I like to be in a constant state of learning. Practice and exposure to other techniques has helped me dial in a system for cleaning a particular fish. After cleaning thousands of tuna, I found that using this technique helps you speedily get through your catch, gives good access to the “meat” and produces clean, ready-to-eat meat.
This is How I Clean Tuna Fish
Start by slicing down behind the head/gill area until you hit the spine.
Slice towards tail along the back, only an inch or so in.
Start slicing along the belly the same way you did on the dorsal side of the fish and connect up to the gill slice.
Continue this 360-degree slice inward using the bones as a guide until you meet at the spine. Cut a hole for your finger by poking the knife through the tail-end of the meat.
Now stop slicing on that side, flip the tuna over and repeat on the other side. Leaving both sides intact supports the fish, making it easier to slice the uncut side.
The meat on both sides should only be connected right on top of the spine. Lift the meat with your finger in the hole and slice the connection towards the head. I use this method on most larger fish.
Repeat on the opposite side and toss the carcass. Any meat left above the spine makes great sushi!
Remove the rib section, slicing at an angle to save some meat.
Now we have two sides with bone and dark meat down the center. Using the finger hole, slice down through the skin on either side of the bones in the center line
Cutting down the center on either side of the bones will remove the largest portion of the bloodline and the bones in the middle of the meat.
Remove the meat off of the skin. Start with half of the fish. On a big fish just do a 10-inch chunk at a time.
You should have two loins with no bone but a concave piece of very dark meat. This dark meat is the oily, fishy portion of the meat and needs to be removed. Trim this out in small slices taking a little at a time until you hit the lighter meat.
You can slice these loins into steaks of your desired thickness. Cook medium-rare to retain the tuna’s moistness. Tuna will continue to cook after you place the meat on a plate so take it off the heat while it’s still red or rare in the middle.