Norwegian Atlantic salmon aquaculture has made some significant strides in technological innovations, especially in the development of closed and semi-closed rearing systems. This has resulted in the conservation of water and a greater ability to control the production environment.

However, other challenges with these systems have presented themselves. Specifically, hydrogen sulphide (H2S) has become increasingly prevalent in Norwegian salmon recirculating aquaculture system (RAS) facilities, with several events of mass mortality in recent years. There is, however, a substantial gap in the current understanding concerning the biology and physiology of H2S-fish interactions, specifically in salmon.


H2Salar is a timely and ambitious project that aims to create knowledge and advance our understanding of the risks and impacts of H2S to the physiology of Atlantic salmon in RAS. Instead of immediately developing solutions to combat the threat, the lack of fundamental knowledge prompts this initiative to adapt a process-based, research-driven approach that will identify the risks both under laboratory and field-based trials; elucidate underlying mechanisms involved in H2S-salmon interaction from molecular to organismal level; and provide a holistic documentation of the impacts to the different physiological systems that are key for fish health, welfare and robustness. It is expected that the results will be valuable across different sectors of the aquaculture industry that are affected by this issue and the challenges of land-based salmon production in general.

A strategic project consortium has been assembled, including two of Norway’s leading R&D institutes on the environmental and biological aspects of recirculation technology (Nofima, NIVA) and a top-rank academic institution with strong expertise in fish physiology (DTU). In addition, an Industry Reference Group will be set up composed of key industry actors in land-based salmon production in Norway.

This is a 4-year project financed by the Research Council of Norway (Project number 300825).

H2Salar is an associated project in CtrlAQUA SFI.