Investigations on some technological parameters in intensive rearing of pike-perch (Stizostedion lucioperca)

Abstract

Market demands and competition force the production of high quality freshwater fish in European aquaculture. Traditional pond fishes like common carp, usually having high fat content in flesh, become more and more difficult to export. In Hungary pike-perch is the most ,,noble ” and perhaps the most sensitive fish species. One of the constraints that lead to an increase in its production in natural waters, reservoirs and ponds is the shortage in alevins of adequate size. The possible solution to this problem can be the elaboration of intensive rearing technics of pond pre-reared fry. The aims of the present study were to test the growing capacity, feed conversion and survival of pike-perch in intensive circumstances. Fish were kept in 130 L aquaria working in a recirculation system at an average water temperature of 22±0,5°C. Two stocking densities were applied (18 and 36 fish/aquarium). Minced fish (test) and live prey (control) were offered twice a day till satiation in two replications. The experiment lasted for 4 weeks. According to our results minced fish is suitable feed in the intensive rearing of pike- perch alevins. Daily food intake was only influenced significantly by different feeds (2.01 g vs. 4.53 g, test and control, respectively). Feeding and stocking density had significant effect (P=0.001 and 0.017) on the average weight gain (0.52 g and 1.40 g for minced fish and live feed, respectively, 1.02 g in lower and 0.90 g in higher density). Due to the high variances treatment effect on feed conversion proved to be nonsignificant. The average survival of the minced fish fed group was 62.2% vs. 78.8% of the alevins that were fed live fish. This difference was significant (P<0.01) in the first two weeks when almost all of the losses happened due to cannibalism and other unknow reasons. Based on our results a 10 – 14 day period is needed for pike-perch fingerling to change gradually their feeding from zooplankton to minced fish diet.