Oyster farms forced to stop harvesting as trigger levels are reached in recent flooding

Merimbula oysters served on ice from melbourne restaurant, Society (Photo: Lauren Richardson)

Extreme weather conditions are continuing to cause issues for the Australian oyster industry as flooding on the eastern coast continues to shut down farms.

The New South Wales Food Authority harvest area status shows almost a dozen oysters farms have closed “due to rainfall exceeding the trigger level” in the last month.

Despite typical forecasts expecting floods “once a year”, extreme weather has persisted for three years along the eastern coast of Australia according to Merimbula Lake oyster farmer Dominic Boynton

“[For] The guys on the north coast, I don’t think it’s ever dried out,” he said.

With increased rain, farms are hitting estuary trigger levels regularly, which are designed to maintain the quality and safety of oysters eaten by the Australian public.

“When we reach these trigger levels, we can't sell until we test and make sure the oysters are safe to eat,” he said.

Sitting in freshwater from rain and rivers for long periods of time reduces the salinity required for oysters to grow and survive, leading to losses up to 90 per cent.

Over “a million dozen” oysters have been lost in some parts of the state alone.

Integral to the persistent rain has been an “unusual” third year of the La Niña weather system, said Atmospheric Sciences Associate Investigator for Melbourne University, Josephine Brown.

Some of the highest recorded rainfall occurred along the Queensland and NSW border in September, with around 40 sites surpassing previous daily totals.

However, “It’s running to its natural limit, so they think this one will actually come to an end in summer,” she said.

Government grants have been made available to affected farmers, said Program Manager for Aquaculture at Oceanwatch Australia, Laura Stoltenberg.

But long term resilience is needed to safeguard the industry for future flood events.

“I think in the future it's important to develop relay areas to move their spat to so they can protect their stock,” Stoltenberg said.