The Savage V-24 in 30-30/12ga is my favorite survival gun. It also was my first gun back when I was a teen. Just one problem with it, it's awful heavy. I am afraid that the tendancy would be to leave it leaning against a tree, or on the bank while you fish.
Is it enough gun? Well that depends, if you can wait till the target is real close. YES! The 12ga that is. The 30-30 is a little light for most things here.