Freshwater mussels may not be cute or “insta famous” but they are the unrecognised heroes of Murray-Darling Basin river systems.
Mussel populations improve water quality, provide a crucial food source for native fish and many waterbirds and play an important cultural role for First Nations people.
A recently completed research project has determined the survival time for floodplain and river mussels under different dry and heat conditions.
The results of the project will help the Commonwealth Environmental Water Office (CEWO) and other environmental water managers to better support freshwater mussel populations, particularly during future droughts.
Commonwealth Environmental Water Holder Hilton Taylor said the CEWO’s work in delivering water for the environment helped protect many populations of native fish, birds and other animals.
“While the freshwater mussels are often overlooked, these small animals filter large volumes of water while feeding, which helps to keep the water clean. Mussels are critically important for our river and wetland systems.
“Drought conditions between 2017 and 2020 had a big impact on mussel populations, with mussel deaths estimated in the millions.
“The summer and autumn rains of 2022 have provided continued relief, but we must be ready for when drier conditions return.
“Targeted delivery of water for the environment can help support populations of this vital river hero,” he said.
NSW DPI Fisheries Senior Research Scientist Dr Jason Thiem said freshwater mussels are extremely vulnerable when rivers dry out, only surviving a few days when temperatures are hot.
“In order to preserve mussel populations, complete drying out of mussel habitat should be avoided at any time.
“Our research team compiled several recommendations including maintaining river flows for critical mussel populations, protecting and enhancing vegetation that shades mussel habitat and developing flow targets that support mussels throughout their life cycles.
“Larval mussels must attach to fish for the first few months of life, so conserving native fish populations is also vital.
“We look forward to working with the CEWO and other water managers to continue this vital research,” he said.
The research was funded by the CEWO and undertaken by New South Wales Department of Primary Industries Fisheries in collaboration with the Harry Butler Institute, Murdoch University.
For further information on freshwater mussels see below link containing a fact sheet: The Mighty Mussel (PDF 2.37 MB)