Update on Salvinia infestation in Muddy Lake


3rd February 2022
Most people who drive through Dora Creek would be aware that what is known as Muddy Lake has been overtaken by a waterweed. The weed is Salvinia, and its rapid
¿ UPDATE ON MUDDY LAKE WEED INFESTATION AT DORA CREEK
¿ Most people who drive through Dora Creek would be aware that what is known as Muddy Lake has been overtaken by a waterweed.
¿ The weed is Salvinia, and its rapid growth has now fully taken over all of the waterway taking away the habitat that is otherwise used by a range of water birds. No doubt fish life has been heavily impacted along with other aquatic animals and life that rely on light penetration and oxygenated water.
¿ Salvinia forms a thick mat on the water and in this case is so well established that there are now other plants growing on it. This weed is an exotic pest originally introduced for the aquarium trade and like so many introduced species has had major impacts on natural systems where they often flourish. The plant does not do well in full saltwater but freshwater and brackish water can be ideal for its growth.
¿ Both Lake Macquarie City Council and Crown Lands have been working to fix the problem for more than a year now. Before the entire area was overtaken by this noxious weed, Crown Lands supplied a bio-control in the form of Salvinia Beetles which were introduced many years ago to help control the pest. But it’s a slow process and the problem appears to be bigger than what the beetles can handle.
¿ I’ve again written to the Minister for Lands and Water Kevin Anderson this week, asking for more resources to be thrown at the problem. I’m hoping that the Government might undertake at least some physical removal of the weed which might work better alongside the bio-control measures already introduced. Simply removing the existing weed won’t fix the problem as Salvinia is an expert at quickly regenerating, but perhaps it will give the beetles a chance to bring it under control quicker.
¿ In my own observations, this is the largest Salvinia outbreak I’ve seen, although there was a significant outbreak which overtook large parts of Pourmalong Creek near Morisset Hospital many years ago. That outbreak eventually resolved itself when a weir which held freshwater back from the lake broke, thus releasing the weed into the lake, killing the Salvinia.
¿ This is a seriously invasive weed and in its own way can have huge impacts on natural environments in the way that lantana, bitou bush and other exotic invasive species have done to terrestrial habitat.
¿ I'll let you know when I hear something back from Minister Anderson.

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