Assessment of the atka mackerel stock in the Gulf of Alaska GOA Chapter 17

Gulf of Alaska (GOA) Atka mackerel have been moved to a biennial stock assessment schedule to coincide with the availability of new survey data from the biennial trawl survey. A full assessment was presented in 2015, which included data from the 2015 GOA bottom trawl survey. On alternate (even) years we present an executive summary with updated catch, last year’s key assessment parameters, any significant new information available in the interim, and projections for this year. Gulf of Alaska Atka mackerel have been managed under Tier 6 specifications since 1996 due to the lack of reliable estimates of current biomass. In 2007, the assessment presented Tier 5 calculations of ABC and OFL based on 2007 survey biomass estimates, for consideration. However, the Plan Team and SSC agreed with the authors that reliable estimates of Atka mackerel biomass were not available and recommended continuing management under Tier 6. The 2016 executive summary presented Tier 6 recommendations and did not present Tier 5 calculations given the large variances associated with the 2015 survey biomass estimates, which was essentially based on one significant haul encountered in the western Gulf of Alaska off the Sanak Islands. The 2015 full assessment is available on the web (Lowe 2015, http://www.afsc.noaa.gov/refm/docs/2015/GOAatka.pdf ). The Council set the Gulf-wide 2017 OFL, ABC, and TAC for Atka mackerel at 6,200 t, 4,700 t, and 3,000 t, respectively. 2017 NMFS (National Marine Fisheries Service) Submitted Public Domain 1863