$广汽长丰(SH600991)$ According to United Nations data, the global demand for seafood will grow at least 40 percent in the next two decades given current population and economic trends. But wild populations of almost every fish species, including salmon, are declining because of overfishing, climate change, and other environmental pressures. “There will be no way to meet the new demand without farming it,” says Josh Goldman, owner of Australis, an aquaculture company. But whether farmed seafood can be sustainable on a mass scale is the subject of much debate.