• Local rainfall, cooler temperatures and care from Charles Sturt University researchers means rescued Murray crayfish can be returned home

Charles Sturt University researchers who have been nursing Murray crayfish rescued from the Murray River below the Hume Dam late last month said the recent cooler weather has made it safe for the crustaceans to return home.

The crayfish were returned to the Murray River below Hume Dam on Wednesday 31 March by Charles Sturt and NSW DPI Fisheries staff members who had rescued them a month earlier and taken them to be housed and fed at Charles Sturt’s new aquatic research facility in Albury-Wodonga.

According to Fish Ecologist in the Charles Sturt Institute for Land, Water and Society (ILWS) Professor Lee Baumgartner, many crayfish died before staff from the NSW DPI Fisheries intervened.

He said at the time the oxygen in the water was too low for the crayfish to survive. But with the cooler temperatures and improving conditions at the Hume Dam and in the river below, along with their health restored, thanks to a team of the University’s researchers, the crayfish are now ready to return home.

“Over the past couple of weeks, the Hume Dam has de-stratified as a result of the cooler weather we’ve been experiencing,” Professor Baumgartner said.

“This means that the water and conditions have improved for our aquatic life.

“But just because we’ve had recent rainfall doesn’t mean the water issues with the Hume are now fixed.

“There is still significant bushfire silt and sediment in the upper catchment. We need to be exploring options to de-stratify Hume Dam or otherwise we will be right back in this position, where we need to rescue aquatic life such as these crayfish, again next year.”

ILWS researcher Dr Katie Doyle, who helped care for the crayfish said when they first arrived at the facility, staff were shocked by their appearance.

“The crayfish were sluggish, coated with a brown film (from the high iron and manganese levels), and took several weeks to settle,” she said.

“Firstly, it was about ensuring we provided good water quality for them to recover. It was then about feeding them and ensuring they strengthened to the point where they were ready for release. It has been a long process watching them recover from the brown film.

“Overall, this collaboration with NSW DPI Fisheries has had a great outcome, lives have been saved and it was very rewarding to watch the now-healthy crayfish be released back into their natural environment .”

The crayfish were rescued from the Hume Dam by trained staff from the NSW DPI Fisheries. Charles Sturt University fed and housed the crayfish at one of its aquatic facilities under permit from Fisheries.