Focus on intensive juvenile production
This topic is particularly relevant in juvenile production. It is normally possible to control the water quality during this phase, but there is still a lack of knowledge about individual factors and combinations of different water qualities.
We are focusing particularly on the consequences of intensive farming which involves high fish densities, reduced water use and the adding of oxygen to the water. This can produce unstable and elevated levels of gases (e.g. carbon dioxide and oxygen) and other changes to the water which may be harmful to the farmed fish. We are also working on topics such as nitrogen saturation, intermixing of seawater and water temperature.
Water Quality Laboratory
In order to study the effect of water quality, Nofima Marin has established a water quality laboratory at the Tromsø Aquaculture Research Station where the different water qualities may be mixed, controlled and registered in an effective and adequate manner. Through the Water Quality Study, under the supervision of the Norwegian Institute for Water Research, we have documented that the quality of the untreated water that is used in the trials is extremely well suited.
Salmon and marine species
Much of the research involves salmon, but increasing more research involves new aquaculture species such as cod. For salmon, the smoltification phase is particularly vulnerable and it often coincides with poor water quality in commercial farming. Consequently, we have chosen to focus on this phase and the consequences for ongoing farming in sea cages. With respect to cod, we are working on both the larvae and juvenile phases.
Combining many biological parameters
In order to assess the fish's welfare, we have chosen a strategy where we measure many different biological parameters which tell us something about the fish's physiological, behavioural and health status. Examples of this include watching the fish eat and grow and its level of susceptibility to disease by carrying out challenge experiments with viruses and bacteria.
Examples of such challenge experiments include the infectious pancreatic necrosis virus (IPNv) which causes infectious pancreatic necrosis (IPN) and the bacteria Mortiella viscosa which causes winter ulcer. By studying physiological and immunological responses, we can also find out about why the fish is eating and growing poorly or has a poor survival rate. The effects of smolt quality may be studied by physiological analyses and seawater tests on fish in freshwater, and by following the fish's performance in seawater.
