A survey-based assessment of the Northeast Arctic cod stock

Acoustic and bottom trawl surveys of the Northeast Arctic cod stock provide fishery independent estimates of abundance and population characteristics. Given the recent uncertainties in the catch based assessment of the stock, survey based abundance estimates of ages 5+ cod and spawning stook biomass , generated by calibrating survey indices with converged estimates from a v irtual population analysis (VPA), were compared with the estimates front th e annual assessments. The results indicate that the survey-based estimates were more accurate than the estimates from the annual assessments. Since th e VPA abundance estimates for younger cod tend to be inaccurate, the amount of information contained in the surveys was tested indirectly determining how well estimates based on previous survey indices could predict the follo wing year's survey value. A time-series model of ages 3+ cod and haddock su rvey indices predicted the subsequent value of the cod survey index fairly accurately. It is concluded that it is likely that these fishery independen t surveys are providing a more accurate assessment of the current size of t he cod stock than the assessment based on combining the survey data with co mmercial catch statistics. (C) 2001 International Council for the Explorati on of the Sea.