Are you using jigheads? Try using a weighted hook. That may get the barb closer to the end of the soft plastic...i.e. Stingers
I was using a Strike King Redfish Magic spinner jig with a New Penney Gulp shrimp on instead of the original plastic. Has been a "go to" for years for me for inshore redfish and trout.
The bait thieves are only nipping about 3/4" off the tail. I can see small mouth patterns. I have seen guys catch small trash fish, piggys, pin fish, etc. with small hooks and chunks of Gulp.
I think next time out if it is still a problem I will throw a #8 hook on my fly rod and catch some of these little thieves. Then I will cut up their carcass and fish it under a popping cork.