Sturgeon of the Caspian Sea
Historically, the Caspian Sea has been home to the world's largest abundance of sturgeon. The largest inland body of water on Earth, the Caspian is fed by more than 100 rivers, the most important of which for sturgeon is the Volga River in Russia, which supplies 75 percent of the Caspian Sea's sturgeon catch.
The Caspian Sea and surrounding nations
The Caspian Sea is bordered by Russia, Kazakhstan, Turkmenistan, Azerbaijan, and Iran. Russia, Kazakhstan, Azerbaijan and Iran supply the majority of the world's sturgeon catch and caviar production. The remainder comes from China, Romania, the United States, Canada and others. Virtually all of the caviar produced by Caspian Sea nations comes from four species: beluga sturgeon (also known as giant or great sturgeon), which produces beluga caviar; Russian sturgeon, which produces osetra caviar; stellate sturgeon, which produces sevruga; and Persian sturgeon, which produces Persian and osetra caviar. The fifth Caspian Sea sturgeon species, the ship sturgeon, is highly endangered and trade of its caviar is prohibited.
Beluga, stellate and Russian sturgeon populations have declined precipitously over the last 20 years. (The status of Persian sturgeon populations is less certain.) While overfishing is the principal reason for the decline, the loss of spawning habitat and pollution also are responsible.
Overfishing and poaching for the lucrative caviar market is perhaps the single biggest threat to sturgeon in the Caspian Sea region. Each egg-bearing female can produce 8 percent or more of her body weight in caviar. With caviar retailing for as much as $105 per ounce, the financial rewards of sturgeon fishing and poaching are enormous.
With the collapse of the Soviet Union, regulation of northern Caspian Sea fisheries -- at one time strong and effective -- largely has fallen apart. With the exception of Iran, Caspian Sea fishing nations lack the resources to implement and enforce effective sturgeon management programs. Though several nations have regulations limiting fishing and prohibiting poaching, enforcement has been crippled by lack of funding and reported violence against enforcement officers. Illegal fishing is thought by many to be increasing.
As a result, the illegal catch in the Caspian Sea and Volga River is estimated to be 6-10 times greater than the legal catch, and less than 15-20 percent of the actual sturgeon catch is thought to be registered in official reports. In 1995, virtually all the Russian and stellate sturgeon migrating to spawn in the Volga river were thought to have been caught by poachers. By 1998, the U.S. Fish and Wildlife Service estimated that more than 50 percent of the worldwide trade in caviar was illegal. While international trade requirements adopted in 1998 have helped reduce illegal trade, one sturgeon still can provide the equivalent of a month's salary in the economically depressed region, and there is little reason to believe that poaching for this "black gold" will cease any time soon.
Sturgeon in the region spawn in the rivers principally the Volga -- feeding the Caspian Sea. Immediately after hatching, sturgeon larvae of most species migrate to the sea where they live for 6-20 years (depending on the species) until they mature. At that point, females migrate back to their river of origin to spawn.
Dam construction has taken its toll, particularly on beluga sturgeon. By preventing sturgeon from reaching their main spawning grounds, dams have significantly reduced spawning habitat for sturgeon in the Caspian Basin. Historically, Caspian sturgeon populations spawned in the Volga, Ural, Kura, Terek, and Sulak rivers. Now, the Ural River is the last free-flowing river feeding the Caspian Sea, the only such river where sturgeon continue to reproduce naturally, without the benefit of hatcheries. However, some believe that the spawning population of sturgeon in the Ural has been essentially destroyed by poachers, and the river suffers from significant industrial and pesticide pollution.
On the Volga River, the most productive in the world for sturgeon, as much as 85 percent of the spawning grounds for Russian sturgeon and virtually all of the beluga spawning grounds are blocked by the Volgograd dam.
Population growth and industrial development in the Caspian region have generated an immense pollution problem. The World Bank estimates that one million cubic meters of untreated industrial wastewater is discharged into the Caspian annually. Ten million people live adjacent to the Caspian Sea and 60 million more live in the Volga River watershed. Soviet oil extraction left behind polluted soil and water, rusty equipment, and well fires that burned for years. The long history of oil contamination combined with untreated sewage from towns along the Volga River, industrial discharges and agricultural runoff have significantly degraded the Caspian Sea. Meanwhile, the five countries surrounding the sea are rushing to exploit still untapped oil deposits. Pollutants from urban and agricultural runoff and industrial discharges have been associated with reproductive and other abnormalities, as well as large fish kills.
Overfishing, habitat destruction and pollution have left a grim legacy. In the late 19th and early 20th centuries, annual sturgeon catches often exceeded 20,000 tons. By the late 1990's, the annual catch had declined to roughly 1,000 tons. The Russian State Committee for Fisheries projects that catch for the 2000 fishing year will be 441 tons of sturgeon, half the Russian quota. Fishermen have been unable to find enough fish to meet their quotas. Russia expects to produce 40 tons of caviar for export, a drop from 110 tons in 1999 and from 1,200 tons in 1985. Similarly, while Iran was authorized to export 90 tons of caviar in 2000, it reduced that amount to 70 tons to conserve sturgeon. The Russian State Fisheries Committee reportedly is concerned that diminishing catches may compel Russia to ban commercial sturgeon fishing in the northern Caspian Sea by 2002.
Source: Khodorevskaya, R., et al., 1997.
In the 1950s, the Soviet Union initiated artificial reproduction and population enhancement programs for beluga, Russian and stellate sturgeon in hatcheries along the Volga River. Although hatcheries have their problems, they have made important contributions to maintaining the three Caspian Sea species, particularly beluga sturgeon, in recent years.
The one relatively bright spot for sturgeon in the Caspian Sea is the Iranian fishery that operates in the southern part of the Caspian Sea. The Iranian Fishery Organization (IFO), or Shilat, is the government institution that controls the sturgeon fishery and caviar trade. Only about 5 percent of the Iranian catch is beluga sturgeon. About two-thirds of Iran's caviar production is osetra, produced mostly by Persian sturgeon, a southern Caspian Sea native whose status is uncertain. Iranian sturgeon fisheries are tightly controlled and generally thought to be well managed. Despite their controlled system, Iran does not have important spawning grounds for sturgeon and therefore has limited ability to restore threatened Caspian Sea sturgeon.
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