Some 200 dead birds have been found at Lake Koroneia near Thessaloniki, prompting experts to express fears yesterday that there could be a repeat of the disaster three years ago when about 30,000 birds died near the lake due to poisoning.

Staff at the Hellenic Wildlife Hospital (EKPAZ) said they have been collecting the bodies of dead birds, including flamingos and ducks, since last week and fear the numbers will rise.

Samples have been sent to laboratories in Athens and Thessaloniki for tests to determine why the birds are dying but it is feared that toxins similar to the one that appeared at the lake, some 20 kilometers east of Thessaloniki, in 2004 due to low water levels has returned.

At least 29 types of birds died three years ago when the bacteria Clostridium botulinum - an anaerobic, spore-forming rod that produces a potent neurotoxin - increased in the lake due to low water levels.

This form of bacteria is quite common in lakes but it is thought that the large amount of water that was drained from Koroneia for irrigation at the time, combined with heavy pollution, meant it multiplied much faster than usual.

Environmentalists warned this May that the water level of Lake Koroneia had plunged to a record low of 1 meter, causing a buildup of harmful bacteria. It is thought that a different type of toxin-producing bacteria called Arthrospira fusiformis is now causing the deaths of the birds.

Maria Moustaka, a biology professor at Aristotle University of Thessaloniki, told Kathimerini yesterday that the bacteria was first detected in February and has now reached a level of high concentration.

"It is likely that there will be more deaths as the toxins collect in the birds' tissue," said Moustaka.

The Thessaloniki Prefecture introduced a set of measures after the disaster in 2004 designed to protect the lake but EKPAZ yesterday asked for the protection of the lake to be boosted.

Many of the projects drawn up three years ago have not been put in place despite Greece having been given access to European Union funds to implement the scheme.