Cost benefit analyses into the viability of certain kinds of aquaculture must incorporate issues such as declining wild fisheries, water pollution, habitat destruction and impacts on wild stocks. Examples of better aquaculture practices include farming vegetarian species and employing technologies that recycle nutrients and minimize polluted discharge. Dr. Jason Clay released the findings of a three year study by the World Wildlife Fund, the World Bank, the United Nations Food and Agriculture Organization and the Network of Aquaculture Centres in Asia Pacific on the best and worst practices of shrimp farming. Shrimp farming now produces half of all internationally traded shrimp. Impacts have included the destruction of mangroves and wetlands, the large scale capture of wild larvae and brood stock, pollution, use of chemicals and antibiotics, intensive fish meal demands and the privatization of public resources.
Fish farms can have negative impacts on surrounding ecosystems as well.
Nils Kautsky from the University of Stockholm in Sweden demonstrated how fish farms can affect surrounding areas by discarding excess fishmeal, transferring parasites to wild populations and introducing exotic fish into native ecosystems. Jurgenne Primavera of the Southeast Asian Fisheries Development Center noted that shrimp farms frequently displace rice paddies, boat landings, houses and even burial grounds. He pointed out that saltwater from inland shrimp ponds can seep into nearby soil and reduce rice yields. Several of the AAAS participants discussed ways that the farming industry can produce more efficiently and with fewer negative environmental effects. These may include reducing food input and developing closed water systems that prevent waste and parasites from escaping.