Sturgeon stocking programme in the Caspian Sea with emphasis on Iran

INTRODUCTION The sturgeons of the Caspian Sea are considered highly valuable species. The Caspian Sea has traditionally been regarded as the sea of sturgeon since it produces more than 90 percent of the world’s caviar. Despite a remarkable decline of sturgeon numbers over recent years, the Caspian Sea still continues to be of considerable importance in sturgeon fisheries. In 1997, the global landing of sturgeon amounted to 6 126 million tonnes, which the Caspian Sea sturgeon catch accounted for 3 872 million tonnes (FAO, 1999). At the turn of the last century (1900) the former Soviet Union used to produce some 29 000 million tonnes of sturgeon. The fishery decreased operation following the First World War (1921–26) resulting in dramatic decreases in catch down to 1 100 million tonnes, which in turn boosted the sturgeon stocks in these years. Numerous sturgeon hatcheries were created as mitigation for lost spawning habitat as a result of dam construction in the former Soviet Union and the Islamic Republic of Iran. With the partial destruction of natural sturgeon spawning grounds the artificial breeding of sturgeon species and fingerling release was started in the former Soviet Union in 1955 (Ivanov and Majinic, 1997). The same trend began in Iran in 1970 through the assistance of Russian fisheries technicians (Abdolhay, 1997). The growth in sturgeon fingerling released grew to such an extent that production reached 100 million fingerlings in 1985. The production and release of sturgeon fingerling continued by the establishment of 11 sturgeon hatchery centres in USSR along with three and five hatchery centres in Azerbaijan and Iran respectively; hatcheries played a crucial role in rehabilitation and restoration of sturgeon stocks. After fingerling production, release to the sea and fisheries management the capture increased to 28 000 million tonnes in 1977. During this period, sturgeon catch in Iran ranged from 1 500–2 500 million tonnes. In the 1990s, there was a sharp decline in sturgeon stocks due to ecological changes caused by human activities (i.e. illegal fishing). The catch of sturgeon fish plummeted from 28 126 million tonnes in 1980 to 3 872 million tonnes in 1997 (FAO, 1999). In this article, attempts are made to briefly review the sturgeon landing in recent years as well as the production and release of sturgeon fingerlings and the role hatcheries play in the development of the sturgeon fisheries in the Caspian Sea.