Oysters, it might surprise you, have terroir. At least, according to the growers, who say oysters are flavoured by the rivers they grow in, which in turn are influenced by saltiness from the sea and land run-off up river.
Asked whether he could pick the difference blind, Narooma grower David Maidment says he could certainly tell an oyster from Tuross, where he has also farmed, from one grown in Narooma. Tuross oysters are softer and fresher, influenced by the large river that runs from the back of Cooma towards the coast, he says.
Narooma oysters are more oceanic, saltier, possibly a bit sweeter, a little creamier when very fat, and a little oilier as well. Their shells are harder because of the saltier water. ''Because oysters are grown in estuaries and you get freshwater input, there's a distinct flavour difference, just like wines,'' he says.
If you want to test this terroir claim for yourself, Maidment, Ewan McAsh and other growers will open oysters from Merimbula, Pambula, Narooma and the Clyde for a tasting at the Narooma Oyster Festival on May 4. They'll also compare Sydney rock oysters with angasi.
McAsh, a Batemans Bay grower, is equally confident about picking terroir. ''Every estuary, even different leases within an estuary, have a different flavour,'' he says. From the deep, fast-flowing Clyde, oysters emerge salty and sweet, he says. From the shallower Narooma, they're also salty but sharper. From Wonboyn, they're ''super creamy and fruity''.
The problem for people buying oysters is they're not usually sold by their terroir, but McAsh says this is being addressed, with plans for an oyster trail for the south coast, where people can visit farms and discover differences for themselves.
South coast oyster farmers are struggling with declining production. Farms in Batemans Bay and south of the town produced 2.1 million dozen in 2008-09, but 1.6 million in 2011-12, a fall of 24 per cent. On the Clyde River alone - by far the biggest oyster-growing river in the area - production is down from 880,000 dozen to 590,000 dozen. McAsh says the reasons are a mystery and he is using a Nuffield Scholarship he won last year to look at ways to turn production around.
He points to a couple of issues: the need for more reliable hatcheries and spat suppliers; and the challenges of switching from the old stick-farming method to a basket-farming system, which means better, more consistent oysters but high set-up costs.
McAsh was a newcomer to the industry eight years ago, when his father bought an old oyster lease on the Clyde River - perhaps a little naively, he comments. He studied marine biology with the idea of working in aquaculture, and says that after working in fish farms and prawn farms, he was drawn to oysters because the industry was sustainable in the sense that you don't have to feed oysters or treat them with chemicals or antibiotics. They do, however, need ''love and care''.
The farm has expanded rapidly to 20 hectares on the river, producing 80,000 dozen (with plans for 120,000 dozen), and the pair have overhauled the traditional farm to one of the most modern on the coast. They've switched from stick farming (allowing oysters to clump on sticks in the water) to basket farming, also known as ''single-seed'' farming because the oysters grow individually rather than as clusters. This involves catching them first on slats, then, when just fingernail size, putting them in baskets, where they grow to maturity.
They take three years to grow, and must be brought in about every four months to clean out the baskets and wash and grade the oysters.
Despite the challenges, McAsh says he loves the job and has also opened an oyster and wine bar in Ulladulla, where he works on weekends.
In Narooma, Maidment has been oyster farming for 32 years after studying agriculture. He chose oysters partly because a lease was more affordable than freehold land. He reflects on three decades of ''ups and downs''.
''It hasn't been an easy road,'' he says. ''You've got to be consistent and methodical, get to know your areas. Some leases are better than others.'' But he believes oyster farming is more stable than other forms of farming, given the limited number of leases available, the stability in prices and the fact that the market is still under-supplied.
Maidment grows Sydney rock oysters and angasi, also known as flat oysters, which grow deeper in the estuary at a sub-tidal level. They have a fuller flavour and more oceanic taste than rock oysters, he says.
He produces 40,000 to 50,000 dozen a year. They're at their best now and through winter, he says.
Three decades in the industry haven't put Maidment off eating oysters. He sits down to a meal of them every week, he says, usually eating them raw, but also exploring the classic oyster dishes - in vol-au-vents, carpet-bag steak, and Kilpatrick.
David Maidment and Ewan McAsh will lead the Ultimate Oyster Experience masterclass at the Narooma Oyster Festival on Saturday, May 4, $49.50, including wine and Tilba cheese. Bookings narooma.org.au/oysterfestival.html. McAsh runs an oyster cocktail lounge at the festival.