Methods of controlling the sex of fish

Controlling the sex of fish is an effective way to increase fish yield. In general, the use of sex hormones can induce the sex of fish to develop in the desired direction. There are two kinds of sex hormones, testes secrete androgens, ovaries secrete estrogen. The primitive reproductive epithelium of fish has two components of the medulla that determine the development to female and male. Under the action of estrogen, the cortex becomes ovary, the medulla is undeveloped and the female has the function of spawning and reproduction; on the contrary, under the action of androgen, the fish will become male. Therefore, in the process of developing fishery production, if you want to increase the number of fish such as female carp and crucian carp, estrogen can be used, that is, when the fish in the fry pond begins to feed, a certain amount of benzoate diol is added to the feed. after continuous treatment for 2 ~ 3 months, the female ratio can reach about 95%. Similarly, more than 99% of male fish can be obtained when tilapia, tilapia and other fry are treated with the androgen methyltestosterone. Because of the single sex and fixed density, the treated fish not only grow fast, but also have low cost, and can generally increase production by about 30%.