Behavioral experiments of Atlantic salmon, Salmo salar, for individualized feeding stations

Abstract

These experiments set out to test whether Atlantic salmon, Salmo Salar, would pass through a narrow hatch, thus imitating the action of entering a feeding station, and whether this behavior could be influenced. In the first two experiments a tank was divided into two sides by a barrier with a small opening in the middle. To induce crossing through the opening, feedings were alternated between the sides. The tank and fish were observed via camera and the time of each crossing and the total number of crossings were recorded. In the second experiment, pavlovian conditioning was used in an attempt to influence the crossing behavior. In the last experiment two hatches were cut into the divider to determine if fish had a preference for crossing with or against the current. In the first experiment a general upward trend in crossings through the hatch occurred as the time in the experiment increased. In the second experiment the effect of pavlovian conditioning was undetermined due to aggressive territorial behavior developing within the test subjects. In the third experiment fish were shown to prefer crossing against the current. Crossing behavior was divided into four categories, a direct cross, a searching cross, a delayed cross, and a joint crossing. These behaviors can help in the design of the systems in future experiments. Lastly, the effect of the hatch on growth statistics was observed and deemed to have significant negative impact, however, the impact lessened with time.