Polyculture rearing of Cyprinus carpio (L.) and Oreochromis aureus (St.) using a closed circulated system

Abstract Two monoculture (100% Cyprinus carpio and 100% Oreochromis aureus ) and two polyculture (60% carp — 40% tilapia and 60% tilapia — 40% carp) groups were reared using a closed circulated system, for 291 days. The mean initial weight of carp was 9.3 ± 0.3 g and that of tilapia 7.1 ± 0.1 g. The aim of the experiment was to investigate the interactions between the species and their influence on fish growth characteristics, under polyculture conditions, using an intensive-superintensive production system. Polyculture groups (C 60% — T 40% and T 60% — C 40%) showed the highest final yield (126.1 kg/m 3 and 132.S kg/m 3 , respectively) compared to that of the monoculture populations (C 100%: 116 kg/m 3 and T 100%: 98.8 kg/m 3 ). Also, the polyculture populations of both species showed the highest specific growth rates. It is concluded that the achievement of the well known advantages of polyculture fish rearing, in the case of an intensive production system, is mainly based on fish ethology, food habits and the percentage combination of species.