The operator of a Big Island experiment that has the potential to increase the volume of fish raised in farms said Monday that initial tests were going well.

The tests are being run by Kampachi Farms, which is run by the same individuals who pioneered farming Kona Kampachi in Hawaii waters over the past decade as Kona Blue Water Farms.

The company sold its operation growing fish in anchored pens and is now pursuing new technology by growing the fish — amberjack or Hawaiian yellowtail — in a large unanchored, underwater pen in federal waters off the Kona Coast.

Only one quarter of 1 percent of the 2,000 Kona Kampachi fish stocked in the pen on July 20 have been lost, said Neil Anthony Sims, head of Kampachi Farms. The fish are eating vigorously and growing "very well," he told media in a teleconference call from Kailua-Kona.

The fish are being kept in a pen 30 feet below the surface that is tethered to a boat that has traveled between seven and 75 miles offshore over the past several weeks. The fish are expected to be ready for harvest in March.

"This is the world’s first beta test of an unanchored fish pen system," Sims said.

Open-ocean aquaculture has the potential to expand fish farm production because there is more space farther from shore for larger pens that should in theory be able to grow more fish than cages closer to coastlines.

The experiment has faced legal challenges.

Two environmental groups sued the National Marine Fisheries Service last month, saying the federal agency failed to adequately assess the environmental effects the fish farm was likely to have when it issued a permit to the company to carry out the experiment.

Honolulu-based KAHEA and Food and Water Watch Inc. of Washington, D.C., asked the court to declare the permit illegal and order the fisheries service to suspend or revoke it.

Sims said the project had minimal environmental impact. Asked about the potential harm from fish waste, Sims said the pen is in water at least 12,000 feet deep in an area with strong currents. He said the farm would have no impact on coral reefs in waters that deep.

The National Marine Fisheries Service showed its support for the project.

Eric Schwaab, fisheries service administrator, issued a statement read at the news conference praising Kampachi Farms for its innovations. Schwaab said aquaculture was a critical component of meeting increasing consumer demand for "healthy, sustainable seafood" and was a tool to restore fisheries. Increased aquaculture would also create employment and business opportunities in coastal communities, he said.

About 30 percent of the fish’s diet comes from Peruvian anchovies, but Sims said it would not be sustainable to feed amberjack this much fish if it were farmed on a larger scale.

Kampachi Farms is working with the Illinois Soybean Association to raise the share of soybean protein concentrate that the fish eat to reduce the ratio of fish meal and fish oil in the farmed fish’s diet. Currently about 20 percent of the fish’s diet comes from soybeans.

The venture also has help from defense contractor Lockheed Martin, which is supplying satellite technology to link shore facilities and the pen.

Sims said the technologies could be taken elsewhere in the world if proven.

"Everybody wants to eat sashimi, so pretty much everybody around the planet is looking at where they’re going to get the next seafood from. And almost universally around the globe countries are no longer looking at wild stocks as being where they can grow their seafood supply. They are looking at aquaculture," he said.