for National Geographic News
In the future, giant, autonomous fish farms may whir through the open ocean, mimicking the movements of wild schools or even allowing fish to forage "free range" before capturing them once again. Already scientists have constructed working remote control cages.
Such motorized cages could help produce greener, healthier, and more numerous fish, just when we need them most.
The world's growing population is devouring seafood as quickly as it can be caught and has seriously depleted the world's wild fish stocks, experts warn. (See National Geographic magazine's "Saving the Sea's Bounty.")
The UN's Food and Agriculture Organization says 70 percent of all the worlds' fisheries are exploited—that is, barely able to replenish themselves at current catch rates—overexploited, or depleted. (Learn more about sustainable agriculture.)
Aquaculture, or fish farming, currently produces about half of the fish eaten worldwide and seems destined to play an even bigger future role. The UN organization estimates world seafood demand will spike 40 percent by 2030.
"We've got doctors and nutritionists asking us to eat more seafood because of the healthy benefits," said Michael Rubino, manager of the Aquaculture Program at the U.S. National Oceanic and Atmospheric Administration (NOAA).
"We're doing a better job of ending overfishing of our wild stocks," Rubino said. "But most people agree that even if we can do that, most of the increase in consumption is going to have to come from aquaculture."
Free-Floating Farms on Horizon?
Traditional fish farms typically consist of cages submerged in shallow, calm waters near shore, where they are protected from the weather and easily accessible for feeding and maintenance.
But raising fish in such close quarters can contribute to the spread of disease among the animals, and wastes may foul the waters. Cages must be moved to keep the waters clean and the fish healthy.
Deepwater cages offer cleaner, more freely circulating ocean water and natural food, which can yield tastier fish. But the deep-sea cages must be built to withstand the rigors of the deep ocean. And because they are harder for humans to access, "smarter," self-sufficient cages could be key.
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