If you've enjoyed sushi or sashimi in the modern age, this chapter might feel a bit strange. Isn't salmon one of the most common and ubiquitous sushi toppings to ever exist?
Surprise! Historically, salmon has rarely been eaten raw in Japan. It would usually be eaten salted, as aramaki salmon. The modern popularity of raw salmon was a product of Norwegian salmon farms, which started exporting their salmon to Japan in the late 1980s. Notably, the Norwegian salmon is a different species from the Japanese salmon, and is quite a bit fattier too. Norwegian farmed salmon, being raised in a controlled environment, are generally free from the parasites we see in this chapter, finally allowing the Japanese populace to taste raw salmon in large quantities.
So what was the ubiquitous sushi topping before salmon took over Japan? In most of Kanto, it would be tuna (maguro), and in Kansai, it would be seabream (tai) and flounder (hirame). Tuna is especially favored, to the point that it's got several dedicated cuts to be used as sushi toppings (toro, chutoro, ootoro are some of the more straightforward ones).