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2014 Pollock Operational Assessment. 2014 Operational Assessment Meeting Woods Hole, MA August 11-13, 2014. Outline. Background Fishery Research Surveys Assessment Biological Reference Points Projections Summary. Outline. Background Fishery Research Surveys Assessment
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2014 Pollock Operational Assessment 2014 Operational Assessment Meeting Woods Hole, MA August 11-13, 2014
Outline • Background • Fishery • Research Surveys • Assessment • Biological Reference Points • Projections • Summary
Outline • Background • Fishery • Research Surveys • Assessment • Biological Reference Points • Projections • Summary
Background • Last assessed in 2010 as part of SARC 50 • Accepted methods from SARC 50 used in this assessment • Four additional years of data incorporated (2010-2013)
Outline • Background • Fishery • Research Surveys • Assessment • Biological Reference Points • Projections • Summary
Fishery: MRIP • MRIP estimates used 2004-2013 • Converted MRFSS to MRIP 1981-2003 • MRFSS to MRIP conversion factors: • Landings (num): -11% • Landings (kg): -10% • Discards (num): -4% • Discards (kg): -5%
Fishery: Age Structure • SARC 50: commercial discard fall ALKs for 2001-2008 did not include fall survey data. • 2001-2008 fall ALKs reconstructed with both commercial and fall survey data • SARC 50 base model was rerun with revised commercial discard at age matrix
Revised SARC 50 / SARC 50 Commercial Discards at Age Fishery: Age Structure
Revised SARC 50 vs SARC 50 Fishery: Age Structure
Outline • Background • Fishery • Research Surveys • Assessment • Biological Reference Points • Projections • Summary
NEFSC Bottom Trawl Surveys Spring Research Surveys Fall
Outline • Background • Fishery • Research Surveys • Assessment • Biological Reference Points • Projections • Summary
Assessment: Model • ASAP version 3.0.17 • First age: 1 • Last age: 9 (plus group) • First year: 1970 • Last year: 2013
Used SARC 50 maturity schedule • Assumed constant over time • Estimated with pooled-year data from NEFSC fall survey Assessment: Maturity
Assessment: Natural Mortality • Used SARC 50 final M value • M = 0.2 for all ages (1-9+) and years (1970-2013)
Assessment: Discard CVs • Could not reproduce method used to estimated recreational discard CVs • Used average recreational discard CV from SARC 50 (0.68) for annual recreational discard CVs • For consistency, used average commercial discard CV from SARC 50 (0.30) for annual commercial discard CVs
Assessment: Selectivity • Commercial: 4 time blocks • 1985/1986 • 1993/1994 • 2003/2004 • Recreational: 3 time blocks • 1993/1994 • 2001/2002 • Surveys: dome-shaped • Age 9+ selectivity fixed at 0.5
Assessment: ASAP Results • MCMC simulation used to obtain marginal posterior distributions of SSB and F5-7 • Total iterations: 10,000,000 • Burn-in period: 5,000,000 • Thinning interval: 5,000 • Final iterations: 1,000 • All Gelman-Rubin PSRF between 1 and 1.01
