One morning on a recent trip to my dad’s hometown of Hamamatsu, Japan, I found myself on a secluded bank of Lake Hamana, overlooking a small dock where seaweed harvesters keep their boats. I was there to see the bodhisattva of mercy, Kannon, a stone statue bearing a prayer to protect the local population of eel, or unagi, for generations to come.

The statue was erected in the late 1930s—just before World War II—with funding from the local fishing and aquaculture groups whose names are inscribed on her granite base. At around 15 feet tall, the statue is unimposing, even friendly-looking, with her basket and smiling eyes. Like many of Hamamatsu’s residents, she appears blissfully unaware that Japan’s freshwater eel is now endangered.

Bordering Hamamatsu’s western edge, Hamana is a ragged mitt-shaped lake in Shizuoka Prefecture, some 40-square-miles in size and linked at its southern end to the Pacific Ocean through a narrow channel. The channel was formed in 1498, when an earthquake broke the land barrier that had separated the lake from the sea. What was once the site of a catastrophic disruption is now host to prized aquaculture industries, unagi chief among them.

The area’s first unagi farm was established in 1891. Today, unagi is one of Hamamatsu’s major exports, famous across Japan for its trusted quality and sweet taste. But it’s more than just an export: Anyone who comes to Hamamatsu will know within minutes of arrival that unagi is this city’s star, a major source of local pride and identity, like crab cakes to Baltimore or lobsters to coastal Maine. The evidence can be found in the snacks on display at department-store kiosks, farmer’s markets, convenience stores, even the gift shop of the local castle: cookies called Unagipie, unagi-flavored soda, unagi-enriched potatoes, fried unagi bones. It seems like every street has its own a certified-local unagi restaurant, many of them more than a century old. Even the city’s current mascot, an adorable incarnation of the 17th-century shogun Ieyasu Tokugawa, features a cartoon eel as his topknot.

Growing up in the U.S., I understood unagi as a (delectable) way of connecting with the Hamamatsu half of my heritage. I ate unadon—tender and juicy unagi, grilled and served over rice—at family dinners. I’ve visited my relatives in Japan 10 times, and we’ve celebrated each infrequent reunion by going out for unagi. One of the restaurants they’ve taken me to, Atsumi, is located just around the corner from the building where my grandmother was born. It was a rare treat to sit with her in its low-slung tatami room on my last trip, both of us devouring our unadon and clear-toned eel-gut soup as she described the ways the neighborhood has changed during her 88 years as a resident.

So when overconsumption landed Anguilla japonica (better known as Japanese eel) on the International Union for Conservation of Nature’s Red List of Threatened Species in 2014, it presented more than one type of challenge to Hamamatsu. According to the United Nations’ Food and Agriculture Organization (FAO), Japan’s residents are responsible for roughly 70 percent of global freshwater eel consumption—about 130,000 tons annually. A huge portion of this consumption occurs on the Day of the Ox, a Japanese food ritual celebrated with meals of eel; the day occurs when summer temperatures are at their peak, and nutrient-rich unagi is said to prevent heat exhaustion. According to the Japanese Bureau of Labor Statistics, the average Japanese household eats 30 percent of its eel each year in the period around the Day of the Ox. To meet demand, as the Japan Times has reported, eel imports more than double during the month of July.

Unagi’s endangered status has a lot to do with its unique life cycle. The eel is catadromous, which means it splits its life between fresh and saltwater. Hatched at sea, the small, transparent young eels, known as glass eels or elvers, migrate to freshwater, where they mature before eventually traveling thousands of miles to the open ocean to spawn and die. Scientists have been trying to replicate spawning conditions for eels in captivity since the 1970s, with limited success. Eel farms, therefore, rely on wild-caught glass eels—a fundamentally unsustainable system that effectively withdraws from an account every year and reinvests nothing.

Around Hamamatsu, fishermen catch migrating glass eels between December and March and sell them to the region’s eel farmers, or unanchu. The eels are then raised to market size in greenhouses that hold warm, aerated freshwater ponds. When I visited one local farm in December—Daiwa Eel, one of the region’s oldest—the atmosphere inside the greenhouse was thick as oil, with a tropical humidity, a fishy odor, and the persistent background roar of rushing water. It was the end of the unagi season, just before the arrival of the next generation of glass eels. When my guide lifted a protective plastic cover to show me the pond below, I caught a glimpse of a shimmering tangle, bodies flowing with the artificial current like muscular, silver seaweed.

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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