In the end, not even a whale whisperer could save Colin, the baby humpback which has spent the week nuzzling up to yachts in a Sydney waterway in a desperate search for its mother.

The plight of the two-week old calf, (who has turned out to be a female) captivated the world after the whale was discovered bonding with a boat in Pittwater harbour on Sunday, trying to suckle its hull after being abandoned by its mother.

Despite an international call for help, an offer of assistance from the Army, and a last-minute attempt at spiritual healing by an Aboriginal whale whisperer, nothing could save Colin, who was humanely put down by vets in the early hours of this morning.

National Parks and Wildlife Service officials had unsuccessfully tried to lure Colin out to deeper waters in the hope it would be adopted by nursing mother in one of the whale pods currently travelling along Australia’s east coast as part of their annual northern migration.

A vet report and blood tests revealed the two-tonne calf, believed to be only two to three weeks old, was in poor condition and had only hours to live. She was suffering from shark bite wounds and breathing difficulties and by this morning was having trouble swimming.

Dozens of members of the public gathered at dawn on Friday at The Basin, in the picturesque Pittwater waterway just north of Sydney, to watch Colin’s final hours as vets prepared to put it down.

Amid emotional scenes from wildlife campaigners, some of whom wept and shouted “murderers”, rangers in an inflatable boat injected a fatal dose of anaesthetic into the 14-foot-long (4.5m) whale, which took around 10 minutes to take effect.

The whale was seen to be thrashing about as it was guided close to shore. Officials reached out to stroke the calf before others hoisted it onto a tarpaulin. The whale was then pulled into a tent on the beach and grey tarpauline was hung to obscure the operation.

A wildlife group had organised a legal injunction against the National Parks and Wildlife Service to prevent the whale being euthanised, but had been unable to serve it in time.

Captain Alexander Littingham, from Devine Marine Group who organised the injunction, described the scene as “absolutely disgusting”.

"It looked like a scene out of the Antarctic with a Japanese fishing boat," he said.

The whale's struggle to survive has dominated the news most of the week in Australia. She even her has own Facebook sites, the most popular of which, Save Colin the Whale, has 3000 members. The Australians strongly oppose Japanese "scientific" whale killing and flock to whale-watching tours during the giant mammals' annual migration to the Antarctic.

Animal welfare groups defended the decision to euthanase the whale. Steve Coleman, an official with the RSPCA, said Colin needed to be destroyed and that it was done humanely. “It was cruel to keep it alive,” he said.

The parks service was this morning investigating reports of an adult whale carcass being eaten by sharks off the southern state of Victoria on Friday, Sally Barnes, the head of theNational Parks and Wildlife Service, said. Officials hoped to collect a DNA sample to determine if it is the missing mother.

Colin’s body was examined by zoo experts to determine whether she might have been ill and will be buried at an undisclosed location in NSW.

She was named after a National Wildlife and Parks officer who first tried to rescue her. Australian tabloids have now re-named her Colleen.

There has only been one documented case of a baby whale being successfully reared by humans, when a team of veterinarians from Sea World in San Diego managed to save a baby grey whale which had become stranded in 1997.