Salmon smolt ‘trained’ to become stronger adults Published: 22 March, 2013
A research project is examining whether or not, with the correct physical exercise and good health screening, salmon smolt will become stronger and better at tackling the stress of being transferred to sea cages.
Senior Scientist Harald Takle at the Norwegian food research institute Nofima is managing a three-year project FitSmolt, which is funded by the Norwegian Seafood Research Fund (FHF) and the Research Council of Norway and has a budget of round NOK 10 million. The main goal of this research project is to improve the survival rate and health of salmon smolt transferred to sea cages when they are about one year old.
In order for the industry to achieve the production increase they wish in the future, it is a necessity that as many smolt as possible survive until they reach harvest size. In this project we will focus on how the smolt can develop stronger disease resistance, how we can get it to handle various types of stress better and how the smolt can grow rapidly but with a natural development of organs, says Takle.
The project comprises three parts, and the scientists will coordinate the results and develop knowledge and tools that may be used to strengthen the robustness of the smolt.
The Nofima researcher explained that the first part involved sorting. “It is desirable to remove the weakest individuals as early as possible in the production cycle. This is achieved, amongst other methods, by testing the swimming ability of the salmon smolts. The individuals with poor swimming capacity will be excluded from the project. Part two involves training the smolt to become stronger. In earlier trials involving physical exercise, the salmon started the exercise as youth, but in this trial they will start the physical exercise at an earlier stage. In this way it is possible to see whether the smolt achieves a higher survival rate if they are well trained before being transferred to the sea cages.
It is not only physical exercise that is required, but it needs to be the correct exercise. Not too much, not too little and varied. We then test the cardiac capacity, the ability to deal with disease and general performance after transfer to the sea. Only in this way can we see whether the salmon youth tolerate more if they start physical exercise both earlier and better, says Takle.
In part three of the project, the scientists will learn from the wild salmon.
We will compare smolts from two rivers, Lærdal and Flekke, to see whether there are any differences. The river in Lærdal is far more demanding in which to live than the river in Flekke as it is steeper and has a greater flow of water, and we wish to see whether the salmon smolts from the river in Lærdal are more robust than those from the Flekke river. We also want to compare the farmed smolts with the wild smolts in order to look for differences in cardiac capacity and find markers in order to identify these differences, says Takle.
Besides Nofima, NIVA and scientists from the Universities of Brest and British Columbia are participating in the research group.