Sturgeon is the common name for the 27 species of fish belonging to the family Acipenseridae. Their evolution dates back to the Triassic some 245 to 208 million years ago. The family is grouped into four genera: Acipenser, Huso, Scaphirhynchus and Pseudoscaphirhynchus. Four species may now be extinct.
Sturgeons have been referred to as "primitive fish" because their morphological characteristics have remained relatively unchanged since the earliest fossil record. Several species of sturgeon are harvested for their roe which is processed into caviar—a luxury food and the reason why caviar producing sturgeons are among the most
valuable of all wildlife resources.
They are particularly vulnerable to overexploitation and other threats, including pollution and habitat fragmentation. Most species of sturgeon are considered to be at risk of extinction, making them more critically endangered than any other group of species.
Sturgeons are long-lived, late maturing fishes. Their average lifespan is 50 to 60 years, and their first spawn does not occur until they are around 15 to 20 years old.
Sturgeons are broadcast spawners, and do not spawn every year because they require specific conditions. Those requirements may or may not be met every year due to varying environmental conditions, such as the proper photoperiod in Spring, clear water with shallow rock or gravel substrate where the eggs can adhere, and proper water temperature and flow for oxygenation of the eggs.
Totally 27 species of Sturgeons (Caviar fish) are living in natural water sources of the northern hemisphere, out of
which 5 species are native to Iranian side of the Caspian Sea that are as below:
- Beluga (Huso Huso)
- Sevruga (Acipenser Stellatus)
- Asetra (Acipenser Persicus)
- Russian Sturgeon (Acipenser Gueldenstaedti)
- Ship Sturgeon (Acipenser Nudiventris)
With rapid decrease of the Sturgeon populations in natural resources of which the Caspian Sea was considered the most important source which used to give about 90% of the caviar presented to the world markets, The Convention of the International Trade of Endangered Species of Wild Flora and Fauna (CITES), included the sturgeon species in the list of endangered species in 1998 and with the continuation of the severe decrease of the fish population, finally banned commercial fishing of caviar fish and global trade of products derived from them, especially caviar.
After declaration and execution of this ban, some local entrepreneurs invested on founding farms for production of caviar in different parts of the country especially in the areas close to the Caspian Sea in which optimum environment for production of farmed caviar prevails, the industry developed quit rapidly.
They started harvest of caviar since some years ago and introduced the product to the market. The product indicated that like Iranian Caspian Sea caviar, the farmed caviar also has supreme quality.