CANBERRA, May 16 (Xinhua) -- An iconic crustacean species has been reintroduced to South Australian wetlands about 40 years after being wiped out.
Researchers on Tuesday started releasing Murray Crayfish back into the River Murray system in the Australian state of South Australia (SA) after a decade of research and planning to re-establish the species in the state.
Once common in the river, which is Australia's longest and also flows through Victoria and New South Wales (NSW), overfishing and pollution caused the demise of the species in SA.
It was last spotted in the wild in SA in the early 1980s, prompting it to be declared virtually extinct in the state.
However, recent floods in the area have improved conditions and hopes that the crustaceans can again thrive.
Two hundred individuals saved from blackwater events in NSW, where organic material was washed into the river causing an increase in dissolved carbon, were released at an undisclosed location in SA on Tuesday.
Darren Willis, the wetlands team leader at the Murraylands and Riverland Landscape Board, said it was an exciting step but stressed it was important the species is not disturbed.
"We'll release 200 this year and then another 200 each year for the next four to five years," he told News Corp Australia.
"One of the key messages is while people are excited -- and a lot of fishermen are -- what we've got to say is be excited but don't go and try and catch them straight away."
"It's going to take us 10 years before the population establishes itself and becomes more robust. That's why we aren't disclosing where we are releasing them."
Murray crayfish grow to 30 centimeters in length, making it the second-largest freshwater crayfish species in the world.
A number of those released on Tuesday were fitted with trackers to allow for monitoring.
Nick Whiterod, a senior aquatic ecologist, said he was optimistic the release would improve understanding of conditions required for the crayfish to become self-sustaining. ■
