Method to obtain reliable records of individual feed intake in Atlantic salmon

In selective breeding programs, direct selection for improved feed efficiency is not possible due to lack of technology to record individual feed intake accurately on a large number of fish. The main objective is to investigate if individual Atlantic salmon will swim through into a small tank (feeding station) placed inside a larger tank, and after having eaten all or part of the given pellets, leave the feeding station, after which the entrance be re-opened for another fish. To obtain individual feed intake and growth records, each fish in the feeding station need to be identified. This will be obtained by tagging the fish with a PIT-tag that will be recorded by a PIT-tag reading device when the fish enter the feeding station. PIT-tagging of fish of the planned body size (average weight 100 and 300 g) is to be looked upon as slightly stressful (lett belastande). There is no alternative for live animals for such a pilot study. Technology for individual feed intake records will open for direct selection for increased feed efficiency and thus more efficient use of limited marine feed resources than possible today with indirect selection for the trait. We will perform four short term (2-4 weeks) experiments with 10 PIT-tagged Atlantic salmon per experiment, which is to be looked upon as a minimum for such pilot experiments. We will PIT-tag all 50 fish prior to the start of the first experiment. If a fish need to be taken out of the tank in the early phase of an experiment, it will be replaced with another of the 50 tagged fish.