations in mountain snowpack and steelhead recruitment performance Quantify an increase in extinction risk due to climate change based on linkages with snowpack Quantify an increase in extinction risk due to climate change based on linkages with snowpack Suggest that facilitating the evolutionary process of population adaptation to climate change should be the primary focus of steelhead management in the future Suggest that facilitating the evolutionary process of population adaptation to climate change should be the primary focus of steelhead management in the future

Summary of Evaluation Approach General Model General Model Recruits = (Beverton-Holt Equation) * exp(c * Indx) Examined 29 variations of model per population Examined 29 variations of model per population Evaluation Evaluation Was model statistically significant ? Was model statistically significant ? Which model had lowest AICc score ? Which model had lowest AICc score ?

Pretty Cool!

CRSI Reflects this Decline

Air Temperature the Last 1300 Years From 2007 IPCC Technical Summary Report

Major Extinction Events