Physiology, behaviour and welfare of fish in exposed aquaculture operations
The purpose of these experiments is to define welfare parameters for fish in exposed aquaculture operations by examining swimming performance and metabolism in Atlantic salmon, lumpfish and ballan wrasse in strong water currents together with other relevant environmental conditions such as different temperatures and moderate hypoxia. We have included lumpfish and ballan wrasse since they both act as cleaner fish in sea cages (they eat sea lice). However, they have different temperature preferences and swim morphology. Thus, it is relevant to asses any differences in their applicability as cleaner-fish in exposed aquaculture operations.
The main experimental method will be swim tunnel respirometry, which is a mild non-invasive technique. Therefore we do not expect any significant or unusual harm to the animals other than the unavoidable short-term stress associated with being moved from a fish tank to a swim tunnel chamber. A key parameter measured in swim tunnel trials is the critical swimming speed (Ucrit) which is obtained by incremental increases in the current velocity until the fish fatigues. The Ucrit is a good indicator of aerobic capacity, and prolonged exposure to water currents at or above Ucrit is therefore not acceptable in terms of fish welfare in exposed aquaculture operations.
The main expected outcome of these planned experiments are:
-Detailed description of aerobic capacity and swimming limitation within all relevant temperature intervals in acclimated Atlantic salmon.
- Knowledge about swimming performance in Atlantic salmon during isolated and combined exposure to hypoxia and amoebic gill disease.
- Effect of feeding and stress on critical swimming speed.
- Applicability of lumpfish and ballan wrasse in exposed aquaculture operations, used as a delousing agent.
- The anaerobic component of swimming at sub-Ucrit velocities and its implications for long-term sustained swimming.
- A detailed and integrated picture of swimming performance in Atlantic salmon to form the basis of welfare guidelines for this species in exposed aquaculture operations.
Thus, the knowledge gained here will have great value for society by aiding in the on-going development and expansion of humane aquaculture operations. Furthermore, many aspects of these studies will also have general relevance in fish physiology and marine ecology.
We expect to use 18 lumpfish, 18 ballan wrasse and 926 Atlantic salmon in the planned experiments.
All experiments have been designed to minimize the number of experimental animals while still providing useful scientific results.
The main experimental method will be swim tunnel respirometry, which is a mild non-invasive technique. Therefore we do not expect any significant or unusual harm to the animals other than the unavoidable short-term stress associated with being moved from a fish tank to a swim tunnel chamber. A key parameter measured in swim tunnel trials is the critical swimming speed (Ucrit) which is obtained by incremental increases in the current velocity until the fish fatigues. The Ucrit is a good indicator of aerobic capacity, and prolonged exposure to water currents at or above Ucrit is therefore not acceptable in terms of fish welfare in exposed aquaculture operations.
The main expected outcome of these planned experiments are:
-Detailed description of aerobic capacity and swimming limitation within all relevant temperature intervals in acclimated Atlantic salmon.
- Knowledge about swimming performance in Atlantic salmon during isolated and combined exposure to hypoxia and amoebic gill disease.
- Effect of feeding and stress on critical swimming speed.
- Applicability of lumpfish and ballan wrasse in exposed aquaculture operations, used as a delousing agent.
- The anaerobic component of swimming at sub-Ucrit velocities and its implications for long-term sustained swimming.
- A detailed and integrated picture of swimming performance in Atlantic salmon to form the basis of welfare guidelines for this species in exposed aquaculture operations.
Thus, the knowledge gained here will have great value for society by aiding in the on-going development and expansion of humane aquaculture operations. Furthermore, many aspects of these studies will also have general relevance in fish physiology and marine ecology.
We expect to use 18 lumpfish, 18 ballan wrasse and 926 Atlantic salmon in the planned experiments.
All experiments have been designed to minimize the number of experimental animals while still providing useful scientific results.