Coastal Shrimp Aquaculture in Thailand: Key Issues for Research

!Any attempt to identify research issues which may address the overall sustainabilityof shrimp farming as an industry must first fully consider the concepts of sustainabilityas they are currently evolving in scientific, economic, social and politicalcircles. This is done later in this chapter (sustainability issues section), together withan appraisal of the performance of researchers and the government in addressing theissue, and an evaluation of current industry practices in view of these concepts.Thai coastal resourcesThailand is located in the tropical zone between latitudes 6–21°N and longitudes98–106°E. The wet season generally occurs from April to November, withmonthly rainfall in southern Thailand increasing from 36 mm in the driest month ofJanuary to 328 mm in the wettest month of September (Funge-Smith 1997). Thetotal land area is 51,300 km 2 , bounded in the north, west and east by mountainranges and in the south by the South China Sea and the Andaman Sea. The coastlineis approximately 2,600 km in length. There are five major rivers, four of whichflow through the densely populated areas of the Central Plain and drain into theUpper Gulf of Thailand. These are the Chao Phraya, the Mae Klong, the Ta Chinand the Bang Pakong Rivers. The fifth river, the Tapi River drains into Ban DonBay in the south.In recent years, rapid population increases—coupled with industrial, agricultural,aquacultural and fishing activities—have resulted in degradation of the naturalcoastal resources. Many areas are experiencing the effects of water pollution, mangrovelosses and encroachment by urban settlements (Paw et al. 1988).Shrimp productionFigure 1 shows the coastline and shrimp farming areas of Thailand. Table 1shows that Thailand is currently the world’s largest producer of cultured shrimp(Funge-Smith 1997). This has been achieved over the last two decades following dramaticindustry expansion and in tensification of production. Between 1976 and 1991,the area covered by shrimp farms increased at a rate of 14.7% annually and thenumber of shrimp farmers rose by 21% per year. In 1976, there were 1,544 shrimpfarmers and farms covered 76,850 rai (12,300 ha) (NACA 1994a); by 1994, therewere 72,000 ha, divided into around 22,000 farms (Anon. 1995b) (see Table 2). Sincethen, production has declined and the area used for farming has stabilised. The productionin 1998 was estimated at 220,000 t.Also, farming methods initially became more intensive, producing more shrimpper unit area. From 1987–1994 there was more than a six-fold increase from 0.45t/ha/yr to 2.81 t/ha/yr. However, in 1997 productivity fell to 2.14 t/ha/yr (Funge-Smith 1997), then increased to 3.0 t/ha/yr (Anon. 1998b). Currently, 80% of farmsuse intensive methods, 15% semi-intensive and the remaining 5% traditional extensivemethods (Funge-Smith 1997).In 1972, 67,878 t of shrimp were produced, with only 1.5% (991 t) from culture. In1991, 268,565 t were produced, with 60.3% (162,070 t) from culture (NACA 1994b).Production from culture peaked at 72.5% (263,945 t) in 1994 (Anon. 1995b), but thendropped back. In 1997, 62.8% of the shrimp production was from culture (Funge-Smith1997). The annual production figures for this period are given in Table 3.)%