Hundreds of flood-affected Murray crayfish have undergone a Cinderella-like transformation after being rehabilitated in the New South Wales Riverina.
Five weeks ago, nearly 1,000 of the crays were rescued from the Murray River by NSW Department of Primary Industries (DPI) officers, anglers, environmentalists and local residents.
The crays were leaving the water because of low oxygen levels due to the influx of organic material swept into the river during recent flooding.
Most of the crayfish went to the Narrandera Fisheries Centre, with the rest going to Charles Sturt University in Albury and a private aquaculture facility in Mildura.
DPI Fisheries senior manager Luke Pearce said that was a strategic move, as the crays make interesting house guests.
"We had to stop them attacking each other and they will actually kill each other," he said.
"They can be quite aggressive, particularly when they're kept in high densities in captivity," he said.
Staff at the Narrandera Fisheries Centre were tasked with providing the crays with lots of clean, highly oxygenated water to allow them to recuperate, along with a healthy diet of carrots, cucumbers, broccoli and cauliflower.
Crays returned after 'amazing' transformation
Last week they were returned to the Murray, and Mr Pearce said the crays transformation was remarkable.
"When you catch them out of the river, they kind of look pretty grubby. They have algae and grim on them, but after spending five weeks in really clean, fresh water and being fed really well, they looked really clean," he said.
"You could see colours and patterns. They're a really quite spectacular animal, bright blue, some were turquoise.
"I didn't even realise that they were that colourful, because I'd never seen them so clean before."
"It was kind of like they had a spa treatment, then we released back into the wild, like they were going out to the ball. It was amazing, they looked amazing."
The crays were released hundreds of kilometres upstream from where they were collected, partly because water quality is still poor in some parts of the Murray and to help the species future survival.
"We moved them up to merge some genetic material upstream, where they can't get now because the Torrumbarry Weir is in the road, " Mr Pearce said.
"It's going to give a boost to the genetic diversity if the population in that upstream area, which will help with the long-term survival of the species."
