I think the only way to stop it, which may ultimately prove unsuccessful anyway, is an all out war with $Billions and $Billions from the Government. That may mean essentially closing down the areas affected and near areas affected, so the $Billions are not just on the eradication scheme but also compensation for businesses affected from the loss of marine tourism.
But - can you see that happening with the current three headed monster running the ship? They won't even part out the $ for a decent set of Ferries for Cook Strait.
And no mods,not trying to turn this political, just stat