FORTUNE, Prince Edward Island - The big trout in the green tank are voracious eaters, their pink mouths wide open with anticipation as they swarm beneath their automatic feeding tray. Every time the tray drops new food pellets, the water becomes a mad splash of writhing fish.

Who can blame them for being hungry? They are growing boys and girls, genetically programmed to grow about eight times faster than normal during the first year of their lives. Compared to the skinny, ordinary trout swimming in the next tank, these 18-inch fish are giants among Lilliputians.

This is ground zero in what supporters are calling "the blue revolution" that could soon sweep the fishing industry - and the world's dinner plates. By inserting extra genes into fish, the would-be revolutionaries hope to conquer the last wild frontier in the food supply, creating fish that grow faster, live in colder waters, and even fight off disease better than the ones Mother Nature produces.

Already, the Massachusetts-based company that owns this hatchery, A/F Protein, is gearing up for large-scale production of fast growing trout and Atlantic salmon. Worldwide, researchers have found the genetic keys to rapid growth in at least 11 commercially valuable fish species, including shrimp growing at the University of Connecticut.

But, before the first genetically altered smoked salmon hit the market, the fledgling industry is caught in the rising controversy over genetic tinkering with the food supply. Critics warn that the lab-created fish could escape and damage wild fish stocks, while consumers worry that genetically altered food of all kinds may not be healthy or tasty.

"We need to move aquaculture into a better direction than it has right now," said Boyce Thorne-Miller of SeaWeb, a Washington based advocacy group that criticizes aquaculture for polluting coastal waters with concentrated fish feces. Genetic engineering, she fears, "could make things worse."

Representatives of the new industry say the fears are misplaced, promising that their fish will be as wholesome as conventional fish, just more abundant. They also plan precautions to prevent genetically altered fish from upsetting the balance of nature, such as neutering the fish.

"We are very concerned about the amount of misinformation and emotional reactions that are not based on science," said Elliot Entis, chief executive of A/F Protein, whose corporate headquarters is in Waltham. "Our position is that our fish are basically unchanged in all respects from the wild fish. What we have done is really a juggling of the genes."

Still, controversy over genetically modified food, including attacks on crops in Europe, is taking a toll. New England salmon farmers, growers of the region's third most valuable seafood, have shown little interest in genetically altered salmon, fearing that they, too, could be drawn into the backlash.

"Without knowing a lot more about it, I think the consuming public would have difficulties with a genetically engineered salmon," said Michael Hastings, director of the Maine Aquaculture Innovations Center, an industry research group.

Marking a milestone

Without question, the advent of genetically altered fish marks a milestone in the history of food. Nearly every other food group, from meat to vegetables to fruit, has been cross-bred almost beyond recognition after millennia of human agriculture. Fish, by contrast, are mostly harvested from the wild, shaped only by the forces of evolution.

But a rising human population has decimated the world's fishing grounds, increasing pressure to more intensively manage the fishing industry. Japan tried in the 1980s to create genetically superior "superfish," including a tuna that researchers hoped might swim to the net when it is ready for market.

However, the quest for the superfish proved more difficult and time consuming than many had hoped, both because genetics is so complex and because species such as salmon take years to reach sexual maturity. Today, although nearly 20 percent of the world's fish and shellfish come from aquaculture, none, with the possible exception of fish sold in mainland China, have been genetically altered.

Now, inside a modest fish hatchery between the lobster boats and potato fields of rural Prince Edward Island, the West may be closer than ever to a commercially available superfish. A/F Protein officials hope to test their fish in ocean pens next summer and, if they win US and Canadian regulatory approval, begin selling genetically altered salmon and trout by 2001.

Ironically, the researchers who started A/F Protein were not trying to make fish grow when they began in the mid-1970s. They were trying to understand how flounder survive in frigid Canadian waters that would kill salmon; but, it turned out that the same gene that allows flounder to survive the cold could be combined with a second gene to speed growth as well.

Hoping to boost growth by 20 to 30 percent Garth Fletcher, a fish biologist at Memorial University of Newfoundland, and Choy Hew of the University of Toronto injected the salmon embryo with a gene that promotes antifreeze production along with a gene for making salmon growth hormone. Together, the genes programmed the salmon to produce growth hormone continuously, and to produce it in two organs rather than the normal one. To the researchers' surprise, the salmon grew 400 to 600 percent faster during their first 14 months. The combination also worked on other fish, including rainbow trout that grew 8 to 10 times faster than normal in their first year.

And, although these fish needed more oxygen and food than ordinary fish, they were big enough to go to market up to a year earlier as well.

"It strikes me as fantastic. The growth rates and the cost of production of the genetically modified fish are in no way comparable to regular fish," said Sefton Dixon, a Prince Edward Island salmon farmer who recently formed a company called OvaTech with five other fish farmers to distribute A/F Protein's genetically modified fish as soon as they are available.

The Canadian government has backed genetic engineering of fish as well, funding the research, and sending government officials to public events such as taste tests designed to show that genetically altered fish taste fine.

But Canadian enthusiasm has not been matched on the US side of the border, where aquaculture companies face more scrutiny and criticism in part because more people live on the coast. Although Entis of A/F Protein spoke to Maine salmon growers in 1995, fish farmers have been reluctant to commit to a technology that could bring them unwanted publicity.

"None of my farmers have told me that they want me to put out a request for proposals on engineered salmon. They've got a lot of other problems that are a lot higher priority," said Hastings of the Maine Aquaculture Innovations Center.

Flood of critics

Meanwhile, genetic engineering of fish faces a steady stream of criticism ranging from groups such as Greenpeace that oppose it to developing nations that fear the technology will help the industrialized world at the expense of the poor.

Rebecca Goldburg of the Environmental Defense Fund, for instance, has warned that genetically altered fish could be so tough that they out-compete wild fish for limited food and spawning areas. Alternately, the fish could interbreed with wild fish, changing their genetic makeup in unpredictable ways.

Several observers fear that the new fish could cause allergic reactions or other unexpected side effects for consumers that regulators such as the US Food and Drug Administration could easily miss.

But A/F Protein hatchery manager Arnie Sutterlin, over a breakfast of genetically engineered smoked salmon, said people will soon learn they have nothing to fear. "I cannot tell the difference and I've eaten literally 20 pounds of the stuff," he said. "They're just like other fish. They just grow up faster."

Neither US nor Canadian regulators have raised concerns about the safety of the new fish so far. Canadian government-funded studies of the genetically altered salmon have found that they appear, swim, and behave like ordinary salmon, except that they eat and breathe a lot more.

Still, A/F Protein officials are trying to ease public edginess by promising to label genetically altered products and using only fish genes in their research rather than the mouse and bacteria genes that some have used. In addition, they expect the FDA to insist on conditions to prevent the fish from escaping, such as enclosed tanks or fish that cannot reproduce.

Unfortunately, no one can guarantee that these protections will work. Fish farmers are unlikely to support expensive indoor tanks instead of the ocean nets they use now, Sutterlin said, and the pressure treatment to neuter salmon sometimes produces defects such as deformed jaws or poor ocean survival.

Even if A/F Protein's fish can be grown safely, critics conclude, this is the start of a whole new field that has attracted research institutes from Baltimore's Christopher Columbus Center to the University of Connecticut's Biotechnology Research Program. As the number and type of genetic manipulations increase, they say risks could multiply.

But A/F Protein officials are counting on public doubts to fade over time, much as apprehension about eating salmon raised on fish farms did in the 1980s. Then, genetic engineering of fish could become just one more unnoticed tool for managing the human food supply.

"The average consumer has no idea where their food comes from," said Sutterlin. "The chicken comes from the jungle fowl of Asia. It's got the texture of manila rope. All of the food we eat has been manipulated" over the centuries. Soon, he hopes, we'll add fish to the list.

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