Specific Features of the Formation of the Year-Class Abundance of Northeastern Arctic Haddock Melanogrammus aeglefinus during the Warming of the Barents Sea

Resumo

Factors that influence the survival rate of northeastern Arctic haddock Melanogrammus aeglefinus at different stages of the formation of the year-class abundance are considered. It is shown that the patterns of the formation of the year-class abundance of haddock have changed due to warming in the Barents Sea. Since the late 1990s, an enhancement of the relationship is recorded between the year-class numbers at the 0-group stage and at age 3 years. The mortality of this fry during the first two wintering periods has lost its dominant value for the emergence of strong year-classes. Under these conditions, the predation role of cod Gadus morhua as a regulator of the abundance of haddock demersal juveniles increased. This is due to the fact that the increase in water temperature in the Barents Sea provides favorable conditions for the abundance growth not only for haddock but also for its main predator, i.e., cod.