Can farmed tuna save the bluefin from extinction?

Conservationists have long warned that bluefin tuna stocks are declining. While the development of aquaculture may offer an alternative, it doesn't come without a few headaches of its own


Staff Writer

In 1970, a research team at Kinki University’s Fisheries Laboratory in Wakayama Prefecture was handed what was believed to be an impossible task — to create technology that would support the fully-closed life-cycle aquaculture of bluefin tuna.

Joining a number of rival domestic universities and organizations as part of a government-backed project, Kinki University was given just three years to succeed.

In reality, however, it took more than three decades to complete its objective.

Kinki University’s Fisheries Laboratory was founded in 1948, just three years after the country’s defeat in World War II. During a time of poverty and profound food shortages, the research center was built based on the catchcry of the university’s inaugural president, Koichi Seko: “Cultivate the seas!”

And that is precisely what the laboratory has attempted to do ever since. Prior to the aforementioned bluefin tuna project, the university successfully raised from eggs fish such as halibut, red sea bream and amberjack, among others, and nurtured them into reproductive adults.

Hidemi Kumai, former director of the laboratory, highlights the importance of aquaculture amid the decline in stocks of wild bluefin tuna in his 2011 book, “Kyukyoku no Kuromaguro Kanzen Yoshoku Monogatari” (“The Ultimate Bluefin Tuna — The Story of Full-cycle Aquaculture”), which is published by Nikkei Publishing Inc.

“We got too greedy and, as a result, the human race has to pay for overfishing and the destruction it has caused,” Kumai writes. “If the world fights over fish, aquatic resources will certainly become depleted. It is now time to cultivate the seas. An aquaculture that does not rely on natural resources is key to sustainable fishing.”

‘Diamond of the sea’

Bluefin tuna is sometimes called the “diamond of the sea,” accounting for just 9.8 percent of all tuna species supplied to the domestic market in 2013, according to data compiled by the Fisheries Agency.

There are several types of tuna, including Atlantic, Pacific and southern bluefin tuna, bigeye and yellowfin. Atlantic and Pacific bluefin tuna average 2 meters in length, weighs hundreds of kilograms and is believed to live for up to 50 years. Its rich and fatty texture make it a prized item on many sushi menus nationwide.

For years, conservationists have warned that bluefin tuna stocks are declining due to overfishing and a clear lack of resource management.

The Fisheries Research Agency, for example, has noted that imports of Atlantic bluefin tuna from the Mediterranean peaked in 2006 at 22,600 tons. By 2012, however, imports had plunged to 8,200 tons.

Five regional fisheries management organizations have been created to manage tuna stocks worldwide. Although Japan is a signatory member of each entity, only two of the five appear particularly relevant: the International Commission for the Conservation of Atlantic Tunas, which manages Atlantic bluefin tuna, and the Western and Central Pacific Fisheries Commission, which oversees Japan’s exclusive economic zone.

Despite the creation of these international bodies, Atlantic bluefin has continued to be overfished. Indeed, the declining stocks of Atlantic bluefin became so serious a few years back that Monaco proposed a complete ban on the species’ international trade in 2010 at the Convention on International Trade in Endangered Species of Wild Fauna and Flora.

Masanori Miyahara, president of national development organization Fisheries Research Agency, believes measures weren’t taken to restrict overfishing of wild bluefin despite the fact that tuna farming in the Mediterranean Sea took off in the late 1990s. Miyahara is a former senior official of the Fisheries Agency and has represented Japan at major international conferences on a number of occasions.

“Japanese people began to be able to eat cheap fatty tuna at conveyer-belt sushi restaurants,” Miyahara says. “This drew criticism that tuna resources were declining as a direct result of Japan’s appetite.”

Japan is the world’s No. 1 consumer of tuna when all species are accounted for; it also consumes the vast majority of the world’s bluefin tuna catches.

According to data compiled by the Fisheries Research Agency, 42,400 tons of bluefin tuna were processed in Japan in 2014. While 25,900 tons of this were produced domestically, Japan also imported another 16,500 tons of bluefin tuna from countries such as Mexico, Malta and Croatia.

Meanwhile, domestic aquaculture increased from 10,400 tons in 2013 to an estimated 14,700 tons a year later. According to the Fisheries Agency, 92 domestic companies were operating tuna farms by the end of 2013, with many of the farms located near the cities of Nagasaki and Kagoshima.

“The domestic tuna farming business developed because of the harsh catch restrictions imposed on Atlantic bluefin tuna,” Miyahara says.

Kinki University’s first forays into aquaculture initially weren’t very impressive. The research team reported virtually no progress in the first three years of the program’s existence and it didn’t take long for government subsidies to stop altogether.

Tuna at first proved famously difficult to handle, says Shukei Masuma, a professor at Kinki University’s Fisheries Laboratory.

Young bluefin tuna, Masuma says, have an extremely delicate body, which makes it hard to catch them.

“A young bluefin tuna’s skin is so delicate that it burns if touched by human hands and then it rots to death,” Masuma says. “Once a young bluefin tuna matures, it starts swimming at dangerously fast speeds and can easily run straight into the net and die.”

In 1979, a research team at Kinki University (aka Kindai) successfully managed to collect eggs from farmed adult bluefin tuna for the first time. Despite the success, researchers experienced further frustration.

The next step in the process was to create an embryo through artificial incubation and turn larval fish into fry, thereby completing the life cycle. However, not only did the larval fish die off en masse, the adult bluefin tuna stopped producing eggs for 11 years from 1983.

With Kinki University failing to make any significant progress, money very quickly became an issue.

An average holding pen is typically 30 meters in diameter, 10 meters deep and costs about ¥20 million to assemble. The research team needed at least four different sized holding pens to mature the bluefin tuna through different stages, sometimes more.

Bluefin tuna also consume a lot of food on a daily basis. Kumai estimates that 250 bluefin tuna, each weighing about 100 kilograms, require a total of about 1 ton of frozen mackerel every day.

Many research teams in the same position would have found the obstacles daunting, but Kinki University was able to help fund itself by selling other species of fish it had successfully taken through the reproduction cycle.

“We were heavily criticized at the time,” Masuma says. “People said it was embarrassing for the university (to make money from its research). However, you have to make money on your own if you have no money to begin with.”

Commercial interest

It took the research team at Kinki University 32 years to achieve success in establishing a fully-closed life-cycle farming program for bluefin tuna. Almost 14 years have passed since this was achieved in 2002, and the university’s “Kindai” produce is now a recognized brand.

The university created a corporation to oversee the sale of fish from its farms. It has also opened two restaurants — one in Osaka and one in Tokyo’s Ginza district — that serve only Kindai farmed fish.

Masuma, however, says that farming bluefin tuna is still a work in progress because only 1 percent of the fish survives until maturity.

“The project was more difficult than everyone expected and, to be honest, it’s still difficult,” Masuma says. “The number of farmed fish produced under the bluefin tuna program pales in significance to the number of red sea bream we can produce — usually about 70-80 percent of the total stock. In order to succeed as a business, we still need to keep making improvements.”

Kinki University is not the only entity investing in aquaculture these days, with a number of domestic businesses increasingly showing an interest.

A subsidiary of Maruha Nichiro Corp., for example, invested in tuna farms as early as 1985, while Toyo Reizo Co., a subsidiary of Mitsubishi Corp., and Sojitz Tuna Farm Takashima Co. have also invested in tuna aquaculture since 2008.

In 2014, trading enterprise Toyota Tsusho Corp. signed a memorandum of understanding with Kinki University to develop their aquaculture business, including farmed bluefin tuna. They have been working together since 2010 and currently operate two tuna farms — one in Okinawa and one in Nagasaki.

A subsidiary of the trading enterprise also opened a bluefin nursery center in Nagasaki last July, where bluefin fry will be produced through artificial incubation.

Last summer, Aeon Co., the country’s largest supermarket chain operator, sold farmed bluefin tuna at 2,000 of its stores nationwide.

The retail giant teamed up with fisheries firm Maruha Nichiro, which became the first private sector corporation to succeed in the fully-closed life-cycle aquaculture of bluefin tuna in 2010.

A sushi restaurant serving farmed fish, in addition to wild varieties, also opened last October in Tokyo’s Hatchobori district.

In February 2015, meanwhile, fisheries trading company J-Trading Inc. and investment firm Integral Corp. jumped on the farmed tuna bandwagon by purchasing Croatian firm Kali Tuna. Kali Tuna is the largest tuna farming company in the Adriatic Sea.

J-Trading Director Oliver Bolzer says the company can secure a steady supply of bluefin tuna and participate in the farming process with the acquisition of the Croatian company.

“It is about being able to introduce Japanese craftsmanship to the staff in Croatia,” Bolzer says. “By being directly involved in the farming process, we can ensure that all the procedures are completed carefully.”

To instill Japanese knowledge in its Croatian subsidiary, J-Trading has dispatched two experts on tuna to Europe. The experts are expected to pass on their knowledge to local employees, covering everything from how to take care of bluefin tuna to how to conduct business.

One of the Japanese advisers is 69-year-old Ryozo Moriwaka, former managing director of Tsukiji Uoichiba Co., a wholesaler for marine products. Working inside Tsukiji fish market, Moriwaka spent 43 years specializing in the sale and purchase of both wild and farmed tuna.

Moriwaka says the primary difference between the two varieties is that the quality and quantity of farmed tuna can be controlled.

“One can virtually guarantee a steady supply of farmed tuna, whereas fate dictates how much wild tuna is available,” Moriwaka tells The Japan Times by phone from Croatia. “If there is a surplus of wild tuna, people wouldn’t need to invest in aquaculture in the first place. Farmed tuna exists simply because of the need to create a steady supply of fish.”

Moriwaka says the quality of wild tuna varies considerably, with each individual fish offering different colors and ratios of fat. Existing commercial knowledge allows those involved in farmed tuna operations to produce fish with similar traits across the board.

“You can control the quality of farmed tuna and produce 100, or even 1,000, very similar fish,” Moriwaka says. “As far as buyers are concerned, farmed tuna is easy to manage because the fish are all pretty similar in terms of quality and quantity. That’s why an increasing number of conveyer-belt sushi shops and supermarkets have begun ordering them.”

In the seas off Spain and Malta, Moriwaka says, wild bluefin tuna is caught around June each year, bred for six months and then shipped to overseas destinations. In Croatia, however, Moriwaka and his team breed bluefin tuna they have captured for three years before they are caught, slaughtered, processed and shipped off to other parts of the world, including Japan.

The unit price of bluefin tuna increases the longer the fish are farmed, as operating costs rise over time. Moriwaka says that bluefin tuna meat can become particularly fatty if the fish is bred longer than usual.

“We take very good care of these tuna,” Moriwaka says. “We treat them as if they are our children. There’s a lot of difference between breeding a fish for six months and breeding it for three years. We go to great lengths and spend a lot of time ensuring they are well taken care of.”

In 2015, Moriwaka spent more than six months in Croatia and Iceland, from where J-Trading has been importing wild bluefin tuna.

Moriwaka is quietly confident of the quality of bluefin tuna his team produces.

“In Japan, people eat tuna first with their eyes and then with their mouths. Tuna has to look good first so that people will take a bite,” Moriwaka says. “In Croatia, I’m making sure the bluefin tuna looks good, tastes good and is kept fresh so that it can be eaten raw.”

Unresolved issues

Recent measures against overfishing in the Mediterranean finally appear to be bearing fruit. At the 2014 annual meeting of the International Commission for the Conservation of Atlantic Tunas, delegates voted to increase bluefin tuna quotas from 13,400 tons in 2014 to 23,155 tons in 2017.

The Western and Central Pacific Fisheries Commission, meanwhile, adopted measures in 2014 to cut the overall amount of juvenile bluefin tuna weighing less than 30 kg by half, from 9,450 tons to 4,725 tons.

As a result, Japan’s annual catch was effectively cut from 8,015 tons to 4,007 tons. It is estimated that these restrictions will help Pacific bluefin tuna stocks total 68,000 tons in 2024.

Experts, however, are still concerned about a number of unresolved issues.

Miyahara highlights perceived doubts over the existing data. Unlike Japan, which carefully collects data on domestic bluefin tuna stocks every year, there is no comparable data on Atlantic bluefin tuna stocks, he says.

“Young Atlantic bluefin tuna stocks are not monitored and there are concerns about the data because the schools are captured in large numbers using purse seines,” Miyahara says. “Scientists don’t really know what to believe. Right now, no one can say with any confidence just how much Atlantic bluefin tuna should really be caught.”

Although Miyahara doesn’t go so far as to say the quota restrictions on Atlantic bluefin tuna have been an abject failure, he believes the slow response to the problem, as well as the strict regulatory regime currently placed on the industry, damaged a number of fisheries companies, pushing some to fish illegally.

Fully-closed life-cycle aquaculture also has several problems it needs to overcome. A major concern is the large quantity of fish needed to feed the farmed tuna. Kinki University currently feeds its bluefin tuna stocks wild mackerel and sardine.

“In the past, people used to view these fish as leftovers,” Masuma says. “Now, however, people see them as food that is wasted on tuna. The farming industry is also trying to move away from feeding farmed tuna with wild stocks and use resources effectively.”

Naturally, consumers still argue over whether wild bluefin tuna is better than farmed fish and vice versa.

Masuma and other fish experts agree that many Japanese are infatuated with wild fish due to their seasonal characteristics. The best bluefin tuna, for example, is said to be caught in winter.

Masuma acknowledges that wild bluefin tuna probably tastes best when the fish is in season, but believes believes that farmed tuna is tastier during the off-season.

“Looking ahead, there’s really no need to differentiate between wild bluefin tuna and farmed stocks,” Masuma says. “It’s about co-existing, and bluefin tuna is but one example. That’s the beauty of aquaculture — we can continuously look into new ways to improve on the production of bluefin tuna.”

The second installment of a two-part series that focuses on tuna. For the first installment, visit “All at sea: Lack of regulations hurting tuna stocks.”

  • ahmed waddey

    why not approach the government of Maldives for the researche and have a laboratory in here ?

  • jmanngod

    probably not…. but an end to Japan’s greed could possibly save them.