[Stig]

The concept of only letting them produce male offspring is a wonderful theory however for their problem with Carp IMHO that is all it will ever be as there will always be at least a few if not many natural males around which a fully functional in producing both genders . Nice idea but it will never happen . Even if it did work nature will always find a way and fish can change gender if the continuation of the species requires it . Nice idea surrounded by a lot of big words but in reality IMHO it will fail as to make it work you have to erradicate the natural males that are already there .
Fish eggs can be transported on birds plumage and legs many hundreds of miles . Bird then lands on lake or goes paddling in lake fish eggs are dropped and the whole process starts again .

Admittedly from an Aussie point of view it was a big big mistake introducing Carp to their waters but roach and perch are also present .Also trout are an introduced species .The Carp are the thorn in the Australians sides but they are there and short of poisioning every water ,river,pool and puddle in all of the land they are there to stay . Without destroying every other species in every water the best that can be done is control and with the ideal spawning conditions that Austrailia offers the remaining carp could spawn 2 or 3 times in the following year producing probably many billions of offspring over every carp infested water nationwide.

On the brighter side when in roughly 5 billion years time when our sun starts running out of fuel and it expands stripping all the atmospheres off all the inner planets life in all forms will cease to be and Australia will then be carp free . Until then they should just accept the errors of their forefathers and let nature take its course