However, as would be predicted by metabolic theory, many of the areas with the highest GPI were located in warm, tropical regions. The total potential production is considerable: if all areas designated as suitable in this analysis were developed (assuming no further economic, environmental or social constraints), they estimate that approximately 15 billion tonnes of finfish could be grown every year—over 100 times the current global seafood consumption.
Ocean aquaculture is already the fastest-growing food sector, but a lot of work remains to reach its vast potential. There are a few difficult barriers to overcome. In some countries, including the United States, a network of regulations makes it challenging to establish even a single farming operation, the researchers said. In other places, lack of regulation leads to environmental destruction — concentrated waste from poorly managed or designed operations can severely pollute waters and coastal areas.
Also, ocean aquaculture needs to compete in the marketplace and turn a profit, and farming in the open ocean is trickier than doing so close to shore, requiring extra investment. "It takes some engineering to be able to withstand waves and currents," Gentry said. "The offshore environment can be a pretty brutal place. Having strong infrastructure is taking some time to get going."