Captain Kevin Beach of The Mexican Gulf Fishing Company takes you through the steps of filleting a yellowfin tuna after catch. Beginning with a really sharp knife, start cutting under the peck fin. Begin at the bottom fins and cut around and underneath the peck fin all the way towards the eyeball of the yellowfin. Then make a cut on the tail to the spine. For this tail cut, when your knife gets to the finlets on top of the tuna, turn the knife to cut along the spine bones towards the top of the tuna at about a 45-degree angle. Next, cut along the bones on the lateral line, down the yellowfin’s side. Cut deeply, straight down to the tail. Pull out the cut piece. You should have a clean cut along both sides of the bone – side and spine. Now you want to cut the underside of the tuna. Cut straight down the other side of the lateral line down to the tail. On the bottom cut, you want to cut on top of the ribs down to the anus at a 45-degree angle. Once the meat is pulled off the fish, trim off the dark blood line and store in gallon bags, icing immediately.