Threatened freshwater mussels return to Vasse River

Mussel with Valvometer. Image supplied.
Mussel with Valvometer. Image supplied.

One hundred and sixty threatened Carter's Freshwater Mussels are being safely relocated to the Vasse River after their health and habitat were temporarily compromised by the Eastern Link development in Busselton.

Dr Stephen Beatty from the Centre for Sustainable Aquatic Ecosystems (CSAE) at Murdoch University's Harry Butler Institute led the relocation project to prevent the local mussel population being impacted by the development.

Dr Beatty said tThe City of Busselton engaged them soon after they identified the bridge that forms part of the Eastern Link project could potentially impact the safety of the local mussel population's habitat.

"We are excited to demonstrate what a successful relocation looks like after housing and conserving the species for more than six months," he said.

The mussels were remotely monitored using bio-monitoring devices, called 'valvometers', developed by Dr Alan Cottingham from Murdoch University's CSAE, to detect any early signs of possible stress.

Mussel cage setup Iluka. Image supplied.

Mussel cage setup Iluka. Image supplied.

"The project has been a collaborative effort across the board from partnering with Iluka Resources Limited to identify a suitable host wetland at the Capel rehabilitation site through to working with Ottelia Ecology to undertake the relocation and on-ground monitoring," said Dr Beatty.

Dr Beatty explained freshwater mussels play an important role in maintaining our aquatic ecosystems, especially in the south-west region of Western Australia, by filtering water and creating liveable habitats for fish and other aquatic creatures.

"They have a fascinating lifecycle with their larvae 'hitch-hiking' on fish to help spread and maintain their populations on the bottom of rivers or lakes," said Dr Beatty.

"Thankfully, all of the mussels have survived the relocation period.

"Each individual mussel will be tagged before being returned to appropriate habitats around the new bridge site in the Vasse River, where they can resume their role of filtering the water."

Searching for mussels in the Vasse River. Image supplied.

Searching for mussels in the Vasse River. Image supplied.

However, not all mussels will return home to the Vasse River today. Ten mussels will remain at the Capel rehabilitation site to be studied over the next year.

"We still have a lot to learn about the biology of Carter's freshwater mussel. And, after seeing the success from the past six months, it presented a great and safe opportunity to learn more about their behaviour, so we can improve future monitoring programs," said Dr Beatty.

The Carter's Freshwater Mussel relocation project is a collaboration between Murdoch University researchers from the Harry Butler Institute and Ottelia Ecology, in partnership with Iluka Resources Limited with funding from the City of Busselton.