Review of environmental impact, site selection and carrying capacity estimation for small scale aquaculture in Asia

Asia is the leading aquaculture region in the world, contributing to 85% of total world aquaculture production. Of the top 10 aquaculture producing countries 9 are Asian with China accounting for more than 65% of Asian production. Aquaculture in Asia contribute more than 80% of an estimated 17-20 million aquaculture farmers in Asia providing livelihoods, food security and export earning power but at the same time there are growing problems with environmental impact from large numbers of small-scale producers and the difficulties in planning and management of further development. Traditional integrated aquaculture systems which are sustainable environmentally continue to play an important role for many small-scale farmers and local communities, particularly at the subsistence level. However, recently more productive and profitable aquaculture practices have developed using formulated pelleted feed and allowing intensification of production. Small-scale producers are characterised small farm units and low productivity but in many cases, aquaculture develops in clusters of small-scale farms favouring sheltered bays, estuarine areas and coastal fringe, lakes and dams. Whilst individually such farms create little environmental impact, the cumulative effects of large numbers of farms in “clusters” can be significant. Mitigation of these environmental impacts is difficult due to the number of individual small scale-farmers. However the effects of cumulative environmental impact can be reduced by the introduction of carrying capacity estimation using models before development, the implementation of Better Management Practices and control of feed quality and feeding strategy and management can reduce the cumulative impact.