By Chloe Arnold Baku

Ecologists from Russia, Kazakhstan, Turkmenistan and Iran have joined their Azeri colleagues in the capital, Baku, this week to discuss environmental problems in the Caspian Sea.

Among the concerns are the growing levels of pesticides detected in the water, particularly off the coasts of Azerbaijan and Iran.

Demand for caviar has caused sturgeon stocks to fall sharply

Ecological groups are also worried about the amount of oil that is leaking into the water.

The Caspian Sea is thought to hold the world's third largest oil reserves.

There are also fears for the number of sturgeon remaining in the sea.

Demand for their roe, used to make the highly-prized delicacy, caviar, has caused stocks to fall sharply over the past 20 years.

The Convention on International Trade in Endangered Species has ordered a partial ban on sturgeon fishing, but experts say this will do nothing to stop poaching which is estimated to exceed official levels by 10 to 15 times.

Ecologists from the five coastal states are hoping to draw up a strategy to reduce sturgeon poaching and pollution in the Caspian Sea by the end of the year.

But the continuing row over the status of the sea has hampered agreement so far.

Russia, Azerbaijan and Kazakhstan have signed bilateral agreements dividing the sea bed. But Iran and Turkmenistan disagree, insisting on a consensus.

Until a solution can be found, it is feared the environmental problems affecting the Caspian Sea will continue to worsen.