2015 Assessment of the Atka Mackerel Stock in the Gulf of Alaska
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 2011, which included data from the 2011 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. Although a survey was conducted in 2013, we only provided an expanded executive summary with updated catch and the 2013 survey information, due to the government shut-down in October 2013. In 2014, we again presented an executive summary in keeping with the biennial schedule.
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 2012, 2013, and 2014 assessment updates presented Tier 6 recommendations and did not present Tier 5 calculations given the large variances associated with the 2011 and 2013 survey biomass estimates, which were essentially based on one to two significant hauls encountered in the western Gulf of Alaska. The Council set the Gulf-wide 2015 OFL, ABC, and TAC for Atka mackerel at 6,200 t, 4,700 t, and 2,000 t, respectively.