EFFECT OF AERATION SYSTEMS AND STOCKING DENSITY ON GROWTH PERFORMANCE, POND YIELD AND ECONOMIC IMPACTS OF NILE TILAPIA (OREOCHROMIS NILOTICUS) REARED IN EARTHEN PONDS

Ramadan M. Abou Zied

Faculty of Agriculture- Fayoum University- Egypt.

Received 7/4/ 2013                                         Accepted 21/5/ 2013
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Abstract

This study was conducted to evaluate the effect of two type of aerator, paddle wheel and toring turbine in ponds with different fish stocking densities (25, 35 and 45 thousand/pond) on growth performace and survival rate and economic impacts.

Nile tilapia fingerlings with average initial body weight of 10.33 ± 0.28 g were allotted randomly into 12 earthen pond (one feddan/each) divided into four treatments. Three stocking densities with two different aeration systems and the control (without aeration) was tested in the present study. The control group without aeration (T1) was performed in 6 earthen ponds (one feddan area each) and each pond was stocked with 25000 fish. The second treatment (T2) was performed in two ponds (one feddan area each) and stocked with 25000 fish per pond and ponds were aerated with toring turbine aerators. The third treatment (T3) included two ponds (one feddan area each) and each pond was stocked with 35000 fish and aerated with paddle wheels. The fourth treatment was performed in two ponds (one feddan each) and stocked with 45000 fish/pond and received aeration through toring turbine aerator. Fish were fed through then experimental period on a diet containing 30.2 % protein at a rate of 3% daily. The study lasted 225 days after start. Results obtained are summarized in the following:

  1. Fish of T2 showed the highest (P≤0.05) final weight compared to the other treatment groups. The same trend was observed with weight gain and daily gain in weight, while the applied treatments had no significant effects on the specific growth rate.
  2. The applied treatments had no significant effects on feed intake per fish, feed conversion ratio or survival rate.
  3. The T4 (45000 fish/pond with toring turine aerator) showed the highest profit index followed in a decreasing order by T2, T3 and T1 respectively.

Based on the obtained results on stocking density of 45000 Nile tilapia per feddan with toring turbine aerator is recommended for pratical aquaculture for higher yield of fish and better profit index.

Key words: Nile tilapia, aeration, stocking density, growth performance