On the issue of stock assessment and forecasts of the total allowable catch of cod in the Barents and Norwegian seas

Abstract

   Comparison of the spawning stock biomass, calculated using the SAM model, with the volume of catch indicates a multiple underestimation of biomass estimates. During 1946–2023, the excess of catch volumes over the spawning stock amounted to 18 million tons. Correlation analysis of comparison of the spawning stock biomass of cod in the period 1980–2020 and the number of cod recruitment at the age of 3 years with a lag of 3 years ago showed the absence of any relationship between these phenomena (r = 0,03). The modern Harvest control rule for cod fisheries in the Barents and Norwegian Seas is based on the dependence of fishing mortality on the spawning stock biomass. However, significantly underestimated estimates of the spawning stock lead to low estimates of the TAC, which explains the prevalence of catch over the spawning stock biomass. A way out of this situation may be to replace the spawning stock biomass with the fishable stock in the Harvest control rule.