live bait

Bait Limitations

Recently I've been wanting to target flathead catfish & after doing some research I've found that they almost exclusively eat live bait & cut bait. But when cut bait isn't available why can't I use live bait? Is it the worry of invasive species? I mean you guys let us use live cray fish as long as they're caught in the same body of water you're fishing, why not do the same with the bait? Is there any such thing as a live bait permit? Thanks in advance.