Deepwater Fish Farm Raises 1000 Tons of Tuna [VIDEO]

A technology company plans to begin construction of a huge deepwater fish farm off the North Kohala coast of Hawaii Island by the end of this year, according to a company release.

Hawaii Oceanic Technology, Inc. (HOTI) has 247 acres of ocean where it will grow yellowfin and bigeye tuna, or ahi, as part of an effort to sustain the growing market for farmed seafood. The 180-foot-wide Oceansphere prototype will be capable of holding 1,000 tons of tuna at a depth of 60 feet below the surface. Fish grow faster in deep ocean settings, have fewer parasites and better food conversion ratios, according to the company.

This is HOTI's first Oceansphere, and officials don't know yet how many of these underwater pens it will build - it has a permit to build up to 12 as part of a 35-year lease.

"That depends on how well (the first one) goes," company CEO Bill Spencer told West Hawaii Today. "Our goal is to develop a new, environmentally responsible way to raise tuna in deepwaters."

Almost one third of wild caught ocean species are being depleted beyond sustainability according to the UN Food Agriculture Association. Meanwhile, the market for farmed seafood is expected to surpass $200 billion in 2020, Big Island Now reported. But building 12 Oceanspheres in less than half of a square mile could yield as much as 24,000 tons of seafood, HOTI wrote in a company release.

This multi-million dollar project has been years in the making, and HOTI has been fighting to make the idea a reality. According to West Hawaii Today, 1,700 people signed a petition opposing the sphere, and 400 more wrote letters challenging the extension of construction deadlines in 2012.

"The bottom line is the benefit does not outweigh the risks, no matter what kind of fish they plan to grow," Diane Kanealii of theKailapa Community Association in Kawaihae told the paper.

But that's not going to stop HOTI, which believes the global market for deep sea fish farming equipment will be worth $75 billion by 2020.

"The deep ocean is the only place left to produce enough seafood naturally to feed the world efficiently, economically and with minimal environmental impact," Spencer told Big Island Now.

Once the sphere is fully assembled, it will be deployed and tested in the water for six months before it is stocked, Spencer said. It takes about 18 months to grow the fish to market size, so the earliest harvest would be in late 2017.