Macrobrachium prawns are voracious predators of the freshwater snails that host the flatworms responsible for bilharzia (schistosomiasis), a health burden in many African countries. A novel strategy to decrease the disease in Africa involves the use of prawns as biocontrol agents of the snails. Although the endemic African river prawn Macrobrachium vollenhovenii is a natural candidate for aquaculture and biocontrol, efforts to domesticate it have been unsuccessful to date, and it is not available in the large quantities required for aquaculture and biocontrol. The Asian giant prawn Macrobrachium rosenbergii has been cultured worldwide for decades. Recently, novel biotechnologies were developed to create monosex (all-male) non-breeding populations for aquaculture that we suggest are also ideal for biocontrol in Africa. Since the above 2 prawn species are of the same genus, exhibit similar sizes and require a female pre-mating molt prior to egg fertilization, the potential for cross-breeding between the 2 species must be tested. To assure that all-male populations of M. rosenbergii will not pose such an ecological threat, we carried out cross-breeding experiments with M. vollenhovenii. Both interspecies encounters and attempts at artificial insemination revealed that fertilization does not occur between the 2 species. Our results demonstrate both behavioral and physiological pre-zygotic reproductive barriers between these species. We suggest that all-male M. rosenbergii can be used as an aquaculture species and as a biocontrol agent in areas where M. vollenhovenii occurs without concern for hybridization.

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40 Recent evidence suggests crustacean snail predators may aid schistosomiasis control 41 programs by targeting the environmental component of the parasite's life cycle through 42 predation of the snail species that serve as intermediate hosts of the parasite. We evaluate 43 costs, benefits, and potential synergies between schistosomiasis control and aquaculture of 44 giant prawns using an integrated bio-economic-epidemiologic model. We identified 45 combinations of stocking density and aquaculture cycle length that maximize profit and offer 46 disease control benefits for sustainable schistosomiasis control. We consider two prawn 47