Rivers in central and northern Victoria have historically had their highest flows in spring, and animals that rely on these rivers to survive and thrive have evolved accordingly.
That means they rely on natural triggers to set up for breeding season. However, river regulation, historic farming practices, and climate change are making those triggers a bit trickier to understand.
North Central Catchment Management Authority environmental flows project manager Darren White said a Campaspe River flow in mid-September aimed to trigger those cues for platypus and native fish.
“Native fish have responded really well to the repair work we have done since the 2022 floods, and this flow will tell them the time is right to start looking for a mate,” he said.
Mr White said the flow is also important for platypuses as they begin their breeding cycles.
“By raising water levels a little bit, we are giving platypuses the signals they need to build their burrow,” he said.
“They will note the level this flow gets to and build their homes a little higher up the banks, helping avoid burrow inundation if flows naturally increase later in the season.
“It’s the best indication we can give them of potential higher water levels over the next few months.”
September is platypus month in Victoria, coinciding with the monotreme’s breeding season.
“Pregnant and lactating platypuses can consume 100 per cent or more of their body weight daily, which is why this flow is also important,” Mr White said.
“Increasing the health of the river’s aquatic vegetation, as well as encouraging slime growth on rocks and sticks, increases the amount of water bugs, which means more platypus food.
“The Campaspe River platypus population is really important regionally, as there aren’t too many populations in the Murray River downstream of Echuca.”
Up to 1400mL a day flowed from Lake Eppalock down the Campaspe for three days, starting on September 9.
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