Many farmed fish attain sexual maturity before reaching market size. S exual and early maturation is associated with a substantial decrease in somatic growth due to the diversion of energy into development of massive gonads. The period of intensive gonadal growth also results in deterioration of flesh quality and an increase in susceptibility to stress and disease, all of which can have significant economic, biological and business consequences for aquaculture. In the past, the prevalence of grilsing in farmed Atlantic salmon was estimated at 20-30%. Additionally, precocious male maturation has been reported as high as 80% by harvest time in land-based, closed containment grow-out systems. As land-based aquaculture is becoming an increasingly important and popular approach to meet the demand in aquatic food production, especially for high value species, it is imperative that highly effective methods are developed to prevent and/or block sexual maturation. Triploidy often results in reproductively sterile salmon but because of associated performance issues, it is not always accepted by industry. We have developed a practicable technology to efficiently produce infertile fish. Sterilization minimizes energy input toward gonadal growth while enhancing muscle (flesh) development and promoting fish health. Our technology uses a bath-immersion to execute a transient gene-silencing method that doesn't introduce any genetic modification into fish. It will thus alleviate the concerns associated with Atlantic salmon early maturation in land-based farming. Of particular interest, we discovered that a molecular transporter, Vivo, can effectively carry the Morpholino oligomer (MO) across the chorion, enter the embryos and reach the target cells. Vivo-conjugated MO against Deadend (dnd; an essential gene for early germ cell development) effectively disrupted germ cell development and resulted in the production of reproductively sterile fish. The technology was first developed in zebrafish and, very promisingly, has also been shown to induce sterility in tilapia, sablefish, rainbow trout and Atlantic salmon. Currently, w e are optimizing this sterilization technology in Atlantic salmon and studying its impacts on growth-related performance traits by comparing growth, performance and fillet yield among sterilized, normal fertile diploid fish, and triploid Atlantic salmon.