Eastern Bering Sea Walleye Pollock Stock Assessment

Abstract

Changes in the input data The 2001 NMFS bottom-trawl survey estimates of population numbers-at-age were available for analysis in this assessment. In terms of biomass, the bottom-trawl survey estimate for 2001 is 4.14 million tons, down by 19.5% from the 2000 estimate of 5.14 million tons. This level of decline was expected given the estimated age-structure of the population relative to availability patterns of pollock to the bottom-trawl survey. For the echo-integration trawl (EIT) surveys we used an updated estimate of abundance-at-age from the 2000 summer survey and also used revised sample-size values for the time series of EIT abundance-at-age data that reflects the number of trawl-hauls.