Mr Putin and Sergei Shoigu, the Minister of Civil Defence, Emergencies and Disaster Relief, laid flowers on the monument of Valery Chkalov, a renowned pilot of the 1930s, whose name the island bears.

Mr Putin met with an expedition team from the Russian Academy of Sciences, who have been in the island for two weeks studying the habitat and migration routes of white porpoises. He went to a laboratory tent to see the equipment used for the observation of animal behaviour and migration-specifically, Russian- and US-manufactured satellite transmitters. Vyacheslav Rozhnov, expedition leader and Deputy Director of the Severtsov Institute of Ecology and Evolution, told the visitors about a unique physiological peculiarity of white porpoises: one cerebral hemisphere is always alert when they are asleep. The guests were next shown an instructional film describing how to fix transmitters on the animals.

After that, the visitors and the scientists went to the sea by car. Vladimir Putin put on a scuba suit and went waist-deep into the sea, where several fishermen were holding a netted porpoise on whose body a satellite transmitter was to be fixed. "Her name is Dasha," Mr Rozhnov said.

Mr Putin patted the porpoise and asked: "Can she eat us?" "Never-but she can splash water all over us," a zoologist replied. "If she gets angry with us," Mr Putin took up.

When he approached, he examined the transmitter just put on Dasha's fatty hump. "The lock doesn't hold fast enough-it might hurt her," he remarked as he got down to fixing the device with pliers. He was very careful not to disturb the animal. After the adjustment, a veterinarian made an ultrasound examination and said that everything was OK and that the device would not hurt the porpoise or come off.

After that, the fishermen and Mr Putin carried the net deeper into the sea to set Dasha free. "Now, off with you, quick!" he said when she emerged from the net.

His companions said Dasha was large, but that they had seen bigger ones. Mr Putin spent a long time examining porpoises in open cages, and fed them with fish. He ventured to feed even those who had never eaten from a man's hand. He took a huge salmon out of the bucket and beat its tail on the water. A porpoise responded to the summons and gobbled the fish up.

"And you say it wouldn't eat from a hand! You've got to know the tricks!" Mr Putin said.

He was photographed with the fishing team before he left the island.