The tall, bearded man in the white coat and hard hat walks briskly across the floor of his salmon-processing factory in the north Scotland city of Inverness, past women slicing smoked sides of salmon and racks of salted fish browning in an oak-smoke kiln. With the glibness of a lifelong expert, he talks of stocking densities, water flow, disease risk, cage design, mooring methods, percentage yields and other arcane aspects of his trade. Except for the mass of disheveled hair and scraggly beard, there is virtually nothing to connect this cool entrepreneur with the eccentric, mesmerizing musician whose stage antics once earned him the sobriquet "the deranged flamingo of rock." Yet this is none other than the lead singer and flutist of the '70s' supergroup Jethro Tull, Ian Anderson, 37, who, in the twilight of his musical career, is going from Aqualung (the group's classic 1971 LP) to aquaculture—and achieving equally impressive results.

Anderson got into salmon farming in 1978, after purchasing a rugged, 15,300-acre estate on the remote isle of Skye off northwest Scotland. He hired a trained staff of three workers and one manager, read a few books on the subject, began growing salmon in cages submerged in the adjacent Loch Slapin and produced his first mature salmon three years ago. He grossed $500,000 last year from a two-and-a-half-ton weekly harvest, selling his smoked delicacy to top London shops such as Harrods and Selfridges and, through a contract with Qantas, supplying all airlines flying out of Australia. Prince Charles recently ordered a special consignment as gifts for his staff. Now Anderson has begun to expand his business to the U.S. as well, with arrangements to deliver 20 tons of fish this year to delicatessens in Florida, Texas, New Jersey and New York. "Shoppers are going crazy for Scottish salmon because it's so much better than anything they've ever had," claims Anderson, who, with a salesman's smile, dismisses the Pacific variety commonly eaten as lox in America as coarse, salty and bland. "This year a number of British producers are making a major exporting effort in the U.S. It is the year to establish the superiority of Scottish smoked salmon."

It's clear Americans are taking the bait. The British salmon-export trade with the U.S., virtually nonexistent in 1982, is forecast to leap to more than 500 tons this year. Most of the salmon is farmed by the giant Marine Harvest Co., which has 18 farm sites in Scottish lochs (coastal inlets), but Anderson is already making a dent in its business. Marine Harvest, in fact, held the lease on Loch Slapin when Anderson bought his estate, and Ian threatened to pillory the company in the national press as an unfair monopoly until it agreed to surrender the lease to him. "In a way I regret my behavior because I was a bit pompous and aggressive," he says. "We are all more gentlemanlv in our dealings now." Anderson has since surveyed 30 more potential fish-farm sites on Scotland's west coast and expects to develop three or four new farms this year. "I believe I have actually tied up the rest of the country," he says with a grin.

The musician's love for Scotland was fostered during his childhood in Dunfermline, across the Firth of Forth from Edinburgh. At 12, however, his parents moved to the English seaside town of Blackpool, where they operated a boardinghouse and a corner grocery. Anderson, who says he "recoiled at the dreadful normality of it all," quit school without his parents' permission, worked at a newsstand, spent some time in art college and in 1967 set off for London with some musicial friends to try his luck. Only after he returned in triumph two years later with the hit record Living in the Past and enough money to buy his parents a new house did they finally warm up to their wayward son. Gold albums, platinum albums and world tours have filled Anderson's years since then; Jethro Tull has generated more than $100 million, making Anderson a multimillionaire.

In 1976 he married Shona Learoyd, a former secretary at his Chrysalis record label. (The couple has a son, James, 8, and a daughter, Gael, 6.) They bought a 16th-century redbrick farmhouse with 630 surrounding acres in Buckinghamshire and two years later purchased the Scottish estate, pumping $120,000 into restoring the property's derelict 11-bedroom Victorian mansion. "I've always had a passion for the wilder and more rugged parts of the country," says Anderson. "And like most expatriates I rather fancied having a wee corner of Scotland waiting for me when I weaned myself away from music business."

Anderson travels from Buckinghamshire to Scotland regularly, flying to Inverness to inspect the factory and journeying by road and ferry 80 miles to visit his spread on Skye. Despite the steady growth of his fishery, he still found time to devote most of the last year to music, recording a new album and touring through Europe, America and Australia. But the loss of his voice, probably from fatigue, at the tail end of his U.S. jaunt convinced him that it might be time to contemplate at least partial retirement. "I wouldn't like to do this and not ever play music again," says the increasingly successful entrepreneur. "But I'm at the point now where there's no way I'd be happy just being a musician the rest of my life."