2013 Assessment of the Thornyhead Stock in the Gulf of Alaska
Gulf of Alaska (GOA) thornyheads are assessed on a biennial stock assessment schedule to coincide with the availability of new survey data. For GOA thornyheads in on-cycle (odd) years, we present a full stock assessment document with updated assessment results to recommend harvest levels for the next two years. However, due to the 2013 government shutdown, we present an executive summary with updated survey biomass estimates and recommended harvest levels. Please refer to the last full stock assessment report presented in 2011 for further information regarding the assessment calculations (Murphy and Ianelli 2011, available online at http://www.afsc.noaa.gov/refm/docs/2011/GOAthorny.pdf). A full stock assessment document with updated assessment results will be presented in next year’s SAFE report.
We use the exploitable biomass from the most recent trawl survey to determine the recommended ABC for thornyhead rockfish, which qualifies as a Tier 5 stock. For this update year, we use the same extrapolation method (Alternative 2) from the 2011 assessment applied to the 2013 survey biomass estimate to provide estimates for the next two years.