The baltic cod stock is presently at its lowest level on record. The drastic decline appears to be caused by a substantial reduction in the reproductive success during the last decade while high fishing pressure continued to remove large numbers of adults from the population. The proposed study will examine the mechanisms governing long term trends in the recruitment and their implications for fisheries management. The project will investigate three closely linked components within an internationally coordinated multidisciplinary research programme:

a) Trend analysis : Long-term trends in physical/biological variables and stock recruitment to identify the main factors influencing the reproductive biology and recruitment success of Baltic cod.
b) Process analysis : biotic and abiotic processess and interactions in respect to their effects on survival and maturation of juvenile cod, adult fecundity, quality and viability of spawned eggs and rates of development, drift and mortality of the early life stages.
c) Modelling : Results form the first two components will be utilized for incorporating O-group cod into multispecies assessment models and for improving predictive models on future cod recruitment.
Improving understanding of the recruitment processes as obtained during this research project will enable more efficient fisheries management strategies with reference to environmental changes; it will also allow to identify prerequisites for successful stock enhancement programmes and provide the biological basis for assessing their economic value.