2015 Assessment of the Arrowtooth Flounder Stock in the Eastern Bering Sea and Aleutian Islands
Arrowtooth flounder (ATF; Atheresthes stomias) have historically been assessed on an annual basis in the Bering Sea/Aleutian Islands region to coincide with the annual Bering Sea shelf multispecies groundfish trawl survey conducted each summer. In 2012, Bering Sea/Aleutian Islands (BSAI) arrowtooth flounder were moved to a biennial assessment schedule to coincide with the frequency of trawl surveys in the Aleutian Islands (AI) and the eastern Bering Sea (EBS) slope. These surveys occur in even years, and for these years a full assessment of arrowtooth flounder in the BSAI area will be conducted. Arrowtooth flounder are managed as a Tier 3 stock using a statistical age-structured model as the primary assessment tool. The full 2014 assessment can be found at http://www.afsc.noaa.gov/REFM/Stocks/assessments.htm. The 2015 and 2016 estimate of B40% was 222,019 t. Arrowtooth flounder biomass was estimated to be above this reference point. The estimated exploitation level remained below 5% for 2015.
Because this is an “off-year” for the BSAI ATF, new survey information is not incorporated into the assessment model for this update. Instead, a projection model is run with updated catch information. This projection model run incorporates the most recent catch information and provides estimates of 2016 and 2017 ABC and OFL without re-estimating the stock assessment model parameters and biological reference points. The projection model is based on last year’s model results.
New catch information for this update includes the final 2014 catch (19,109 t) and an estimate of 2015 catch. The estimated 2015 complete catch of 13,710 t was obtained by summing the total catch through October 27, 2013 (10,592 t) and the average catch from November-December for 2012 – 2014 (3,118 t). The 2016 catch was set to the average annual catch from 2012-2014 (22,714 t). A summary of the updated projection model results is shown below.