An orphaned killer whale nurtured back to health hundreds of kilometres from home appeared thrilled Sunday when released into familiar Canadian waters, scientists said.

The two-year-old orca, nicknamed Springer, was transferred from Washington to B.C. Saturday.

The 11-hour journey didn't appear to bother her a bit, said observers, who described her as chipper. She spent the night loudly calling to members of her family pod pushing against the safety net and trying to look over as more than two dozen relatives swam by.

Marine biologists had been unsure what Springer's reaction to her old surroundings would be, or if the other whales would welcome her back. By late Sunday afternoon, scientists decided it was time to let her free.

"Based on what we saw last night, we were quite sure that when we opened the gate, she'd go charging off, and she did," Vancouver Aquarium President John Nightingale said.

Springer frolicked in the water for a while, playing with a piece of kelp and chasing a fish.

"This is not very scientific, but I think she knows she's home," said Lance Barrett-Lennard, a marine mammal expert at the aquarium.

It's still not clear if Springer, officially known as whale number A-73, will rejoin her pod permanently. She is wearing a temporary radio transmitter so her movements can be tracked for a few days. The tags are designed to slip off eventually.

"Let's keep our fingers crossed," Nightingale said.

By late Sunday, scientists estimated the orca had travelled about 10 kilometres from the pen, heading towards Johnstone Strait between the mainland and Vancouver Island.

"The fact that her family's around, the pod is around, that's very encouraging, " said John Ford of the federal Department of Fisheries and Oceans.

Although Springer's relatives expressed little interest in her once she was freed from the holding pen, Ford said she might still join them or perhaps link up with a different pod over the next few weeks.

Springer was found in busy shipping lanes near Seattle six months ago, and was nurtured back to health. Her rescue and move back to Canada is being closely watched by scientists because it's the first time they've ever tried to reunite a wild killer whale with its family.