1. Environmental capacity and management of shrimp culture in tropical developing countries A case study of south west coastal part of Bangladesh TROPECA Abstract River water instead of shrimp farm has major influence on the dynamics of shrimp culture based ecosystem. Nutrient assimilative capacity of aquatic environment may in danger of being degraded with the intensification of shrimp culture areas. Consideration of depth (2.5- 3.5 ft), clean water entrance with controlled application of urea and cow-dung may enrich the shrimp production rate. Formation of small scale farmer association is prerequisite to make a effective management system. Management issues concerning shrimp production Limited supplementary feed Lack of ability / don’t take risk/unable to maintain regularly Not aware and no technical support Theft Small scale farmers are not registered and haven’t access to get technical support from FD Law and enforcement problem Remote area and border area Chingree committee and shrimp farmer association work for large scale registered farmers Less Production -- High mortality rate -- Low yield -- Susceptible to disease Horizontal expansion Salinity intrusion Sedimentation problemMuch nutrient uptake from environment Hampered household activities Reduce vegetation production WHY WHAT HAPPAND Lack of knowledge on pond preparation Less fry stocking Temperature fluctuation Limited natural food Low Oxygen support Less pond depth Pond weeds Salinity fluctuation No nursing from 2 nd stage fry stocking Frequent turbid water entrance Remote and border area Limited natural feed Nitrite and or Ammonia spike Inappropriate fertilization Fertilizer is the major source of nutrient and large proportion sinks to substrate or assimilated within the system Paddy Stable 3.3% Water exchange 14.5% Harvest drainage 0.0002% Sediment & unaccounted 39.1% Shrimp harvest 20.2% Other fish 13.21% Water exchange 14.9% Shrimp stocked 0.0002% Rainfall 0.6% Fertilizer 60.2% Feed 21.1% Denitrification 13% Mass Balance of Nitrogen Water exchange 2.2% Paddy Stable 5.3% Shrimp stocked 0.0002% Rainfall 0.6% Fertilizer 82.4% Feed 9.3% Water & Harvest drainage 2.0% Sediment 32.7% Shrimp harvest 2.6% Other fish 3.5% Assimilation 59.3% Mass Balance of Phosphorus Capacity (nitrogen and phosphorus) of aquatic systems not exceeded  Large size farms should be divided into small units (1-5 ha).  Multiple pond depth ranged should be kept to reduce sudden shock.  There should have seperate nursing pond within a farm.  Farms that use ‘tob’ (surrounding canal) initially for fry nursing, can also use them for subsequent fry nursing by seperating a part from the tob.  Farm should be filled with river or canal water just after high tide or at the beginning of low tide, so that precipitation or settle down of waste could take place. If possible, a reservoir to allow river or canal water to precipitate for further use is also preferable.  Farm effluents should not be discharged into freshwater areas or on to agricultural land.  Accumulated sediment of ponds need to be dug out and can be put into pond dike or as earth-filling.  Integrated water exchange system should be developed considering the benifit of both small and large scale farmers as well as shrimp cultivators.  Small scale farmers may form a association, so that they may avoid information gap, water management problems, marketing complexity and local threats.  Shrimp culture should be developed under integrated coastal zone management plan.  Government should develop a convenient way for small-scale farmers to registrar and get training. What should we do Paddy cultivation Shrimp harvest Effluent discharge Shrimp culture Pond prepara tion River, canal and pond water quality are more or less same and within the standard limit (except NH 3 -N) River water controls the farm water system Muhammad Abdur Rouf Associate Professor, Khulna University, Bangladesh Local Research Manager, TROPECA, Nautilus Consultant Co. Ltd. (UK) email: roufku@yahoo.com A joint collaboration of Nautilus Consultant Co. Ltd. (UK) Stirling University (UK) Fisheries and Marine Resource Technology Discipline, Khulna University, Bangladesh Uttaran NGo, Bangladesh Funded by : Department for International Development (DFID)