This strikes me as a great use of genetic engineering. If it works, it will eliminate the problem species without harming any other species or introducing any new alien species.
There might be a problem with the larger bioregion, though:
Fixing one feral problem often triggers another. When foxes were eradicated from a west coast peninsula two years ago, the cat population soared.
If the carp population is linked to some other harmful competitor, destroying the carp could lead to a harmful boom. But the scientists think they'll have plenty of time to work around that sort of problem -- wiping out the carp will take over 20 years of continious stocking. If something goes wrong, they can simply stop stocking daughterless carp and the geneticly engineered fish will quickly become extinct.
I look forward to seeing the results of this experiment.