An ambitious effort in Hawaii to farm one of the ocean’s biggest fish prized as food has come to an end after more than a decade and several million dollars invested.

Hawaii Oceanic Technology Inc. has dissolved itself along with its work to raise ahi in gigantic cages hovering in the deep ocean off Kawaihae on the west side of Hawaii island.

Bill Spencer, Hawaii Oceanic’s CEO, said the Hono- lulu-based company he started could not raise the money to build, test and deploy an initial cage big enough for 20,000 100-pound yellowfin or bigeye tuna.

The company was permitted to deploy 12 such cages, but the estimated $10 million for just one cage was an investment for which Spencer said he could find no takers.

“When push came to shove, it was just too far out there,” he said. “The high cost of proof of concept was off-putting to investors.”

Hawaii Oceanic’s cages, dubbed oceanspheres, were designed to dangle anchorless about 65 feet below the surface and about 1,250 feet above the ocean floor using a combination of ballast, thruster control and surface buoys.

The diameter of each oceansphere was 177 feet, or about half the length of a football field. The interior area for the fish was about 3 million cubic feet, and at full capacity could have produced 12 million pounds of ahi annually harvesting fish from half the cages each year.

At a target price of around $12.50 per pound, the business would have generated $150 million in annual revenue if operations worked as planned. The company also planned to sell its patented oceansphere technology for similar ventures in the United States and other countries.

However, Spencer said prospective investors were wary about risks and challenges, which included opposition from fish-farming opponents, difficulty in obtaining permits, stringent conditions placed on some permits and the high price for a single oceansphere.

“I scoured the world for investors, traveling from Japan to Abu Dhabi and from Silicon Valley to Seattle with little luck,” he said.

Spencer, a former president of the Hawaii Venture Capital Association, started Hawaii Oceanic in 2006. It took him eight years to get eight necessary permits, including an Army Corps of Engineers permit obtained in 2013. A 35-year lease was obtained in 2011 from the state Board of Land and Natural Resources to use 247 acres of ocean area.

Hawaii Oceanic was current on its lease payments, according to the state, and was allowed to withdraw from the lease in a BLNR decision Friday.

Spencer said the difficulty raising money for a prototype cage led him into discussions to sell Hawaii Oceanic to a larger company. But that sale effort, which lasted for more than a year, could not be realized.

“It’s a shame,” he said, “because (the ahi farm) would have created a lot of tax revenue and created a significant number of jobs and met some food sustainability goals.”

Despite the failure, Spencer said he has no regrets spending 10 years of his life on Hawaii Oceanic, and he hopes others will expand Hawaii’s fledgling mariculture industry to counteract impacts on wild fish from fishing. “How else are we going to feed 10 billion people in this world without using the ocean as a farming resource in an environmentally responsible manner?” he said.

Opponents of open-ocean fish farming fear that wild habitat could be harmed by concentrations of uneaten food and fish waste, farmed fish escaping, and cages posing a danger to other sea creatures, among other things.

Existing and past farm operators that include a moi farm off West Oahu and two kampachi farms off Hawaii island have said years of monitoring demonstrate no significant negative environmental impacts.