FEEDING-BEHAVIOR OF THE ARCTIC CHARR IN COMPARISON WITH THE RAINBOW-TROUT

Appropriate feeding techniques are important in order to optimize feed intake and minimize feed losses in net-pen aquaculture operations. The ability of the Arctic charr to feed in the water column was studied using different techniques of feed pellet release. For comparison, the same study was carried out with rainbow trout. The pellets were all released simultaneously or with a 5-s interval between delivery and with or without dispersal of pellets over the water surface. When the pellets were all delivered simultaneously, the charr only caught 39% (not dispersed) or 65% (dispersed). The charr took more than 94% of the pellets in the water column if they were released at 5-s intervals, irrespective of whether or not the pellets were dispersed over the surface. The rainbow trout, on the other hand, caught nearly 100% of the pellets in the water irrespective of feeding technique. When reared in net-pens, Arctic charr should, therefore, be fed a few pellets at a time, and the pellets should be released at intervals and dispersed over the water surface.