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Data-moderate assessments for 9 groundfishes. NWFSC and SWFSC STAT teams. Context and objectives. Data-moderate = catch and index data Methods (XDB-SRA and exSSS ) already reviewed. 3 Objectives Fit index data Provide stock status (depletion) Provide OFLs for 2015, 2016.
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Data-moderate assessments for 9 groundfishes NWFSC and SWFSC STAT teams
Context and objectives • Data-moderate = catch and index data • Methods (XDB-SRA and exSSS) already reviewed 3 Objectives Fit index data Provide stock status (depletion) Provide OFLs for 2015, 2016
Things to expect • First data-moderate STAR panel • Base cases are currently fluid • Terms of Reference “open” • How much to show • How to present? • Executive summary • Many topics germane to “full” assessments • Future research topics important • How can we improve future applications?
Biology and ecology Flatfishes Rockfishes Nearshore-shelf (<250 m) English sole Shelf-slope (up to 500 m) Rex sole Nearshore(<120 m) Shelf-Slope • Sharpchin • Stripetail • Yellowtail • North of 40.10 • South of 40.10 • Brown • China • Copper • Vermilion • North of Pt. C • South of Pt. C (“complex”) Table 1: Life history parameters
Assessment scope Yellowtail Sharpchin China Vermilion Copper Stripetail Rex sole English sole Brown Yellowtail
Generalized Linear Mixed Models (GLMM) • Model set-up • Delta approach: models positives (binomial) and magnitude of positives (lognormal or gamma) • Extreme Catch Events (ECE): modeled as a mixture distribution • Model Interpretation • Convergence: Neff > 500 • Goodness-of-fit: Q-Q plots (ECE or non-ECE?) • Model selection: Deviance (lognormal or gamma?)
GLMM survey stratification: Rockfishes Sharpchin Stripetail Yellowtail
GLMM survey stratification: Flatfishes English sole Rex sole
Interpreting trawl survey catchability “The distance between the trawl doors is three times greater than the distance between the wings on the NWFSC trawl (Figure 2). Since abundance data was expanded to the index of biomass using net wingspread, the survey biomass estimates are three times greater than if door spread was used. The subsequent estimate of q using door spread would therefore be approximately 1, one-third of the value estimated in the assessment. Catchability in a stock assessment is solely used as a scalar and is difficult to interpret. However, the observations of herding presented here illustrate one process that contributes to a larger than expected estimate of q.” -Bryan et al (in press)
Extended Depletion-based Stock Reduction Analysis (XDB-SRA) Extended Simple Stock Synthesis (exSSS) Common data (Catch, indices) Selectivity = maturity Age-structured Delay-difference Life history: Two-sex Life history: Single-sex VBGF parameters No growth parameters (no SPR) R0 prior (MLE;MCMC); depletion prior (AIS) Depletion prior Productivity: Steepness (h) Productivity: FMSY/M; BMSY/B0
Depletion prior: Vulnerability analysis The 2012 review panelrecommended that we use three bins Unfortunately, the results were not captured in the report This is an attempt to re-create the analysis None of the 2013 assessment cases fall in the right-hand bin
Depletion prior: Vulnerability analysis “Depletion”2000 = 65%: Stripetail, English and Rex sole Beta distribution peaks at right “Depletion”2000= 30%:Brown, China, Copper, Vermilions, Sharpchin, Yellowtails Beta distribution peaks at left The “uninformative” case is beta, based on all data Has not been used in any 2013 analyses
Sharpchin rockfish: Index fits All surveys combined XDB-SRA Triennial- early Triennial- late NWFSC exSSS
Sharpchin: Index fits with combined Triennial Triennial NWFSC
Stripetail rockfish: Index fits All surveys combined XDB-SRA exSSS
Yellowtail rockfish (N): Index fits Triennial NWFSC RecFIN CPFV XDB-SRA Tri early Hake bycatch RecFIN NWFSC exSSS Tri late Trawl CPUE CPFV
Yellowtail (N): Index fits with combined Triennial Triennial RecFIN Hake bycatch NWFSC CPFV Trawl CPUE
Yellow rockfish (S): Index fits RecFIN cenCal/OR CPFV XDB-SRA exSSS
English sole: Index fits Triennial- combined NWFSC XDB-SRA Triennial- early Triennial- late exSSS
English sole: Index fits with combined Triennial Triennial NWFSC