Coastal Aquaculture Developments in Tanzania: Sustainable and Non-sustainable Experiences

Coastal aquaculture of seaweeds and prawns has developed in Tanzania during the past two decades. Farming of Eucheuma seaweeds commenced in 1989 along the east coast of Zanzibar and it has since expanded to other areas. This form of aquaculture does not pollute the environment with feeds, wastes or other chemicals, although there are some negative interactions causing inhibition of surrounding biota, but which appear to be relatively mild. Monoculture may result in some self-inhibition and disease vulnerability over time. The socio-economic impacts of seaweed farming was initially overwhelmingly positive, providing income to women from relatively poor remote villages. Annual production reached 7000 tonnes, constituting an important earning of foreign exchange. However, monopoly control by a few international corporations recent years has led to reduced prices being paid to producers. Aquaculture of penaeid prawns has also been attempted in Tanzania. A huge project was proposed for the Rufiji mangrove delta, but met strong opposition from local communities, government managers, scientists, journalists, lawyers and environmental NGOs. Although it was clear that the consequences of the project would have been seriously deleterious, the government approved it. Conclusions are drawn from the lessons learned through Tanzanian and international experiences, and suggestions are put forward concerning principles for the development of more ecologically viable and socially just aquaculture development.