The tail is the first place to chill down, so it should be the best looking part of the fish. Next, a core sample is taken from right underneath the fin all the way through the belly. This is the last part to chill and also the last to go bad, making it a great indication of quality.
Dragging is a crucial step of the process which is often neglected. Dragging is when you tail-rope your tuna and drag it behind the boat at a slow pace. This process allows your catch to cool down as they have just fought a hard battle, and their internal temperature has risen well beyond average.
The third is a tail cut, which you should only do if you are bleeding the fish on deck. Make a shallow cut across each side of the fish in the tail region between the 3rd and 4th dorsal finlets (Fig. 2 ). Again, cuts should only be deep enough to sever the main artery located just under the skin in the mid-line.
Bluefin are endothermic—capable of producing their own heat. During the stress of capture they can become so hot they literally cook themselves, a phenomenon that buyers call “burn.” This can only be avoided by raking the freshly caught fish's gills and bleeding it out.
The price per kilogram was JPY 80,000 (USD 690, EUR 610). For comparison, the current market price for fresh bluefin from Aomori Prefecture is normally JPY 17,000 to 20,000 (USD 146 to 172, EUR 129 to 152) per kilogram.
Fish safe to eat raw
Tuna: Any sort of tuna, be it bluefin, yellowfin, skipjack, or albacore, can be eaten raw. It is one of the oldest ingredients used in sushi and is regarded by some as the icon of sushi and sashimi.
Kill and Bleed the tuna
Commercial fishermen tend to slide the arteries located just behind the pectoral fins and place the fish back into the water to bleed out over the next 10-15 minutes. This also helps cool the tuna while helping oxygenate the fish and preventing the issue mentioned above from occurring.
Because bleeding your fish helps get all the blood out – which produces tastier fillets. It's amazing how much better a well-bled fish tastes over a fillet that hasn't been bled properly. Plus, it's a humane way to kill fish quickly.
Tunas are caught by purse seine, long-lines, gillnet, pole & line and handline from coastal waters to high seas. Purse seine tuna fishing vessels will target free school swimming tuna or tuna attracted by man-made Fish Aggregating Devices (FADs).
Bluefin Tuna Quality
This is due to the high demand for excellent fish for sushi and sashimi. This fatty fish is especially prized for its toro cuts. These cuts are from the belly, which is the fattiest part of the cut.
Raw tuna is a common ingredient in sushi and sashimi, which are Japanese dishes made from a combination of rice, raw fish, vegetables, and seaweed. Tuna is a lean protein that contains omega-3 fatty acids as well as several vitamins and minerals. It's often served raw or barely cooked but is also available canned.
Tuna uses its tail to swim, so the tail meat is the leanest, containing the least amount of fat, therefore tastes less flavorful compared to the belly. Here is a top view and some side views of Yellowfin tuna. You see white tendon left side of this loin (just outside of the green line,) This part is too tough to chew.
The tail of a tuna is stiff, rigid, and has a bonelike density. Because of this, it is easy to preserve, and although it takes a good amount of time to do it right, it's an easy and inexpensive process.
The tail fin (called the caudal fin) is the main source of movement for most fish. It's like the motor on a boat. It shouldn't be surprising then, that it is shaped differently according to how the fish needs to move most of the time. This helps the fish to move more efficiently through the water.
Bleeding improves the appearance of uncooked tuna flesh, helps initially to reduce the fish's body temperature and also gets rid of all the bacteria located in the fish's blood stream that may foul the flesh. All tuna should be bled for 10 to 15 minutes after iki-spiking and then immediately chilled.
“The effervescence from soda pop swells the blood vessels on a bleeding fish and stops the bleeding.
If you cut a freshly-caught fish near major blood vessels, you will see red blood. But if the fish is old (i.e. store-bought), the blood may have coagulated, or the store may have drained out the blood during the beheading and gutting processes.
The tuna sandwich is a lunchbox staple. But several species of tuna — like other large ocean fish — contain higher-than-average amounts of mercury, a highly toxic metal that can cause severe health effects.
Though tuna is very nutritious, it's also high in mercury compared to most other fish. Therefore, it should be eaten in moderation — not every day.
Myoglobin changes color, however, depending among other things on how much oxygen is available to it. The dark, purplish red color of freshly cut tuna is due to deoxymyoglobin, which in air changes first to bright red oxymyoglobin and then to brown metmyoglobin.
And yes, ALDI actually carries sushi-grade ahi tuna in their freezer section: This 12 oz package with two good-sized steaks ran just $5.39 at my store. Wherever you shop, though, you'll want to be sure to look for sushi grade (also sometimes called sashimi grade) frozen tuna for this recipe.
Pacific salmon and tuna which have never come into contact with fresh water are generally safe to eat raw straight out of the ocean.
In comparison to Bluefin Tuna, Yellowfin Tuna meat is leaner, with a lighter taste. While it may lack the coveted fat content of Bluefin Tuna, Yellowfin meat is still of great quality. Yellowfin meat is great for sashimi and steaks. You can also find Yellowfin Tuna in tins.