Oyster farmers are under pressure in the Camden Haven as they await water testing results to reopen a harvesting season plagued by rain.
Oyster zones in the Camden Haven have been closed for harvest since early December after heavy rainfall and water runoff.
Camden Haven's Rockin' Oysters owner James Wood said the oyster harvest has been delayed since December 10 and growers are awaiting the results of water samples taken in the Camden Haven.
"It's mainly because of the rain, there has been so much rain that once we get over a certain amount the river salinity can change and this affects the oysters," he said.
"There's a certain amount of runoff that comes off the land and goes into the river system. Oysters are a bit like the canaries in the mine, they feel whatever is going into the river.
"Any kind of problems in the water that's running into the river can potentially get into the oyster because they are filtering that water. That's why we can't harvest those oysters at the moment.
"They do filter out over time and there is a time delay put by the food authority and DPI to make sure that there's no issues there.
"There's a bit of a supply issue at the moment as you would expect. I'm getting phone calls constantly from restaurants and also private consumers who have seen us and want to have that oyster experience, but we can't offer because there's no oysters.
"I'm hopeful we'll be back in time for Easter or if we might be open in February, but whether or not we've got a sale-able oyster is a different question."
The Christmas holidays are a traditionally busy time for oyster sales and some growers were able to harvest in early December. However oysters harvested before the closure have a short shelf life of around three weeks, according to Mr Wood.
Camden Haven Shellfish Program coordinator and Harper Oysters owner Brett Harper said harvesting had been further hampered by a sewage spill on January 7, requiring an immediate 21 day closure.
"We have begun meat and bacteriological testing, testing algae in the water. We are hoping for test results by Wednesday, January 3 and Friday, January 5. If we have no more heavy rain I'd be confident of opening after Friday (Jan 5) next week," he said.
"Since the shellfish program was set up after the 1990s this would be twice as long as the longest time without a harvest for the area. It's unprecedented.
"We have a finite selling season from December to March and we've already lost nine weeks of that selling season, it's a fair chunk.
"There is a likely to be a higher mortality rate of oysters in the river because of the reduction in salinity. I've spoken one farmer who is saying there is a 40 per cent death rate."
Growers further north have fared little better, Hastings River Shellfish Quality Assurance Program chairman Rex Marks said oyster farmers in Port Macquarie are optimistic the season would extend until after Easter.
"We still have a reasonable time to sell our product, providing we don't get any substantial rainfall in the catchment area," he said.