A Massachusetts Institute of Technology researcher has developed a self-propelling underwater cage that may help offshore fish farms cut production costs and reduce environmental impact.
Cliff Goudey, director of MIT Sea Grant's Offshore Aquaculture Engineering Center in Cambridge, Mass., recently tested his technology at Snapperfarm, a cobia farm off Culebra, Puerto Rico, by fixing a pair of large, slow-turning propellers to 62-foot-diameter Aquapod fish cage. Attached to the propellers are 6.2-horsepower motors powered by a diesel generator.
Goudey says he was able to maneuver the cage as well as any boat-based system. Usually, offshore fish farms are repositioned by towboats.
"These tests demonstrate that the concept of mobile cage operations is technically feasible," he says.
The propellers can also be used to supplement water flow through the cage, boosting oxygen levels and possibly allowing fish farms to increase stocking densities.
The project was funded by the National Oceanic and Atmospheric Administration's Marine Aquaculture Program.
"I was incredibly impressed with the power and efficiency of the [propellers] and Cliff's ability to steer the cage," says Snapperfarm Founder Brian O'Hanlon. "I see this technology having a broad range of applications in mariculture and other marine industries. This futuristic concept of farming the high seas just came one step closer to reality."
"My opinion of the [propellers] is very high," adds Steve Page, CEO of Ocean Farm Technologies, which developed the Aquapod. "I want to consider using them to help with future installations. There is also a growing demand for self-propelled harvest pens that may be a great market for this technology."
