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Monday, 18 Dec 2017

Roleystone's Freshwater Mussels

In 2010 a new doctoral study began at Murdoch University on the type of freshwater mussel (Westralunio carteri) that naturally inhabits the waterways around Roleystone. This mussel only lives in the Southwest of WA and is now listed on the International Red List as "Vulnerable" which means it is "Facing a high risk of extinction in the wild in the medium term future".

Very little information is known on the biology, abundance, and distribution of this animal. This study aims to identify the mussel's life cycle and growth rates, environmental tolerance to salinity, temperature and drought, as well as updating and monitoring the species distribution and population information.

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Freshwater mussels are important to river health. They feed by sucking water in and filtering out microscopic plankton, algae, bacteria and plant debris through their gills. They release clean, fresh water. Some scientists believe they have an especially important role in keeping a good standard of water quality in pools where freshwater fish retreat to over the dry, hot summer period.

Some species of freshwater mussels live for 50 years, and one of the outcomes of this study will be an assessment of age distribution of known populations. Although you may see many large animals in a pool, if they are not breeding and there are no young they could represent an elderly, dying population. 

"Nut case with a cause" in Roley Pool

Nutcase with a case

"Mussel Observers"

Mussel observers"

 

 

 

 

 

 

 

 

 

 

 

 

 

In Roleystone the mussels can often be seen in the mud in the Canning River such as in the Roley Pool Reserve.

The mussels have quite an unusual lifecycle. Eggs are kept within the females and once they hatch the females brood the larvae until they are ready for release. They then attach to fish, using a special hook on both side of their shell, and become encysted and live as a parasite for some period of time. After they have transformed into juvenile mussels, they release themselves from their host fish and begin life in the sediments, where they grow into adults.


Help local study

The Murdoch team have established a website www.musselwatchwa.com , where you can read about their latest findings and see maps of where the mussels have been found. They are asking people to help them by contacting them to tell them about the mussel locations and observations in our area. If you would like to help in some of the local studies please contact Michael Klunzinger on (08) 9360 7419.

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