The official name of Mirugai is Mirukui. The part of the Mirugai used as a sushi topping is the siphon, which protrudes from the shell. The siphon is removed from the shell and then split lengthwise. A single Mirugai yields only about four pieces of sushi. Due to overfishing and the deterioration of its natural habitat, wild Mirugai has become extremely scarce. Although it is still harvested in the Seto Inland Sea and Mikawa Bay, strict catch limits mean it is one of the most expensive sushi toppings.
However, many conveyor belt sushi restaurants offer Mirugai at reasonable prices. The topping is usually quite white. In fact, it is actually Shiromiru (also known as Namigai or Japanese geoduck), which is mainly harvested in Aichi and Chiba Prefectures. As its name suggests, its siphon is larger and whiter than that of Mirugai (“shiro” means “white” in Japanese). It has a distinctive flavor typical of shellfish that live in sandy seabeds, which some people enjoy while others dislike. However, at less than half the price of Mirugai, it is an excellent substitute.
Unfortunately, Shiromiru is also becoming less abundant. To meet demand, Pacific geoduck is now imported from Canada and the United States and is also sold under the name Shiromiru at Toyosu Market.
We hope this information will be helpful.
Revision date: July 15, 2026
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