Passengers aboard a ferry in Lyttelton Harbour were surprised with a rare treat this morning - two large pods of orca.
Orca were initially spotted by Diamond Harbour locals about 9am today.
Nearly two hours later, passengers aboard the Black Cat Cruises ferry travelling from Lyttelton Harbour to Diamond Harbour noticed a large pod including a mother and young calf heading toward Quail Island.
On the return journey at 11am another large pod of "inquisitive" orca were seen near Purau Bay.
"Orca rarely travel into Lyttelton Harbour so today's sighting was very unusual," said Black Cat Cruises skipper Dan Facer.
Facer has skippered with Black Cat Cruises for five years and this was his first sighting.
"The mother and calf were likely going to feed near Quail Island as the surrounding waters are a common breeding ground for large fish.
"The second pod sighted in Purau Bay was very active and inquisitive. It was a large pod with orca of all ages and sizes.
"They put on an awesome display of tail slapping and breaching at the back of the boat. It was the best sighting we've ever had on our Diamond Harbour Ferry."
Facer slowed down the ferry and made sure to keep a safe distance from the orca.
The engines were also turned off when orca approached the back of the boat, allowing passengers to marvel at one of the world's largest apex predators.
"Orca are very intelligent animals that are well-organised and follow highly complex social structures within their pods, which often consist of large groups of family members that can span several generations," Facer said.
While there is not a typical orca migration season in New Zealand, Black Cat Cruises usually reports a number of sightings each year with the majority occurring in spring.
The first orca of the season were sighted in Akaroa Harbour in October last year.
• Orca are the largest animal in the dolphin family and one of the only known cetaceans to attack sharks, whales and other large marine animals.
• Having no known predators, orca are known as an apex or alpha predator. This means it's able to hunt freely without fear of being attacked by another marine animal.
• Orca are protected in New Zealand waters under the Marine Mammals Protection Act 1978, administered by the Department of Conservation (DoC).
• New Zealand is home to an estimated 150-200 orca, which travel long distances throughout the country's coastal waters.