All-female monosex culture in the freshwater prawn Macrobrachium rosenbergii – A comparative large-scale field study

In crustacean aquaculture, size dimorphism between males and females is the main key factor determining the advantage of monosex aquaculture over that of mixed populations. This factor is particularly relevant for the freshwater prawn, Macrobrachium rosenbergii, for which intensification of cultures is complicated by a complex social structure in which large dominant males are territorial and inhibit the growth performance of smaller males and females. It has therefore been suggested that all-female mono-culture could be the practice of choice, since females are less aggressive and less territorial and are believed to exhibit a relatively homogenous growth pattern. Here we report the first large-scale comparative field study of all-female and mixed populations under extensive and intensive stocking conditions in earthen ponds. The study was facilitated by application of our novel biotechnology based on a single injection of suspended hypertrophied androgenic gland cells. Under both our intensive and extensive conditions, the all-female cultures showed better performance than the mixed cultures in most key aquaculture parameters including survival rate and yield per hectare. Also, the intensively stocked all-female ponds showed better feed conversion ratio than mixed ponds. Furthermore, while the mean size of the animals did not differ significantly between the two treatments, the all-female populations exhibited significantly higher size uniformity. Our study suggests that for M. rosenbergii, female monosex aquaculture is a sustainable method to yield a homogenous crop.