Culling

Any fish you catch is included in your daily limit unless you release it unharmed immediately. You may not replace smaller fish in your possession with larger ones caught later. You need to make a keep-or-release decision as soon as the fish is caught.
There is one exception: if, from September through June, you are a participant in a bona fide catch-and-release black bass tournament (one after which all bass are released alive) that requires entrants to have a boat livewell with adequate capacity and a pump constantly adding fresh or recirculating water, the black bass you release unharmed from the livewell need not be included in your daily limit. At no time may the daily limit be exceeded.

https://huntfish.mdc.mo.gov/fishing/regulations

(Don't know if the below includes fish too. But I think it may)

Excessive waste


Excessive waste

It is illegal to intentionally leave or abandon any portion of any wildlife that is commonly used as human food.
Possessing, transporting, and storing wildlife

You must keep any wildlife you take separate or identifiable from that of any other hunter.
You can possess and transport wildlife as part of your personal baggage. It may be stored at your home, camp, place of lodging or in a commercial establishment.

https://huntfish.mdc.mo.gov/hunting-...ng/regulations