A moving light stimulus elicits a sustained swimming response in farmed Atlantic salmon, Salmo salar L.

The productivity and welfare benefits of sustained swimming in fish are well documented, but are not yet exploited in commercial aquaculture. We report here on a study designed to test the feasibility of inducing sustained exercise in Atlantic salmon (Salmo salar L.) using a novel lighting device that provides an apparently moving light pattern. It was found that such a device could induce sustained swimming in Atlantic salmon held in tanks and that a centrally placed (inner ring) light system was far more effective in this context than one in which lights were placed on the outer wall of tanks. The central configuration was associated with enhanced rates of growth, feed conversion and reduced levels of plasma cortisol. Such developments in fish swimming technologies may assist the sustainability of finfish aquaculture through promotion of sustained exercise leading to improved productivity and welfare.