2013 Assessment of the Arrowtooth Flounder Stock in the Eastern Bering Sea and Aleutian Islands
April 22, 2013
Arrowtooth flounder (ATF) 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.
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 and provides estimates of 2014 and 2015 ABC and OFL without re-estimating the stock assessment model parameters and biological reference points. The projection model is based on the previous year’s model results. The 2012 model was rerun retrospectively to incorporate a new maturity ogive (Stark 2011), which was approved by the Plan Team in September, 2013.
New catch information for this update includes the final estimate of 2012 catch and a revised estimate of 2013 catch. The 2012 catch was 22,714 t, 53% higher than the reported catch as of October 15, 2012 was 14,832. The 2013 catch through October 20, 2013 was 19,681 t. The estimated 2013 complete catch of 21,124 t was obtained by summing the total catch through October 27, 2013 (19,722 t) and the average catch from Nov-Dec from 2010 – 2012 (1,402 t). The 2014 catch was set to the average annual catch from 2010-2012 (19,675 t). A summary of the updated projection model results is shown below.