The worldwide trade in caviar and other products that come from the wild sturgeon has been banned by the Convention on International Trade in Endangered Species.A spokesman said the decision was imposed for scientific reasons connected to dwindling stocks of sturgeon, and to bring an end to illegal poaching in the Caspian Sea. Every year the organisation approves fishing quotas for sturgeon proposed by nations from the Black Sea, Caspian Sea and Danube regions. Now it is asking for confirmation about stocks of the fish before it can agree to new catches, saying exporting countries should adopt a common management plan. Stocks have declined as much as 30 percent since mid-2004. The legal trade in caviar is thought to be worth about 85 million euros a year but the black market may be worth up to five times that amount.