Fishery and the state of the Barents and Norwegian Seas cod stock

Abstract

The assessment of the stock status and prospects for the fishery of the Barents Sea cod is characterized by significant uncertainty caused by the peculiarities of the age structure, which often led to significant differences in the results obtained using different models. As a result, this caused intense discussions both within the framework of the International Council for the Exploration of the Sea (ICES) and at the meetings of the Joint Norwegian-Russian Fisheries Commission. In 2021, at a specialized ICES workshop («benchmark» group), the input data and configuration of the main assessment model - SAM, were refined, related to the inclusion of additional information on older age groups. As a result, two models currently used by the ICES working group to estimate cod stock (SAM and TISVPA), which are very different in their approaches, showed that the number of generations born in 2004–2005 significantly decreased, which led to a decrease in cod biomass. An assessment of the prospects for the state of the stock, performed both on the basis of calculations using the SAM model and on the basis of an alternative approach using the AMO (Atlantic Multidecadal Oscillation Index), showed a high probability of further decline and stabilization of the spawning stock biomass (and catches) in the next 2–3 years, after which restoration of spawning stock biomass is likely due to sufficiently abumdante generations born in 2011 and 2014.