Fish farming can help fight poverty in Bangladesh
"Almost every household in Bangladesh has its own pond which is suitable for raising fish," says Azim who works at the Fish Culture and Fisheries Group. Many people in Bangladesh make a pond next to their house, as they dig up soil for building their houses. Rainfall fills these ponds and the water is used for irrigating farmland but also for washing and bathing. Raising fish can make these ponds even more useful.
For his PhD degree, Azim investigated how fish farmers can make optimal use of the ponds and generate high fish production using their household resources. He focused on the use of artificial substrates that are put in the ponds to enhance the growth of periphyton, tiny organisms such as fungi, bacteria and plankton which are eaten by many fish. With more food in the pond, the fish will grow faster.
"I discovered that fish farmers can double production by driving jute or bamboo sticks vertically into the bottom of the pond. The use of jute sticks especially is a simple technique that does not cost much but has great results." Azim tested the materials for several fish species including Indian carp. Besides doubling fish yields, Azim points to another advantage of the sticks in the ponds: they can discourage people who try to steal fish from fish farmers.
"When the ponds are full of sticks, the thieves get their nets stuck on these sticks. If you want to catch the fish, you first have to remove all the sticks, which takes quite a long time." This means that thieves are more likely to be seen and caught red-handed.
Azim has already had many responses from people who are interested in the techniques he tried out: people from Bangladesh and neighbouring countries, as well as from Africa. The idea of using bamboo and other materials to attract fish is not new; it was derived from traditional fishing methods in rivers, lakes and coastal waters, for example in the Ivory Coast. But applying this technique to fish farming in closed ponds is a new approach that Azim has tested successfully.
Azim also looked at the use of water hyacinth. In open waters this plant attracts fish as it provides shade for them during hot weather. However it is not suitable for fish ponds, as it blocks also sunlight necessary for the growth of periphyton, says Azim. The bamboo branches and jute sticks are very promising materials however for fish ponds, but there is one danger says Azim: if everyone decides to use bamboo for fish ponds, there may not be enough bamboo left for other purposes such as building houses. Jute sticks however, which are also used as fuel for cooking food, are present in much greater quantities than bamboo in Bangladesh. And as jute is also cheaper than bamboo, it is a more suitable material for the fish farmers.
Mohammed Ekram-Ul-Azim received his PhD on 10 December 2001. He was supervised by Professor E.A. Huisman and Professor Johan Verreth of the Fish Culture and Fisheries group, Wageningen University. Dr Azim can be reached at Fish Culture and Fisheries Group, Wageningen University, P.O. Box 338, 6700 AH Wageningen, Netherlands. E-mail: email@example.com