On the surface, fish farms seem like a brilliant solution to the problem of too few fish in the sea. Instead of further depleting threatened populations of wild fish with traditional fishing methods, simply hatch thousands of fish from eggs, cultivate them in pens, and when they grow big and strong, sell them off.
But a deeper look reveals that it's not always that easy. Negative reports on the impact of some forms of aquaculture - especially salmon - have flooded the media in recent months.
Claims from conservationists and environmentalists are familiar to followers of the farmed-salmon saga: Pens are overcrowded and polluted with waste, males often escape and weaken the gene pool of wild fish, and many farmed fish are fed fishmeal, which depletes stocks of smaller wild fish.
Still, the news isn't all bad on the fish-farming front. At the University of New Hampshire (UNH), an innovative program is showing that these problems can be overcome - at least for some types of fish and shellfish.
The Open Ocean Aquaculture (OOA) demonstration project at UNH is experimenting with cultivating halibut, haddock, cod, and mussels up to 8 miles offshore and deep below the ocean's surface. A big advantage of this - as opposed to the current practice of farming fish close to shore and near the surface of the ocean - is that sealife is protected from harbor pollution and turbulence caused by storms or passing boats. And because farming far offshore doesn't obstruct views from expensive oceanfront houses, it doesn't raise the ire of coastal property owners.
Richard Langan, an aquaculturist and researcher at UNH, started the demonstration project, which is part of the Cooperative Institute for New England Mariculture and Fisheries (CINEMAR). He and his crew are pioneers in the United States and North America in farming cod offshore. They are also the first in the world to cultivate mussels in exposed open-ocean conditions.
Dr. Langan has chosen not to farm salmon, but he isn't doing this simply to dodge potential flak. The fish and shellfish he farms are, for various reasons, easier to cultivate in an offshore, submerged environment.
Unlike salmon, for example, heartier cod and halibut like the dark and don't need regular access to the surface, so their cages can be submerged.
There's also a historic precedent for farming cod in waters off the coast of Portsmouth, N.H. As early as the 1630s, the first settlers on the Isles of Shoals, including those on Star Island and White Island, would fish cod and then dry it and salt it.
And mussels are generally considered ideal for farming for a host of reasons: They filter tiny plankton for their food instead of eating small wild fish. They improve water quality by consuming the plankton, of which there's an overabundance in the sea. And lastly, because mussels require clean water to qualify them for the dinner table, their cultivation often spurs efforts to keep coastal waters clean.
Mussels are also attractive as a demonstration project because they take less time to mature than other shellfish - about one year versus about three for other types, so the researchers can more quickly evaluate the success of their experiment.
And it doesn't hurt that there's a robust market for cod, halibut, and mussels, making them worth the hassles of farming.
Indeed, open-ocean aquaculture, however revolutionary, is not without its hassles. Access can be hampered by storms, high winds, or frigid temperatures, and it's costly in any weather to shuttle back and forth eight miles out to sea.
All of this adds up to potential for negligence, says Sebastian Belle, director of the Maine Aquaculture Association. "The farther offshore you go," he explains, "the fewer days you can get to the site, and the fewer opportunities you, as a shepherd, have to check on your flock. It becomes an issue of animal welfare, which is important for financial reasons as well as one's craft, one's artistry, and one's personal pride."
But when conditions get too dicey to make the trip, the fish "shepherds" at UNH tend their flock remotely. Thanks to funding from the National Ocean and Atmospheric Administration, which backs the UNH project, Langan's team of five engineers has rigged up a wireless, ethernet communications system that facilitates observation and feeding in any weather.
Specifically, for feeding, they can preprogram a solar- and wind-powered electric pump that will direct feed into a hopper. The food is then pushed down through tubes into the fish cage. Feeding occurs every other day during the winter, which is sufficient, as the fish are less hungry in cold months than during warmer ones, when they are fed daily.
Clearly thrilled with what Langan calls the "miracle of computers and circuitry and remote communications," he says, "We are not in the fish-farming business; we are in the business of developing and implementing technology for the fish market."
On a recent Indian summer morning, it wasn't necessary to shepherd from shore. Weather conditions couldn't have been better. The UNH team of Langan; research technician Forbes Horton; his brother Nate Horton, who helps out with the project on occasion; and boat captain Hunt Howell, a professor of zoology at UNH, ventured out on the Rock 'n' Roll III, their 40-foot fishing vessel, to feed halibut and harvest mussels.
With them, they brought wellies, rubber overalls, sunscreen, and a couple of out-of-town visitors.
The affable crew clearly enjoys its forays out to sea. En route, they chat among themselves and bask in the sun's warmth, knowing it won't be long before winter's chill settles in and the journey becomes less pleasant.
But on arrival at a large orange, solar-powered buoy, the site of cages for 1,200 halibut, they get to work rigging up the feeding contraption - a giant funnel attached to PVC tubes and an electric pump that thrusts fish-oilpellets 50 feet down into the depths of the ocean. The three-year-old halibut enjoy a feeding frenzy that will help grow them to the 15-pound weight necessary for harvesting in the spring.
These are thought to be the first halibut ever raised in open-ocean net pens.
Next, Rock 'n' Roll III hums over to the nearby mussels. By farming the mollusks close to halibut, the fin fish benefit from nitrogen generated by the plant-eating shellfish.
The UNH team raises "rope-cultured" blue mussels on submerged long lines that measure about 1,500 feet. They say that rope culturing results in a greater meat-to-shell ratio than other methods and makes the mussels easier to harvest. The team has adapted this technique - used in Canada, Europe, and New Zealand - to make it usable in the open ocean, where rope-cultured mussels had not been grown before.
For this day's harvest, the crew simply hoist the rope into the boat and run rubber-gloved hands down it, forcing mussels to fall off into a large plastic bucket. Then the real work begins: shucking mussels from horrid-smelling tubularia, a yellowish seaweed that clings to the rope.
Typically, their harvest goes to 11 restaurants in Portsmouth, N.H., as well as to a major local fish market. One of the goals of the project is to refine the technology so that fishermen across New England can use open-ocean aquaculture to meet the needs of their local restaurants and businesses.
But the UNH crew knows they must prove the value of their methods before commercial fishermen will follow their lead.
Open-ocean technology is costly and will require a substantial investment from the private sector. There are also logistical limitations to consider. Sites must have a relatively flat seabed and not too much "energy" - wind and waves in layman's terms.
Fish farmers must also make sure that they do not intrude on sites that are already being used by local fishermen.
Those involved in the project have a feeling of satisfaction that they are on the cutting edge of aquaculture in America, which they all agree is here to stay.
"It's unrealistic to think that fish stocks will recover," says Langan. "There's too many people fishing and too much demand not to drastically hurt the world's supply."
Aquaculture, he concedes, isn't perfect. "Fish farming still needs to learn from past mistakes, use better judgment, and better cages.'
But when done well, he adds, "it's an excellent solution."
• For more information, visit http://ooa.unh.edu.