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Health

Saving Seafood: Can We Grow Fish in Giant Robotic Cages?

DiscoblogBy Boonsri DickinsonAugust 21, 2009 8:08 PM

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We recently covered a study in which every single fish tested from U.S. streams was tainted with mercury. But that may be the least of our worries: The demand for fish will increase by 40 percent in the next two decades. As the world population hits 9 billion by 2050, the continued depletion of biodiversity and poor environmental conditions of the ocean could end up wiping fish completely off our menus. Not surprisingly though, aquaculture is picking up, and now more than 50 percent of the fish that ends up in our bellies was raised in coastal fish farms. Fish raised in farms near the coastline are exposed to more pollution than wild fish, and therefore grow to be less nutritious. Ideally, we'd like our fish to roam around freely in the sea before we eat them. Enter MIT’s Offshore Aquaculture Engineering Center, which is building robotic cages so fish can be farmed in the ocean away from the coastal waters. The Aquapod cage has 8-foot long propellers, which are controlled and powered from a generator in an attached boat. The cage, which strikingly resembles the Apple Store on New York’s Fifth Avenue, is built with triangular panels that are coated in steel nets. National Geographic reports:

"The idea of a cage towing a buoy, with the buoy in radio contact with the shore, is quite feasible," [director Cliff Goudey said]. "It's a little futuristic for today's industry, but we could have a sensor on the cage which gives its heading and a GPS system to report its effective speed over the ground.”

Another group at Woods Hole Marine Biological Laboratory has a more open idea for a "cage": They allow their fish to swim freely, but train them to return to their cage at the sound of a dinner bell. Granted, fish are hardly terriers: The bell worked for black sea bass for about a week, but when a school of bluefish came to dine on the bass, they refused to return to their cage despite the researchers' offer of free food. Related Content: 80Beats: Are Fish Farms The Answer To World Hunger? DISCOVER: Are You Poisoning Yourself With Fish? DISCOVER: Fish Farming Threatens Wild Salmon

Image: flickr/ Swamps

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