"Back in the day" WDG required that every steelhead be punched. The limit was 2 per day, whether released or killed. It also included kelts. You C&R a kelt and that was supposed to be punched. This "each fish counts to your limit" applied to all species. I think the trout limit was 6, and when you had brought 6 to hand you were done.

New Zealand is noticing a problem with C&R on Brown Trout in some rivers. The fish are sore mouthed to the point that they are thin from not eating. One suggestion was that the limit be X fish per day, regardless of kept or released.