Some diseases, for example Hematodinium, appear to be related to the conditions under which crabs are kept. As optimal conditions for different Scylla spp. become better known, extreme conditions should be avoided, as they increase stress on stock and make them more susceptible to disease. Towards the edge of some mud crabs’ distribution, this might mean that one rather than two crops a year may be produced, linked to favourable weather conditions. Alternatively, innovations can be developed to ameliorate conditions to support farms operating outside of ideal conditions, as has happened with overwintering of mud crabs in areas of China.