Aquasulfat & RAS: growth, health and welfare
1 Purpose
This study is designed with a common control where one fish group will be used to test how RAS with sulfate reduced brackish seawater affect fish welfare, performance and water quality. The second group will test how fish density influence water quality and gill health in RAS.
2 Distress
Fish will be PIT tagged for individual growth and fish welfare determination and will be handled during monthly measuring of weight and length. PIT tags will improve the statistical significance since the three fish groups are kept in two systems each (duplicates). Otherwise production conditions will be mimicing commercial grow-out practices. The use of an acute stress test on a sub sample of fish from both control and sulphate reduced water with give significant information with regard to whether sulphate reduced water affects the stress response of fish.
3 Expected benefit
The use of sulfate reduced brackish water in RAS will significantly reduce the likelihood of H2S related mortality in RAS, which is a significant problem in the marine RAS aquaculture industry. In the first project we would verify that sulfate reduced brackish water will have no impact on fish welfare and growth performance or the ability of the fish to mount an effective stress response. At the same time, we will assess the effects of both sulfate reduced brackish water and stocking density on gill health.
4 Number of animals, and what kind
In total up to 1600 Atlantic salmon (Salmo salar L.) post smolts would be used in this study
5 How to adhere to 3R
Although replicate RAS systems are being used, the systems are very adaptable and commercial stocking densities can be tested with low risk compared to large commercial systems. This replication gives more confidence in the results compared to fewer larger systems that put more fish at risk. RASLab has closely controlled water quality monitoring systems and backup systems to optimize fish welfare and perform studies like this to optimize water quality for RAS production. We also reduce the number of fish used by having a common control for both tests.
This study is designed with a common control where one fish group will be used to test how RAS with sulfate reduced brackish seawater affect fish welfare, performance and water quality. The second group will test how fish density influence water quality and gill health in RAS.
2 Distress
Fish will be PIT tagged for individual growth and fish welfare determination and will be handled during monthly measuring of weight and length. PIT tags will improve the statistical significance since the three fish groups are kept in two systems each (duplicates). Otherwise production conditions will be mimicing commercial grow-out practices. The use of an acute stress test on a sub sample of fish from both control and sulphate reduced water with give significant information with regard to whether sulphate reduced water affects the stress response of fish.
3 Expected benefit
The use of sulfate reduced brackish water in RAS will significantly reduce the likelihood of H2S related mortality in RAS, which is a significant problem in the marine RAS aquaculture industry. In the first project we would verify that sulfate reduced brackish water will have no impact on fish welfare and growth performance or the ability of the fish to mount an effective stress response. At the same time, we will assess the effects of both sulfate reduced brackish water and stocking density on gill health.
4 Number of animals, and what kind
In total up to 1600 Atlantic salmon (Salmo salar L.) post smolts would be used in this study
5 How to adhere to 3R
Although replicate RAS systems are being used, the systems are very adaptable and commercial stocking densities can be tested with low risk compared to large commercial systems. This replication gives more confidence in the results compared to fewer larger systems that put more fish at risk. RASLab has closely controlled water quality monitoring systems and backup systems to optimize fish welfare and perform studies like this to optimize water quality for RAS production. We also reduce the number of fish used by having a common control for both tests.