Mich. Comp. Laws § 324.48722: Game fish; carried as open hand baggage; transportation.

Sec. 48722.

A resident or nonresident who holds an unexpired fishing license issued in his or her name may carry as open hand baggage not more than 1 day's legal catch of fish. However, any person holding an unexpired fishing license may obtain only 1 permit from the department authorizing that person to ship 1 day's legal catch of any species of game fish or combination of species. The catch of 2 or more licensed anglers may be combined in a single package. However, the permit of each angler whose catch is combined in the package shall be attached to the package.