Effects of swimming training in Atlantic salmon performance

The main purpose of this study is to establish a swimming training protocol for Atlantic salmon that can be implemented in a commercial setting. The Norwegian aquaculture industry has invested large resources in developing cost-effective protocols for the introduction of various types of semi-closed and closed facilities. However, recently farmers have experienced that even though the salmon is optimally smoltified, fish show health and welfare problems, which is also causing major financial losses. One strategy that has shown to have positive effects on health and welfare of farmed salmon is the active use of swimming training. However, an effective protocol with defined parameters (such as water velocity, time and temperature) and a thoroughly documentation of the beneficial effects of this practice in the salmon's general health and robustness in the sea phase are still lacking. One pilot experiment and three trials are planned in this study to design an effective swimming training protocol and a total number of 1560 Atlantic salmon will be used. For the pilot study, which aims to test the system, i.e., adjust all parameters to ensure the right swimming speed and water conditions, 120 fish will be randomly distributed into 6 tanks (20 fish per tank). In each trial, fish will be randomly distributed in 6 tanks (80 fish per tank). All fish will be PIT tagged to keep track of the fish health and growth rate. To decrease the stress from the handling we will use light anesthesia. For tissue and blood collection, fish will be euthanized with an overdose of NaCO3-buffered tricaine methanesulfonate. At the moment, there is no available model (in silico) that can illuminate our research questions. However, the data collected in this study can (and will be) used to develop in silico models so that the three R's (replacement, reduction and refinement) can continue to be implemented. The facility and all personnel involved in the trial have the necessary authorization and training to carry out the experiment according to Norwegian and European legislation. Fish health and feed intake will be constantly monitored and if signs of abnormal behavior or infection are observed, the fish will be euthanized following the present ethical guidelines.