Fisheries Research Agency and Yanmar Holdings Acquire Joint Patent for Mass Production Technology of Full-Cycle Aquacultured Japanese Eel

The Fisheries Research and Education Agency (FRA) and Yanmar Holdings have announced the joint acquisition of a patent for core technologies aimed at the mass production of the endangered Japanese eel through full-cycle aquaculture. This development opens up significant prospects for stable eel supply and resource conservation, raising the possibility that consumers will be able to enjoy affordable and safe eel in the future.

The newly acquired patent primarily covers two groundbreaking technologies. One is a special tank technology that enables high-density rearing of glass eels (juvenile eels) at approximately 10 times the conventional density. The other is a low-cost feed technology capable of promoting healthy eel growth while reducing production costs. Yanmar Holdings reportedly collaborated with the FRA on tank development and contributed to equipment aspects such as automated feeders.

In recent years, the population of eels has drastically declined due to overfishing and environmental changes, leading to their classification as an endangered species. Consequently, there has been an urgent need to break away from reliance on natural resources and establish a sustainable supply system. This patent acquisition for full-cycle aquaculture technology marks a crucial and unique step for Japan towards solving this challenge.

If this technology is put into practical use, it is expected to lower the currently soaring prices of eel, making it more accessible for general households. Furthermore, consumer demand for domestic and safe eel is growing to the extent that some voices even suggest that "unless fully cultured, sales should be prohibited in supermarkets and convenience stores." The FRA has previously achieved results in full-cycle eel aquaculture research, and this latest advancement represents the culmination of many years of research efforts.

This patent acquisition demonstrates the high level of Japan's aquaculture technology, and future developments in mass production are highly anticipated. While concerns about profitability, similar to those faced with full-cycle cultured bluefin tuna, remain, as many citizens wish to "eat delicious eel affordably," this technology is expected to significantly transform Japan's food culture and the future of eel.

The context

The Japanese eel (Anguilla japonica) is a culturally and economically significant fish in Japan, traditionally consumed during summer as "unagi" (grilled eel). It is a highly prized delicacy, often associated with stamina and well-being. However, its population has plummeted due to factors like overfishing, habitat degradation, and climate change, leading to its classification as an endangered species by the International Union for Conservation of Nature (IUCN).

The traditional method of eel aquaculture relies on catching wild glass eels (juvenile eels) to raise them, which contributes to the depletion of natural stocks. Full-cycle aquaculture, or closed-cycle aquaculture, means breeding eels from eggs, raising them to maturity, and then breeding the next generation from those cultured adults. This completely eliminates the need to rely on wild-caught glass eels, offering a truly sustainable solution for eel production and conservation. Japan has been at the forefront of this research for decades, given the deep cultural significance of eel consumption and the urgency of its conservation.