Tilapia belongs to a family of fish that is commercially cultured throughout the world. They tend to overpopulate when reared in ponds because they mature and reproduce early and frequently. This results to smaller-sized fish at harvest commanding lesser prices in the market.
Male tilapias are preferred over the females for aquaculture activities because of their bigger size. In order for the males to be selected over the females, manual sexing can be done, but very laborious, time-consuming, and only 80% accurate.
Dr Rafael D Guerrero III studied this problem. He developed a feed mixed with the sex hormone methyltestosterone. The formulation converted the female tilapia fries to males, thus, bigger tilapias and overcrowding was prevented. For this, he received the prestigious Mgr Jan DF Heine Memorial Award in 2004 given by the International Je Dois Faire Assembly.