Gaia Series 57: Pioneer in saving the "sea crisis"

In this week’s episode, we are taken on an insightful journey into Japan’s fish farming industry which is evolving to deal with declining marine resources to sustain traditional Japanese cuisine.

This episode takes us on a fascinating journey into Japan's evolving fish farming industry, where innovative techniques are being developed to address the country’s pressing challenges of overfishing and climate change. As traditional marine resources become increasingly scarce, the industry has employed creative solutions to ensure the sustainability of Japan's rich seafood culinary heritage.

The story begins in the heart of Ginza, Tokyo, where a unique restaurant operated by Kindai University’s Aquaculture Research Institute introduces the public to the wonders of farm-raised fish. This institution has achieved a world first by successfully breeding Pacific bluefin tuna entirely through aquaculture. In the bustling restaurant, diners savour dishes made entirely from these farm-raised fish. “I thought naturally bred fish would be more delicious, but that’s not the case,” remarks one patron, surprised by the quality of the sashimi platter, which includes luxurious cuts such as medium-fatty tuna and striped jack. Priced at 5,700 yen for three people, this dish exemplifies the potential of farm-raised seafood to rival its wild-caught counterparts.

Their research efforts have extended beyond just the popular bluefin tuna; They have also developed hybrid fish species like the Kuetama, a cross between the longtooth grouper and the giant grouper. This hybrid combines the best traits of both species—the rich taste of the longtooth grouper and the rapid growth rate of the giant grouper. 

Innovations like these are vital as Japan grapples with dwindling marine resources. Takuya Sugimura, a chef at the Aquaculture Research Institute, underscores this urgency, noting: “Our existing marine resources are being exhausted,” emphasising the importance of new methods to sustain Japan’s fish supply.

Professor Masahiko Ariji from Kindai University emerges as a central figure in this story, having dedicated years to researching and developing farm-raised fish. His work led to the creation of the acerola Japanese yellowtail, a hybrid that combines the taste of Japanese amberjack with the texture of yellowtail amberjack. The secret to this innovation lies in the fish's diet, which comprises 10 per cent of acerola—a fruit rich in vitamins and polyphenols. This addition not only enhances the nutritional value and flavour of the fish but also gives the meat a vibrant colour, thanks to the antioxidants in the acerola.

Now available in select markets, the acerola Japanese yellowtail is priced at 499 yen per 100 grams—about 1.5 times the cost of farm-raised Japanese amberjack. Despite the higher price, the fish has quickly gained popularity among consumers. “It looked really delicious,” remarks one shopper, attracted by the fish’s appealing appearance and the reputation of Kindai University’s research.

However, the path to success is not without its challenges. The production of acerola powder, crucial for the fish feed, has been hampered by adverse weather conditions in Brazil, leading to shortages and increased costs. The weak yen has further compounded the issue, raising the price of imported raw materials. Despite these setbacks, there is optimism that the product will take off; A chain restaurant Kurasushi, with 545 stores, has already committed to selling the acerola Japanese yellowtail nationwide because of the fish’s high quality and stable supply. 

Moving from Tokyo to Seiyo City in Wakayama, the documentary introduces us to a groundbreaking project by Marukome, a leading miso producer, to farm sea lettuce on land in 48 vats. This initiative is a response to declining green algae sea lettuce yields, which have dropped to a third of their levels from 837 tonnes in 2000 to 311 tonnes in 2023 due to rising sea temperatures. The land-based farming project, which took seven years to bear fruit, aims to secure a stable supply of this essential ingredient for miso soup, alleviating concerns about its future availability. 

Elsewhere in Japan, in Miyazaki’s Tsuno Town, its fishing industry also faces an uncertain future as both fish numbers and fisherman have dwindled through the years. Enter Associate Professor Toshimasa Yamamoto from Okayama University of Science. He is leading an innovative effort to raise giant groupers and other fish species on land using his “optimal environment water.” This special water enables the successful farming of saltwater fish in freshwater environments, presenting new possibilities for sustainable aquaculture.

Yamamoto’s groundbreaking technology is gaining recognition beyond Japan’s borders. In Mongolia, a country without access to the sea, his methods are being used to farm saltwater fish, proving that this approach has the potential to revolutionise fish farming globally. Reflecting on the broader impact of his work, Yamamoto notes, “I thought it would be great if you could farm fish in the desert,” underscoring the transformative potential of this technology.

As the story draws to a close, the message is one of hope and resilience. Despite the formidable challenges facing Japan’s fishing industry, the pioneering efforts of individuals like Professor Ariji and Associate Professor Yamamoto offer a promising vision for a future where traditional Japanese cuisine can thrive sustainably.