Mark Flaherty

Marine shrimp aquaculture and natural resource degradation in Thailand

Rising demand for shrimp in the developed nations has helped to foster a dramatic growth in marine shrimp aquaculture, particularly in South America and South Asia. In Thailand, Marine shrimp aquaculture is now an important earmer of foreign exchange. The growth in Production has been achieved through the expansion of the culture area and the adoption of intensive production methods. The conversion of near-shore areas to shrimp culture, however, is proving to have many consequences that impinge on the environmental integrity of coastal areas. This paper reviews the development of Thailands marine shrimp culture industry and examines the nature of the environmental impacts that are emerging. It then discusses the implications these have for rural poor and the long-term viability of the culture industry.

Rice Paddy or Shrimp Pond: Tough Decisions in Rural Thailand

Abstract Thailand is the world’s largest producer of cultured shrimp. Despite problems with poor environmental conditions and outbreaks of disease that have led to the large-scale abandonment of culture areas along the coast, production has remained high. A primary factor has been the establishment of marine shrimp farming in Thailand’s rice growing Central Plain. This paper describes the development of inland shrimp farming in Thailand, and discusses the environmental concerns that have arisen. We then examine the evolution of the government’s response to inland shrimp farming and assess the capacity of the state to implement a proposed ban. We conclude by arguing that other countries with irrigated agriculture need to be proactive in prohibiting this activity before it is entrenched in ways that are difficult to reverse either ecologically or politically.

Low Salinity Inland Shrimp Farming in Thailand

Abstract Thailand has been the worlds largest exporter of cultured shrimp since 1991. Despite problems with poor environmental conditions and disease outbreaks that led to the failure and abandonment of numerous farms along the coast, Thai shrimp production has remained high. A primary factor has been the establishment of low salinity shrimp farming for black tiger shrimp (Penaeus monodon) in areas much further inland from the coast than once thought feasible. The rapid development of low salinity culture in freshwater areas that are predominantly used for paddy rice cultivation, however, now represents a major land and water management challenge. The debate over the potential environmental impacts of inland shrimp farming revolves around three key questions: i) the ability of so-called “closed” production systems to minimize environmental impacts, ii) the capacity of the Thai government to enforce environmental protection regulations, and iii) the potential emergence of cumulative environmental impacts. This paper concludes that a ban on inland shrimp farming is a prudent measure, needed to protect soil and water quality in freshwater areas.

Salt balances of inland shrimp ponds in Thailand: implications for land and water salinization

Brackish water ponds for farming black tiger shrimp ( Penaeus monodon ) have recently proliferated in inland areas of Thailands central plain, raising concerns about land and water salinization. The environmental impacts of inland shrimp farming were assessed by analysing the salt balance for an inland shrimp farm. Field data on water fluxes and pond salinity, collected from nine ponds in Chachoengsao Province from May–July 1999, were used to model the salt balance for a typical shrimp pond over one growout cycle. During growout, seepage represented 38% (11.5 tonnes crop −1 ) of salt losses, pond discharge 33% (9.7 tonnes crop −1 ), and accumulation of salt in pond sediment 6% (1.8 tonnes crop −1 ). About 23% of the initial salt content remained at harvest and could have been recycled. However, the majority (84% on average) was discharged to the irrigation canals. Much of the salt in pond sediment was also exported to the canal system through tidal flushing of the ponds. Field measurements of salinity were taken in adjacent canals and rice paddies to explore the impacts of salt exports from shrimp ponds. Pond discharge caused increases in canal salinity above levels that would impact on yields of irrigated rice and orchard crops, the main land uses in the region. Elevated soil and water salinity in adjacent rice fields was probably related to lateral seepage from the ponds. The salt budget was also modelled for a zero discharge farming system, promoted by proponents of inland shrimp farming as having few impacts. However, the results suggest that, even in zero discharge ponds, almost half of the initial pond salt content is exported through seepage (45%, 12.4 tonnes crop −1 ), with another 6% (1.8 tonnes crop −1 ) deposited in sediments. While techniques exist for mitigating much of the salt leakage, the likelihood of their uptake in Thailand is low. Further expansion of inland shrimp farming in the central plain is therefore likely to contribute substantial salt load to the areas land and water resources.

Hydrology of inland brackishwater shrimp ponds in Chachoengsao, Thailand.

This study focuses on a new trend in shrimp aquaculture, the development of brackishwater ponds for Penaeus monodon culture in inland freshwater areas of Thailand’s Central Plain. Water balances were calculated for ponds and reservoirs at an inland shrimp farm in Chachoengsao, Thailand, between May and July 1999. Regulated inflow and outflow were the largest water fluxes, averaging 0.94 and 0.70 cm:day. Other daily average water gains were rainfall (0.52 cm:day) and runoff (1.7 cm:day), and other water losses were evaporation (0.31 cm:day) and seepage (0.52 cm:day). Over an entire crop cycle, of average length 109 days, average water inputs were: initial pond filling (84 cm); regulated inflow (103 cm); rainfall (57 cm); and runoff (3 cm). Average outputs were: regulated outflow (76 cm); seepage (57 cm); evaporation (34 cm); and draining at harvest (87 cm). The main feature of note in the water balance is the large volume of regulated outflow. All regulated outflow and most (82%) of the pondwater drained at harvest went directly to the irrigation canal system. Such large volumes of discharge could have serious environmental implications because small inland waterways have low assimilative capacity and pond effluent is saline. Consumptive water use for 14 inland shrimp ponds and reservoirs averaged 0.839 0.14 cm:day. Consumptive water use was also measured for 11 nearby rice fields, the main land use in the regions where inland shrimp farming is proliferating. Rice paddy water use averaged 0.919 0.17 cm:day. There was no significant difference in the daily consumptive water use of shrimp ponds and rice fields, suggesting that conversion from rice farming to shrimp farming would have little net impact on water availability for irrigation.

National Initiatives, Local Effects: Trade Liberalization, Shrimp Aquaculture, and Coastal Communities in Orissa, India

Commercial shrimp farming in India expanded rapidly after trade liberalization initiatives were introduced in the early 1990s. This article examines the social, economic and environmental impacts that have been generated in communities along Orissas Coast in east India. The results suggest that macro-level policies such as trade liberalization are useful at the national level, but at the local level they can generate imbalanced growth. Although the shrimp farming industry has generated substantial foreign exchange, at the local level it has widened the gap between rich and poor. To protect the livelihoods of the rural communities and the environment, India needs to formulate effective coastal resource management policies and establish adequate institutions at the local level. This will help ensure a stable source of income from shrimp farming for small-scale farmers and minimize adverse impacts on the local environment.

Historical perspectives and recent trends in the coastal Mozambican fishery

Historical data describing changing social-ecological interactions in marine systems can help guide small-scale fisheries management efforts. Fisheries landings data are often the primary source for historical reconstructions of fisheries; however, we argue that reliance on data of a single type and/or from a single scale can lead to potentially misleading conclusions. For example, a narrow focus on aggregate landings statistics can mask processes and trends occurring at local scales, as well as the complex social changes that result from and precipitate marine ecosystem change. Moreover, in the case of many small- scale fisheries, landings statistics are often incomplete and/or inaccurate. We draw on case study research in Mozambique that combines national landings statistics and career history interviews with fish harvesters to generate a multi-scale historical reconstruction that describes social-ecological interactions within the coastal Mozambican fishery. At the national level, our analysis points toward trends of fishing intensification and decline in targeted species, and it highlights the significant impact of small-scale fisheries on marine stocks. At the local level, fishers are experiencing changes in fish abundance and distribution, as well as in their physical, social, and cultural environments, and have responded by increasing their fishing effort. We conclude with a discussion of the governance implications of our methodological approach and findings.

Forest management in Northern Thailand: a rural Thai perspective

Abstract Deforestation is considered to be one of Thailands most pressing natural resource management problems. Critics of past management practices argue that protection policies have been ineffective because of inadequate attention to the needs and concerns of local people. This study compares the responses of men and women. The results show that men are quite involved, and that the genders do not differ in their perceptions of deforestation.

Cumulative environmental effects of low salinity shrimp farming in Thailand

The cumulative environmental effects of low salinity shrimp farming in the Bangpakong River Basin, eastern Thailand, were investigated using a GIS-assisted approach. Water supply, water quality, and agricultural land use were used to represent key environmental resources. Shrimp farming is a major consumer of freshwater, but cumulative effects on water supplies are probably negligible because of ample rainfall and similar water consumption of rice and shrimp crops. Assessment of water quality effects focused on organic nutrient loading. Low salinity shrimp farming was a significant new source of organic pollution. Agricultural land use effects were evaluated using land conversion and soil suitability ratings. Soil productivity has been degraded as a result of direct salinization of shrimp pond bottom soils; indirect salinization may affect a considerably larger area.

Shellfish aquaculture in Thailand

Abstract Shellfish have been farmed in Thailand for over 100 years, and during this time, traditional culture techniques have gradually given way to more sophisticated and capital intensive methods. Farmed shellfish production increased from 73,976 to 138,202 metric tonnes between 1988 and 2000. Major species currently under cultivation include the green mussel Perna viridis, the blood cockle Anadara granosa, and three species of oyster (Saccostrea cucullata, Crassostrea belcheri, and Crassostrea iredalei). The horse mussel Arcuatula arcuatula is also produced in limited amounts for animal feed, and gastropods such as the abalone Haliotis asinina and the spotted babylon Babylonia areolata are in the initial phases of commercialization. With the globalization of fisheries commodity markets, the Thai shellfish sector is slowly implementing more rigorous management and certification processes. These procedures are required to access European, American and Japanese markets, and would also serve to decrease the risk of gastrointestinal disease for local consumers.