When dining in Nantong, one often hears people talk about the "Four Freshes of the Yangtze River." Naturally, the first on the list is the pufferfish, followed by the knife fish, the shad, and the mandarin fish. Situated at the confluence of the river and sea, Nantong's selection of the Four Freshes more accurately represents the delicacies of the lower reaches of the Yangtze River, or what could be called the "Yangzi River Four Freshes." These are species that travel between freshwater and saltwater, found at the estuary where the river meets the sea—rarely seen elsewhere. This makes them even more distinctive to the region.
For example, the shad: "It lives in the sea most of the year, but enters the Yangtze River only in early summer to spawn in freshwater. Its range rarely extends beyond Nanjing upstream." (as noted by Zhu Wei). Nantong is fortunate, lying along the necessary migratory route for fish like the shad; living near the end of the river seems to offer more culinary luck than living at its source. Even residents of Wuhan in the middle reaches can't enjoy shad, settling instead for Wuchang fish. Though Wuchang fish has a certain fame, it doesn’t match the flavor of the shad.
Among the Four Freshes of the Yangtze River, the pufferfish was praised as early as the Song Dynasty by Su Dongpo: "Beyond the bamboo, peach blossoms bloom here and there; the ducks know first that the spring river water is warm. The ground is covered with reed shoots and young bamboo sprouts—it’s just the time when the pufferfish is about to ascend." Thanks to this poem, the pufferfish gained fame. I even suspect the popularity of Nanjing's salted duck might owe something to Su Dongpo's auspicious words ("the ducks know first").
Moreover, in folk sayings, there’s the phrase "risking death to eat pufferfish," which elevates the significance of pufferfish almost above life itself. This is something that fish from the middle and upper reaches of the Yangtze, like the Wuchang fish, cannot compare with. Like the shad, the pufferfish also grows in coastal waters, returning to the Yangtze after the Start of Spring each year. However, "those in the sea are highly toxic, while those in the river are less so," leading people to consume more of the river variety. Even so, throughout history, there have been numerous cases of poisoning. This isn't because the pufferfish is poisonous—it's because people couldn't resist the temptation. The allure of the pufferfish drives some to crave it to the point of "no regret despite nine deaths."