BSAI Northern Rock Sole Assessment Raised an Important Issue About Using Localized Gear Performance Studies (E.G
Chapter 8 Assessment of the Northern Rock Sole stock in the Bering Sea and Aleutian Islands Thomas K. Wilderbuer and Daniel G. Nichol Executive Summary The following changes have been made to this assessment relative to the last full assessment in November 2015: Summary of changes to the assessment input 1) 2015 fishery age composition. 2) 2015 survey age composition. 3) 2016 trawl survey biomass point estimates and standard errors. 4) Estimate of catch (t) for 2016. 5) Estimate of retained and discarded portions of the 2016 catch. Summary of Results Models 1 is the preferred model evaluated in this assessment. Models 2-7 represent Model runs made to examine alternate states of nature for contrast to the primary models results. Northern rock sole continue to be moderately exploited and the female spawning biomass is in a slow decline but well-above BMSY. Model 1 As estimated or As estimated or specified last year for: recommended this year for: Quantity 2016 2017 2017 2018 M (natural mortality rate) 0.15 0.15 0.15 0.15 Tier 1a 1a 1a 1a Projected total (age 6+) 1,085,200 977,200 1,000,600 923,200 Female spawning biomass (t) 584,400 522,600 539,500 472,200 Projected B0 682,800 918,500 BMSY 257,000 257,000 257,000 257,000 FOFL 0.152 0.152 0.160 0.160 maxFABC 0.148 0.148 0.155 0.155 FABC 0.148 0.148 0.155 0.155 OFL (t) 165,900 149,400 159,700 147,300 maxABC (t) 161,000 145,000 155,100 143,100 ABC (t) 161,000 145,000 155,100 143,100 Status As determined last year for: As determined this year 2014 2015 2015 2016 Overfishing No No No No Overfished No No No No Approaching overfished No No No No Model 1 Responses to SSC and Plan Team Comments to Assessments in General The Plan Team discussion relative to its choice of a preferred model for the BSAI northern rock sole assessment raised an important issue about using localized gear performance studies (e.g.
[Show full text]