Here are some of the most common sturgeon species used for caviar:
* Beluga sturgeon: The most expensive and prized caviar, with large, light-grey eggs.
* Osetra sturgeon: Known for its delicate flavor and medium-sized, dark-grey eggs.
* Sevruga sturgeon: A smaller sturgeon with smaller, firm, dark-grey eggs.
It's important to note that many sturgeon species are critically endangered due to overfishing and habitat loss. Therefore, it's crucial to buy caviar from sustainable sources to help protect these magnificent creatures.