How Many Little Fish Does It Take to Grow a Big Fish? ; Aquaculture’s Abundant Promise Must Be Buttressed By Appropriate Safeguards.

At first glance, offshore aquaculture looks like a potentially elegant solution to an intractable economic problem.

Years of overfishing have depleted stocks of cod, halibut, yellowtail flounder and other groundfish in the Gulf of Maine and Georges Bank.

Fishing regulations meant to help stock recover are choking the life out of the fishing fleet, along with onshore support industries like seafood processors. Many are just hanging on.

The idea of growing cod and flounder in stout underwater baskets to help increase production of fish protein from the Gulf has an inherent allure.

Raising groundfish in cages can potentially boost landings without increasing fishing pressure on struggling stocks. The farms’ position offshore could help disperse plumes of fish poop and other pollution that fish husbandry produces.

If successful, operations like this would not only produce maritime work for aquaculture employees, but for chandlers, divers, welders and seafood processors. And it would provide a new and potentially perpetual supply of fresh fish for regional restaurants.

All good, yes? Maybe.

Aquaculture is the fastest-growing form of seafood production in the world. Yet the United States lacks a regulatory framework to permit its development in our nation’s expansive offshore waters.

Maine salmon farmers grew 11.6 million pounds of salmon in 2005, but the near-shore pens have raised serous concerns about pollution, disease, escapes and other impacts.

One offshore pilot project run by the University of New Hampshire certainly appears to be taking a promising approach.

Six miles off the coast of New Hampshire, researchers have been growing groundfish in large, stout cages capable of resisting the Gulf of Maine’s robust weather. Since 1999, researchers have raised summer flounder, halibut and haddock. Now the cages are inhabited by 45,000 young cod.

The production methods employed by UNH are designed to avoid causing problems seen with inshore salmon farms: No chemicals or antibiotics are used. The feeding system has been tailored to minimize waste and leachate into the surrounding waters. Water- quality tests taken 100 yards away show no deviations from background chemistry.

In addition, fish are grown from wild stock only, so there’s no concern about genetic pollution of wild populations from escaping “Frankenfish,” a problem that’s arisen with Atlantic salmon farms in the Pacific Northwest.

The United States is on the cutting edge of aquaculture innovation and technology. But this country lags far behind other nations in the commercial application of this technology to our home waters. Almost all commercial cage manufacture occurs in the United States. But there is no offshore U.S. aquaculture program

In an effort to change that, the National Oceanic and Atmospheric Administration has drafted legislation to establish a federal, offshore aquaculture permitting program that has captured some of the New Hampshire program’s sensible sideboards.

The permit process called for under the National Offshore Aquatic Act of 2007 would establish environmental requirements that address risks (like escapes) and impacts (such as pollution) on the marine ecosystem. Operators would be required to grow native species only, unless risk analysis showed potential harms were negligible or could be avoided. Permits for these facilities, which would be located beyond the 3-mile state waters’ boundary, would run for 20 years. However, states could “opt out” of the program, preventing such operations within 12 miles of their shores.

While fishermen and environmental groups have a number of concerns, the biggest goes back to basic biology.

Fish that eat plants, like tilapia or catfish, can be fed vegetables grown on land with little or no impact to aquatic systems. Farm-grown shellfish, like the Bangs Island mussels raised in Casco Bay, require no feed at all. They filter their food directly from the water.

But carnivorous fish, like cod, halibut and salmon, are the ones consumers will pay most for. And carnivorous fish are not terribly efficient at turning food into weight. It takes more than two pounds of fish meal to add a pound to a caged cod.

If offshore aquaculture is to become widespread, it can’t be at the expense of forage fish, like herring, that support the Gulf of Maine’s groundfish, stripers, tuna and whales, and are the chief bait for our lobstermen.

One key piece of the act directs NOAA to work with the Department of Agriculture to develop non-fish-meal based feeds. If cod can be enticed into eating soybeans, large-scale cod farming will be a lot easier to swallow.

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