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CDFG SJR Fall-run Chinook Salmon Model CWEMF November 4, 2005. Objectives. Brief Overview of Model Development Describe Model Structure Describe Model Calibration/Validation Describe Model Scenarios. Overview. San Joaquin River Salmon Production as a function of Spring Vernalis Flow.
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Objectives • Brief Overview of Model Development • Describe Model Structure • Describe Model Calibration/Validation • Describe Model Scenarios
Overview San Joaquin River Salmon Production as a function of Spring Vernalis Flow
Study Area Courtesy of USFWS
Salmon Cohort“Singe Year Production Indicator” Brood Year Production Juvenile Age 1 Age 5 Age 2 Age 4 Age 3 CWT Recovery Scale Analysis
Salmon Escapement“Multi-Year Production Indicator” Age 1 Year 1 Annual Carcass “Creamer” Survey Age 2 Year 2 Age 3 Year 3 Age 4 Year 4 Age 5 Year 5
1995 WQCP Triennial Review • CDFG Challenge: • Are the Flow Objectives Working? • What is the status of the salmon population? • What fraction of juvenile salmon are receiving protection? • What is the status of the VAMP experiment?
1983-1995 Average 42,285 1996-2004 Average 35,004 SJ Basin Production Year Populations Are Declining
VAMP Implementation • VAMP: • Lock Down Uncertainty at Extremes First • Since 2000: • Result: • Continued uncertainty • Need several successive high flow range tests to define/solidify relationship
2005 SWRCB ’95 WQCP Review • CDFG: • presented its concerns • asked for peer review • SWRCB: • peer reviewed already occurred • CDFG: develop flow recommendations
Chalkboard E = mc? What +/- What = More Salmon? Harvest? Exports? Disease? Predation? Flow? Gravel?
Model Logic • Delta Exports • weak correlation to cohort production
Model Logic • Ocean Harvest • weak correlation to cohort production Harvest - Sacramento, San Joaquin and CVI Ocean Harvest versus Tuolumne Escapement
Mossdale Smolts Previous Year Escapement Model Logic • Adult Stock Density Limitations Ricker Stock-recruit relationship (density dependent mortality governor) appears questionable More females = more juveniles (Tuolumne River)
Adult Stock Density Limitations Density Dependent Governor ? Higher Escapement Higher Spring Flow Higher Cohort Production Higher Escapement Lower Spring Flow Lower Cohort Production Multiple Regression 1973-1999 R-square = 0.75 P = .001 Tuolumne River data
Model Logic • Instream Flow Strong correlation to cohort production in relation to spring flow SJB east-side tributaries principle flow & salmon contributor
Flow Features • Increased Vernalis Flow Magnitude/Duration/Frequency all projected increased adult salmon production
Now What? • Challenge: “How to link salmon life history production to flow magnitude & duration?” • Solution: “Develop a tool”
Model Concept • Flow primary driving factor in population (not harvest, exports or adult stock density) • Quantify relationships between: • flow and juvenile production • flow and juvenile survival • juvenile survival and adult escapement • Simulate production over time
Model Features • Excel spreadsheet platform • Links life history stages by numerical production at each phase • Predicts adult escapement (1967-2000) • Flow duration & magnitude variable • Predicts escapement change & water volume • Has 95% confidence level predictions • Customizable input parameters
Model Refinements • Limits predictions to data set • Uses San Joaquin Basin data for age cohort reconstruction • Smolt Outmigration pattern WY Type specific • Allows for HORB/non-HORB smolt survival • 95% confidence levels predictions
Conceptual Model Vernalis Flow Mossdale Smolts Delta Survival Adult Cohort Annual Escapement (spawners) Chipps Smolts Escapement Reconstruction
Conceptual Model Vernalis Flow Mossdale Smolts Delta Survival Adult Cohort Annual Escapement (spawners) Chipps Smolts Escapement Reconstruction
Conceptual Model Vernalis Flow Mossdale Smolts Delta Survival Adult Cohort Annual Escapement (spawners) Chipps Smolts Escapement Reconstruction
Repeat Cycle Combine spawners with Vernalis flow to predict Mossdale Smolt Production Vernalis Flow Mossdale Smolts Delta Survival Adult Cohort Annual Escapement (spawners) Chipps Smolts Escapement Reconstruction
Model Calibration & Validation • Two Approaches • Calibrate with subset/validate with remaining • Calibrate with entire data set • Parameters • Escapement pattern • Time period average • Replacement ratio • Stay within 95% CI
SJ Basin Escapement 1967-2000 -----Historic -----Modeled
95% Confidence Intervals HistoricUpper 95% CILower 95% CI
Model Scenarios • Ten model runs • Four presented
What Scenarios • Possible Goal Attainment Scenarios • Vary Flow with Window Constant • VAMP (3200-7000 with 31 day window) • Constant Flow & Window Constant • 10,000 all WY Types & 31 day window • Constant Flow & Variable Window • 10,000 all WY Types & Variable WY Window • Variable Flow & Variable Window • 5-20K Flow & 31-90 day Window