Environmental capacity and management of shrimp culture in tropical developing countries A case study of south west coas

1. Fertilizer 82.4% Rainfall 0.6% Feed 9.3% Shrimp stocked 0.0002% Water exchange 2.2% Water & Harvest drainage 2.0% Assimilation 59.3% River, canal and pond water quality are more or less same and within the standard limit (except NH3-N) Paddy Stable 5.3% Sediment 32.7% Shrimp harvest 2.6% Capacity (nitrogen and phosphorus) of aquatic systems not exceeded Other fish 3.5% Fertilizer 60.2% Rainfall 0.6% Feed 21.1% Denitrification 13% Shrimp stocked 0.0002% Water exchange 14.9% Water exchange 14.5% Harvest drainage 0.0002% Paddy Stable 3.3% Sediment & unaccounted 39.1% Shrimp harvest 20.2% Other fish 13.21% Mass Balance of Nitrogen Remote and border area Remote area and border area Small scale farmers are not registered and haven’t access to get technical support from FD Chingree committee and shrimp farmer association work for large scale registered farmers Law and enforcement problem Lack of ability / don’t take risk/unable to maintain regularly Theft Not aware and no technical support Limited supplementary feed Lack of knowledge on pond preparation WHY Pond preparation Shrimp culture Shrimp harvest Frequent turbid water entrance Effluent discharge Paddy cultivation Less pond depth No nursing from 2nd stage fry stocking Less fry stocking Inappropriate fertilization What should we do Pond weeds Salinity fluctuation Temperature fluctuation Limited natural food Low Oxygen support Limited natural feed Nitrite and or Ammonia spike • LessProduction • - High mortality rate • - Low yield • - Susceptible to disease WHAT HAPPAND Horizontal expansion Salinity intrusion Sedimentation problem Much nutrient uptake from environment • 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 wastecould 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. Hampered household activities Reduce vegetation production Environmental capacity and management of shrimp culture in tropical developing countries A case study of south west coastal part of Bangladesh TROPECA Fertilizer is the major source of nutrient and large proportion sinks to substrate or assimilated within the system 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. River water controls the farm water system Mass Balance of Phosphorus Management issues concerning shrimp production • 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)