Feeding behaviour of juvenile Eurasian perch Perca fluviatilis and its relation to aquaculture

SUMMARY Eurasian perch (Perca fluviatilis) has recently been introduced as a potential new species in aquaculture. There are currently several areas of research in developing economically sustainable perch farming. These areas are, for example, feed composition and nutritional requirements, stocking densities, weaning, farming environment, day length manipulations, use of steroids, feeding regimes, feeding behaviour and reducing the variation in growth. A large variation in growth, as is often found in perch, is not desirable in aquaculture for several reasons. For example there is a lower demand on the market for a batch of fish with a large size disparity compared to a batch of similar sized fish and also, the degree of cannibalism increases with increasing variation in growth. The large variation in growth may depend on several factors, such as individual variation in morphological, physiological or behavioural traits. I will focus on social behaviour and feeding competition and individual variation within these factors. To understand the background for perch behaviour, I am first looking into its ecology and thereafter concentrating on social behaviour and feeding competition. More precisely, I will focus on the following behavioural aspects: anti-predatory behaviour, shyness vs. boldness, experience and learning, and social hierarchies. I will also discuss the physiological trait metabolic rate and make a short summary of what is known so far about how the farming environment should be arranged for perch