What Japanese term names herring roe, sometimes served as sushi?

Kazunoko is the Japanese term for herring roe, sometimes served as sushi.

The name usually refers to the intact, firm egg sac of a female herring, especially Pacific herring. The roe is commonly salted or brined and has a distinctive crisp, popping texture. Its yellow-gold color and crunchy bite make it easy to distinguish from softer individual roe.

Kazunoko is especially associated with osechi, the assortment of celebratory foods eaten at Japanese New Year. Because it contains many eggs, it traditionally symbolizes fertility, prosperity, and the continuation of the family line. Historical Japanese records mention the food as early as the 15th and 16th centuries.

A common mix-up is with masago, which is capelin roe, or tobiko, which is flying-fish roe. Ikura is salmon roe: larger, orange-red eggs usually served as individual beads. Kazunoko can also appear as “spawn on kelp,” when herring eggs adhere to seaweed, but that is a related preparation rather than the ordinary roe sac.