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Comparing Current and Desired Status: Gaps Analysis. Brief overview: ICTRT Viability Criteria Abundance/Productivity Gaps: Concepts and Calculations Considering Uncertainties – future environmental conditions, continued direct hydro survival improvements.

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Comparing current and desired status gaps analysis
Comparing Current and Desired Status: Gaps Analysis

  • Brief overview: ICTRT Viability Criteria

  • Abundance/Productivity Gaps: Concepts and Calculations

  • Considering Uncertainties – future environmental conditions, continued direct hydro survival improvements.

  • Results Summaries: Snake Basin Chinook and Steelhead

General trt tasks
General TRT Tasks

  • Define goals

    • Population identification

    • Viability criteria (ESU & population levels)

    • Example ESU Scenarios

  • How far do we have to go to get there?

    • Current status assessment

    • Defining “gap” between status and goal

  • Choosing and implementing actions

    • Limiting factors analyses

    • Evaluating the effect of proposed actions

Trt hierarchical criteria
TRT Hierarchical Criteria


ESU Status

Stratum/Geographic Unit/Major Population Group Status

Stratum 2

Stratum 3

Stratum 1

Pop Status

Pop Attributes

Ictrt viability criteria
ICTRT Viability Criteria

  • ESU level criteria

    • Major Population Groupings

      • Minimum number of viable populations in each

      • Major life history patterns represented

      • Historical population size representation

  • Population Level Criteria

    • Abundance/Productivity

    • Spatial Structure/Diversity

What are the ictrt criteria designed for
What Are the ICTRT Criteria Designed For?

  • Providing benchmarks for:

    Setting planning goals and objectives

    • Starting point for delisting criteria, recovery goals

  • Assessing the current viability of an ESU

  • Formulating protection and/or recovery strategies

  • Designing monitoring/evaluation efforts

    • To assess changes in population status, contributions from recovery and/or protection efforts

Purpose of mpg criteria
Purpose of MPG Criteria

  • General VSP recommendation: An ESU needs multiple spatially distinct and diverse populations to be viable.

    • 1) To protect against catastrophic loss of any one population.

    • 2) To ensure maintenance of long-term meta-population processes

    • 3) To ensure that AMONG population diversity is maintained

Comparing current and desired status gaps analysis

Snake River Spring Summer Chinook

Major Population Groupings

& Populations

Upper Salmon R. Group

Lemhi R. Pahsimeroi R.

North Fk Panther Cr

Valley Cr. Yankee Fk

East Fk Upper Salmon

Upper Salmon tribs.

South Fork Salmon Group

South Fork

East Fork/Johnson Cr.

Secesh R.

Lower Snake Tribs Group

Tucannon R.

Asotin R.

Middle Salmon R. Group

Big Cr. Bear Valley

Marsh Cr . Sulphur Cr.

Loon Cr. Camas Cr.

Chamberlain Cr.

Upper Mainstem & tribs

Lower Mainstem & tribs

Grand Ronde/Imnaha Group

Imnaha R. Big Sheep Cr.

Wenaha R. Minam R.

Lostine/Wallowa R.

Catherine Cr.

Upper Grand Ronde




Hells Canyon


Population level abundance productivity criteria
Population Level:Abundance/Productivity Criteria

  • Abundance should be high enough that:

    • In combination with intrinsic productivity, declines to critically low levels would be unlikely assuming recent patterns of environmental variability

    • Compensatory processes provide resilience to the effects of short-term perturbations

    • Subpopulation structure is maintained (e.g., multiple spawning patches, etc)

    • Status estimates should consider statistical uncertainties

Parameters contributing to risk abundance productivity
Parameters contributing to risk (Abundance &Productivity)


Variance (& autocorrelation)




Population level spatial structure and diversity
Population Level: Spatial Structure and Diversity

  • Three interrelated categories

    • Structure – spawning aggregations, spatial relationships

    • Maintaining Natural Variation

    • Habitats and Natural Processes

Integrating across ssd criteria
Integrating Across SSD Criteria

  • Simple Weighted scoring

  • A population would be rated at HIGH risk if:

    • Average rating across spatial distribution criteria is HIGH RISK or

    • Rating for life history or direct genetic criteria at HIGH Risk or

    • Average rating across Life history, genetics, habitat and selectivity criteria is HIGH

Ictrt viability curves
ICTRT Viability Curves Criteria

  • Expressed in terms of a simple hockey stick model (can generate curves for other functions)

  • Used a constant Quasi-extinction risk level of 50 spawners

  • Incorporated minimum abundance thresholds (function of historical spawning area of the population)

  • Modeling includes average age structure, estimated autocorrelation/variance in brood year productivity rates

Viability curve basic principles intrinsic productivity
Viability Curve: Basic Principles CriteriaIntrinsic Productivity



At Capacity







1 spawner for every

1 parent spawner

Parent Spawners

Population size thresholds
Population Size Thresholds Criteria

  • Populations with fewer than 500 individuals are at higher risk for inbreeding depression and a variety of other genetic and demographic concerns.

  • Increased thresholds for larger populations promote the full range of abundance/ productivity objectives.

    • Avoid Allee affects

    • Ensure compensatory processes

    • Provide for spawning in multiple sub-areas

Viability curve
Viability Curve Criteria

Comparing current and desired status gaps analysis

Wenatchee River Criteria

Current abundance & productivity

  • Comparison to Viability Curve

    • Abundance: 10-year geomean Natural Origin Returns

    • Productivity: Geomean of spawner to spawner return rates most recent 20 years, parent escapements below 75% of the threshold. Indexed to annual marine survivals to improve estimate of rate under average conditions.

    • Conclusion: Wenatchee Spring Chinook population is at HIGH RISK based on current abundance and productivity. The point estimate for abundance and productivity is below the 25% risk curve.

Oval: +/- 1 standard error

Lines: +/- 2 standard errors

Observed a p gaps
Observed A/P Gaps Criteria

  • Quantitatively gauging the relative change in survival/capacity required to move a population from current status to alternative viability levels (e.g., 5% or 1% risk over 100 years).

  • Expressed terms of return/spawner.

  • Gaps can be reduced by improved survival at any life stage from parr to returning adult.

  • Assume recent (post-1980) climate, hydropower system, hatchery and harvest influences

  • For a given population, more formal limiting factors analyses should be used to evaluate the potential for change at any given life history stage.

  • Caveat: All four VSP parameters (abundance, productivity, spatial structure and diversity) contribute to population viability. The ICTRT uses a series of metrics to assess current risk with respect to these factors. Comprehensive risk assessments are included in population specific status reports.

Ictrt gaps reports
ICTRT Gaps Reports Criteria

  • Two components

    • Observed Gaps: Generic assessment of a/p gaps for populations with sufficient abundance data series

    • More detailed stochastic matrix modeling for selected populations with sufficient data

      • Incorporates alternative climate scenarios

      • Improvements to life stage survivals (e.g., current vs historical hydro)

      • Can incorporate more detailed (life stage specific) analyses of recovery strategies

        • projected improvements in survival or effective capacity

      • Matrix Model Populations

        • Yearling Chinook: Wenatchee, Marsh Cr., South Fork and Catherine Cr.

        • Steelhead: Umatilla River, Rapid River (subarea of Little Salmon River population).

A p gaps
A/P Gaps Criteria

  • Observed Gap: Quantitative change required to meet ICTRT A/P viability criteria

  • Simple Algebraic approach

    • Starting Point – Population Current Status draft abundance/productivity summaries. Calculated using data from 1978-1999(2001) brood years

    • Most populations: Shortest distance from point defined by current status (abundance & productivity) to a selected risk curve.

    • Alternative calculations for higher productivity populations – capacity considerations

Comparing current and desired status gaps analysis

A/P Gap Criteria

Key considerations
Key Considerations Criteria

  • Productivity affected by mortality and survival at all life stages.

  • The gap analyses themselves do not identify or target a particular life stage – A/P gaps can be addressed by improvement opportunities at any life stage.

  • Gap calculations can be sensitive to assumptions regarding relative hatchery effectiveness when parent spawners have high proportions of hatchery origin fish.

Considering uncertainty
Considering Uncertainty Criteria

  • Different ways to consider uncertainty

    • Checking current status: evaluate the impact on projected risks of directly incorporating uncertainty measure

    • Gaps analyses – point estimates of ‘gap’ under a range of potential future climate/ocean scenarios

    • Status assessment approach can be adapted to gaps

Snake river steelhead populations

Major Population Group # Analyzed Base Gap(5% Risk) Criteria

Lower Snake 1* 1.23

Grande Ronde/Imnaha 7 of 9 1.04 (0.59 to 3.09)

South Fork Salmon 6 of 8 0.45 (0.32 to 1.33)

Middle Fork Salmon 6 of 8 1.27 (0.65 to 1.70)

Upper Salmon 7 of 9 1.07 (0.44 to 2.28)

Snake River Steelhead Populations

Results Criteria

  • Snake Fall Chinook

    • One of three historical populations extant, largest populations extirpated

    • Considerations

      • Strong upward trend in abundance in recent years BUT

      • Relatively short time series of applicable A/P data

      • Lack of data to calculate SAR, parr to smolt relationships

      • Changes in exploitation and hydro/transport over time

      • Increased presence of multiple life history patterns

    • Observed Gaps dependent on time frame

      • 5% Risk 0.01 to 0.28

      • 1% Risk 0.07 to 0.47

Modeling alternative futures
Modeling Alternative Futures Criteria

  • Matrix modeling:

    • Alternative Future Environmental Scenarios

      • Historical patterns (50-100 years)

      • Recent patterns (25 Years)

    • Direct hydro survival improvements

      • Continuation of recent observed improvements

    • Modifications from Zabel et al. 2006

      • Population-specific (rather than ESU-level)

      • Climate function relies on PDO, upwelling, SST and WTT

Climate scenarios
Climate scenarios Criteria



South fork chinook a p gap example
South Fork Chinook Criteria A/P Gap Example










Warm PDO Years

Base Environmental

Recent 60 Year

Summary Criteria

  • Base gaps for Snake River Spring/summer chinook populations range from 0.32 to greater than 3.00.

  • Alternative climate assumptions can substantially affect the absolute value of gaps: Assuming that the future would be more like longer term conditions reduces gaps by 60-70%, assuming consistent poor survivals (like 1990s) increases gaps by about 20%

  • Survival increases required to meet the 1% risk level would be 1.3 to 1.5 times the levels needed to meet the 5% risk criteria.

  • For most populations, the survival changes being modeled for hydrosystem actions alone would not be sufficient to meet ICTRT viability criteria.

  • Next steps: modeling projected survival benefits of strategies generated through regional recovery planning efforts.