RESOURCE USE-AQUACULTURE-ENVIRONMENTAL TRADE-OFFS

There are various opinions about the most efficient and environmentally-responsible methods for aquaculture production. However, all methods require resources and can cause negative environmental impacts. Therefore, one must carefully examine a number of variables in assessing the desirability of one particular method over another. There probably is no best method across all situations in which a particular species may be produced, because in order to conserve a particular resource or avoid a specific impact, there is a "trade-off" requiring another resource or resulting in another kind of environmental impact. For example, the intensification of pond aquaculture lessens the amount of land and water necessary to produce a unit weight of fish or shrimp. However, there are trade-offs for more resources and associated negative impacts to provide feed and mechanical aeration for more intensive production. Cage culture requires little land and does not consume water directly, but it requires resources for feed and can impose a large pollution load on natural water bodies into which it is superimposed. Efforts should be made to assess the trade-offs that result from changing from one method of aquaculture production to another or from altering one or more steps in a particular production system. Information from such investigations would be useful in determining the most efficient and environmentally-responsible aquaculture systems for specific situations.