Breeding 'designer fish' to feed the developing world

The Port of Miami and the high-powered banks along Brickell Avenue may get by far the biggest slice of Florida's international trade pie - but not the whole thing.

Here outside Palmetto, a small town a few miles south of Tampa Bay, a geneticist-cum-entrepreneur has developed a way to help meet the protein needs of the developing world with the help of some ''tough little fish'' from Africa.

Mike Sipe, president of Natural Systems Inc., has used two species of the genus Tilapia and some classical applied genetics to design turnkey hatchery systems - and the fish to go with them.

Tilapias are indeed tough little fish. They can eat just about anything from mud to zooplankton to finished commercial feed. They are subject to no known diseases of consequence.

They can survive in water that is fresh, salty, brackish, - or so polluted that it would kill just about any other species. They breed with a speed and exuberance that puts rabbits to shame - one female can produce 5,800 fry in a year.

One of Mr. Sipe's associates describes tilapias as they occur in nature as ''ugly as sin.'' A close look at a photo of the fish suggests the young man is being charitable.

For all their ugliness, though, tilapias have a proud history, Mr. Sipe says. Members of the Cichlidae family, related to angelfish, they were grown for Egyptian royalty 6,000 years ago. King Tut's tomb was decorated with hieroglyphs illustrating ancient fish-farming technology. ''They were really quite advanced, '' he notes.

Much more recently a United Nations commission studying the nutritional needs of developing countries determined the tilapia would be a good fish to farm.

Mr. Sipe, who had a background in genetics but no experience with fish, not even an aquarium as a boy, read about the UN commission's work in Scientific American in the 1960s and decided to try to breed the fish, initially to sell to local farmers as livestock feed. His first attempt was a glorious disaster: He had his fish in metal garbage cans and accidentally electrocuted them when the tank heaters malfunctioned.

''These fish will outbreed any amount of food you throw at them,'' says Mr. Sipe. The prolificacy of the tilapia works both ways, though. It facilitates the applied genetics, but since their reproduction slows their growth, and since they eat their smaller brethren, it's hard to get the fish up to market size.

He got around this difficulty by exploiting a quirk of genetics: A cross of males of the species Tilapia honorum with females of the species Tilapia mossambica will produce a virtually all-male hybrid. He reasoned he could improve both species through selective breeding and then cross the ''purelines'' for trouble-free male fish.

As for knowing whether you've got girl fish or boy fish in a tank, well, they're pretty hard to tell apart, even for experts. But Mr. Sipe found a way around this problem: color coding the fish by changing black fish to red.

He found mossambicas with just a speck of white or red. Then through selective breeding, he produced fish which had bigger red splotches each generation, and ultimately, red fish with only occasional black splotches.

''It took 27 generations, nearly eight years, to get red as a reliable characteristic,'' he says, noting that the fish breed so fast he gets three or four generations in a year.

Each generation consisted of about 10,000 fish, and of this batch, only two or three would be chosen as parents for the next generation.

And so now he sells hatchery systems in which the black fish are males and the red fish are females. The color change has a further advantage: The resultant hybrid fish are an attractive reddish color with a few black spots, which makes for much greater consumer acceptance.

The hybrids also have the meatier body shape of the improved Tilapia honorum: they produce 40 to 60 percent boneless fillets, a 20 percent improvement over nature. A one-pound fish thus produces an eight- or nine-ounce serving, ideal for restaurants.

The year-round availability of the fish at a stable price is another plus. Moreover, Natural Systems can produce a pound of fish with only a pound and a half of feed.

His first big deal involved selling 17 hatcheries to the Mexican government, five of which he and his crews installed themselves.

He says he has nibbles from 35 potential customers overseas, including six in Saudi Arabia. But he has learned that international trade goes slowly, especially when foreign governments are involved. And the world has not exactly been beating a path to his door.

And so the road to success in the developing world has detoured a few miles south on the Tamiami Trail to Zinn's Restaurant in Sarasota, where Sipe's ''superfish'' have made their debut on the menu. Billed as ''cherry snapper,'' they are identified as a freshwater fish specially grown for the restaurant by Natural Systems.

In the name of research, this correspondent visited Zinn's to sample cherry snapper, graced with hollandaise, and found it a sweet, mild white fish, utterly unweird - a far cry from its angry-looking African forebear on the wall in Sipe's office.

A recent taste test found 90 members of the local Sarasota-Manatee County restaurant association gave cherry snapper an overwhelming vote of confidence.