Breeding Bluefin Tuna in captivity: A recipe for success?

When I went over to Japan- I went there with an open mind to try as much as possible. As I’ve mentioned in a previous post the first 3 weeks were a sort of ignorant bliss- I ate, enjoyed but frequently was at a loss to identify what I was eating. With one exception- I knew very well of the Japanese love of Bluefin tuna Read more

HiNGEd on Unique Stories

 “i’d rather wear a unique story…”- Boticca I’ve always been fascinated with the origin of the product I am using, eating, wearing, smelling or consuming in some way or another. I am curious about the intricate relations, history and most importantly the story that lies behind a product. I assume this is what lends itself to my passion for sustainability, and ethical issues since full transparency and Read more

Free Money + Sloths= a better life?

On the 15th September, in over 15 countries worldwide, people handed out their money two coins, or two notes at a time to complete strangers with one condition attached: the recipient must pass half this amount to someone else. Who are these people? Benevolent billionaires who would like to donate to my new handbag fund (a bona fide cause I assure you…)? Well, no Read more

Kuromame-Cha cha cha

In other words black soybean tea; possibly my most treasured discovery during my sojourn in Japan. It all began one cold spring trip to Hakone-the mountain escape for Tokyoites for a bit of rest and relaxation. My boyfriend and I were visiting to try out my first onsen (hot natural springs/baths) and experience the calmer, more picturesque side of Japan which had somewhat evaded Read more

Japan Earthquake & Tsunami

I'm really sad to hear and see the terrible impact of the earthquake of magnitude 8.9 and subsequent tsunami in Japan, whose far reaching destruction is slowly revealing itself day by day. For any worried English speaking expats in Japan-a great and reassuring resource can be found here: For those on twitter you will find a number of regular tweeters who are keeping everyone Read more

How unique is UNIQLO?

UNIQLO is among one of Japan's best exports, along with their ubiquitous technology, anime, manga and J-Pop. For me UNIQLO signalled a welcome sense of familiarity when I first stepped into Japan- a country which managed to confound all my senses upon arrival. And when I say 'first stepped into Japan' I mean this in the strictest sense of the word; since my interest in Read more

Ja-Pan du jour

'This bread demands a very slow fermentation and a lot of attention. However the result is worth it; the taste is incomparable, its texture sealed in and authentic, handcrafted product' Beck Pain Gris (2010) Toit Vert- A Japanese Bakery The translation is not quite as poetic as when read in French, but this description on the bread paper sachet demonstrates the care, attention and Read more

Ain't no Blue Mountain high enough

“Coffee should be as black as the devil, hot as hell, pure as an angel, sweet as love"- Charles Maurice de Talleyrand. And that's exactly how I take mine. Coffee and I have had their ups and down, I briefly abandoned my caffeinated companion following my dissertation induced sleep deprivation, in the final year of my degree. It would be more accurate to describe this Read more

Toilets ...a metaphor for Japan?

Toilets are Japan in a nutshell. Ok stick with me here, on first observations, what I have just said may sound a little disparaging about the Japanese culture, people and land. I see Japanese toilets as a wider metaphor of Japan, the paradox between tradition, ancient history and culture juxtaposed with modernity, high-technology, and the latest fashions in Asia. Juxtaposition of a traditional Inari shrine Read more

Bling bling fruit and bargain bananas

When we think of bananas and the Japanese, the heralded 'Morning banana diet' may come to mind. Indeed a banana buying craze broke out in Japan when this diet debuted in March 2008. In a week, sales increased by 70% causing a price spike and pressure on imports.  The basic premise is that by only consuming bananas for breakfast with a glass of room Read more

Negotiating the foggy waters of product labels

My greatest difficulty since arriving in Japan has been the interpretation of product labels, be it food, cosmetics or simply flushing the toilets (some of which are more hi-tech than my mobile phone-I'm sure.)  This has been a sticking point for me since I tend to analyse everything I put onto my skin and into my body-an obsessive label checker some may call it. Read more

blue fin tuna

Breeding Bluefin Tuna in captivity: A recipe for success?

When I went over to Japan- I went there with an open mind to try as much as possible. As I’ve mentioned in a previous post the first 3 weeks were a sort of ignorant bliss- I ate, enjoyed but frequently was at a loss to identify what I was eating. With one exception- I knew very well of the Japanese love of Bluefin tuna and despite the oft repeated exclamations of its wonderful taste and fondant texture, it was one fish I actively tried to avoid. Why? As one of the most endangered, or arguably the most endangered fish in the world with currently only 20 years’ worth of stock left in the wild, I could not comfortably eat and enjoy fish that would leave a taste of guilt in my mouth.

Tsukiji Fish Market in Tokyo

The Bluefin tuna is known as the “tiger of the sea”- a hefty sized fish which can grow up to 635 kg and measure 5 metres long- that is a lot of sushis. They can be found in the Northern Atlantic, and the Mediterranean but are increasingly commercially cultivated off the coasts of Japan, which I will expand upon further. Although Bluefin tunas have fascinated and fed humans for centuries, they only became a global foodstuff towards the end of the 20th century. Their delectable taste has led to a global boom and demand which has made Bluefin tuna a profitable business which has succumbed to overfishing and hence the now endangered state of Bluefin tuna. Quotas do little to control this problem since they are difficult to enforce, and scientists estimate we only have 20 years of stock left in the oceans, and if they are to recover fully there needs to be total ban on fishing of Bluefin tuna for at least a generation.

Tuna, tuna, tuna

Before leaving to go to Japan I attempted to learn the Japanese word for Bluefin tuna to avoid any crises of conscience when chomping on some sushi.  However this proved more difficult then I initially thought, and the vocabulary is still not clear-cut for me. Generally Bluefin tuna will be labelled as “Maguro” pronounced (mah-goo-roh). However Yellowfin tuna may also be labelled as Maguro, though more often than not this will still refer to Bluefin tuna. Then there are the different names for the cuts of the tuna:

  • Akami (ah-kah-me)- the leaner parts of the tuna from the side of the fish
  • Toro (toh-roh) literally translating as the fatty part of the tuna found in the belly portion of the fish, which is then sometimes further subdivided into different cuts of the fatty belly which fetch even higher prices:
    • Chutoro (choo-toh-roh)- from the fatty part of the belly portion of the fish which is usually preferred since it is less fatty than Oturo.
    • Oturo (oh-toh-roh)- the fattiest part of the fish found on the underside and so will melt in the mouth.



Are you still with me? Now I am unsure if these cuts refer uniquely to Bluefin tuna or to all types of tuna, so it was a tricky water to navigate as a non-speaker of Japanese trying to stick to my ethics! Fortunately in almost all sushi bars in Tokyo (except the most traditional, hidden ones) the Latin script and spelling was provided alongside the plate descriptions. Sushi bars are where (but not exclusively) you will most frequently encounter Bluefin tuna so it was when eyeing up the conveyor belt of fishy delights whizzing past me that I was at my most vigilant. In any case, the easiest way to avoid Bluefin tuna was to stick to my travelling budget and choose the cheaper sushis and tuna! Bluefin tuna will always be among the most expensive tuna sushis on the sushi conveyor belt.

It seemed a great shame that due to my personal guilt and ethical wrangles I was not able to sample this very popular and local delicacy but equally it seemed ridiculous to want to eat something which is so dramatically overfished it is not going to survive into the next century. I was therefore extremely curious to stumble upon a documentary by France 24 about Bluefin Tuna fish farms. The thought or concept had never crossed my mind, but seemed logical if they can make salmon farms work. However that is another kettle of fish altogether (excuse the pun) and I’m not a huge proponent of salmon farms either, which in my view produce lower quality, intensively farmed, worst tasting and unhealthier fish which have a bigger environmental impact than wild salmon. However this is the toss-up between Western societies eating as much salmon as they friggin’ well want to, or as a society forgoing and reducing our salmon intake, and hence reduce our intake of those all-important brain boosting Omega 3’s which are so out of whack with our Western processed diets which are heavily reliant on too many Omega 6’s. I should address this in a separate post- but this link adequately explains the importance of balancing our ‘Omegas’.

The concept of farmed tuna has actually existed for some time but in a structure whereby wild Bluefin tuna are caught and then fattened on farms, which does not resolve the issue of rapidly diminishing stock of Bluefin. A new concept of tuna farms, highlighted in the above France 24 report, have been set up on the western coast of Japan to breed tuna from eggs so that there are raised in captivity their whole lives. This may seem the somewhat logical step seeing since other fish such as salmon and catfish are already bred in captivity, but Bluefin are notoriously difficult to breed and for years it was assumed to be impossible. Until now.

“Impossibilities are merely things which we have not yet learned.
– Charles W. Chesnutt

So why are our fast-disappearing tasty tuna friends so tricky to breed in these glorified ponds that we are bestowing upon them? Well, when it is put like that, would you prefer to be swimming, having sexy time and indulging in your preferred behaviours in the big blue ocean, or in an artificial, confined pool of water? Apparently the 5 star floating sea cages or giant tanks are not harbouring the right environmental cues to switch on sex hormones needed for reproduction. A European Union project focusing on this issue has been using drug implants mimicking the lacking sex hormones to incite Bluefin to produce fertilised eggs in captivity. It is hoped this technique will be useful to get tunas to breed at a younger age than they currently do. In experiments conducted only 1% of tuna babies have survived demonstrating the difficulty of breeding the tuna. A more recent experiment from Kinki university for Pacific Bluefin had a 6% survival rate from eggs hatched, which is a good number of tuna surviving since the average tuna lays tens of millions of eggs; and these survival rates are steadily increasing.



Another challenge of these tuna compared to other farmed fish are that they reach sexual maturity at a much higher age of 12 years compared to other fish such as catfish which are mature around 3 years. Bluefin also need a tremendous amount of space owing to their size and their method of oxygen extraction which requires them to swim very rapidly to absorb oxygen into their gills. They have an enormous appetite, so much so that if this was to become a more widespread commercial endeavour, it could extinguish other fish species such as anchovies and sardines, or other cheaper fishes which are currently principal food sources for developing countries. Feeds have been developed which are made of fishmeal, oils and nutrients, claimed to be less polluting and more fattening than a diet of small fish, and with an aim to develop vegetarian feeds. However I do question how dramatically this must affect the quality and taste of the fish since I adhere to the philosophy of “you are what you eat”. Do we really want to be eating fish fed on artificial processed pellets?

The sizes of the Bluefin also pose another challenge for drug delivery such as antibiotics, sex hormones, and other medication. To dose a salmon, a man can pick it up to do so; this is not so easy with a Bluefin tuna unless you are currently competing for the World’s Strongest Man competition. Scuba divers therefore shoot time-release implants with spear guns into the tuna, and the drug then spreads through the tunas’ bodies over a week.

Bluefin tuna breeding has been strongly researched for the past 30 years in Japan but had been a fruitless endeavour due to the long wait for sexual maturity. However with improved techniques, a rapidly depleting stock of wild Bluefin tuna; it would seem the potential financial gains are auspicious. Indeed a Japanese firm which has been working on the prized Pacific Bluefin tuna aims to begin sales by 2013 with a sale of 10,000 fish by 2015.

The Foodie critique:

So is the result worthwhile? The farmed tuna from Maruha Nichiro Holdings Inc. (Japan’s biggest seafood company) Pacific Bluefin tuna farms still commands a significantly lower price than wild Bluefin which is somewhat disappointing when the years of research, development and investment that have gone into these farmed varieties is taken into account. It is criticised for lacking a ‘fish’ taste and the colour does not have that rich-red colour we expect to see in Bluefin tuna, demonstrating a white colour.  However as many Japanese concede, they cannot rely on wild tuna forever and expect significant improvements in the quality of farmed Bluefin tuna.

Is this the solution?

I am hesitant to regard this as a perfect solution, since as many emphasise, it does not resolve the problem of overfishing, it only


diverts attention to breeding efforts in a highly costly manner. By using small fish as feed, this creates the same problem of other farmed fish- that we risk depleting other fish species stock at the expense of raising other ‘favoured’ fish such as salmon and Bluefin in captivity. And to replace the feed by a special meal mix does not seem to be a healthy alternative to me, and I do not feel we will extract the same health benefits eating farmed fish as we do from wild fish. Of course if we continue eating Bluefin fish at the current rate we do now, there will be no more of these beautiful fish left to eat, and also to admire. Others point out that breeding studies still need to continue, if not for feeding our appetites, but simply to tackle the problem of diminishing wild Bluefin tuna, and perhaps eventually boost wild stocks with tuna bred in captivity.



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