Polyculture

This study explored the viability of giant freshwater prawn (Macrobrachium rosenbergii, locally known as ulang) culture in six regions in the Philippines. Twelve farmer-cooperators employed ulang monoculture and eight employed ulang-tilapia polyculture. In Region 8, all farmer-cooperators conducted both monoculture and polyculture systems. This paper is focused on comparing ulang monoculture and ulang-tilapia polyculture.

The production performances of giant freshwater prawn Macrobrachium rosenbergii and Nile tilapia Oreochromis niloticus in C/N-controlled periphyton-based polyculture systems were evaluated in triplicate. The result of this study could be useful in improving the sustainability of freshwater prawn farming in terms of ecological, social and financial benefits.

Based on lessons learned from field trials, carp-small indigenous fish species (SIS)-prawn polyculture technology was improved to a "carp-SIS polyculture" technology suitable for small scale farmers in Terai, Nepal. In December 2008, the project was initiated to improve income and nutrition of Tharu women in Chitwan (100 farmers) and Kailali (26 farmers) districts. The present paper presents the final results of the project.

Technology and knowledge transfer has been a great challenge for many developing countries in South Asia due to poor information and communications technology networks. A limited number of institutions focused on science and technology, weak linkages among private and public institutions and political instability. These factors have hampered the successful transfer and diffusion of new and proven technologies between countries.

Following two decades of work on aquaculture technologies for smallholder farmers, WorldFish is leading the aquaculture component of the Agriculture and Nutrition Extension Project (ANEP), targeting poor farmers in Bangladesh and Nepal.The main goal of ANEP aquaculture component was to increase fish production, household nutrition, incomes and alternative employment opportunities for smallholders by facilitating the adoption of productive and environmentally sustainable agricultural technologies.

Tilapia is the main cultured fish species in Egypt, contributing 43.5% of farmed fish production and 24% of total fisheries production. The main problem facing tilapia producers is early reproduction before fish reach marketable size, leading to overpopulation and smaller fish at harvest. Approaches to this problem include the use of all-male hybrids and hand-sexing to remove females.

This study aims to update the typology of shrimp farms in a province of the Mekong Delta’s coastal area. We analyzed technical and economic characteristics of 170 farms using factor and cluster analysis on the different variables collected during the survey. This allowed us to characterize four different shrimp production systems: intensive commercial and intensive family farms, and the more extensive brackish water polyculture and rice–shrimp farms. The systems differed in their level of intensification, diversification and origin of labor.

The production of snakeskin gourami (Trichogaster pectoralis) from wild stocks and traditional culture systems has been declining in central Thailand, although they are on the increase in modern culture practices adopted in some provinces. Net yields of T. pectoralis in traditional systems are about a third of those in modern systems. The potential of T. pectoralis as a candidate for more intensive waste-fed polyculture appears promising if seed supply constraints can be removed.

The viability of integrating rice farming with fish culture was studied in ten (10) rice plots. The onfarm research was done during one rice-growing season starting May 2003. The rice variety used was IR 2793-80-1 while the fish species was the Nile tilapia, Oreochromis niloticus. The fish culture period lasted 77 days. An average fish production of 132.4 kg/ha was obtained. The mean recovery rate of tilapia was 43 per cent. Total rice yield from the fields stocked with fish was lower than from unstocked fields. The net returns were not significantly different.

Experiments with fish enclosures were conducted at the Deepwater Rice Farming Systems Research Site at Shuvullah, Mirzapur, Bangladesh. The objective was to study the performance of silver barb (Puntius gonionotus) called Thai sharputi or rajputi in Bangladesh in mono-and-polyculture with grass carp (Ctenopharyngodon idella), common carp (Cyprinus carpio), catla (Catla catla) and rohu (Labeo rohita). Each enclosure measured 21 m x 21 m with an approximate net height of 3.5 m.