New results suggest that there may also be challenges with fish that have grown very fast before being released into the sea
Slow production of atlantic salmon smolt is better for the fish's heart
Wednesday, August 12, 2020, 15:00 (GMT + 9)
A new study from NMBU Veterinary College and the University of Oslo shows that slow production of salmon smolt leads to larger and fresher salmon.
Fast smolt production yields increased heart size. Representative 3D reconstructions of MRI captures in hearts from slow and fast smolt groups. (Photo: Aquaculture 529 (2020) 735615)
Although the smolt must be optimally smoltified and robust enough to handle challenges at sea, the industry is experiencing increasing health and welfare problems in both the hatchery and sea phases. In the Norwegian aquaculture industry, a lot of work has been done in recent years to produce a fast-growing and large smolt that does not need that much time in the sea. The idea has been to reduce the time the salmon are exposed to salmon lice and other problems that only occur in the sea phase. The danger is that it can affect the smolt quality. Based on this issue , FHF announced funding last summer for research to contribute to the development of knowledge that can lead to preventive measures in juvenile fish production that can provide improvements in the smolt's heart and circulatory health.
Fast smolt production is associated with rounded ventricles, bulbus misalignment and thicker compactum. Fish produced under fast (11 months at 13°C) compared to slow smolt production conditions (18 months at 8°C) had reduced ventricular height (Photo: Aquaculture 529 (2020) 735615)
One of the projects that was initiated was HELSMOLT , which aims to investigate whether a slower and more natural smolt development means that the fish better handle the transition to the sea and get better heart health and survival in the production phase. This is now confirmed in the latest findings from the project, which has also been published in the journal Aquaculture .
Also read the press release from NMBU " Slow production of salmon smolt is better for the fish's heart " where the findings are described in more detail.