Since 1984 investigators and producers in several countries, including the US., Israel, Thailand, Philippines, Jamaica, Ecuador, Panama, and Honduras, have demonstrated that tilapia can be effectively sex reversed on a commercial scale in hapas (fine mesh net enclosures) held in ponds with abundant natural plankton. The fish grew faster, the incidence of disease was reduced, the basal diet did not have to be nutritionally complete, and the infrastructure requirements were reduced. The procedure, as described in this publication, is relatively simple and can be practiced by producers without wells, pumps, or indoor wet lab facilities.
This publication is organized to facilitate field application of the hormonal sex reversal technique for production of all-male fingerlings of tilapia. Detailed discussions on the justification and acceptable modifications or alternatives are minimized in the main body of the text. A final section, entitled "Common Questions on the Procedures" is included to assist managers in decisions on the general appropriateness of sex reversal, on site specific modifications, and on overall farm management.