Camden Haven oyster farmer says sewage research is positive

An experiment took place in the Camden Haven River on May 18 and May 19 as part of an assessment of sewage overflows on oyster leases.

The research is being undertaken by the University of NSW, Water Research Laboratory and in partnership with the NSW Food Authority, DPI Fisheries and Port Macquarie-Hastings Council.

The experiment aims to validate how pollution might mix and dilute, by releasing a fluorescent red dye in the main channel between Laurieton and North Haven, and in Stingray Creek.

UNSW Sydney Water Research Laboratory at the School of Civil and Environmental Engineering senior engineer Alice Harrison said the experiments are part of a larger project, with the results set to be released at the end of 2024.

"This research will help to understand where pollutants may get transported, and where they are likely to have an impact on the health of the oysters and consumers," she said.

Armstrong Oysters coowner Brandon Armstrong said sewage overflows into the river has been an issue for about 20 years.

If there is a sewage spill, they are required to close for a mandatory 21 days, which means they can close for weeks in periods of heavy rainfall.

Ms Harrison said sewage overflows occur when the flow through sewers exceed their capacity, putting stress on the system.

"This can happen during wet weather, particularly when stormwater enters the sewer system," she said.

Camden Haven oyster farmers have raised their concerns to Port Macquarie-Hastings Council and Mr Armstrong said council have been responsive in upgrading the sewer system.

"This dye experiment is going to be another feather in the cap in identifying where the flow runs in the river system," he said.

Mr Armstrong said he hopes the research can find to what extent oyster farms are impacted, if any.

He said the best case scenario would be if the legislation could change so that farms aren't required to close for 21 days, if the sewage doesn't appear to pose a threat to their produce.

However, Mr Armstrong is willing to adhere to any potential finding.

"It's about food safety too and recognising that if there is a spill we want to make sure our product is safe," he said.

The study involves 11 NSW river systems where oyster farms are located.

Ms Harrison said results of the work will help decision makers with informed and targeted responses to sewage overflows.

"This will include improved confidence in understanding when sewage overflows have the potential to reach oyster leases, and subsequent decisions regarding commercial oyster harvesting following these events," she said.

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