Yonathan Zohar beams like a proud parent as he cradles the freshly netted fish in his hands.
He didn't catch this glistening branzini. He raised it - and thousands more - in large fiberglass tanks at the Columbus Center at the Inner Harbor.
"This is a happy moment here," says Zohar, director of the Center of Marine Biotechnology at the University of Maryland Biotechnology Institute. "Green fish, as good as it gets. Clean, environmentally friendly, sushi-quality fish, delivered to the restaurant a few hours after harvesting."
Zohar and his team of scientists and technicians have been laboring for years to perfect techniques for captive breeding and rearing of fish as quickly and cleanly as possible. For marine species like branzini, otherwise known as European seabass, they make artificial sea water, then recycle nearly all of it, filtering out waste and even capturing methane to offset some of the energy used in raising the fish in captivity.
With public interest growing in sustainable seafood, they hope to demonstrate the commercial viability of their fully contained, land-based, indoor fish farm.
"This is the next wave of seafood development," Zohar predicts. "We know we are running out of fish. We know we cannot continue to hunt and gather."
Experts have been warning for some time that the Earth's oceans can no longer be relied upon to meet the global demand for seafood. According to U.N. estimates, 75 percent to 80 percent of wild fish stocks worldwide are overfished or nearly so.
While gains have been made in recent years in managing harvests, the seemingly insatiable demand for seafood has fed an explosion of fish farming. Nearly half the fish consumed worldwide were raised rather than caught, the United Nations says.
Aquaculture, though, has produced its own environmental issues, including water pollution from the concentrated fish waste and potential contamination of the fish. Some decry the sacrifice of vast quantities of less valuable fish to feed the pricier farmed ones.
UM's marine biotechnology center has worked out a better way to farm fish, Zohar contends, which addresses the complaints of many of aquaculture's critics. The fish swim in 12-foot diameter tanks holding 3,200 gallons of water, the temperature and suitability constantly monitored by computer.
Not a drop of the water comes from the Inner Harbor, and not a drop gets into it, the marine scientist points out. The artificial sea water is recirculated after being filtered and treated to remove fish waste and excess food. By maintaining high water quality, he says, the tanks are able to hold denser concentrations of fish than the typical open-water fish farm but without the disease or parasite problems that can plague them.
The center also is developing and testing new recipes for fish food made from plant material and algae, instead of ground-up fish.
"These fish are as clean, green and organic as you can get," say Zohar, who has bred and raised striped bass and blue crabs in the Columbus Center laboratory. He's focusing the center's efforts on fish that he believes have commercial potential, such as branzini, a popular European fish that is farmed extensively in the Mediterranean to protect what remains of the wild stock. But Zohar notes that he's raised daurade, or sea bream, another Mediterranean fish, and recently began working with cobia, a popular sport fish also prized for its flavor. Staff members are preparing to try bluefin tuna in larger tanks.
Shawn Martin of Martin Seafood Co. in Jessup says he thinks there might be an opening for someone to produce a popular restaurant fish like branzini, which are now flown in from Europe and sell wholesale for $5.50 to $6 a pound. And if they can be branded as sustainable, they could command a premium price, Martin says.
"There's a big swing toward seafood sustainability," Martin says, "and there have been quite a few restaurants trying to serve only fish products that are sustainable. ... It's become a new niche market."
It's a tough business, though, for an entrepreneur to break into, notes Doug Lipton, a fisheries economist at the University of Maryland, College Park.
"The prospects are there. The technology is fascinating," he said, but relatively few finfish aquaculture operations in the United States have been able to attract investors because of the vagaries of the global seafood market.
But Casson Trenor of Greenpeace says Zohar could be onto something. The environmental group's seafood sustainability campaigner says a closed-loop fish operation like the UM center's could ease harvest pressure on the world's wild fish stocks without generating the environmental problems that crop up in open-water fish farming.