Tetraodontidae

This article is about the fish. For the cipher, see Blowfish (cipher).

The fish

There are 185 known species of the Family Tetraodontidae, of which 38 can be found in Japan, and 25 species belonging to the group Takifugu (also known as fugu). Fugu can be found worldwide from about 45° latitude north to 45° latitude south, mostly in salt water near coral reefs or the shore, but some species also live in fresh water or brackish water.

The pear-shaped pufferfish is not a very good swimmer, and uses mainly the pectoral fins for propulsion. Pufferfish appear to be rowing themselves along with their undersized fins, which do not allow them to escape predators very well. In case of danger, the fish inflates itself by filling its extremely elastic stomach with water (or air when outside of the water) until the fish is almost spherical (hence the name blowfish or pufferfish) with spines sticking out. The fish's main defense, however, is the neurotoxin contained in its internal organs, mainly the ovaries and the liver, to a lesser extent in the intestines and the skin, and only minute amounts in the muscles and blood. This makes the fugu a lethal meal for most predators, including the occasional human.

The toxin is called tetrodotoxin, or more precisely anhydrotetrodotoxin 4-epitetrodotoxin and is about 1200 times deadlier than cyanide. This poison can also be found in other animals such as the Blue-Ringed Octopus, Cone Snails, or even some newts. The pufferfish does not create the poison itself; rather it is generated by the bacteria Pseudomonas within the fish. The fish obtains the bacteria by eating food containing these bacteria. Pufferfish that are born and grown in captivity do not produce tetrodotoxin until they receive some of the poison-producing bacteria, often by eating tissues from a toxin-producing fish. Also, some fish are more poisonous than others. A poisonous fish has enough poison to kill 30 adults.

Tetrodotoxin is a very potent neurotoxin and shuts down electrical signaling in nerves by binding to the pores of sodium channel proteins in nerve cell membranes. It does not cross the blood-brain barrier, leaving the victim fully conscious while paralyzing the remainder of the body. In animal studies with mice, 8μg tetrodotoxin per kg body weight killed 50% of the mice. The puffer fish itself has immunity to the poison due to a mutation in the protein sequence of the sodium channel pump on the cell membranes.

Apparently due to some unknown selection pressure, intronic and extragenic sequences have been drastically reduced within this family. As a result, they have the smallest-known genomes yet found amongst the vertebrate animals, while containing a genetic repertoire very similar to other fishes and thus comparable to vertebrates generally. Since these genomes are relatively compact it is relatively fast and inexpensive to compile their complete sequences, as has been done for two species (Fugu rubripes and Tetraodon nigroviridis).

Fugu are also one of few kinds of fish that can blink or close their eyes. (Some claim the fugu is the only fish that can close its eyes, but certain attacking sharks close their eyes to protect themselves from struggling prey).

Consumption

The people of Tokyo at the Tsukiji fish market buy fugu rubripes — after the highly toxic liver has been removed.

The most prestigious edible pufferfish is torafugu (also known as Fugu rubripes or Tiger Blowfish), which is also the most poisonous. However, other species of the genus Takifugu are also consumed, as for example the fugu pardalis, fugu vermicularis, and the fugu vermicularis porphyreus. The table below shows which species contain body parts that can be consumed according to the Japanese Ministry of Health and Welfare. In addition to that, other genus in the family Tetraodontidae contain pufferfish that can be consumed according to the Japanese Ministry of Health and Welfare, namely some fishes in the genus Lagocephalus, Sphoeroides, and Diodon.

Fugu has been consumed in Japan for a long time, although its historic origins is unclear. Bones of fugu have been found in several mass garbage burial sites called kaizuka that date back more than 2000 years, but the fate of those who ate these fish is unknown. The Tokugawa shogunate (1603-1868) prohibited the consumption of fugu in Edo and its area of influence, yet it became common again as the power of the shogunate weakened. In Western regions of Japan, where the influence was weaker and fugu was easier to obtain, various cooking methods were developed to safely eat these fish. During the Meiji Era (1867-1912) fugu was again banned in many areas of Japan. Fugu is also the only delicacy officially forbidden to the Emperor of Japan, for his own safety.

A rakugo, or comic short story, tells about three men that prepared a fugu stew, but were not sure about how safe it was. To test the stew, they gave some to a beggar. When they checked on the beggar later, he was still healthy, so they ate the stew. Afterwards they met the beggar again who told them that he was happy that they still looked healthy, so now he knew the stew was safe and he could eat it. The three men had been had by the wise beggar.

The high demand of fugu has led to overfishing. Strict fishing regulations are now in place to protect fugu from being decimated. Most fugu nowadays is harvested in the spring during the spawning season, and then farmed in floating cages in the Pacific Ocean. The very few fugu that grow in the wild are considered priceless and most, if not all, are sold directly to special customers.

Fugu prices rise in the fall and peak in winter, which is the best time to eat fugu, as they fatten to survive the cold. The fugu is shipped to the restaurant alive and stored in the restaurant in a large tank, usually prominently displayed. As fugu are aggressive and have sharp teeth, in captivity the mouths of fugu are often sewn shut to avoid the fish injuring each other. Prepared fugu is also often available in grocery stores which must display official documents which license them to distribute fresh fugu.

Since 1958, only specially licensed chefs can prepare and sell fugu to the public. The fugu apprentice needs a two- or three-year apprenticeship before being allowed to take an official test. The test consists of a written test, a fish identification test, and a practical test of preparing fugu and then eating it. Only 30 percent of the applicants pass the test. This, of course, does not mean that 70 percent die from poisoning; rather, they made a small mistake in the long and complicated procedure of preparing the dish. Due to this rigorous examination process, it is generally considered safe to eat the sliced fugu sold in restaurants or markets.

Furthermore, most fugu sold nowadays comes from fish with only a small amount of toxin. Selling or serving the most toxic liver is illegal in Japan, but this "forbidden fruit" is still sometimes eaten by amateur cooks, often with fatal results. After several homeless people died from eating fugu organs that had been discarded into an insecure trashcan, restaurants in Japan are required to store the poisonous inner organs in specially locked barrels that are later burned as hazardous waste.

A dish of fugu can cost easily ¥5000 (ca. US$50) but it can be found for as little as ¥2000 yen (ca. US$20), and a full course fugu meal can cost between ¥10,000 and ¥20,000 (ca. US$100 to US$200) or more. Due to the expense of fugu, the fish is sliced very carefully to obtain the largest possible amount of meat without the poison. A special knife called fugu hiki is traditionally used to slice fugu and it is usually stored carefully in a separate location from other knives.

The most popular dish is fugu sashimi, also called Fugu sashi or tessa, sliced so thin that you can see the pattern of the plate through the meat. These plates are often beautifully decorated so that removal of slices is a pleasure as well.

While fugu connoisseurs love the taste and the texture of the fugu, many people actually find it rather bland and tasteless. Some professional chefs prepare the fish so that there is a minute amount of poison in the meat, giving a prickling feeling and numbness on the tongue and the lips. The fins of the fish are also fried and served in hot sake, a dish called Fugu Hire-zake.

Vegetables and fugu can also be simmered as Fugu-chiri, also called techiri, in which case the very light taste of the fish is hard to detect among the taste of the vegetables and the dip. Fugu can also be eaten deep fried as Fugu Kara-age.

The more poisonous testicles of the fugu can also be eaten; they contain a milky liquid and taste slightly salty. This is also considered to be an aphrodisiac. If the spikes in the skin are pulled out, the skin can also be eaten as part of a salad called yubiki.

In several remote locations, people have devised a complex pickling process allowing them to eat the poisonous parts of the fugu. While the exact methods are kept secret, they involve long and heavy saturations in sake and salt for over three years.

Although the tetrodotoxin is very stable and not affected by the heat of cooking, nowadays professionally prepared fugu is very safe to eat. Nevertheless, it seems one of the attractions of the low-flavored fish is the risk of potential death, regardless of how low that actual likelihood stands in a commercial restaurant. This can also be found in the slang name from Kansai region teppo (鉄砲) for fugu, meaning rifle or gun, a play on words on the verb ataru (当たる), which can mean either to be poisoned or to be shot.

Fugu poisoning

As mentioned above, commercially available fugu in supermarkets or restaurants is very safe and while not unheard of, poisoning from these products is very rare. Most deaths from fugu occur when untrained people catch and prepare the fish, accidentally poisoning themselves. In some cases they even eat the highly poisonous liver on purpose as a delicacy. As not all fishes are equally poisonous, this may not always lead to death, but sometimes give only the desired numbness on the lips and tongue while eating and shortly thereafter. However, in many cases this numbness of the lips is only the first step of a lethal fugu poisoning.

If an ingested dose of the fugu's poison is lethal, as more and more muscles are paralyzed, symptoms may include dizziness, exhaustion, headache, nausea or difficulty breathing. For 50 to 80 percent of the victims, death follows within four to 24 hours. The victim remains fully conscious throughout most of the ordeal, but cannot speak or move due to paralysis, and soon also cannot breathe and subsequently asphyxiates. If the victim survives the first 24 hours, he or she usually recovers completely.

There is no known antidote, and treatment consists of emptying the stomach, feeding the victim activated charcoal to bind the toxin and taking standard life-support measures to keep the victim alive until the effect of the poison has worn off. Japanese toxicologists in several medical research centers are currently working on developing an antidote to tetrodotoxin.

Some sources claim that about 100 people die each year from fugu poisoning, while others sources say only 10 to 20 per year, and still others state only 1 person dies each year from fugu. This reported variation may be the result of different sequences of years being studied, as for example in 1958, the first year the preparation of fugu required a special license in Japan, 176 people died of fugu poisoning. According to the Fugu Research Institute, 50 percent of the victims were poisoned by eating the liver, 43 percent from eating the ovaries and 7 percent from eating the skin. One of the most famous victims was the famous Kabuki actor and "living national treasure" Mitsugoro Bando VIII, who died after eating four servings of fugu liver in 1975.

There are some reports of completely paralyzed but fully conscious victims that were believed to be dead, and woke up a few days later or just before being cremated. In some parts of Japan a fugu victim is put next to his coffin for three days to verify the death. If the body does not decompose, it is not yet dead.

The pufferfish is also reported to be one of the main ingredients used in voodoo to turn people into zombies. According to Wade Davis, an American botanist, the pufferfish is the key ingredient in the first step of creating a zombie, where the tetrodotoxin creates a 'death-like' state. In the second step, hallucinogens are used to hold the person in a will-less zombie state. There was considerable scepticism to Davis's claims, he was widely accused of fraud and there has been no final statement as to the veracity of his findings.

Non-Toxic Fugu

Scientists at Nagasaki University have reportedly succeeded in breeding a non-toxic variety of pufferfish by restricting the fish's diet. With over 4800 fish raised and found to be non-toxic, they are fairly certain that the fish's diet and digestive process are what actually produce the toxins that make it deadly. The non-toxic version is said to taste the same, but be completely safe for consumption.

Social aspects

The popularity of fugu in Japan is an interesting phenomenon. Fugu is a very expensive fish, has some potentially lethal side effects, and is by most people considered to have a very weak taste (although many Japanese gourmets would disagree). The combination of these factors would normally give humans a low preference for its consumption. Nevertheless, it is a very popular dish in Japan. While this may be in part because the consumption of fugu is a tradition in Japan with a long history, it may also be the titillation of playing with death, especially when the actual risk is quite low. It can be assumed that the fish would be much less popular if it were not so poisonous.

The Japanese poet Yosa Buson (1716–1783) expressed some of this feeling in a famous haiku:

I cannot see her tonight.

I have to give her up

So I will eat fugu.

Perhaps the most well-known fugu incident in America was when the fictional character Homer Simpson of the TV show The Simpsons ate fugu served by an amateur chef. Due to the chef's lack of fugu-preparation knowlege, he was given 24 hours to live, during which he vowed to do all the things he always meant to do but never got around to. However, most of the time was spent either asleep, with his senile father, and in jail. He did survive the 24 hours in the end, to the joy of his family and friends.

Availability

Most Japanese cities have one or more fugu restaurants. They may be clustered together as past regulations had placed limits on where they may open the store and also the location of restaurants made it easier to have fugu delivered fresh. A famous restaurant specializing in fugu is Takefuku, a restaurant in the Ginza district in Tokyo.

Few restaurants in the United States carry "fugu." When served in the United States, it typically does not contain any tetrodotoxin. Thus, though the meat is taken from the same fish, it does not produce any of the sensations for which it is famous.

Miscellaneous

Lanterns can be made from the bodies of preserved fugu. These are occasionally seen outside of fugu restaurants, as children's toys, as folk art or as souvenirs for tourists. Fugu skin may also be made into everyday objects like wallets or waterproof boxes.

There is a fugu museum in Osaka.

Takifugu species table

**Species of the Genus Takifugu**
Species (Old Names)	Author	Common Name	Distribution	Max. Size	Comments
Takifugu alboplumbeus (Tetrodon alboplumbeus)	Richardson, 1845	Komon-damashi (Japan)	West Pacific	23cm	Poisonous, Salt Water
Takifugu basilevskianus	Basilewsky	Darkgreen Puffer, Sansaifugu (Japan)	?	?	?
Takifugu bimaculatus (Tetrodon bimaculatus)	Richardson, 1845	Futatsuboshi-fugu (Japan)	Northwest Pacific	30cm	Poisonous
Takifugu chinensis^* (Sphoeroides rubripes chinensis)	Abe, 1949	Eyespot Puffer, Karasu (Japan)	Northwest Pacific	55cm	Poisonous
Fugu coronoidus^*	Ni & Li, 1992	暈環多紀魨 (China)	Northwest Pacific	?	Not poisonous
Takifugu chrysops^* (Tetrodon chrysops)	Hilgendorf, 1879	Red-eyed Puffer, Akamefugu (Japan)	Northwest Pacific	20cm	Poisonous
Takifugu exascurus (Spheroides exascurus)	Jordan & Snyder, 1901	Mushifugu (Japan)	Northwest Pacific	15cm	poisonous
Takifugu flavidus	Li, Wang & Wang, 1975	Towny Puffer, Sansaifugu (Japan), Hwang-jom-pok (Korea), Jú húng dong fang tún (China)	Northwest Pacific	35cm	Poisonous
Takifugu niphobles^* (Spheroides niphobles)	Jordan & Snyder, 1901	Grass Puffer, Starry puffer, Kusafugu (Japan), Cá Nóc sao (Viet Nam)	Northwest Pacific	15cm	Poisonous
Takifugu oblongus (Tetraodon oblongus, Tetrodon oblongus, Torquigener oblongus, Sphoeroides oblongus	Bloch, 1786)	Oblong blow fish, Lattice blaasop (India), Bebo (India) Buntal (Malaysia), Pita-pita (Indonesia), Ruitjies-blaasop (South Africa)	West Pacific	40cm	Not Poisonous
Takifugu obscurus^* (Sphoeroides ocellatus obscurus)	Abe, 1949	Obscure Puffer, Mefugu (Japan)	Western Pacific	40cm	Poisonous
Takifugu ocellatus (Tetraodon ocellatus)	Linnaeus, 1758	Ocellated Puffer	Asia	?	not poisonous
Fugu orbimaculatus (Takifugu orbimaculatus)	Kuang, Li & Liang, 1984	圓斑多紀魨 (China)	Asia	?	not poisonous
Takifugu pardalis^* (Tetraodon pardalis)	Temminck＆Schlegel,1850	Panther puffer, Higanfugu (Japan), Chol-pok (Korea), 'Bào wén dong fang tún (China)	Northwest Pacific	30cm	?
Takifugu poecilonotus^* (Tetraodon poecilonotus)	Temminck & Schlegel, 1850	Fine Patterned Puffer, Komonfugu (Japan), Huin-jom-pok (Korea), Ban dian dong fang tún (China)	Northwest Pacific	20cm	Poisonous
Takifugu porphyreus^* (Tetraodon porphyreus, Fugu vermiculare porphyreum, Fugu vermicularis porphyreus, Spheroides borealis)	Temminck & Schlegel, 1850	Purple Puffer, Namera-fugu (Japan), Mafugu (Japan), Kom-pok (Korea), Zi sè dong fang tún) (China)	Northwest Pacific	52cm	Poisonous
Takifugu pseudommus (Lagocephalus pseudommus, Takifugu pseudomus)	Chu, 1935	Nameradafugu (Japan), Nameradamashi (Japan)	Northwest Pacific	35cm	Poisonous
Takifugu radiatus (Sphoeroides vermicularis radiatus)	Abe, 1947	Nashifugu (Japan)	Northwest Pacific	20cm	Poisonous
Takifugu reticularis	Tien, Chen & Wang, 1975	Reticulate Puffer, Amime-fugu (Japan)	Northwest Pacific	29cm	?
Takifugu rubripes^* (Tetraodon rubripes, Sphaeroides rubripes, Fugu rubripes rubripes)	Temminck & Schlegel, 1850	Torafugu (Japan), Tiger Puffer, Hóng qí dong fang tún (China), Cha-ju-pok (Korea)	Northwest Pacific	70cm	Poisonous, Used in Chinese Medicine, Genome sequenced completely
Takifugu snyderi^* (Fugu vermicularis snyderi)	Abe, 1988	Shosai-fugu (Japan)	Western Pacific	30cm	Poisonous
Takifugu stictonotus^* (Tetraodon stictonotus)	Temminck & Schlegel, 1850	Spotback, Spottyback Puffer, Gomafugu (Japan)	Northwest Pacific	35cm	Poisonous
Takifugu vermicularis (Tetraodon vermicularis, Spheroides abbotti)	Temminck＆Schlegel, 1850	Pear Puffer, Shosaifugu (Japan), , Nashifugu (Japan), Kuk-mae-ri-bok (Korea), Chóng wén dong fang tún (China)	Northwest Pacific	30cm	Poisonous
Takifugu xanthopterus^* (Tetraodon xanthopterus)	Temminck & Schlegel, 1850	Yellowfin puffer, Shimafugu (Japan), Kka-ch'i-pok (Korea), Tiáo wén dong fang tún (China)	Northwest Pacific	50cm	Poisonous

^* Fish that have edible body parts according to the Japanese Ministry of Health and Welfare

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