My own feeling is bounties and rewards for hunting or fishing do help but dont accomplish the goal. Pigs are invasive animals in about half the states and as far as I know unlimited killing hasn't removed them all. Nature finds a way to continue especially when an invasive only has man as its predator. It had been shown that wild pigs cant be contained and when they do escape cant be eliminated totally. These snakeheads can breath air so they can exist outside water for a period of time. Once fully grown they dont have many enemies other than man. Most of the places where they have shown biologists killed off the lake in order to remove them.