If the world utilized every appropriate ocean habitat for aquaculture, it could outproduce the global demand for seafood by 100 times, says a study by scientists at the University of California-Santa Barbara in the journal Nature Ecology & Evolution.
“In their research, the scientists analyzed the potential of virtually every square mile of the ocean’s surface for producing 120 different species of fish and 60 species of bivalves — that is, mussels, clams, oysters, and scallops,” says NPR. “They immediately eliminated ocean waters deeper than about 650 feet, since ocean aquaculture generally requires anchoring floating pens and cages to the seafloor. They sought out areas rich in dissolved oxygen and phytoplankton — essential for bivalves, which filter microscopic food from the water.”
The researchers found that if marine aquaculture were pushed into every viable ocean area, it could provide 4,000 pounds of seafood per person, per year.
“And we were being very, very conservative in our calculations,” says coauthor Halley Froehlich, a postdoctoral researcher at UC-Santa Barbara, adding that she doesn’t expect aquaculture to be practiced wherever it’s feasible. “And we certainly would never need so much production,” she says. “That number was really an overestimate to show what the potential is.”
By the team’s estimates, even a much smaller area — say the size of Lake Michigan, or roughly 1/67th of a percent of the ocean’s surface — “could produce about 110 million tons of fish and shellfish per year,” says NPR. That’s roughly equal to the total global catch by commercial fishermen, explains Froehlich, and five times the current aquaculture harvest.
However, the key will be how to sustainably scale up aquaculture, since fish farming has been linked to environmental damage, including the overfishing of wild stocks, which are caught to feed the raised fish. Deforestation is another concern. In Southeast Asia, for instance, vast swaths of mangrove forests have been cut down and replaced with shrimp farms.