Evolution of shrimp aquaculture systems in the coastal zones of Bangladesh and Vietnam: a comparison.

Abstract

Based on on-farm surveys implemented in the Ganges Delta in Bangladesh and the Mekong Delta in Vietnam, the dynamics of shrimp aquaculture in salinity-influenced coastal areas were analysed. Qualitative data were collected through interviewing both individual and group farmers in 2005 and 2006, as well as key informants and value chain stakeholders, to obtain an overview of the dynamics of salinity-influenced aquaculture in these two deltas. The first phase of the coastal area's agroeconomic evolution is related to the policy and infrastructure in the course of agroeconomic transformation. A second phase is characterized by the spread of shrimp aquaculture (in successive levels of technology), causing these coastal zones to become areas of strategic export product generation. Different factors such as government policy, demography and international market demand drove this evolution in both deltas. In a third phase, the risk associated with shrimp farming because of shrimp virus outbreaks led farmers to diversify or intensify the aquaculture farming system. The evolution of shrimp farming systems in both deltas has been toward greater diversification of aquaculture technologies and is dependent on both natural environmental factors such as saltwater period duration and soil quality, technical factors such as access to drainage and socio-economic factors such as investment capacity and market demand. Comparing the coastal area of Bangladesh and the Mekong Delta in Vietnam, the key factors identified were land ownership, access to knowledge for the improvement of shrimp culture technology and diversification of aquaculture production. The alternating rice-shrimp system (i.e. rice in the rainy season, followed by shrimp in the dry season) and diversified brackishwater polyculture show more stable economic returns in comparison to extensive and intensive shrimp monoculture in both areas. In Bangladesh, water management infrastructure, access to information and the development of information networks were highlighted as key factors necessary for the improvement of brackishwater aquaculture. In Vietnam, the higher level of technology used in coastal aquaculture underlined the need for the development of better management practices to reduce the environmental burden and to evolve towards sustainable production systems.

Differential livelihood adaptation to social-ecological change in coastal Bangladesh

“…Compared to other Asian countries, which practice semi-intensive and intensive shrimp/prawn farming, Bangladeshi farmers are still dependent on extensive and improved extensive methods. There is huge potential to increase production by adopting best practice from other countries like China, Thailand, Indonesia and Vietnam (Joffre et al 2010). If Bangladesh seeks to increase yield by promoting intensive and semi-intensive methods, it must take adequate precautions to avoid the adverse effects experienced by other countries, particularly in terms of discharging antibiotics, fertilisers and other chemicals into adjacent water bodies (e.g.…”

Livelihood Capabilities and Pathways of Shrimp Farmers in the Mekong Delta, Vietnam

“…Other studies have focused on integrated agriculture and aquaculture models (Brennan et al, 2000;Bosma et al, 2006;Hoanh, 2006;Phong et al, 2006;Can et al, 2007;Nhan et al, 2007;Joffre and Bosma, 2009), differences in shrimp farming systems across countries (Hall, 2004) or economic analysis of the value chain and market (Macfadyen et al, 2005;Nguyen et al, 2005;Sinh and Khuyen, 2006;Hobbes et al, 2007;Sinh and Chanh, 2009). Surprisingly, there are few studies of livelihood strategies and decisionmaking among shrimp farmers (Hue and Scott, 2008;Joffre et al, 2010). This article focuses on the diversity of farmers' livelihood strategies, how they access various sources of capital to finance shrimp farming, to what uncertainties and vulnerabilities they are exposed and the pathways they have created to mitigate these risks and sustain their livelihoods.…”

Nutritious ponds : valorising waste using natural production

“…27 -30 ºC; (Wyban, Walsh et al, 1995)), shrimp showed normal growth. Given a production of 3047 kg/ha and 2244 kg/ha (control and Lw-HUFA groups respectively) over an 8 week period, our experimental mesocosms mimicked a farming system of semi-intensive shrimp farmers in the Vietnamese Mekong Delta well (Joffre 2010). The mesocosms maintained low TAN, nitrite and nitrate concentrations during the entire experiment.…”

“…In natural systems without external feed input, autotrophic primary production reaches an average of 4 g carbon (C) m -2 d -1 (Brune 1991, Verdegem et al, 1999, Brune et al, 2003, an equivalent of 7-8 g organic matter (OM) m -2 day -1 . These extensive systems can produce approximately 300 kg shrimp ha -1 per 120 days, an equivalent of 30 g wet weight shrimp m -2 , or 7 g OM shrimp m -2 in 120 days (Joffre, 2010). In such systems, less than 1 % of the pond's primary production contributes to shrimp biomass production.…”

“…The water and sediment were then homogeneously redistributed over the six tanks in an attempt to ensure a similar start situation for each mesocosm. One day before the start of the experiment each mesocosm was stocked with 50 ind/m 2 1.5-g juvenile whiteleg shrimp (Florida Shrimp International Shrimp Harvesters USA, SPF-line, imported by Crevetec Belgium), mimicking an intensive shrimp pond in the Vietnamese Mekong Delta (Joffre, 2010).…”