CAUTIOUSLY OPTIMISTIC: While Richmond River Chapter of OzFish chairman John Larsson was disappointed by the theft of research oysters in the Richmond River last week, another research project is providing a glimmer of hope of returning the filtering molluscs to the river in large numbers.
CAUTIOUSLY OPTIMISTIC: While Richmond River Chapter of OzFish chairman John Larsson was disappointed by the theft of research oysters in the Richmond River last week, another research project is providing a glimmer of hope of returning the filtering molluscs to the river in large numbers. Graham Broadhead

Oyster project giving a new lease on life

WHILE the theft of research oysters from the Richmond River last week could impact on the results of a two-year project, another separate study is providing a glimmer of hope for a return of the molluscs to the river.

It's no secret that the Richmond River has the poorest health of rivers in NSW, which is why, Richmond River Chapter of OzFish chairman, John Larsson said, the NSW Department of Primary Industries was keen to use the waterway for the oyster trials.

In October 2016, 9000 oysters - 3000 each from three families - were planted in Richmond Oysters' leases, moving alternatively from Mobbs Bay to near Burns Point, to see which ones could survive the poor conditions.

Mr Larsson said there are no oysters left from the first family, only 50 from the second family and of the 260 survivors from the third family, nearly half were stolen.

The oysters are due to be removed in a couple of weeks, though Mr Larsson said the theft could now potentially skew the results and impact on any propagation attempts.

Mr Larsson said the project was significant as oysters are a natural water filter, but also create an eco-system which attracts micro-organisms and in turn fish - all important for a healthy waterway.

"Theft of the oysters is one thing; the other is this despicable act defies the wider Richmond community of solutions to bring back clean healthy water that oysters can bring with their huge filtering characteristics," he said.

Oysters haven't been farmed from young in the Richmond River since the mid 1970s, though there are leases which are used to finish off oysters grown in other rivers.

Meanwhile, in April last year, oysters were found on retaining walls at Mobbs Bay away from the research leases.

Mr Larsson said these oysters were not native to the area, so they were sent away to DPI fisheries researchers who came back to say they were a new sub-species of oyster.

Mr Larsson said how the animals came to be in the Richmond River is not known - either the oysters have adapted to suit the environment, or they floated into the river from eleswhere.

The OzFish volunteers collected 42 samples of the oyster - with two males - and DPI researchers were able to propagate them.

In August, 10,000 of them were placed on leases at Mobbs Bay, and researchers are watching them closely, thanks to the efforts of the OzFish volunteers.

Mr Larsson said what has everyone very excited is the animals in what is now referred to as the Richmond Sub-species were about 18 months old when they were found.

He said their age meant they had already survived the wetter periods in early part of the year - February through to April - which is the season for the oyster-killing QX disease, which is borne from sediment and pollutants that wash downstream.

"It really is exciting," Mr Larsson said.

"But February to April next year will be the real test."

Mr Larsson added that most research oysters are not suitable for eating and the perpetrator of last week's theft "runs a significant risk eating them".

Anyone who is keen on supporting improvements to the health of the Richmond River is asked to report any suspicious activity around the oyster leases to fisheries watch hotline on 1800 043536.

The two research projects are not only supported by the volunteers of OzFish, but Richmond Oysters has allowed use of its leases and Ballina Professional Mullet Haulers are providing funds for equipment.