Sex Control in Aquaculture

With the world population growth, food demand grows. Aquatic foods provide high quality protein, essential for human health. It is clearly visible that the culture of aquatic organisms will have to increase. With activity development, several researches have been made a round the world to search methods to increase productivity in crops. Among the areas researched, those related to the control of sex, have earned a lot of attention in recent years. The control of sexuality in fish has great interest due to the differences presented between the sexes, which end up affecting commercial production. Also has a lot of Importance in fish breeding cause there are differences in growth rate, survival, breeding time, shape, size or behavior pattern between male and female depending on the cultured species. In addition, the sexual maturation, result in decreased weight gain, loss of meat quality and greater susceptibility to diseases. That way, the mainly goal on the most cases is to produce monosex batches. Currently, obtaining monosex population in fish has been widely studied. There are a lot of advantages that can get with this method. One of them occurs when one of the sexes presents a marked superiority in the rate of growth compared to the other. However, depending on the species, the techniques of gender control can bring other benefits, such as suppression of reproduction, less energy spending with reproductive activity, uniformity of size in the harvest, reduction of the effects of sexual maturation in the appearance and quality of the meat, as well as the decrease of the risks of environmental impacts arising from the escape of fish for the natural systems. Some methodologies are used to produce monosex populations in fishes, among them hybridization, genetic manipulations or using sexual steroids. Several factors, however, change the efficiency of sexual reversal, such as the type of hormone, the dose employed, the duration of treatment, the route of administration and the period of initiation of treatment. In addition, to develop this technology for determined specie, previously studies must been carry out to understand the mechanisms of sexual determination and gonads differentiation process. In this way, it is essential to know and evaluate the potential and characteristics of the species that will be cultivated, aiming to apply the techniques of sexual manipulation in a responsible way to achieve the desired production indexes. Book jacket.