Sydney, Mar 19 (IANS): An emergency operations centre has been activated in Menindee, a small town in the far west of Australia's New South Wales (NSW), to facilitate multi-agency operations, after millions of native fish were found floating down the Darling river.

The NSW Police Force said on Sunday that the massive fish deaths are believed to be attributed to hypoxic blackwater, a naturally occurring phenomenon that causes extremely low dissolved oxygen levels, Xinhua news agency reported.

"The scale of this event has been exacerbated by recent hot weather and significantly increased number of fish in the system as floodwaters recede," the police noted.

According to the police statement, authorities are continuing to release higher-quality water to boost dissolved oxygen levels in this area, while the emergency operations center (EOC) was established to ensure fresh and clean water supply as well as to coordinate the removal and disposal of fish.

NSW Police Force Assistant Commissioner Brett Greentree, who oversees the centre, pointed out that numerous agencies are already on the ground in the area with more on the way to conduct and support operational activities.

"Significant planning, including risk assessments, is already underway for clean-up efforts, which will include the removal of as many of the dead fish as possible, prioritising the immediate areas around Menindee, as well as other areas deemed high-risk in terms of water supply," Greentree said.

"While this will require specialised skills and equipment, experts in the EOC have already identified suitable contractors, and it is expected work will commence this week," he added.

On Friday, the NSW Department of Primary Industries (NSW DPI) confirmed on social media that the agency is aware of a developing large-scale fish death event on the Lower Darling-Baaka below Menindee Main Weir through to Weir 32, adjacent to the Menindee township.

"It is estimated that millions of fish, predominantly Bony Herring (Bony Bream) have been affected, as well as smaller number of other large-bodied species such as Murray Cod, Golden Perch, Silver Perch and Carp," said the department.

Cameron Lay, Director of freshwater environments at NSW DPI, told local media that the situation is "very distressing".