Japan’s fully farmed tuna almost disappears

In Japan, commercial production of fully farmed bluefin tuna will almost disappear. Maruha Nichiru will reduce its production in fiscal 2025 by 80% compared to the previous year. In addition, large aquaculture companies such as Nissui and Gokyo have withdrawn from related businesses. In 2002, Kinki University in Japan successfully achieved the world’s first fully farmed bluefin tuna. As an ideal technology that can provide a stable supply of rare tuna, related investment was once active, but profitability deteriorated due to the recovery of natural resources and soaring feed prices.

Takahiko Okada, head of the Kinki University Aquaculture Seed Center, which successfully achieved the world’s first fully farmed tuna, admitted: “Now, there are almost no orders for fully farmed tuna fry.” Because they are larger than in the past before they can be shipped, the sales volume of fry in 2024 is about 7,000, which is only one-tenth of 15 years ago.

Fully farmed refers to a farming method that raises artificially hatched fry to the adult stage, and then collects eggs from the adult fish to reproduce the next generation. This farming method is widely used in red sea bream and yellowtail because it has little impact on marine resources and can provide high-quality fish all year round. Although the complete artificial breeding of tuna is extremely difficult, Kinki University has achieved it after 32 years of research.

Kinki University has received a large number of orders for fry from breeders across Japan. In order to meet the demand, Kinki University has cooperated with Toyota Tsusho to produce artificial fry since 2010. In the same year, Maruha Nichiru succeeded in the first complete artificial breeding of tuna among private enterprises, and Gokyo and Nissui also succeeded. In terms of the years with the highest production, Gokyo produced 198 tons in 2021, Nissui produced 670 tons in 2020, and Maruha Nichiru produced 950 tons in 2020. Companies are competing to expand their scale and “strive to reach 1,000 tons.”

However, there are frequent reductions and withdrawals. Maruha Nichiru plans to produce 50 tons in 2025, a reduction of 5% from the peak in 2020. From April, the tuna produced will be mainly exported, and the chances of seeing it in Japanese stores will decrease.

The reason for the latter is the rapid deterioration of profitability. “The production cost is extremely high,” said Tomoki Kimura, president of Nissui’s aquaculture subsidiary Nissui Tuna Co., Ltd., talking about the reason for the “temporary suspension of production” in 2022.

Conventional tuna farming is to raise 2-3 kg natural fry for 3-4 years before supplying them, while fully artificial farming requires hatching from fertilized eggs and breeding from a smaller stage, which takes up to 5 years to ship. Tuna needs 15 kg of feed for every 1 kg it grows. Long-term farming is not easy when the prices of natural mackerel and sardines are rising due to low catches.

In addition, the recovery of natural tuna resources is not conducive to the aquaculture industry. In 2025, the fishing quota in Japan’s coastal waters will be expanded by 50%. The average wholesale price of “tuna (domestic)” in Tokyo’s Toyosu market in 2024 was 3,879 yen per kilogram, down 6% year-on-year. The price of tuna, known as “black diamond”, has stabilized, and the advantages of farming have decreased.

Jiyang’s fully artificial farming subsidiary was dissolved in 2024 due to insolvency. Nissui and Maruha Nichiro no longer focus on fully artificial farming, but on short-term artificial farming that raises about 100 kilograms of natural tuna for half a year before shipping.

Satoshi Imoto, director of Maruha Nichiro’s farming department, emphasized that despite changes in the business environment, “fully artificial farming will never stop.” With changes in the marine environment and a sharp decline in feed mackerel and squid, there is no guarantee that natural tuna can continue to grow. Once you exit the fully artificial farming business, it will take at least 10 years to restart.

Kinki University is strengthening research to solve the problems faced by fully artificial farming, including good-growing fry and feed that does not rely on natural resources. The Japanese have been eating tuna for more than 5,000 years and have a deep relationship with tuna. Efforts to ensure a stable supply of tuna will continue.