Demonstration of polyfarming of Asian Seabass and tilapia
To evaluate the techno-economic viability of polyfarming of Asian seabass and tilapia as forage fish, a demonstration was carried out in a farmer’s pond (0.2 ha) at Madanganj, Namkhana. Tilapia broods were stocked in the well prepared brackishwater pond @1500 nos/ha for two months prior to stocking of seabass fry. The seabass fry (0.15g/ 21.5mm) were stocked @10,000 nos/ha in the pond. By the time seabass fry were stocked, there was adequate availability of tilapia spawn, fry and juveniles, which served as forage fish to seabass.
Tilapia broods were fed with a mixture of rice bran and mustard oil cake (1:1) @ 2% body weight. At the end of 270 days of culture, fishes were harvested with total production of 313.5 kg (73.46% seabass and 26.54% tilapia).Seabass size at harvest ranged from 450-950g. The total productivity estimated from this trial was 1568 kg/ha and within this, the contribution of seabass was 1153 kg/ha. The fi shes were sold in the local wholesale market and the farmers earned a total revenue of Rs.39,398/- (Rs.33,872/- from seabass and Rs.5526/ - from tilapia); the estimated net income being Rs.1.5 lakh/ha. This demonstration confi rmed the techno-economic viability of seabass tilapia polyfarming system and is a signifi cant improvement from the arlier trial during 2007-08 at Akshaynagar, Kakdwip, where an estimated seabass production of 794.81 kg/ha and net income of Rs.1.18 lakh/ha were obtained.