Eels: long and snakelike and slimy, they’re hard to love – unless, of course, they’re grilled and basted with a sweet sauce. Unagi is a signature dish in Japanese cuisine, and you’ve probably encountered it at least in sushi, but if you’re American it’s probably the only place you’ve had the chance to eat it. Strangely, though, even if you’re eating it in Japan, that unagi may actually have spent most of its life in North America. It’s part of a long story about the eel’s strange lifestyle and the bad news about its plummeting numbers.

Unagi: Cooking and Legend


Photo by Patrick

The traditional preparation of eel involves grilling the fillets over charcoal while basting with a sweet sauce made from soy sauce, mirin and sugar. Of course there are regional differences, because what’s Japanese food without regional differences? In Kanto (eastern Japan including Tokyo) the eel is grilled, then steamed to get rid of excess fat, then grilled again. In Kansai (Kyoto, Osaka and the west) there’s no steaming – the eel is just grilled longer, making it crispier and chewier.

There’s also a difference in how the eel is prepared for cooking, which legend attributes to cultural difference in the regions. In Kanto, the eel is split open from the back rather than the stomach, supposedly because Edo was the military capital, and the restauranteurs didn’t want to remind their samurai customers of the practice of ritual suicide, seppuku, which involves stabbing yourself in the stomach. In Osaka, the eel are cut down the stomach – supposedly because people there are more open and frank and inclined to “spill their guts.” Uh, sure.

The grilled eel is usually served with rice and pickles, and Japanese sanshō pepper to sprinkle over it, which if you’ve never tried, you should. It’s an amazing aromatic spice that’s not like anything Americans use. And at a proper eel restaurant, no part of the eel goes to waste: the guts are skewered and grilled, the liver is made into soup, and even the spine is deep fried and eaten like a crispy cracker.

The Eel Days of Summer


Photo by Ray Larabie

Another traditional belief regarding eel might have some basis in reality. It’s supposed to be good to eat in hot weather to restore your energy. There’s said to be some truth to this because it contains various vitamins including B1, which is lost in sweat. To be fair, none of the references where I found this claim made any comparison to other fish – for all I know, there’s just as much vitamin B1 in all the others – but I’m happy to have any excuse to eat eel, so I’ll leave it at that.

Although eel is eaten all summer (and the rest of the year too), the biggest eel-eating day is Doyo no Ushi no Hi (Midsummer Day of the Ox), which is supposed to be the hottest day of the year. The exact date is determined by the lunar calendar, so it moves around, but it’s always in late July or early August, which gives the day a fair shot at being hot as heck if not actually the hottest.

One legend has it that the custom began as a marketing gimmick: in eighteenth century Edo, an eel restaurant hired a famous calligrapher to make a sign that said “Today is the Day of the Ox.” Basically a celebrity endorsement, people noticed the sign because of the fame of the artist, and a connection between eel and the date stuck in their mind. Whether that story is true or not, the day certainly works well as a marketing gimmick nowadays, with supermarkets setting up special sections to sell grilled eel for the day.

Caution: Unagi


Photo by Glen Bowman

Those special eel displays are selling already-grilled eel, because it isn’t usually cooked at home, for a variety of reasons. One is that it’s best to slaughter and fillet them on the spot with special knives, and since they’re very strong and slippery beasts, this is better left to experts.

Then there’s the sauce. Restaurants have their own secret recipes passed down from one chef to the next, and apparently it’s one of those things where the same pot is simmered and added to for years and years, something you can’t really reproduce at home. It’s traditionally said that if there were a fire, the pot of sauce would be the first thing the chef would grab to rescue. (I don’t know if that’s ever really happened, but I found one person who didn’t manage to grab their pot in an emergency and regretted it – this AP article following up on some victims of the Fukushima disaster mentions the owner of an eel restaurant who was devastated at losing the traditional sauce that had been passed down in his family.)


Photo by istolethetv

But the biggest reason eel isn’t cooked at home was quite a surprise to me. You hear all the time about the toxic liver of the famous fugu blowfish and how chefs need a special license to prepare it, right? But in all my years of eel-eating I’d never known that their blood contains a neurotoxin. That’s also why eel is never eaten raw, so that even sushi is made with the grilled kind. Less than one cc can kill a rabbit, and you don’t want to get it in a cut or in your eye because apparently it doesn’t take much to kill a person, either. I couldn’t find out the exact amount, but if I ever get to watch a chef prepare a live eel for me, I’m going to play it safe and sit a ways back. However, cooking neutralizes the poison, so unlike with fugu, no worries about eating the cooked fish.

Eating Eel Elsewhere


Japan consumes about 100,000 tons of unagi per year, about 70 percent of the catch worldwide, but while most Americans have never eaten eel except at a sushi place, it’s a specialty of a number of other countries. They stew them in Sweden, smoke them in Northern Europe, and the Basque boil tiny young ones and then saute them in garlic, just for a few examples. Eel are also eaten in New Zealand, where they’re important in Maori folklore.

Maybe the most famous non-Japanese eel dish comes from England, where since the 18th century, especially in the east end of London, they’ve eaten jellied eels. Originally a cheap dish for the lower classes, it’s made of eels chopped up and boiled in a spiced stock which sets like gelatin when it cools. It’s sold in “eel, pie and mash” shops, and you can reportedly eat it hot or cold, although – sorry, Londoners – from the sound of it, I’d rather not eat it at all, and keep walking till I find a sushi bar.

Journey of the Eel


The eel has a very unusual life cycle among fishes, involving an amazing long-distance migration. In English, unagi is called “freshwater” eel, in contrast to anago the “saltwater” or conger eel, but this nomenclature is somewhat misleading, because unagi spends a large part of its life in the sea. They are born in the middle of the ocean, then find their way to the coast and enter rivers and streams, where they live for ten to thirty years. Then they swim back out to sea to spawn. How eel find their way from the middle of the ocean to the mouths of rivers they’ve never seen is still unknown. Most fish that migrate similarly go the other way round, like salmon: born in a river, they go out to sea, then return to the familiar river they came from.


Much of the eel’s life cycle was a mystery till recently, although people have been trying to figure out where they come from for a long time. All the way back to Aristotle, naturalists were coming up with theories, some of which were pretty peculiar – he thought they emerged from mud, and Pliny thought they reproduced by rubbing against rocks. You can’t really blame the guys for being creative, though: the thing is, when eels were dissected, no sexual organs were found, since they develop only after the eels leave the rivers and head for their spawning grounds.


Photo by Uwe Kils

Another thing that made it hard to figure out the eel’s reproductive story is that the young look nothing like the adults. Called elvers or glass eels, they’re tiny, transparent, and shaped more like a willow leaf than like their snakelike parents. In fact, when first described in 1856, they were considered to be a different species of fish altogether. Not until forty years later did two scientists see one metamorphose into an adult (in a fish tank) and realize that they were different forms of the same fish. The European eel looks so different at different times in its life that at one point, forms of the same species had thirty different names.

And of course, the long distances they travel and the huge size of the ocean made studying their life cycle a challenge as well. The spawning grounds of American and European Eels in the part of the north Atlantic west of Bermuda called the Sargasso Sea weren’t discovered till the 1920s, and the spawning grounds for the Japanese eel were only located – after 60 years of searching – in 1991 near Guam and the Marianas Islands.

The Decline and Fall of Japanese Eel


Photo by David Becker

Although it is generally agreed by the Japanese that the Japanese species is the most delicious, Japan now gets about 80 percent of its eel from elsewhere. The simple answer to “where” is “eel farms mostly in China and Taiwan,” but the full story is more complex.

In the early 1990s, populations of the Japanese eel became so small – and prices so high – that suppliers began to look elsewhere. They discovered that similar species lived in Europe and North America and even better, in North America no one cared about them, so there was no limit on how many could be caught. The complication was the need to get them to market alive, and it’s a long way from the US East Coast to Japan, so what developed was an industry that catches the tiny juvenile glass eels, ships them to Asia, and raises them to market size in fish farms.

The small amount of actual Japanese eel still consumed is also mostly raised in farms – less than one percent is wild eel caught as adults. The most prized are from Hamamatsu, which sell for double the price of the imported ones. Perhaps it’s no surprise that this has attracted dishonesty: some suppliers have been arrested for falsely labeling eel from China as Japanese eel from Hamamatsu.

The Eel Rush


Photo by Jer Thorp

The decline of the Japanese eel has also resulted in crime in the US. When Asian suppliers started to buy North American eel, the fish went from almost worthless to a virtual gold mine: glass eels are now worth up to $2,600 a pound. In 2013, Maine fishermen caught more than 18,000 pounds of the tiny eels, worth about $33 million.

Great for the economy, right? Except now they’ve also got poachers, turf wars, armed guards watching over tubs of glass eels, fights about the local Pasamaquoddy tribe’s sovereign fishing rights, huge amounts of cash attracting criminals including drug gangs… Long story short, it has gotten to the point that Animal Planet made a reality show about Maine eel fishing (this is the Animal Planet that now makes shows like one that claimed mermaids are real, in case you’re remembering the days when it was actually an educational channel).

Vanishing Eel


Photo by Ken Ohyama

Somewhat belatedly, the Japanese government recognized that there’s an issue: In early 2013, the Ministry of the Environment added Japanese eel to its Red List of endangered fish. Statistics cited include the fact that the species has declined by 90 percent over the last three generations and that populations are 5 percent of what they were in the 1960s. Nice that they have finally taken notice, but inclusion on their Red List apparently doesn’t result in any kind of fishing ban, and regulations are only being “considered.”

The problem is even more pressing because it’s not confined to Japan – all the other eel the Japanese are eating are also declining alarmingly. European eel are dropping in large numbers, including in London, home of that other iconic eel dish, the jellied ell. In the River Thames, the population was reported in 2010 to have fallen by 98% in the previous five years – from 1,500 in 2005 to just 50 in 2010.

And although the numbers of eels caught in Maine are mind-boggling, in fact, they’re declining in North America as well. Canada has declared them as endangered in Ontario and the Maritime Provinces and in the US, although an attempt to list them as an endangered species failed, fishing for glass eels is only legal two states, Maine and South Carolina. Maine has introduced fishing quotas, and they’re serious about it: this year, limits started to be enforced with an electronic swipe card system that will allow regulators to monitor how many eels are being caught daily.

The Future of Unagi


Photo by Kenji Oka

Is unagi in danger of disappearing from our plates? It seems to be generally agreed that the species can’t sustain our habit of robbing the cradle of tons of their tiny babies every year. The most respected organization that evaluates the environmental impact of the fish we eat, the Monterey Bay Aquarium Seafood Watch, says that unagi is one of the species you should avoid if you care about sustainability. But this doesn’t seem to have had any effect on whether restaurants offer it, any more than the fact that they say the same thing about tuna has affected the menu at any sushi bar I know of.

And just as I was finishing writing this article, some news broke: the Japanese eel was declared to be an endangered species by the International Union for Conservation of Nature. This is a big deal, because the IUCN’s Red List is the recognized international standard reference for what counts as an endangered species. Like the Japanese national red list, it doesn’t automatically mean fishing is regulated, but it’s taken very seriously when international trade regulations are negotiated. And, as one restaurant owner said to a reporter, “We are already losing customers because of the rising prices. Now, consumers might feel guilty about eating a red-listed species.”

Researchers are at work on the obvious solution, which is to figure out how to breed eels in farms from the start.  But as probably doesn’t surprise you at this point, this has not been easy. Eel eggs were first successfully fertilized in a lab in 1973, but it took till 2001 for the scientists to figure out what the fussy little buggers would eat (which turned out to be a slurry of freeze dried shark eggs. Mmm!) But they didn’t get any of them to live long enough to grow to full market size till just a few years ago. And still, only 1 percent of fertilized eggs survive even to 100 days – and this is a fish that can take a couple of years to get big enough to sell. Of course for all we know, that could be the natural survival rate in the wild, but for market production, it’s a long way from economically viable. And then another problem is that for some unknown reason nearly all the fish born this way are males, which is pretty much backwards from what you’d want – you can get by with only a few males, but you need the females for eggs to make more baby eels.

Scientists are working to solve these problems, and we better wish them luck. Because sadly, the way it’s going now, eventually we’ll all be telling our disbelieving grandchildren about how we celebrated Day of the Ox in the good old days, eating our fill of that luscious grilled unagi.

Bonus Wallpapers!

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Eels: An Exploration, from New Zealand to the Sargasso, of the World’s Most Mysterious Fish by James Prosek. Harper Perennial, 2011

  • Morally Conflicted Unagi Lover

    Aw… this makes me feel bad. I love unagi, but I don’t want to eat it if the eels are endangered.

  • Beetle BANE

    “Although it is generally agreed by the Japanese that the Japanese species is the most delicious” was my favourite line.
    Jokes aside, interesting article! I had no idea that the delicious, little cuties were dying off like morning-after-fireflies. That is a real shame. I also had no idea that their migration and breeding habits had been much of a mystery at all. It is all rather fascinating! I guess there is a lot I never bothered to know about them, which is a little guilt-riddling. As for the abundance of male eels, perhaps they are the sort of fish that has a persuasion to have its sex skewed by particular changing environmental conditions, but are by default a certain sex until said conditions are met. I think that is a thing that happens with some fish types, but I don’t really know much about it.(I could have just made it up even~)

    iou: one comment doodle~

  • Brad Garrett

    This is a really fascinating article

  • linda lombardi

    I know, this makes me very unhappy also. I didn’t have a problem avoiding tuna when I found out it was an issue, but not eating eel is really hard.

  • linda lombardi

    thank you! Who knew there was so much to know about eels?

  • linda lombardi

    Yeah, there are animals like that – reptiles are what comes to mind but I wouldn’t be surprised if there are fish also. They know what conditions control it for some kinds of reptiles, so maybe they can figure it out for eels, except it seems like everything about eels is harder. I’m glad I didn’t have a childhood dream of growing up to be an eel researcher.

  • Beetle BANE

    Well, if you guy’s want, I can eat your share of eels, that way you don’t have to go through with it!
    *puts on lobster-bib and salutes* Taking one for the team~

  • Brennan Dogge

    It’s very cruel of you to have such a delicious looking picture of unagi there right at the end of the article while telling us we should stop eating it.

  • Ji

    Well, fuck. Great read, but extremely depressing to think that being responsible means not eating unagi for the foreseeable future, if ever again. The photo of unadon makes matters worse.


    EEL is epic! I love the taste, but only Japanese preparation. The English pies and jellied versions are pretty bad. I also really like the salt water living “anago”. It usually is really expensive though, but I think is worth it one special occasions.

  • linda lombardi

    It’s so you will have practice being strong and saying no?

  • Musouka

    It’s not just Eel and Tuna, the entire edible fish industry is depleting the available supply way too quickly. If we continue with this pace, the oceans will be virtually empty by mid-century.

  • lychalis

    Granted, I don’t live in the east end of london, but I don’t think I’ve actually heard of jellied eel before – but I’ve no plans on trying it (I think they might sell eel in fish and chip shops, though. Can’t remember.) as it doesn’t sound overly pleasant

  • linda lombardi

    Seriously, I will try anything once, but I will make an exception to that for jellied eel. It sounds quite repulsive.

  • Spenderman

    Words are wind.

    Delicious-looking pictures so vivid you can practically smell the wonderful aroma are accepted as currency in many parts of the world.*

    Which one will have more impact on my unagi-eating habits?. . .

    * At least they should be.

  • Matthew MacEwan

    Aaaa that looks so good! I hope they develop those eel-raising techniques quickly!

  • zoomingjapan

    I do love unagi and I just can’t keep myself from eating it as long as they still offer it in my local supermarket. :/
    I try to cut down my unagi consume to a few times a year, though.