2014 Assessment of the Grenadier Stock Complex in the Gulf of Alaska, Eastern Bering Sea and Aleutian Islands
March 04, 2014
The Secretary of Commerce approved Amendments 100/91 on August 6, which added the grenadier complex into both FMPs as Ecosystem Components. Under this rule, they are not allowed to be targeted but there is an 8% Maximum Retainable Allowance (MRA) (Federal Register, Proposed Rules, Vol. 79, No. 93). The final rule will publish before the end of the year and so it may be effective for the start of the 2015 fishing year.
As an Ecosystem Component, a stock assessment is not required and there is no ABC or OFL. A full unofficial assessment report was prepared for grenadiers in even years since 2006, even though they were “nonspecified”. For 2015, we are presenting an abbreviated SAFE report for the BSAI and GOA combined for the purpose of tracking trends in abundance. This content of future reports is still being evaluated since a SAFE report is not required. This report contains a time series of catch and abundance estimates and unofficial ABC and OFL values based on Tier 5 calculations. These values are not used for management or for determining if overfishing is occurring for Ecosystem Component species/complexes. There is no definition of overfishing for an Ecosystem Component.
Changes in the input data: New data inputs include: 1) updated catch data for 2003-2014; 2) updated 2000-2014 Aleutian Island (AI) biomass from 1-1,000 m using the estimation method presented in the 2012 SAFE; 3) NMFS longline survey results for 2013 and 2014; 4) updated GOA biomass using a random effects model. There was no EBS slope trawl survey in 2014.
Changes in assessment methodology: This year we use a random effects model (a similar method, a Kalman filter, was presented in the 2012 SAFE report (Rodgveller et al. 2012)), that utilizes trawl survey data from 1984-2013 to estimate the exploitable biomass in 2013. Since there was no trawl survey in the GOA in 2014, the estimate for 2013 is used as the most recent value of exploitable biomass.
For 2015, the maximum allowable ABC for the BSAI is 75,274 t and for the GOA is 30,691 t. This ABC is a 12% increase for the BSAI and a 12% decrease for the GOA. The corresponding reference values for grenadier are summarized in the following tables, with the recommended ABC and OFL values in bold. Overfishing is not occurring in either the BSAI or GOA.