The influence of stocking density on the growth performance and production of tilapia (Oreochromis niloticus) in earthen pond

An experiment was carried out to investigate the influence of stocking density on the growth of the initial stocked tilapia (O.niloticus) in earthen ponds, the effect on the reproductive performance of the fish and impact on the economy of production. Six African Regional Aquaculture Centre (ARAC), Aluu, Port Harcourt earthen genetic ponds split into three compartments representing three replicates were stocked with 666 fingerlings of 4.33g average initial weight and 6.06cm average initial length at 37 per replicate. They were fed with a 28%CP blood meal based diet for nine months. The size of the ponds and depth of water was such as to attain average stocking densities of 6.33, 6.45, 5.05, 3.60, 2.88 and 2.05 fish/m3. The result showed distinct increase in growth as the stocking densities decreased. Ponds 5,6 and 4 with lower densities 2.88, 2.05 and 3.60 fish/m3 having higher final weights of 146.10, 120.79 and 108.69g than ponds 3, 2 and 1 with 85.37, 74.36 and 59.68g respectively (P<0.05). Average final length was higher in ponds 5, 6 and 4 at 14.46, 13.86 and 13.79cm than ponds 3, 2 and 1 with 12.09, 10.62 and 11.36cm. Relative weight gain followed suit with 3274.13, 2689.61 and 2410.16% in ponds 5, 6 and 4 as against 1871.59, 1617.32 and 1277.83% in 3, 2 and 1. Percentage survival increased as stocking density decreased at 28.18, 35.45, 37.27, 40.91, 41.82 and 45.45% for the 6.33, 6.45, 5.05 , 3.60, 2.05 and 2.88 fish/m3 treatment respectively, with the 3.60, 2.05 and 2.88fish/m3 treatment significantly higher (P<0.05). The 2.88fish/m3treatment (treatment 5) also provided the cheapest cost of producing 1kg of fish at N178.74 as against N457.14, N351.44, N312.41, N242.81 and N217.25 per kg fish of treatments 1, 2, 3, 4 and 6 respectively. The total number of off-springs produced all in progressive sizes increased as the stocking density decreased at 1530, 1636, 1674, 2053, 3160 and 3234 for ponds 1-6. The experiment showed that tilapia fingerlings stocked in earthen pond at low densities grow and reproduce more and at a lower cost of production than those with higher stocking densities. The ideal appears to be between 2 and 3 fish/m3

Includes:- 5 tables.;4 refs.