Sturgeon does not have small bones and its flesh is firm and uniquely tasty, making it perfect for kababs. But the skin is very tough and must be removed before cooking. Be sure not to overcook sturgeon; as with shrimp or tuna, it can quickly become tough and dry. Once upon a time sturgeon came mainly from the Caspian, but these days it is often farmed —in Iran and the U.S. If you can’t find sturgeon fillets at your local fishmonger, try the internet.