How do oxygen depletion and parasites affect cod growth?
The eastern Baltic cod stock is currently under serious threat due to overfishing combined with oxygen depletion, parasites and seal predation. Although cod fishing in the Baltic Sea has been suspended since 2019, cod in the southern Baltic Sea have not recovered; instead, they are growing slowly and remain small and meagre.
The aim of the project is to investigate how oxygen depletion and liver parasites, individually and in combination, affect cod growth and welfare through comparative field studies and experiments. The results of the studies will increase our understanding of the significance of oxygen depletion and parasite load on cod growth, and may contribute to the development of management measures to conserve Baltic Sea cod.
The project is being carried out by Swedish University of Agricultural Sciences. Through BalticWaters’ program for research projects and pre-studies, the project has been awarded a grant of 1 million Swedish kronor for the scientific part of the project.
Project materials
Article: New research provides insight into why Baltic cod are growing so poorly (2025-09-26)
Fiskeritidende: The decline of cod – what has happened in the eastern Baltic Sea (2023-10-07)
Article: Project will investigate why the cod is small and meagre (2023-09-26)