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2 International Journal of Ecohydrology and Hydrobiology

2 2010

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Integrating aquaculture with traditional farming system: socioeconomic assessment in the Amhara Region, Ethiopia

100%

Adugna B. T. , Goshu G.

tom 10

nr 2-4

Semi-intensive aquaculture practice started in 2005 in the Amhara region of Ethiopia. An evaluation survey was undertaken in September 2009. Beneficiaries, key informants and various groups were interviewed. Constructed aquaculture ponds were different in source of water, structure, age, original purpose, level of integration and the type of fish stocked. Farming households integrated aquaculture with different production subsystems and increased the flow of nutrients. At the same time they gained different benefits. However, the practice has been also constrained by various challenges. Farmers’ research extension group approach, provision of gillnets, appropriate fish species and mono-sex culture, capacity building of the research and extension system, and proper follow up are the recommendations for integrated aquaculture expansion.

Spatial and temporal distribution of commercially important fish species of Lake Tana, Ethiopia

80%

Goshu G. , Tewabe D. , Adugna B. T.

tom 10

nr 2-4

The distribution of Lake Tana fish species was studied from January 2000 to December 2003. Samples were collected monthly using gill-nets of 60, 80, 100, 120 and 140 mm stretched mesh size. Labeobarbus spp., Oreochromis niloticus, Claris gariepinus and Varicorhinus beso are commercially important fish species and form 77%, 13%, 9% and 1% of the pooled experimental fish catch. There was significant variability among years and sampling sites encompassing both temporal and spatial aspects. Population densities of Labeobarbus spp. and V. beso were significantly declining, in contrast, the abundance of O. niloticus and C. gariepinus did not change. The most likely explanations for the decline in Labeobarbus spp. are the increase of the commercial gill-net fishery targeting their spawning aggregations in the river mouths, use of poisonous plant materials and the increasing trend of the disconnectivity and channelisation of rivers. The results stress the need for urgent development of a management plan focusing on ensuring river connectivity, fishing effort and gear restrictions, and control in the river mouths and major tributaries during the breeding seasons.