More than 60 people attended the Revitalising Geographe Waterways Science Update held by the Department of Water and Environmental Regulation on July 20.
The update included talks about how seawater was being used to improve water quality in the Vasse Estuary, if phosphorus binding clay could be used to reduce algal blooms in the Lower Vasse River and the preliminary results from the Vasse Wonnerup wetlands integrated ecological monitoring program.
Department South West region district manager Dr Kath Lynch said it was the first time integrated monitoring of the waterways had taken place.
“It was really interesting to see how something could be positive for one thing, but not so good for something else and how what we do has a different impact on ecology,” she said.
The monitoring program was funded for 12 months through the Revitalising Geographe Waterways program.
Samples were taken every season from March 2017 and researched water quality, levels, fish, birds and plants.
Murdoch University’s Dr Jane Chambers presented the results for aquatic plants.
“The integrated monitoring program enables us to know where plants are growing and when and we can then manipulate the system to get what we want and not what we don’t,” she said.
Dr James Tweedley explained the importance of macroinvertebrate and fish as a food source to the wetlands’ migratory birds.
His result presentation also detailed how fish were a good indicator of what was happening in the environment and how important fish were to the ecosystem.
“If we lost estuarine fish there would be an impact on the commercial fishing industry. 75 per cent of commercial fish and up to 90 per cent of recreational fish spend part of their life cycle in an estuary or wetlands,” he said.
Department of Biodiversity, Conservation and Attractions’ Kim Williams discussed the results for migratory birds. He said the region had received less than half the usual number of birds.
“It could be rainfall, drought, flood – it is very hard to say what the cause is or if the decline has something to do with what is happening locally. It will be many years before we have a handle on what the birds are doing and why,” he said.
Dr Lynch said it was an exciting time for science and management in the region.
“So often in management you can be single mind for about a way of doing one thing, but this shows all these things need to consider and it is a really complex system,” she said.
“This helps us understand the wetlands and how to improve them across all different aspects.
“There have been lots of studies of bird, yearly studies on plants, but it has never all been put together like this.”