This is an unfinished wildlife story. As a fish (the Coho salmon) is the central character instead of a dog or lovable bear, a future television series is unlikely. But a dramatic plot unfolds nonetheless.

It begins with a young Ivy League couple, high-school sweethearts from New Jersey no less, who moved to California, caught the pioneer spirit and together began a new industry. But not in the West. Instead Bob and Linda Mant reversed Horace Greeley's dictum and migrated East to a wilderness land of opportunity: Goose Cove on Maine's Penobscot Bay.

Why Maine? The fishing industry has been hurting badly. Due to overfishing and pollution, Atlantic Salmon has become an endangered species and most salmon sold in the East these days comes from the Pacific. Furthermore, a coastal mining ooperation was closing down and the company, Callahan, was eager to help bring a "clean" industry to the area that might provide employment.

So Bob Mant, a marine biologist who had been working on a project to raise oysters and abalone, came to the state on a University of Maine grant. After eight months of experimenting with salmon and other fish, he was convinced the unprecedented transplant of the West Coast Coho (silver) to Atlantic waters would work. Only 2 to 5 per cent of wild salmon survive to return to their breeding grounds three years later. Mant calculated he could achieve nearly 50 per cent suvivial by raising the salmon in pens. Then the company, realizing the project promised only limited return on investment, backed out.

"So," said Linda Mant last week, "we put our names on a quarter-million-dollar purchase. We weren't event experienced enough to incorporate."

What the Mants bought was 100 acres on the water, three buildings and some valuable equipment plus the unpolluted salt water cove. Once a quarry, it is 300 feet deep, has no housing or pleasure boat traffic and a tidal flow that can be controlled by a gate at the mouth. The salmon were moving into luxury housing and surroundings: an aquatic version of Long Island's Southhampton.

The wild salmon, shipped East as eggs, are placed in the pens 50 feet below the surface. They have to be cared for and fed at regular intervals and, as befits aristocrats, they demand a luxury diet of ground shrimp and crab. It takes about 20 months for them to reach marketable size.

By then they are "yearlings," weighing from 9 to 12 ounces. One salmon of this size, poached, broiled or baked in a pastry crust, usually feeds one person. With their delicate, light pink flesh and special diet they are the milk-fed veal of the fish world.

But rising them meant "two very rough years" for the Mants and their single helper. "We had 18 months of expenses before we could anticipate any income," Linda Mant said during a visit here to promote and sell their project. "We had not heat and water at times. Ice up to two feet thick has to be chipped from the pens in winter and my husband had to go down in a wet suit to check the nets. He and the man who works with him drew no salary during that time. This fish ate better than we did. We had hamburger casserole, sometimes."

On top of that there was considerable culture shock for a couple in their late 20s transported to the wilderness, plunged deeply into debt and totally immersed in "trial and error" innovative work. "I cried a lot," Linda Mant said, recalling the first two years of their project. "But the local people were rooting for us. That made a difference."

Not enough of a difference, however. They had managed the trick of transplating the fish and, after more than a year, they were thriving. But as in the best of melodramas, the young couple was threatened with tragedy. "Technically we were successful, "Linda Mant recounted, "but we literally ran out of feed money. We had 70,000 fish out there almost ready for market and we couldn't finish the job and get them there."

A rescuer appeared at the last minute: Not a masked man on a white horse, but a Boston banker with ties to Maine and a willingness to "help us hang in there without demanding an immediate return." The fish were harvested (in 1975) and were sold to the pleasure of fresh fish fanciers in Maine and Boston.

As she explains it, they had turned down offers from various "dollar-oriented venture capitalists" because "we felt we had an efficient and manageable operation. We wanted to limit growth, give the fish the best diet possible, do hand instead of mechanical feeding and, as far as possible, market only fresh fish." Politely but firmly, she outlines the differences between their operation and farms where trout are "raised like mass-produced poultry."

Since then the sale arrangement with callahan has been renegotiated generously; some loans have been extended and a raft of marine biologists have applied for jobs.

"Things have been falling our way," Linda Mant said. "This winter we should harvest 100,000 or more salmon. But we had to swtich our cycle. We were harvesting them in the summer, but when they came to the surface to feed, the water was too warm and our loss rate was too high. Now we will harvest in the winter."

There is a limited amount of fresh salmon on the market during the winter months, a marketing plus for the Mants and their Maine Sea Farms. But there is a minus, have bought most of the salmon in Maine aren't there at this time of year.

That's what brought Linda Maint to Washington carrying a coller of fish.

It's a story that derserves a happy ending and it may have one. Early next month the Coho yearlings will be available here in at least one fish market (Cannon's) and in a number of restaurants.