Why can't I release fish held in a livewell at the end of a fishing outing?

If allowed, fish that were stressed (e.g. on stringers, in livewells, etc.) would experience delayed mortality after being released. The fish may swim away but may not be healthy and would eventually die. Further, if the release of fish at the end of the day was allowed, it could possibly lead to high-grading or culling. High-grading is the practice of selectively targeting fish – catching a fish, reducing it to creel (e.g. in a livewell), and then later releasing the fish after catching additional fish of a more preferable size. High-grading is and has been against the law for at least the past 60 years in North Dakota. Allowing for some release of fish after being reduced to creel, would complicate enforcement, and greatly confound the overall fishing regulations, as additional restrictions may be the result.