Sixteen 0.1-ha earthen ponds located at WorldFish Center, Abbassa, Egypt, were stocked with male sex-reversed Nile tilapia (Oreochromis niloticus) at a rate of 30,000 fish/ha. Two fish sizes were used in the experiment, young of the year (YOY) and overwintered fingerlings (OWF) averaging 0.4 and 6 g, respectively. Production and economics of both initial stocking sizes were evaluated. One growing period was compared with two growing periods in the season for both used fish sizes. Specific growth rate and average daily gain were calculated for all treatments. Results showed that obtaining one crop of tilapia in the season was more profitable than dividing the growing season into two crops for both initial stocking sizes. Results revealed that although, standing crop of the OWF treatment was higher than that of the YOY, the net return of the YOY size was, however, higher than that of the OWF size. While, total cost of YOY was significantly lower than OWF.
Effect of initial stocking size and length of culture period on the production and economics of the Nile tilapia (Oreochromis Niloticus) in earthen ponds
El-Naggar, G. (2006)
Egyptian journal of agricultural research 84(1B):589-600 2006