Tuna fishing methods include Purse seine fishing, Fixed-net fishing, Drift-net fishing and Longline fishing, among others. Ocean fishing for tuna in the South Pacific Ocean, Indian Ocean and Atlantic Ocean, is often done by longline fishing. A main line can exceed 150 km in length and have over 3,000 hooks hanging from it. A main line is let out for 6 to 7 hours, and it takes 3 to 4 hours from running the line in the sea, to catching tuna. After that it takes another 10 to 15 hours to reel it up, so the tuna that was caught early may have already died during this time. There are times when sea water may feel warm to the touch, even in the dead of winter. The problem here is, that the body of the tuna that died early, will be warmer if the sea water is warmer. The body temperature will also be unusually high if a tuna caught by a hook ends up struggles for a long time and dying before being reeled in. The same is true for Kuromaguro caught in game fishing.
When this tuna is cut into pieces, the meat is whitish, as if grilled in a fire, so it is called “Yake (焼け)” or “Yake-maguro (焼け鮪)” as “Yake” means “burnt” in this case. The meat can also be a grayish-brown. In the industry it’s known as “White tuna” due to its color. It loses its characteristic red color, the texture of the meat when eating it is flakey and it doesn’t taste good.
Even if the fish body is cooled with ice water after catching, once the meat has been “burnt”, it won’t turn back to red. This renders even the premium Pacific bluefin tuna and southern bluefin tuna worthless, with zero commercial value as food. However, the fishermen don’t just toss the dead fish back into the sea without a second thought. This is mostly processed into pet food. Also, since it can’t be determined externally whether the meat is “burnt” or not, no one can tell until the fish has been cut open. It runs a big risk to the broker and can be a cause of its fishing port brand losing credibility.
It is currently believed that burnt tuna occurs from high temperature and low pH in the muscles of the fish after death, and that there is a complicated, indirect causal relationship between the conditions such as the environmental temperature, fishing method, handling of the catch, length of processing time, type of fish and size of fish. However, the mechanism that causes this phenomenon is not clearly understood.
Related contents: TYPES OF TUNA
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Revision date: March 1, 2022
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No people in the world love squid more than the Japanese. Squid ranks third in import volume behind shrimp and tuna. Squid is brought to Japan from the oceans all over the world. There are between 400 and 500 species of wild squid on Earth. Some, like the pygmy cuttlefish, are tinier than 3 millimeters while the giant squid is over 10 meters.
It’s won’t hurt you to eat Magaki (Japanese oyster), which has its spawning season in the summer, but in the months with no R in the name, the glycogen concentration is low, so you can’t get the full-bodied texture that you get in winter. In addition, almost all amino acids such as glutamic acid, glycine, alanine, arginine, which are important components for delicious flavor, are known to accumulate from winter through spring, and conversely, they decrease in the summer, which is the spawning season. You cannot expect the same deliciousness from oysters in summer as you can from months that contain the letter R.
Naturally, the cost price is what it costs the restaurant for the ingredients while the price on the menu is the selling price. The ratio of these two prices is called the cost rate. In the case of a sushi restaurant, the ideal cost rate is 35% or less. A restaurant operating with only Omakase will have a cost rate of 40% with a focus on the quality of the toppings.
First of all, sushi rice made for Inarizushi can be used for a wide variety of uses including Uramaki and Chirashizushi, so it could be useful to learn. However, the recipe is slightly different than Nigiri sushi. The reason is that in the case of Nigiri sushi, the topping is typically one type of seafood combined with a sushi rice recipe that maximizes the flavor of that seafood. On the other hand, Inarizushi, Uramaki, etc., are filled with optional ingredients put together to enjoy multiple layers of flavors spread in your mouth. The sushi rice is essential to harmonize all the ingredients. Therefore, it is made with more sugar than Nigiri sushi. In addition to toning down the sourness of Vinegar, the sugar’s own richness works to bring out a mellow taste. Kombu is also added to the rice while it is cooking. The aim here is to create a synergy between the Inosinic acid contained in Kombu and the Umami of the other ingredients.
① Spread the deep-fried tofu on a cutting board and roll it out with a rolling pin until it is completely flat. This helps to loosen the inside of the deep fried tofu so it will open easier. It might seem like a hassle, but it will help you make Inarizushi that looks even better.
For example, every Frenchman knows that 
Famous for its Belon brand name, the oyster native to Europe has a flat, rounded shell. It belongs to the genus Ostrea. To be honest, Belon oysters aren’t sweet and don’t have a distinguished flavor compared to Japanese oysters, and the salty fragrance of the sea is dulled, so it can seem less flavorful.
Among the many sushi toppings, Pacific bluefin tuna, and actually the Madai (Red sea bream) as well, are toppings that are difficult for an amateur to tell whether it is farmed or wild. However, there is no need to worry about that when it comes to Tako (Octopus). There are no octopus farms to be found in the world, so it is a 100% wild topping.
Amateurs can’t tell the difference between domestic Tako or African imports. However, there is one aspect that even an amateur can use to distinguish between the two. There is one condition for this to work, and that is that at least one of the suckers is in-tact. The suckers are scraped off for most toppings, but in cases where they are sliced by the restaurant, there are often suckers remaining. If the sucker is pure white, it is almost definitely from Africa. Meanwhile, domestic Tako suckers maintain a faint red color in the suckers, even when boiled. The reason the suckers turn white seems to be an effect of the food preservatives added during processing, but this has not been confirmed.
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Toro is an absolute at sushi restaurants and it’s only natural to aspire to such a position. That’s why there are so many sushi dish names that start with “Toro”. The most laissez-faire of these is Toro salmon. In this case the definition of Toro is ignored in an attempt to promote sales. Just as bad is Toro katsuo (pronounced “Toro-gatsuo” in Japanese).
Japan leads the world in shrimp consumption by far. Most of the shrimp is imported, but it is a little known fact that shrimp is called “Meki” among importers and sushi restaurants in Japan. It is said to be a remnant from a time when much of the imported shrimp came from Mexico (pronounced “Mekishiko” in Japanese).
Hirame is a high-quality fish that goes for at least US $50 per kilogram. It can even exceed US $80 per kilogram, depending on the timing and the fish’s body.
Ishigakigai is a shellfish found from Kashimanada northward, Hokkaido, from the Kuril Islands to the Aleutian Islands and even on the west coast of North America. It lives off of plankton in the shallow sandy mud bottoms of the sea at depths of about 50 meters.
It starts to become common at the market when the Japanese rainy season ends, at the beginning of summer every year, which is around the end of the Torigai season. It then disappears from the market at the end of summer. A number of sushi restaurants start using it as a substitute for Torigai all at the same time, so Ishigakigai nigiri sushi suddenly started appearing on menus. Frankly, it is somewhat conservative as a nigiri topping but is known for the crunchy texture when biting into it. It also has strong sweetness and umami, which goes exquisitely with Shari. The sushi chef slaps the meat in his hand directly before serving to stiffen it–a way to increase the crunchy texture characteristic of shellfish. Naturally this texture is evidence of its freshness.
It goes without saying, that each type of fish has its very own scientific name. However, in places like the Toyosu Fish Market, there are seafoods that end up sharing a name.