A Kevlar Sphere To Farm Tuna Of The Futureff

Hawaii Oceanic Technology has devised an aluminum and Kevlar sphere, measuring 162 feet in diameter, in which it hopes to raise sashimi-grade tuna three miles off the coast of Hawaii. The spheres sit 60 feet below the surface.

The company wants to plant these spheres in a 250-acre plot of ocean it has leased off of the coast of the islands. (Hawaii has an ocean leasing program.) A plot this size could generate 6,000 tons of tuna a year, which translates to $120 million dollars in gross revenue. (A single sphere could generate $20 million in revenue.) Plus, it’s a lot easier and more energy efficient for fishermen to extract tuna from what is essentially a large holding pen than fish for them miles out to sea. A single sphere holds 82,000 cubic meters of water.

Demand is not a problem.

“Our [global] aquaculture needs will double in the next 20 years,” said CEO Bill Spencer, at the Dow Jones Alternative Energy Innovations conference taking place this week. “The U.S. already imports 85 percent of its seafood, and half of that amount comes from Asia.”

Japan alone, he added, consumes 630,000 tons of sashimi-grade ahi a year.

Instead, skepticism persists about farm-raised ocean swimmers like tuna and potential environmental hazards. Scientists have experimented with farming tuna in Panama for around 12 years. It seems to work, he said. While the environmental impact needs to be studied, the environment for the fish is similar to the ocean. The Kevlar mesh lets water pass, so the water is continually cleaned and oxygenated.

Power for running the communication devices and some pumps at the spheres can be supplied by outboard motors, but the company is looking at trying to provide energy with a Stirling engine. Stirlings harvest power from the collision of hot and cold masses. In Hawaii Oceanic’s case, the power would come from putting warm surface water into one end of a tube and cold deep water in the other.