Kampachi Farms said Wednesday that it has conducted a successful final harvest of fish farmed in an unanchored pen in federal waters in the Pacific Ocean off the Big Island of Hawaii.

The Kailua-Kona-based company’s “Velella” research project raised the sashimi-grade Kampachi, a brand name for domesticated yellowtail, in a large drifter pen tethered to a manned sailing vessel that has been riding eddies in water up to 12,000 feet deep in the open ocean between 3 and 75 miles off the coast of the Big Island, the company said in a statement.

The company did not disclose the amount of the harvest.

The next phase of research will test a single-point mooring in water 6,000 feet deep, 6 miles offshore, where the pen can move freely with the currents but still be easily reached by boat from shore.

The harvested fish were fed a commercial diet that replaced a “significant amount” of fish and fishmeal with soy and other alternative agricultural proteins during the seven-month trial.

“This final harvest far surpassed our expectations,” marine biologist Neil Anthony Sims, co-CEO of Kampachi Farms, said in a statement. “The fish thrived in the research net pen far from shore, with phenomenal growth rates and superb fish health … and without any negative impact on water quality, the ocean floor, wild fish or marine mammals.”

The Kampachi reached an average of 5.6 pounds in six months, which enabled the harvest to be done three months ahead of schedule, Sims said.

The Velella project was supported by the National Oceanic and Atmospheric Administration, the National Science Foundation, Lockheed-Martin, the International Copper Association, Ocean Farm Technologies and the Illinois Soybean Association, which provided some funding from the Illinois soybean checkoff program.

“The success of the Velella research demonstrates that we can grow fish in the open ocean with no negative impact on pristine ocean ecosystems,” Sims said. “We must now apply ourselves to responsibly scale up this industry, to meet the growing global demand for high-quality seafood.”

Kampachi Farms is the successor to Kona Blue Water Farms, which dissolved last fall and transferred its permits to the new entity.