2019 Assessment of the Shortraker Rockfish Stock in the Gulf of Alaska
Gulf of Alaska rockfish have historically been assessed on a biennial stock assessment schedule to coincide with the availability of new trawl survey data (odd years).
Gulf of Alaska rockfish have historically been assessed on a biennial stock assessment schedule to coincide with the availability of new trawl survey data (odd years). In 2017, the Alaska Fisheries Science Center (AFSC) participated in a stock assessment prioritization process. It was recommended that the Gulf of Alaska (GOA) shortraker rockfish remain on a biennial stock assessment schedule with a full stock assessment produced in odd years and no stock assessment produced in even years. For this on-cycle year, we incorporate Relative Population Weights (RPWs) from the 1992 - 2019 longline surveys, incorporate new trawl survey biomass, and update auxiliary data sources.
This stock is classified as a Tier 5 stock. We continue to use a random effects (RE) model fit to survey data to estimate exploitable biomass and determine the recommended ABC, but we present a new method of combining the AFSC longline survey RPW index (1992 - 2019) with the AFSC bottom trawl survey biomass index (1984 – 2019) within the random effects model. The RE model was fit to the time series of trawl survey biomass and longline survey RPW indices by region (with associated estimates of uncertainty). These regional biomass estimates from the RE model were then summed to obtain Gulfwide biomass.