Senior wildlife ecologist Josh Griffiths of research group Cesar said volunteers sighted a 12-year-old male platypus first located in 2010 again during last week's spring survey.

"Often when we see platypuses we never capture them again, which makes it hard to understand if the animals are still there or if they've moved out from the area" he said.

Mr Griffiths said the 12-year-old was caught near the Wartook Pottery, further downstream than any other animal he had seen in his 10 years working in the region.

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"That supports the eDNA results we have been collecting, and supports the actions of the Wimmera Catchment Management Authority of the past six years," he said.

"There is an environmental watering program on the MacKenzie River which is the only reason we're getting catches this far downstream. The next stage would be to consider whether we need to start looking at supporting the habitat further downstream and even at Burnt Creek."

The CMA contracts Cesar to investigate platypus numbers. Mr Griffiths said six residents joined Cesar in working three 14-hour overnight shifts. In that time, they also found two new two-year-old male platypuses.

Mr Griffiths said one of the two-year-olds and the twelve-year-old were both yet to be named.

"We've been getting a lot of suggestions from the community, and the CMA will decide on that after a bit of time," he said.

Mr Griffiths said three platypuses was the number he had been hoping for going in to the survey.

"It's a reminder that this is still a small and fragile population," he said.

"Platypuses are slow to breed so it is going to take a long time for them to recover from the Millennium drought and Grampians bushfires. We also had summer floods in 2011 and are not sure how many survived - particularly the juveniles who would have still been in their burrows."

A spokeswoman for the Wimmera CMA said platypuses bred between August and October.

She said the babies hatched within two weeks and remained in the burrow with their mothers for about four months before emerging as juveniles from February to April.

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