- Acipenser güldenstädti persicus Borodin, 1897
IUCN: СR; CITES (II)
IUCN: Critically Endangered A2cde
In the past, Persian Sturgeon was considered a subspecies of A. gueldenstaedtii (A. g. persicus). Since 1973 (Lukyanenko and Korotaeva), based on immunological, biological and reproduction studies and also the morphological differences, it is currently accepted as a species. Based on mitochondrial DNA analysis no molecular marker has been found to differentiate between these two species. Research is still ongoing. In Iran catch for the two species exists for the past 40 years where managers and fishermen use 7-8 morphometric differences to separate these two species (M. Pourkazemi pers. comm.). A large scale study (joint between Iran and Russia) on the genetic and morphometric differences between these two species is needed. This was identified as a priority in the World Bank sponsored Regional Workshop on Sturgeon Genetics, June 2009.
This species is known from the Caspian basin, being most abundant in southern part. In its past distribution, the Persian Sturgeon ascended all rivers around the Caspian Sea. It currently now only ascends lower courses of Iranian rivers, the Volga and Ural, and may enter the Terek and Kura. It is not currently stocked in Russia. More than 80% of total sturgeon stocking in Iran is for this species (Pourkazemi pers. comm.). In 1998, 24.5 million fingerlings were released (Abdolhay and Baradaran Tahouri 2006), but in 2008 only 10 million fingerlings were released.
The only legal commercial exploitation of this species is in Iran (mainly from hatchery stock). Restocking in Iran started in 1969. It is estimated that 80% of catch originates from stocked individuals (Pourkazemi pers. comm.).
Iranian catch data shows that there has been between 54-56% decline from 1960/65 to 2006; the catch has continued to decline since 2006 but data is not yet available for this time period. The decline in catch does reflect a decline in abundance even though there are fisheries regulations and a reduction in catch effort (Pourkazemi pers. comm.).
In Russia, commercial catch in the Caspian Sea has been banned since 2000. The 2007 Quota for scientific catch was 8 tonnes; it is unknown if this was met.
The following Iranian catch data (Pourkazemi 2006) shows the total sturgeon catch from Iran (it is estimated that approximately 40% of the catch from 1960 to 1989 and 50% of the catch between 1990 and 2007 was of A. persicus, Pourkazemi pers. comm.): 1960 - 2,000 tonnes (A. persicus = 440 tonnes), 1965 - 2,100 tonnes (A. persicus = 462 tonnes), 1970 - 3,000 tonnes (A. persicus = 750 tonnes), 1975 - 1,675 tonnes (A. persicus = 302 tonnes), 1980 - 1,429 tonnes (A. persicus = 372 tonnes), 1985 - 1,650 tonnes (A. persicus = 297 tonnes), 1990 - 2,645 tonnes (A. persicus = 582 tonnes), 1995 - 1,500 tonnes (A. persicus = 480 tonnes), 1997 - 1,300 tonnes (A. persicus = 559 tonnes), 1998 - 1,200 tonnes (A. persicus = 588 tonnes), 1999 - 1,000 tonnes (A. persicus = 480 tonnes), 2000 - 1,000 tonnes (A. persicus = 540 tonnes), 2001 - 870 tonnes (A. persicus = 557 tonnes), 2002 - 643 tonnes (A. persicus = 418 tonnes), 2003 - 463 tonnes (A. persicus = 315 tonnes), 2004 - 500 tonnes (A. persicus = 345 tonnes), 2006 - 330 tonnes (A. persicus = 201 tonnes), 2007 - 225 tonnes (A. persicus = 137 tonnes).
Habitat: At sea, coastal and estuarine zones. Spawns in strong-current habitats in the main course of large and deep rivers on stone or gravel bottom. Juveniles are found in riverine habitats during their first summer.
Biology: Anadromous (spending at least part of its life in salt water and returning to rivers to breed). Males reproduce for the first time at 8-15 years, females at 12-18. Age range for mature females is 6-40 years; 85% are between 14-18 years, and 80% of males are between 12-16yrs (Moghim 2003). Average generation length is 14 years. This species does not spawn every year. Spawning takes place in June-August when temperature rises above 16°C. In the southern Caspian basin, the Persian Sturgeon spawns in April-September but reproduction is interrupted from June to August when temperature rises above 25°C. Most individuals migrate upriver in April-May, but some may enter rivers at other times of the year. In the southern Caspian basin, there is a second run in September-October. Juveniles migrate to the sea during their first summer and remain there until maturity. At sea, the Persian Sturgeon feeds on a wide variety of benthic molluscs, crustaceans and small fish.
This species has different ecological biological requirements to A. gueldenstaedtii, as it prefers warmer water for spawning and has a shorter migration run.