Springer used to swim alongside passenger ferries off Seattle

The young killer whale, or orca, named by scientists as Springer, was found last year in a harbour in the US city of Seattle, near the busy shipping lanes of Puget Sound.

Springer was taken back to her native waters off Canada's Pacific coast last July - in what was the first attempt by scientists to reunite a wild orca with its family.

Having nursed Springer back to health, they winched her onto a barge and towed her 740 kilometres (460 miles) to Telegraph Cove.

There was no certainty that the whale's family would take her back, but photographs taken this week show them swimming together.

Researchers say Springer looks fat and confident.

"Seeing her come back is clearly a big weight off our shoulders, and everything now looks good," said Clint Wright of the Vancouver Aquarium.

Too friendly

The same process may now be used to rescue another whale living in a small harbour near Vancouver Island. Some scientists say this second whale will have to be removed before it becomes too comfortable with humans.

Orca whales normally stay with their family group, or pod, all their lives. Each pod has a distinctive dialect of clicks and squawks to communicate which each other.

Springer had to be moved from Seattle as she was getting too friendly with boats, and there were fears she might capsize a small vessel as she grew.