WWW.WAS.ORG • WORLD AQUACULTURE • MARCH 2013 39 livelihoods of around 400,000 fishers, many of them women and children, are associated with prawn and shrimp fry fishing in coastal Bangladesh (Ahmed et al. 2010b). Although prawn farming is a valuable industry in Bangladesh, it has been accompanied by concerns over climate change. The country is highly vulnerable to the likely impacts of climate change because of its geophysical position and poor socioeconomic conditions. According to the Global Climate Risk Index 2010, Bangladesh ranks first among countries vulnerable to climate change (Harmeling 2010). The most vulnerable part of the country is the southwest region because of proximity to the Bay of Bengal. This article describes the impacts of climate change on prawn farming communities, particularly on human health. Insights into prawn farming practices as impacted by climate change are drawn from participatory rapid appraisal. Focus group discussions were conducted with prawn farmers and community members in southwest Bangladesh. Qualitative data were collected from October to December 2011. Prawn Farming in Gher Systems A large number of small and marginal farmers are associated with prawn farming in southwest Bangladesh, mainly Bagerhat, Khulna and Satkhira districts (Fig. 2). Because wild postlarvae are available nearby, these districts have been identified as the most important and promising area for prawn culture. Prawns are cultivated in modified rice fields, locally referred to as ghers (Fig. 3). Gher farming is a ‘quiet, indigenous technological revolution’ involving the cultivation of prawn, fish, rice, and dike crops (fruits and vegetables); it can be considered a method of integrated aquaculture-agriculture. Prawns are produced for export markets while other crops are for household consumption and local markets. The Bengali term gher refers to an enclosure made for prawn culture by modifying rice fields through the construction of higher dikes around the field perimeter and the excavation of a canal several feet deep inside the periphery to retain water during the dry season. During the rainy season, the whole water body is used to cultivate prawn and fish. During the dry season, only the trenches are used for fish and rice is planted in the central plot. During winter, crops such as beans, carrots, tomatoes, onions, mustard and yard-long beans are produced on dikes, while crops produced in summer include okra, sweet gourd and other vegetables. A range of short-cycle fruits, such as banana, papaya and guava are also produced on dikes year round. The concept of gher farming makes it possible to incorporate a wide variety of crops. Climate Change and Bangladesh Bangladesh is particularly prone to natural disasters related to climate change because of its geophysical position and poor socioeconomic conditions. Sea-level rise as a result of global warming and glacier melting in the Himalayas will inundate coastal Bangladesh, inasmuch as the country’s topography is very flat and low-lying, with two-thirds of the land area less than 5 m above sea level (Dasgupta et al. 2011). During the next 50 years, temperatures in Bangladesh are predicted to increase by 1.1 oC during the flood season and 1.8 oC during the dry season. Sea level is predicted to increase by 50 cm (Allison et al. 2004). An increase in sea level of 1 m would inundate 18 percent of the country, directly threatening 15 million people with floodwater (Agrawala et al. 2003). In addition, backwater flooding caused by sea-level rise and increased river flow from melting glaciers could affect more than 70 million people in the country (FAO 2007). Bangladesh is flood-prone, with 20 percent of the area of the country normally flooded each year. However, an El Niño event with strong warming can cause the monsoon to switch into a dry mode, resulting in major reductions in rainfall, leading to severe droughts in coastal Bangladesh (Conway and Waage 2010). Sea-level rise in the Bay of Bengal could cause intrusion of saline water approximately 50 km inland from the coast (Jakobsen et al. 2005). Sea-level rise is likely to increase problems of coastal inundation and salinization. Several hundred thousand tons of crop production could be lost as a result of increased salinization from a rise in sea level. Increased inland groundwater salinity has already been observed in coastal Bangladesh in recent years (WorldFish Center 2006). Prawn farming areas in southwest Bangladesh are also prone to violent storms and tropical cyclones. Between 1877 and 1995 (118 years), Bangladesh was hit by 154 cyclones (Dasgupta et al. 2011). Cyclones originate in the deep Indian Ocean and track through the Bay of Bengal where shallow waters cause huge tidal surges when cyclones make landfall. A cyclone in 1970 resulted in around 300,000 deaths and another in 1991 led to the loss of 138,000 lives (World Bank 2000). In November 2007, the coastal area of Bangladesh was affected (CONTINUED ON PAGE 40) FIGURE 2. Map of coastal Bangladesh showing the prawn farming areas vulnerable to climate change.
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