Mr Ralston says his predecessors farmed oysters unchanged for 50 years, accepting low prices from distributors who in turn accepted low prices from the next distributor down the supply chain, leaving the end retailer with the profit.

But he is marketing premium oysters, culled and returned to the water where they are finished in baskets and sold directly to high- end restaurants in Melbourne.

"With oysters, a lot of the shops and restaurants get them pre-opened and serve them on a plate,'' he says. ''Our chefs open them to order - that's what you want at a restaurant.''

Mr Ralston says oysters, when handled correctly, can keep fresh for 10 days after being taken from the water, as long as they remain unopened until eaten.

As well as growing heritage oysters on sticks, he is putting baby oysters the size of a thumb-nail in cylinders tethered to a long line, a metre below the surface.

Through the clear water you can see the cylinders rocking with the tide, constantly turning the oysters, which form a cup-shaped shell instead of growing out to the conventional long-shell oysters that grow on submerged sticks.

Mr Ralston says the smaller waterfall oysters are tastier than the bigger Pacific varieties. This method of cultivation began about 15 years ago, and growers share information to promote the results.

It's a tough journey he and his brother John are embarking on with their 10 hectares of oyster leases on the Clyde River. Having learnt the industry from their father Graham, they are one of the 22 businesses working leases on the Clyde. The logistics of dealing with chefs, keeping control of the products and getting the right oysters to shops and restaurants is the biggest part of Mr Ralston's business. Building relationships, and not allowing the distributors to mix and match his stock with others, enables him to guarantee consistent quality.