It was a sign of changed times that Dylan Thomas was never able to satisfy his legendary love of oysters in his native Swansea.

Nearly a century ago, the port was among the world's leading exporters of oysters but the trade had died out by the poet's day, leaving him to seek out one of his favourite delicacies as far away as San Francisco. Thomas often waxed lyrical to his wife, Caitlin, about the quality of those dished up in small bags on Fisherman's Wharf.

So Swansea's most famous son would presumably be delighted to hear of the city's declaration, this week, that it wants to revive its oyster trade after an absence of more than 80 years.

Spurred on by demand for local produce from a growing number of restaurants around Swansea Bay, and evidence that coastal waters are now clean enough for oysters to thrive, the Welsh Development Agency and Swansea University's aquaculture department are undertaking a development project which, it is hoped, will restore an industry that employed 600 people in the Mumbles area in the mid-19th century.

The industry will never be a major employer again. The sophistication of modern fishing leads the city to conclude that its oyster beds will sustain only a handful of vessels. But there are hopes that Mumbles - still known locally as Oystermouth in memory of the old industry - could again become synonymous with oysters.

Swansea, which also has a small mussel industry, is not the first to hit on the idea. Britain's new-found obsession with the quality and provenance of its food has encouraged several other areas to rebuild old oysters trade.

Kent is introducing the shellfish to one river, and Essex is launching an offensive to promote its own, distinctive flat Colchester oyster, adored by diners as far afield as Paris and Hong Kong but barely known in the UK. A group of eight growers who produce the oyster off the island of West Mersea want to persuade the European Union to give it the same protected status as Parma ham and Brie de Meaux.

Few places can compete with Swansea's rich history of oyster-harvesting. There is evidence that the Romans consumed vast quantities of the produce - already known for its aphrodisiac qualities - from the city's coastal waters in the 5th century. They were still well-established by the Middle Ages and the chronicles of the Duke Beaufort also suggest a prolific industry when he toured his Welsh lands in 1684. Those who held the title in later centuries demanded rent from the workers of the oyster trade in return for their oyster "plantations".

In 1871, 10 million oysters were scraped off the seabeds of Swansea Bay and Gower, with a saleable value of £50,000. Hundreds of oyster pickers collected them, 40 people (mainly women) bagged them and a further 10 carried the bags to the new railways that transported them throughout the UK. The younger oysters (known to harvesters as "the small") were kept in plantations on the beach until they had grown large enough to market.

But by the turn of the century, over-fishing and coastal pollution had reduced the value of the beds and what remained was wiped out by a virus in the early 1920s. The last skiff to work the beds was retired in 1930. The South Wales Sea Fisheries Committee examined the idea of reviving the industry in 1949, but concluded the beds were financially unviable.

The industry has given rise to a number of Mumbles specialities: oyster omelette; oyster in breadcrumbs or oyster with fish and chips, eaten straight from a paper bag.

Swansea's new-found optimism - which has prompted a visit to Mumbles' twin town of Hennebont in southern Brittany for advice from fishermen - was nurtured by a beach cleaning operation last September which revealed pockets of young oysters.

"The water in the bay now is much cleaner than it was so it seems obvious to bring these things together," said Terry Scales, development officer for the Mumbles Development Trust, which is co-ordinating efforts. "We want to develop genetically coded oysters, unique to the Mumbles.

"If we can market the produce in that way it could give it a real marketability, an identity. There's a real feeling around Wales that we should develop produce like this, from our home ground."