To posses Yellowfin or Bluefin Tuna as a sport fisherman in the Gulf of Mexico you need a Bluefin Tuna permit. It costs $18.00 and you can take care of part of it right her on the internet. You can aslo obtain the permit via the telephone. The number is 1 (888) usa-tuna or 1 (888) 872-8862. option 1, 3, 1. The permit is called a Atlantic Tuna Permit and covers Yellowfin and Bluefin Tuna.
To read the regulations and/or apply for your permit via the internet go to http://www.usatuna.com/
Be sure to read the following sections
Bluefin Tuna Permit Requirements: (a) Permit requirements. A vessel that fishes for, takes, retains or possesses Atlantic bluefin tuna must have on board a valid permit issued to the vessel owner under this section...
Other Atlantic Tuna Regulations (a) Permit requirements. The operator of each vessel that fishes for, or takes, Atlantic yellowfin, bigeye, albacore, and skipjack tunas and Atlantic bonito must have on board a valid permit issued under this section...
[ Purchase a New Permit ] [ Renew or Update an Existing Permit ] These sections are near the bottom of the form.
Should you apply via the internet be aware that ther is a documnet that you must mail to the address provided before your actual permit is issued.