To transport another person's sport-caught fish you must carry a letter from that person with their signature, stating you are authorized to transport the fish. Check with customs officials in your country of residence for regulations concerning the importation of your catch.
The letter must state:

• the fisher's name
• complete address
• telephone number
• fishing licence number
• when and where the fish were caught
• the number, species and size of fish
• name of recipient
• address of recipient
• date of receipt