Former rice fields transformed into shrimp ponds in Bangladesh, locally known as ‘ghers’. Photo by: STIP
Production of Penaeus monodon (black tiger shrimp) or ‘Bagda’ as Bangladeshi say, takes mainly place in low land rice fields that are converted into shrimp ponds. These ponds are known as ‘ghers’ and are located in so-called polders that were created to increase the availability of agricultural land. When shrimp farming started to expand due to high market prices and potential high profits for farmers, farmers in so-called polders started to introduce saline water to their ponds and started to add shrimp. Nowadays, most farmers cannot grow rice anymore at all, as saline water has made their land unsuitable for rice farming. Saline water is moving further inlands, forcing more farmers to stop farming rice and making them dependent on the production of P. monodon. Total farming area of extensive P. monodon in ghers covers 160,000 ha (DoF, 2015). Within the Khulna division P. monodon farming is concentrated in Satkhira (66,000 ha), Bagerhat (55,000 ha), and Khulna (38,000 ha).
An important note is that in Chittagong and Cox’s Bazar the typical crop rotation is shrimp and salt. Farmers here use the land for salt production from December to May and grow shrimp from June to September. Further, the production system is largely similar as in Khulna.
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May to August
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Type of farmers
Farming in ghers is done by small-scale farmers. The majority of small-scale shrimp farms are not organised.
Production and harvesting system
Ghers are shallow and characterized by their substantial size ranging from 1 to 5 ha. Small dikes, of 0.5 to 1 meter high, ensure preservation of at least 40 to 50 cm of water in the gher. Farmers use open channels with sluice gates and during high tides farmer will take in fresh water into their ponds. Water is generally not treated before intake.
Shrimp ponds are harvested during full moon and new moon when shrimp would naturally travel from the sea to the Sundarbans and back. Some shrimp will be caught in harvesting traps, which are made from bamboo and nylon net, in the corners of the shrimp pond. Survival rates is this system are low, varying from 20% to 50%. P. monodon shrimps harvested from ghers are generally large sized and almost organic. Many people argue it is one of the best shrimps you can eat in the world.
Target species and byproducts
The target species is P. monodon.
Stocking densities and productivity
Farmers stock their ghers continuously 2-8 times during the production season. On average there is not more than 1 post-larvae per m2. Annual average productivity is between 200-500 kg per hectare. Higher productivity is especially realized by farmers with deeper ponds and those that are using nurseries.
Use of seed, feed and other inputs
Production in ghers is so extensive that farmers do not use commercial feed, but sometimes natural feeds such as rice bran is used. Farmers use almost no chemicals and medicines. They are encouraged however, to use probiotics to improve survival rates and faster growth. The farms do not use any electricity.
Stocking of shrimp starts from February to April and harvest starts from the later part of March, but the high season for harvest is from May until August. Harvest stops completely from November to February. More to the north, the season finishes earlier and farmers will plant rice instead.