The efficient and profitable production of fish, crustaceans, and other aquatic organisms in aquaculture depends on a suitable environment in which they can reproduce and grow. Because those organisms live in water, the major environ mental concern within the culture system is water quality. Water supplies for aquaculture systems may naturally be oflow quality or polluted by human activity, but in most instances, the primary reason for water quality impairment is the culture activity itself. Manures, fertilizers, and feeds applied to ponds to enhance production only can be partially converted...