Increase Central Valley Chinook salmon population recovery in the Sacramento-San Joaquin Delta with natural production to reach the State and federal doubling goal.
- Increase the annual average natural production of Central Valley Chinook salmon runs for the long-term
- Double the 1967–1991 levels for all runs combined, and for individual run types on select rivers: fall, late fall, spring, and winter.
- Annual average natural production of all Central Valley Chinook salmon runs
- Annual average natural production for individual run types on select rivers: fall, late-fall, spring, and winter
The Delta serves as a migration corridor for Central Valley salmon runs and an important rearing habitat for young salmon while they migrate to the ocean. Salmon are native anadromous fish and a strong indicator species of ecosystem health and of the effectiveness of habitat restoration and water quality improvement projects. In addition to ecological importance, salmon have sociocultural significance to many Native American communities. Central Valley Chinook is also an integral part of California’s fishing industry. The Central Valley Project Improvement Act (CVPIA), enacted by the U.S. Congress in 1992, requires improvements to water management to protect fish and wildlife, including achieving the State and federal doubling goal for Central Valley Chinook salmon natural production*, relative to 1967–1991 levels.
Salmon populations are dependent on a wide variety of factors in the rivers, Delta, and ocean, including the suitability of spawning and rearing habitat, predation, and food availability. Extensive drought periods contribute to decreased salmon natural production levels. Management of water operations, habitat restoration, reconnecting migratory routes, and increased agency coordination in the Delta can help contribute toward the salmon doubling goal and to improve the adaptive capacity of salmon to respond to climate change.
This performance measure tracks the annual average natural production of Chinook salmon in the Central Valley For individual runs in select rivers and for all runs combined to indicate that ecosystem conditions are conducive to recovering the salmonid species. Salmon abundances are used as a proxy for natural production due to the higher accessibility of abundance data compared to natural production data.
*Natural production means fish produced from eggs to adulthood without direct human intervention in the spawning, rearing, or migration processes.
Each chapter of the Delta plan includes strategies to achieve the goals of the plan. These strategies are general guidance on achieving the objective laid out in the plan and in the Delta Reform Act of 2009. Associated with these strategies are recommendations. The recommendations describe more specific and implementable actions to support the achievement of Delta Plan strategies. Strategies and recommendations may also have associated performance measures. Delta Plan performance measures track progress in achieving desired outcomes for the Delta Plan. Below are the strategies and recommendations associated with this performance measure.
- Protect Native Species and Reduce Impact of Nonnative Invasive Species
- Fund and Implement Habitat Projects and Reduce Predation to Juvenile Salmon
- Coordinate Fish Migration and Survival Research
- Manage Hatcheries to Reduce Risk of Adverse Effects
Annual average natural production of all Central Valley Chinook salmon runs and for individual run types on select rivers: fall, late fall, spring, and winter. Census will be conducted annually for the general population in the Central Valley and select rivers.
Set by the Central Valley Project Improvement Act (CVPIA), the baseline is the 1967– 1991 Chinook salmon natural production annual average of 497,054 for all Central Valley runs (Figure 1), and for individual run types on select rivers, the baseline values are specified in Table 1.
The 15-year rolling annual average of natural production for all Central Valley Chinook salmon runs increases for the period of 2035–2065 and reaches 990,000 fish by 2065. For each run on select rivers, the target values are specified in Table 1.
Table 1. Central Valley Chinook Salmon Natural Production Baseline and Target Levels by Run Type and Selected Rivers
|Sacramento River Watershed
|San Joaquin River Watershed
|Sacramento River Watershed
|San Joaquin River Watershed
Sacramento River mainstem:
|Tuolumne River Fall-run: 18,949
Sacramento River mainstem
|Tuolumne River Fall-run: 38,000
|Merced River Fall-run: 9,005
|American River Fall-run: 160,000
|Merced River Fall-run: 18,000
|Stanislaus River Fall-run: 10,868
|Feather River Fall-run: 170,000
|Stanislaus River Fall-run: 22,000
|Mokelumne River Fall-run: 4,680
|Mokelumne River Fall-run: 9,300
To provide a short-term assessment of progress toward the doubling target, and to address the limitations of the current datasets, interim milestones are set using two submetrics:
- Positive slope of the 15-year rolling annual average of Central Valley Chinook salmon natural production, calculated, and evaluated annually. The interim milestone is a positive slope of the 15-year rolling annual average to be achieved by 2035.
- Positive slope of the 15-year rolling annual average of natural production using the Constant Fractional Marking (CFM) data which is available from 2010 onwards. The interim milestone is a positive slope of the 15-year rolling annual average by 2035.
The 15-year rolling average was chosen to represent five Chinook salmon generations to provide long enough trends to conclude whether populations are in recovery or not.
The interim metrics are calculated by each run and by selected rivers where production data is available. Interpretation of short-term performance milestones assessments will include consideration of external factors beyond management control (e.g., ocean and climate conditions) and the relative importance of the Delta as the migration corridor and rearing habitat within the salmon life cycle.
Use the U.S. Fish & Wildlife Service’s (USFWS) Chinook Production dataset to calculate the 15-year rolling annual average of natural production for all Chinook salmon runs.
Calculate the slope (linear regression) of 15-year rolling annual averages of natural production for all Chinook salmon runs.
Plot the 15-year rolling averages against year and a slope will be calculated to measure if the salmon population is growing (positive slope).