Pilot reefs show successful and exciting oyster settlement, but extensive boat damage is a problem!

Trial oyster reefs installed in the Noosa River system have shown successful oyster settlement, but recent boat damage means some will need to be removed.

Fourteen reefs with associated buoys and signage were first installed in November 2017 by the University of the Sunshine Coast, to determine the best locations for re-growth on permanent reefs in the Noosa River.

The oyster reefs made of large hessian ‘sausage shaped’ bags filled with recycled oyster shells were installed as part of a pilot program to restore lost habitat in the Noosa River system.

Monitoring of the reefs in May last year showed strong recruitment of juvenile oysters, with vigorous growth recorded by November 2018, only one year after installation. This positive result shows we have identified how oysters can be developed in our river.

Limited boat damage to some of the reefs was evident during a routine monitoring in November last year. However, further inspection this week showed extensive boat damage to eight of the reefs positioned along the northern shore of the Noosa River.

Therefore, eight of the fourteen trial oyster reefs installed in the Noosa River system are being removed. It is believed most of the damage was caused by increased recreational boating on the Noosa River during the Christmas holiday period.

Some of the trial reefs in Weyba Creek and Lake Weyba were slightly damaged, but there was good progress in juvenile oyster growth and consolidation everywhere.

Accurate monitoring is no longer possible on the damaged reefs but will continue in Weyba Creek and Lake Weyba.

All reefs had spat settlement with an average of 300 spat per square metre in May. By November, some juveniles had grown to 60mm in diameter.

Research by the University also showed the reefs were creating good fish habitat.

Chair of the Noosa Biosphere Reserve Foundation, the major funder of the trial reefs, Dick Barnes, says the oyster reef growth indicates very positive signs for future reef habitat restoration.

“The trial reefs were always a pilot research project to test the effectiveness in restoring lost habitat and remediating the Noosa waterway system,” said Mr Barnes.

“We are satisfied that the oyster settlement and growth recorded over the past year provides good input into future reef extensions. However, improvements in the design and protection of the reefs will be needed to meet the conditions in the Noosa River.

“We now have sufficient information to proceed with the positioning and construction of scaled-up reefs and continuing the research program,” he said.

The removals will be conducted by the Marine Group of the University of the Sunshine Coast, the research team which led phase 1 of the trial program.

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