In coastal regions, quite large acquaculture projects may be established using seawater and saltwater fish species. The fish may be held in netted areas, or in large terrestrial tanks or ponds, and fed with baitfish species, such as pilchards, or with oil seed meal, e.g. flax.
Oysters, abalone and other shellfish, and crustaceans, may also be farmed successfully in coastal areas.
Acquaculture of freshwater species, such as barramundi, held in large tanks, may be economically viable if irrigation water is available. (Barramundi will thrive in moderately saline water, as would be available from the irrigation of orchards.) Freshwater lobsters, marron and yabbies are already acquacultured in Australia.
(In an interesting small-scale demonstration on a recent ABC TV Landline programme, a leguminous crop (lupins) was harvested to provide protein-rich meal to feed the fish. The water from the fish tanks was treated in gravel bed filters, to exract the nutrients from the fish effluent and to feed a hydroponic vegetable farm. The filtered, treated water was used to irrigate fruit trees.)