Asetra (Also Osetra, Oscietra or Ossetra) is the name given to three species of Sturgeons of the Caspian Sea. These three species are:
A) Acipenser gueldenstadtii with the common name of Russian Asetra
B) Acipenser persicus named as Iranian Asetra.
C) Acipenser nudiventris called Ship Asetra.
Russian Asetra, known also as Danube or Diamond sturgeon, originates from Volga River in Northern part of the Caspian Sea, but moves in all parts of the sea. It can live up to 50 years and grow to the length of 235 cm.
Russian sturgeon mature and reproduce slowly, making them highly vulnerable to fishing. It is distinguished from other Acipenser species by its short snout with a rounded tip as well as its lower lip which is interrupted at its center.
Iranian Asetra is native to warmer climate of the Southern parts of the Caspian Sea, mostly Iranian waters.
Ship Asetra which can also be found in all parts of the Caspian Sea is very close to distinction. Years before CITES Convention registered the name of Sturgeon fishes in Second Appendix of the Convention as endangered Species, Iran had banned its fishing.
Caviar taken from these three species is also presented as Asetra Caviar. Distinguishing caviar taken from Russian and Iranian Asetra is almost impossible, but Ship caviar is different in size from the other two species.
Sizes of Asetra species are between Beluga and Sevruga Species.