2013 Assessment of the Sculpin Complex in the Bering Sea and Aleutian Islands

April 22, 2013

In 2011, Bering Sea and BSAI sculpins 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). These surveys occur in even years, and for these years, full assessment of sculpins in the BSAI will be conducted. The 2012 full assessment can be found at http://www.afsc.noaa.gov/REFM/Docs/2012/BSAIsculpin.pdf. The sculpin assessment is conducted with Tier 5 methods. In this assessment, the current estimated biomass is obtained from mean biomass estimates over the past four survey years for the six most abundant sculpins in the BSAI: bigmouth (Hemitripterus bolini), great (Myoxocephalus polyacanthocephalus), plain (Myoxocephalus jaok), threaded (Gymnocanthus pistilliger), warty (Myoxocephalus verrucosus), and yellow Irish lord (Hemilepidotus jordani). An exploitation rate is then applied to the estimated current biomass to obtain the ABC and OFL. The sculpin complex mortality rate is a biomass-weighted average of the instantaneous natural mortality rates for these six species. The complex mortality rate may change as new survey data become available.