Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4493189 | The Egyptian Journal of Aquatic Research | 2012 | 7 Pages |
Growth performance and survival rate of improved strains (F5 and F6) and unimproved strain of Oreochromis shiranus were assessed. Three stocking densities (5, 7 and 9 fish/m3) were used to randomly allocate fingerlings, of mean weight 6 ± 0.6 g, into 27 hapas of 9 m3 each, fixed in a pond of 700 m2 at Bunda Fish Farm, Malawi. Stocking density significantly (P < 0.05) affected the growth of the 3 strains though there was no significant difference between stocking density of 5 and 7 fish/m3. The highest final weight was noted at a stocking density of 5 fish/m3 with an average weight of F6 being 28.1 g, followed by the F5 (24.9 g) and the unimproved (24.0 g) strain. The improved strains had a higher final mean weight (F6: 23.41 g, F5: 21.84 g) than the unimproved strain (18.70 g) but there was no significant difference between improved strains (P > 0.05). The apparent genetic gain due to selection between the unimproved strain and F5, F6 strains was estimated to be 16.8 and 25.2%, respectively. Based on this, farmers can be encouraged to use F6 strain at a stocking density of 5 fish/m3. The revelation that there was no difference between the improved strains has implications on the continuity of the selection program.