The loss of affordable glass eels will spell doom for this and the more than 30 other unagi farms and processors that surround Lake Hamana, the Daiwa unanchu told me. In 1965, the Japanese glass-eel catch measured 140 tons, according to the FAO; in 2000, it measured just 40 tons, a 71-percent decline over 35 years. As the Japanese catch becomes less plentiful, glass eels are increasingly imported from China, Taiwan, Indonesia, the Philippines, and even as far away as the United States. At the moment, Daiwa’s glass eels are all domestically sourced, but high prices have made cheaper eels from China and Taiwan a more attractive option for many consumers.

But the biggest blow to Japan’s unagi industry may be yet to come: The Convention on International Trade in Endangered Species may place restrictions on the buying and selling of Japanese eel when it meets later this year. In the meantime, some in Japan believe that tighter regulations on the practice of eel farming may be enough to save it. Hoping to stave off any restrictions, the Japanese government, the All-Japan Eel Culture Association, and the Union of Eel Farmers Corporation of Japan have all discussed measures to improve how the industry monitors and reports its numbers. The Japanese Fisheries Agency requires eel farmers to be licensed, with monetary penalties for those who exceed certain limits on glass-eel procurement. And in 2014, Japan, China, Taiwan, and South Korea, agreed to limit their glass-eel catch to 80 percent of the four countries’ 2014 volume. The problem with this measure, though, is that it sets an artificially high ceiling. The 2014 catch was unusually plentiful compared to the years preceding it—triple what was reported in 2013, according to the Japanese Fisheries Agency.

In Hamamatsu, there are few signs that the species is in peril, beyond elevated prices. Unagi is as ubiquitous as ever: Supermarkets, department stores, and restaurants appear to be doing business as usual. And on my trip last month—even with the knowledge that unadon is no longer a responsible choice—I happily joined my relatives at two different venerated unagi restaurant in Hamamatsu, where I ate some of the best unagi I’ve had.

Or maybe it’s that I now experience the unagi as more of a precious treat, something meant to be savored before it disappears.

If people are lucky, their cultural needs happen to align with sustainable practices. But as the strain on the planet’s natural resources becomes greater, there will be many more places like Hamamatsu, where the gulf between the two seems impossibly wide.

The relationship between a person and her food is rarely purely rational, though, no matter how clear the environmental and social consequences. I know that sating my appetite for unagi can be a powerful, self-defeating act, and that the cumulative effect of so many family meals can be powerfully destructive. But cultural connections to food are also valuable, and the choice to swear off a certain part of my heritage is not a simple one. Hamamatsu’s choice to swear off a core part of its identity, if it happens, will be a wrenching one. The question is whether the city really has a choice at all.

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