Tuna, once considered a luxury fish, has become a staple on the dinner tables of ordinary people due to relaxed international regulations. Tracing the history of tuna, it wasn’t a luxury fish in the early Edo period. Around the mid-Edo period, fixed-net fishing developed, and tuna began to be caught on a large scale. Currently, tuna from Oma, Aomori Prefecture, is famous. However, during the Edo period (1603-1868), it was caught in the seas around the Kanto region. In the late Edo period, the influence of sea temperature led to large-scale tuna catches. It’s said that at the end of the Tenpo era, there was so much tuna caught that it was difficult to find a place to dispose of it. It’s said that Ebisu Sushi in Bakurocho used this leftover tuna as sushi topping, which led to its popularity. In the latter half of the Edo period, the four famous Edo foods—soba noodles, tempura, eel, and nigiri sushi—were born. However, the prices of these common foods, especially eel and fish (which were once affordable for everyone, such as tuna, octopus, and salmon roe), are becoming increasingly unaffordable.
For the past few years, the price of grilled eel on “Doyo no Ushi no Hi” (a traditional day for eating eel) has been soaring due to poor catches of wild eel fry. But there’s also good news. In 2023, Kinki University became the first university to successfully achieve complete eel farming. Currently, they are honing their skills to create the next generation of ace eels, following in the footsteps of their symbolic “Kinki University Maguro.” Tens of thousands of eels swim freely in Kinki University’s research institute in Wakayama Prefecture. From newly hatched larvae to five-year-old adults, all are born and raised here—these are “Kinki University eels.” The technology for collecting eggs from adult eels, hatching them, and raising them to the juvenile stage is improving daily, and a certain degree of stable production is now possible. However, it seems that commercialization is not yet at that stage. University officials say that if mass production technology is established, the stable supply of eels will improve, leading to price stability.
The world’s leading research institution for complete eel farming is the Fisheries Research and Education Agency (Yokohama City), under the jurisdiction of the Fisheries Agency. The Fisheries Agency and this agency launched a project team in November 2024 to promote the spread of complete aquaculture. Participating companies include Mitsubishi Corporation Group, Fuji Oil, Sinanen Zeomic, Kinki University, Yanmar Holdings, Shinko Technos, Yamada Suisan, and Bushu Gas. They have already repeatedly raised eels to adulthood, and the average time from hatching to juvenile stage has been shortened by 25%, from 200 days in 2008 to 150 days now. The production cost of artificially farmed eel fry was 40,000 yen per eel in 2016, but is projected to drop to 1,800 yen per eel by 2024, a reduction to one-twentieth of the original cost. Currently, 100% of the eel fry used in aquaculture are wild-caught. The market price for eel fry in 2025 is projected to be 1.3 million yen per kilogram, but in years of poor catches, it can soar to 2 to 3 million yen. Once fully farmed eels are supplied stably, it will contribute to the stability of aquaculture businesses. The research and development team is ambitious, aiming to have fully farmed eels on dinner tables by 2028.
