Intensive poly culture of common carp cyprinus carpio and herbivorous fish silver carp hypophthalmichthys molitrix and grass carp ctenopharyngodon idella
Aquaculture 38(3): 241-254
ISSN/ISBN: 0044-8486 Accession: 005718505
Intensive polyculture of common carp and herbivorous fish (silver carp and grass carp) at high stocking densities and with intensive feeding with fodder and mineral and organic fertilization was carried out without mechanized aeration and automated feeding. Two stocking patterns were tested. The first, in Pond 1 (2.5 ha), had the following stocking rates: 1-yr carp (C1), 8000 fish/ha; 1-yr silver carp (S1), 1500 fish/ha; and 1-yr grass carp (G1), 200 fish/ha. The yield was 6292 kg/ha of standard consumer fish (C1+ 743 g, S1+ 944 g, and G1+ 1000 g) at a relatively low food conversion ratio (2.24) and high survival of all fish. Within the total yield the 2-yr carp contributed 76%, the silver carp 21% and the grass carp 3%. The 2nd stocking pattern, in Pond 2 (0.25 ha), had the following rates: C1 8500 fish/ha; S1, 2000 fish/ha; and G1, 200 fish/ha, and produced a still higher total yield (6629 kg/ha) at a relatively low food convesion ratio (2.10). The 2-yr carp in Pond 2 contributed 88% of the total yield and the herbivorous fish only 12%, even though they accounted for 20% of the stock. The results (Pond 2) are compared with other record yield experiments under similar conditions but including tilapia. At a total stocking rate of 10,700 fish/ha and without participation of tilapia, over a period of 186 days (as against 126 days in the other experiment), these experiments gave a total yield which was 347 kg/ha higher at a food coefficient 15% lower. The growth period was 60 days longer in these experiments, but it included April and Oct. when water temperature is much below the optimum and only 4% of the total amount of fodder was assimilated.