36 March 2009 thatched shelter, perched on the dike, where a night guard can be stationed, because theft or the fear of it is rampant. The average gher size in the study area was found to be 0.29 ha, with thousands of tiny ghers and only a few large units. The principal water sources for ghers are rainfall, ground water and sometimes river water through canals. During the rainy season the whole water body is used for the cultivation of prawns and fish. However, when the weather is dry then only the trenches are used for fish and rice is planted in the central plot (Ahmed 2001). Production Technology The concept of gher farming makes it possible to incorporate a wide variety of crops together with prawns, fish and rice. While prawns are produced for export markets, fish and rice are grown for local markets and household consumption. Prawn culture in ghers is fully dependent on wild postlarvae that are stocked when they become available in May or June and are harvested primarily from November to January. The average stocking density of postlarvae is 20,984/ha. Various carp species are cultured with the prawns and harvested throughout the year. They include the Indian major carps catla (Catla catla), rohu (Labeo rohita) and mrigal (Cirrhina mrigala) and exotic carp including silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella) and common carp (Cyprinus carpio). The average annual stocking density of fingerlings is 2,462/ha. In general, farmers did not attempt to stock any specific ratio of carp species. Almost all farmers cultivated boro rice inside the gher during the dry season from January to April. The majority of farmers (62 percent) avoid cultivating aman rice during the monsoon when the prawns are in the gher. Farmers suggested that aman rice competes with the prawns for living space and placed demands on the limited capital of the farmers during the prawn growing season. Aman rice is also thought to pollute the water when the stalks are left to rot. In addition, farmers believe that the use of pesticides for rice negatively affects prawn growth. A variety of feeds are used for prawn farming but the preferred feed is the freshwater snail, Pila globosa. An average 65 kg/ha/day of snail meat is offered from June to October. In general, chopped snail meat is fed in the morning and evening. The supply of snails is not regular so farmers also use a mix of cooked rice, rice bran, oil cake and fishmeal. These feeds are also used for fish. Most of the respondents (92 percent) used fertilizers in their gher, mainly cow-dung, urea and triple super phosphate (TSP) at varying frequencies. On average, annual fertilization rates were 1,511 kg/ha of cow-dung, 455 kg/ha of urea and 223 kg/ha of TSP. The purpose of using fertilizers in the gher is to create conditions that help increase the production of good quality natural feeds, phytoplankton, zooplankton and benthos; thereby, increasing prawn and fish production. Productivity of gher systems is variable. The average annual yield of prawns (heads-on) and fish were estimated at 465 and 832 kg/ha. A number of interdependent factors affected growth rate and productivity of prawns and fish, A typical gher for prawn-fish-rice farming. creased dramatically as more and more farmers watched their neighbors profiting from prawn cultivation and decided to become involved. The news spread to other areas, and farmers in other parts of Bagerhat district began to adopt this new technology. The number of prawn farms and farmers continue to be the highest in the Fakirhat area. Potential returns for prawn farming are good and farmers have been attracted by its potential as an income generator. For the people of Fakirhat, proudly called the Kuwait of Bangladesh, prawn production is reported to have increased subsistence farmer income considerably (Kendrick 1994, Rutherford 1994). The early innovators tended to be large and middle size farmers, but increasing numbers of small and marginal farmers are also producing prawns (Rutherford 1994). The expansion of prawn cultivation has been dramatic and, since 1990, adoption has accelerated, spreading to other southern districts, such as Khulna, Satkhira and Jessore. Since the early 1990s, prawn farming has become one of the most financially attractive investment opportunities in many areas of Bangladesh (Ahmed 2001). Gher Systems The cultivation of prawns in modified rice fields, locally referred to as ghers, was originated by farmers (Rutherford 1994). According to Kamp and Brand (1994), gher farming is a “quiet, indigenous technological revolution,” suitable for the cultivation of prawn, fish and rice. Gher farming can be considered a method of combining aquaculture and agriculture in one plot. The Bengali term gher is an enclosure made for prawn cultivation by modifying rice fields through building higher dikes around the field and excavating a canal inside their periphery to retain water during the dry season (Kendrick 1994). Inasmuch as ghers have been converted from rice fields, their boundaries often follow existing rice fields, although some farmers may choose to subdivide a field. Sometimes there are canals between neighboring ghers, but in intensively developed areas, ghers are often laid out back to back, uninterruptedly covering hundreds of hectares (New 1995). Many are provided with a small
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