No abstracts are to be cited without prior reference to the author.Decrease of the catch ability and fishing mortality in gillnets in conditions of long-range lower water temperatures cause underestimation of the population size, while catch ability dynamics of traps affects the stock abundance indices in opposite direction. Appearance of additional hyaline and opaque zones, induced by variability of temperature, can result overestimation of the age. Therefore long-range upwellings must be considered in stock assessment.