It's known that escaped fish from Norwegian salmon farms can interbreed with wild salmon, and thus must have changed the genetic and physical makeup of the country's famed wild salmon stocks, says the Norwegian University of Science and Technology (NTNU).
This guide from the FAO Cultured Aquatic Species Information Programme provides information on farming milkfish - from sourcing fry to marketing milkfish globally.
Aquaculture is growing so rapidly that it accounts for almost 50 per cent of all fish brought to the table. Rebecca Chappell, SDNN looks at leading fish farms in San Diego, US.