Police believe the people behind a “significant” theft of up to 100,000 oysters on the NSW south coast may have links to the industry.

Young Sydney rock oysters were stolen from leases from two separate oyster businesses in Narooma during October.

Detective Sergeant Michael Calleja from the NSW Police Rural Crime Prevention Team said while there were reports of oyster theft “from time to time” on the NSW south coast, he had not witnessed oyster theft in this magnitude in recent years.

“This is not an incident where a few bags were taken for human consumption,” he said.

Sergeant Calleja said none of the young oysters were yet ready for human consumption.

“They weren’t ready to be sold, so they may have been taken for the purpose of growing them.”

An oyster business lost about 72,000 smaller oysters with a shell size of about 8 mm.

Meanwhile, at a second business in Narooma, more than 24,000 young oysters with a shell length of about 40mm were stolen from their lease.

Sydney rock oysters are usually harvested when they reach an average shell length of 65 to 77 mm.

Sergeant Calleja said the oysters stolen from the second business weighed up to 150 kilograms and would have taken some time to get out of the water.

The value of oysters could triple

Pambula oyster farmer Andy Baker said the theft was “quite significant” and that production losses and opportunity costs would affect affected farmers.

He estimated the losses to be between $10,000 and $20,000.

“Oysters smaller than 8mm would sell for three to five cents an oyster at that stage … and 40mm oysters might be around 40 cents each,” Mr Baker said.

Mr Baker said the current value of young oysters could triple if someone were able to grow them to full size.

“Over time, they can turn that theft into a pretty significant profit,” he said.

Major suppliers involved

The Australian Oyster Coast has been confirmed as one of two businesses that had oysters stolen from their leases in Narooma.

The company is Australia’s largest producer of food-grade Sydney rock oysters and has seven farms along the NSW coast in estuaries – from the Hastings River to Merimbula.

“The theft has been reported and we are working with the authorities on this matter,” Australian Oyster Coast said in a statement.

NSW oyster growers have faced the challenges of disease and rising water temperatures this year.

According to police, there have been no other recent oyster thefts in the region and investigations are ongoing.