The Shetland Islands, 150 miles off the northern tip of Scotland, are about as remote as it gets from London or the Caribbean. But for Laurent Viguie, 44, a financier in the City, and Karol Rzepkowski, 41, who was running a scuba and windsurfing business on Grenada, the storm-swept Shetlands with their clean, cold water were the perfect place to set up an environmentally friendly aquaculture business to produce cod.
Throughout European history, cod has been a staple food. But cod populations have plummeted. The worldwide catch has declined from 3.1 million tons in 1970 to around 800,000 tons today. The...