Fish culture in rainfed rice fields of northeast Thailand

Abstract

Adoption of rice-fish culture by farmers in the rainfed areas of northeast Thailand is examined with reference to recent field research and extension in the region. The practice is placed in perspective with the development of aquaculture per se and the human and agricultural ecology of this heterogeneous region. Rice-fish culture is a recent activity in the region and has been promoted by government and non-government agencies with variable success among small-scale farmers. The widespread availability of private hatchery-produced fish seed and perceived decline in wild fish have been important stimuli. Rainfed rice fields are marginal agricultural environments and lack of water constrains both rice and fish production. Wild swamp fish are tolerant of these conditions and traditional systems for their management and capture have expanded greatly in recent years. In much of the region 'trap' ponds are used more for catching wild fish than as refuge sumps or ponds for fish culture per se; wild fish typically constitute between 20 and 80% of the total yields in stocked systems. Widespread availability of fish seed allows more farmers to try rice-fish culture but the small size of seed at purchase is still a problem particularly where carnivorous, wild fish are prevalent. Appropriate on-farm nursery techniques may improve success and adoption of hapa nursing has been high in some parts of the region. Species ratio and density of fish stocked depends mainly on their availability from fry traders; the major species stocked in rice fields are the silver barb (Puntius gonionotus), common carp (Cyprinus carpio) and Nile tilapia (Oreochromis niloticus). Farmers adapt rice fields for fish culture as part of their whole farm strategy; benefits to rice, vegetable and fruit and livestock may be considered more important than fish yields. The high value attached to even small quantities of fresh fish is a major incentive for rice-fish culture, but women who are decision makers in terms of changes to rice fields and household consumption have often not been fully considered during promotion of rice-fish. The relatively small areas of riceland that farmers can stock and harvest fish, low yields per unit area and high consumption of fish reduces the importance of rice-fish culture in many rural households. The analysis suggests that stocking fish in rice fields in areas with poor access to wild fish supplies from community water bodies would have most impact. Although rice-fish culture can contribute to subsistence requirements, the high labour demand often means that intensified capture of wild fish or pond-based culture of fish are more attractive for poorer and better off farmers, respectively.