they have destroyed most of the recreational fishing.
http://www.abc.net.au/news/2016-05-01/herpes-to-eradicate-carp-in-murray-river-pyne-says/7373736
a csiro tested strain of herpes is about to be unleashed on the pests, hopefully erradicating most of them.
there is one item in the article that rankles me because I know it is false.
Carp were first introduced to Australia in the mid to late 1800s, and are now found in every Australian state outside the Northern Territory.
Widespread flooding in the 1970s helped spread the pests throughout the Murray-Darling system.
in victoria they were introduced by a stupid farmer who imported them under the noses of the biosecurity at the time and had his farm dam stocked with them.
why he did it is anyones guess because the bloody things are inedible.
it was flooding in the 1970's during a particularly wet year that overflowed the dam and saw them swept downstream into the murray river.
I lived in albury during the time the pestilence first started and saw the encroachment first hand.