What is a Caspian sturgeon?

Acipenser persicus, commonly called the Persian sturgeon or Caspian sturgeon, is a critically endangered species of anadromous sturgeon native to the Caspian Sea and its connected freshwater basins. It is one of the most valuable sturgeon species in the world, historically reaching lengths of up to 6 m (20 ft) and weights of up to 1,571 kg (3,464 lb), and is listed as "Critically Endangered" by the IUCN due to overfishing, poaching, and habitat degradation.