The pair, part of the New Zealand coastal orca population, had been documented from the Bay of Islands to Foveaux Strait and had been seen on both coasts of both the North and South Islands, Dr Visser said.
She had personally been documenting the animals since 1995, but she had records of them going back to 1982, she said.
Prop, estimated to be more than 50 years old, was readily recognisable, she said.
When she was first spotted as an adult, Prop had been run over by a boat and had suffered significant damage to her spinal ridge with at least three deep cuts into her back.
The damage was done with a trailer-sized fizz boat, she said.
A ship’s propeller would have killed her.
Even so, the damage was so significant that it stunted her growth.
Her dorsal fin was about a third smaller than in orca of a similar age.
"I have seen these individuals hunting a range of species including long-tailed stingray, short-tailed stingray, eagle ray, hammerhead shark, and blue shark," Dr Visser said.
Department of Conservation biodiversity ranger Jim Fyfe said Doc received reports of two orca near the Portobello Marine Laboratory about 1.30pm.
It was thought they were on their way out of the harbour at the time, he said.
"They [orca] are commonly seen around the entrance to the harbour when passing and do venture into the harbour to feed, but it is rare to see them come this far up into the harbour," Mr Fyfe said.
He asked people to respect orca and provide the animals with plenty of space.
- Orca sightings: 0800 SEE ORCA (0800 733 6722)
