CB1 you are correct on both counts. It does differ some from state to state. If you are a licensed fish producer you can do things under state regulations that others can't. In some cases Fed. regulations come into play such as saltwater fish, US owned waters or trans-state waters or sales. Some states allow no one to sell game fish for food to commercial business (restaurants) some allow it under permit. Those that don't then leave out food fish like catfish , farm raised trout or tilapia, etc from the definition of game fish so they can be sold. Most public waters are managed under separate regulations or plans. Sales to other countries by commercial operations are subject to separate plans usually under treaty/international governing standards etc.

One of the things most states are trying to stop is the impact on public and private waters that occurs when some people try to harvest game fish (LMB ,BG , Crappie) and sell them for public consumption. They do this by harvest regulations , sales prohibition and licensing of sellers and restaurants.