A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 1999

This study collected both primary and secondary data from one hundred and twenty shrimp farmers and twenty-five Provincial Fisheries Offices. The study showed that intensive marine shrimp (Penaeus monodon) culture in inland water was first established from intertidal coastal areas such as Samut Prakan, and Chachoengsao province, and later expanded to completely fresh water areas. Success and high profits stimulated the expansion of intensive inland marine shrimp farming. Most farmers engaged in inland shrimp farming were local household heads who had only primary school education and age of 35-45 years relating closely with investment and land ownership, and 43% of them were rice farmers before entering to shrimp farming. They learned site suitability and farm design from other successful inland marine shrimp farmers (about 47%). The main sites selection criteria were land ownership and freshwater accessibility. More than 60% of farms are open systems without water treatment pond. Information from media publication, and successful inland marine shrimp farmers were the most important sources of information about culture techniques. They developed and exchanged culture techniques within their group throughout culture period. The farm management strategies used took little account of possible impacts on environment and traditional surrounding farmer's interests. More than 50% of farms stored water in a water storage pond, set the water salinity to about 5-1 Oppt, and stocked more than 60 PL/m2 directly to growout pond or nursery pen inside growout pond. Ponds were filled with freshwater during first 2 months and after that pond water was exchanged. More than 60% of farms discharged their pond effluent directly to natural water bodies, including the pond sediment after harvest. Only 11.4% of them had reported conflict with traditional surrounding farmers in the study area. The main problems were water quantity and diseases, caused by lack of water supply in dry season and seed infected from hatcheries. The average shrimp culture production was 5 .4 MT/ha/crop with 55% survival within 3-4 months, and total cultured crop was about 2.5 crops/year on average. The average FCR was 1.35 and size harvested about 53 shrimp/kg. Total cost was about 16,185 US$/ha/crop including variable cost and fixed cost of 14,254 and 1,931 US$/ha respectively. Total income was 26, 196 US$/ha/crop, and net income of this farming system was 10,011 US$/ha/crop on average.