I suggest the fish catch from the Coorong and Lower Lakes is insignificant compared to ocean fishing and the potential of sea cage fish farming in bays. It is an attempt to justify the extraordinary amount of river water the present diversion requires. If I recall Tim Flannery points out the lower lakes evaporate 1900 GL a year, water that could be used in upstream agriculture.

The barrages that prevent seawater incursion are unnatural. They will eventually be overwhelmed with 1.2m sea level rise predicted this century. The Murray channel should have a salt barrier weir built and the barrages opened. Whatever happens then will be less unnatural. Some fish species will find it to their liking and anglers will adjust their expectations.

Drain the lake.
Turn the rotten rotting foreign fish into fertilizer.
Refill and restock the lake, with native species!
If there's another solution?
And, could there be a more admirable task, for PM Abbott's new green army?
Rhrosty.

Whatever you say Jenifer is totally ignored and people like Rhosty start on about "Rotten foreign fish". I would point out that nature abhors a vacuum and will fill it with whatever likes that environment. Pine away for Aussie fish all you like but they cannot live in the rivers with locks etc. Natives need flood and drought to thrive. That's why Carp and Redfin are prevalent. Kill all the foreigners (That has been done at so much cost in other places) replace with Aussie natives and in a few years no natives only rotten, well you know!
We really need to take these charlatans in the guise of scientists to task. By that I mean SLASH funding and keep slashing it until it sinks through their heads who is paying them. Not the Greens and certainly not any of the plethora of "Environmental" groups that grow on our taxes.

Just a couple of points of clarification…

JBowyer, what Rhrosty is advocating is perhaps the removal of the barrages/opening of the barrages so the dammed estuary could be flooded with seawater, at least during drought.

If this were allowed to happen the "foreign" carp could be replaced with native species, in particular the Mulloway. It would be that simple!

A wave dominated barrier estuary like the Lower Murray is not meant to experience drought as it did recently, if the barrages had been opened the sea would have flooded in. Instead the barrages were kept closed and the lake waters receded.

Meanwhile the Australian Broadcasting Corporation (the ABC of propaganda), quoting experts from the CSIRO, pretended that the problem was over extraction upstream. There was no water upstream to grow rice or cotton. There was drought upstream. But there needn't of been drought at the estuary because the Southern Ocean could have pushed in.

On a big tide the ocean would have bought mulloway, and washed away the carp.

Yes. Cut the funding to the ABC and also the CSIRO and also SARDI. As a nation we would be so much better off without these rent seekers who hide the truth or distort the truth for their own self interest and continued employments.

"Hardly a week goes by without another announcement from government that additional millions of dollars will be spent ostensibly improving the environment of the Lower Murray. Such announcements are popular with the general public in South Australia. They mostly believe the propaganda that the Lower Lakes really do represent a wetland of international importance and that government expenditure can somehow buy further improvement. In reality their dammed estuary, known as Lake Alexandrina, surrounded by rabbit-infested farmland and overpriced housing estates is brimming with invasive European carp (Cyprinus carpio) and the voracious predatory English perch, otherwise known as redfin (Perca fluviatilis)."

If only more South Australians visited the dammed ( or should that be damned) estuary -- as I did 18 months ago -- they would soon realise that they were being conned by the propaganda propagated by the SA Government.

Taswegian, make that closer to 3 metres!
Cheers Rhrosty.