# Presentation: 175960

## 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

**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

- Pop Attributes

- Pop Status

- Stratum/Geographic Unit/Major Population Group Status

- ESU Status

- ESU

- Stratum 1

- Stratum 2

- Stratum 3

## 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?

**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

**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**

## Snake River Spring Summer Chinook 

- Major Population Groupings
- & Populations

**Lower Snake Tribs Group**
- Tucannon R.
- Asotin R.

**South Fork Salmon Group**
- South Fork
- East Fork/Johnson Cr.
- Secesh R.

**Grand Ronde/Imnaha Group**
- Imnaha R.       Big Sheep Cr.
- Wenaha R.     Minam R.
- Lostine/Wallowa R.
- Catherine Cr.
- Upper Grand Ronde

**Middle Salmon R. Group**
- Big Cr.          Bear Valley
- Marsh Cr   .   Sulphur Cr.
- Loon Cr.        Camas Cr.
- Chamberlain Cr.
- Upper Mainstem & tribs
- Lower Mainstem & tribs

**Upper Salmon R. Group**
-   Lemhi R.        Pahsimeroi R.
- North Fk         Panther Cr
- Valley Cr.         Yankee Fk
- East Fk Upper Salmon
- Upper Salmon tribs.

- Above
- Hells Canyon
- (Ext)

- Clearwater
- (Ext.)

## Figure E-2

## 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)

- trend

- Variance (& autocorrelation)

- abundance

- time

- N

## 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

- 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

## Assessing Population Viability:  Integrating Across VSP Criteria

|  |  |  | SS/D rating |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |  |  | Very Low |  | Low |  | Moderate |  | High |  |  |
| A/P rating |  | Very Low (<1%) | highly viable |  |   |   |   |   |  

maintained 
  |  |  |
|  |  |  |  |  |   |   |   |   |  |  |  |
|  |  | Low (<5%) |   |   | viable |  |   |   |   |   |  |
|  |  |  |   |   |  |  |   |   |   |   |  |
|  |  | Moderate (<25%) |   |   |   |   | maintained |  |   |   |  |
|  |  |  |   |   |   |   |  |  |   |   |  |
|  |  | High |   |   |   |   |   |   | high risk |  |  |
|  |  |  |   |   |   |   |   |   |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  |  |

## ICTRT Viability Curves

- 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

**Parent Spawners**

**Next**
**Generation**
**Spawners**

**Replacement**
- 1 spawner for every
- 1 parent spawner

**At Capacity**

**Below**
**Capacity**

- R=a*S

- R=a*Smax

## Population Size Thresholds

- 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

***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.

**Wenatchee River**

**Current abundance & productivity**

**Oval:  +/- 1 standard error**

## Observed A/P Gaps

- 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

- 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

- 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

## Slide 23

## Slide 24

## Slide 25

## A/P Gap

**A/P Gap**

## Slide 27

## Slide 28

## Slide 29

## Key Considerations

- 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

- 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

## Slide 32

## Snake River Steelhead Populations

- _Major Population Group__	__# Analyzed__	__Base Gap(5% Risk)_
- 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)

## Results

- 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

## Slide 35

## Modeling Alternative Futures

- 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

- Poor

- Historic

## Slide 38

## Insert fig 2 flowchart

## South Fork Chinook A/P Gap Example

- Gap

- Gap

- Gap

- Base Environmental

- Recent 60 Year

- Warm PDO Years

**Recent **
**Hydro**

**Recent **
**Hydro**

**Recent **
**Hydro**

## Summary

- 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.