Effect of Point Source Feeders on Cultured Sockeye Salmon Social Behavior

The study examines the effect of a point source food supply on the social behavior of sockeye salmon (Oncorhynchus nerka) reared in a conservation hatchery setting.  The three treatments consisted of a control in which fish were not fed, an experimental treatment in which fish were fed using point source automated feeders and an experimental treatment in which fish were hand fed.  Each replicate consisted of placing three fish in a 3.6 m grey circular tank, allowing  them overnight to recover from the effects of handling, and starting at 0900 the next morning photographing them at half hour intervals until 13 photographs were acquired. The photographs were examined for grouping, mean angle between fish and mean distance between fish.  General observations made over the course of the study and analysis of the photographic data indicate Snake River sockeye salmon vary their social behavior from solitary to paired to aggregated to schooled and the presence of a point source food supply increases aggression, but does not elicit territorial defense.