No it's not wrong. Killing with a "good" reason is not wrong. Broken down simply they are attaching your property-your livelihood - your power.
Regarding catch and release. When Gophers were digging up my dads land so bad he couldn't even run a swather safely because of gopher holes, he hired me to shoot them for like 10 bucks a gopher or something. I got about 10 or so, left the bodies out in the field. Guess what, no more gophers - they all fucked off. There was waaay more than 10 of the little bastards on 2 sections of land. The rest probably lived happily ever after, on some Dairy farmers land.
Did your dad ask you to do it because he couldn't kill them himself? or he just couldn't be bothered. In situations like this I agree it is for a good reason. I don't however agree with these hunters who head out with their buddies, get drunk and go into the woods for a day of shooting practice.