Bird numbers in the region have fallen dramatically and freshwater turtles continue to die in large numbers.

Professor Richard Kingsford said estimates of waterbirds for the region were 250,000 in November 2007 but a similar survey last year showed numbers had declined 48 per cent.

Professor Kingsford, who also advises the Federal Government on the Coorong and Lower Lakes, said one of the most disturbing developments in the wetlands has been the explosion of tubeworms in the freshwater lakes. The marine worms attach themselves to the backs of the turtles, colonising them until they are so weighed down they drown.

''It is the most poignant example of the collapse of the system,'' he said.

''Because there is not enough fresh water coming down the river, the lakes are becoming more salty and this marine tubeworm is invading the freshwater lakes.''

''Down along the lakes there are schoolchildren that go out and try to rescue them with buckets and try to chip off the worms. That tells the story about what is happening in this system''.

Professor Kingsford and five colleagues, including Keith Walker from the University of Adelaide, are calling for a radical reappraisal of how the Coorong, Lower Lakes and Murray mouth in South Australia can be saved by a massive injection of water into the Murray from eastern states.

Flows to the mouth of the Murray have been declining for decades as dams and irrigation have siphoned off water in upstream Victoria and NSW.

But in recent years the flows have dropped so much that several of the lakes have fallen below sea level and the Murray mouth now needs continual dredging.

The report argues strongly against plans under consideration by the federal and SA governments to flood the lakes with sea water because of their rapidly increasing salinity. They say seawater flooding would signal that governments are giving up on the region as as freshwater wetland that supports vast numbers of bird and animal life.

Professor Kingsford and Professor Walker argue that instead the federal and state governments should aim to bring 3800 gigalitres (a gigalitre is a billion litres) back into the system.

But a spokesman for Climate Change Minister Penny Wong said last night that the report would be rejected because, to do otherwise would be ''highly irresponsible''. It would require a total ban on drawing any water from the Murray or the city of Adelaide or towns, cities and irrigation along the river.