ECOLOGICAL FOOTPRINT FOR ASSESSMENT OF RESOURCE USE AND DEVELOPMENT LIMITATIONS IN SHRIMP AND TILAPIA AQUACULTURE

We review estimates of the spatial ecosystem support required to run a typical semi-intensive shrimp farm in a coastal mangrove area in Carr ibean Colombia, and to produce food inputs and process wastes for larg e-scale industrially managed tilapia cage culture and small-scale, sem i-intensive tilapia pond farming in Lake Kariba, Zimbabwe. The tilapia farming is discussed in relation to the pelagic kapenta, Limnothrissa miodon (Boulenger), fishery and to inshore fisheries in the Lake. The results show that a semi-intensive shrimp farm needs a spatial ecosys tem support-the ecological footprint-35 to 190 times the surface area of the pond, mainly mangrove area, Based on the analysis, we conclude that shrimp farming in Colombia is already utilizing close to the full support capacity of its coastal environment. In intensive tilapia cag e farming, the ecological footprint for feed production is 10 000 time s larger than the area of the cages. In contrast, a tilapia pond farm maintained on offals from fisheries, agriculture and households depend s very little on external ecosystem areas. As long as there is a direc t market for human consumption of all kapenta caught in the Lake, fish cage farming based on fish meal from kapenta would be doubtful from e thical, ecological as well as resource management points of view, even if it was economically feasible.