Production of Genetically Female Common Carp, Cyprinus carpio, through Sex Reversal and Progeny Testing

The common carp, Cyprinus carpio L., an introduced species to India, is an im-portant species for aquaculture and enhanced fisheries in Karnataka state. Common carp has a number of advantages over the other carp species. However, one of the major disadvantages is that the present stock exhibits early sexual maturation and unwanted reproduction during grow-out, resulting in suppressed growth and small size at harvest. Considering the importance of the species, there is a need to find suitable solution(s) to this problem. The production of sterile or monosex populations are among the options. Fry of different age and size groups were treated with two androgens, namely 17α-methyl testosterone (MT) and 17α-methyl-di-hydroxy-testosterone (MDHT), in a series of trials. MT treatments at 100 mg•kg^-1 yielded only partial sex reversal (77.14% male), while MDHT treatments at 50 and 100 mg•kg^-1 resulted in complete masculinization (100% male) in “small” size 50 day old common carp. The hormone treated fish were crossed with normal females to identify neo-males, which produced all or predominantly female progeny. The results indicate the potential of MDHT for hormonal masculinization and the possibility of producing all female common carps through this approach.