A rare white whale similar to the one seen in Cook Strait.

A rare white humpback whale has been seen in Cook Strait, one of only four ever recorded in the wild.

The white humpback was spotted with a black humpback on Sunday, during the Conservation Department's 12th annual Cook Strait whale survey.

The two contrasting humpback whales were spotted by former whaler Ted Perano and left researchers stunned, DOC spokeswoman Trish Grant said.



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* Record numbers of humpbacks spotted



Whale survey leader Nadine Bott said distinctive features on the whale were similar to those on one known as Migaloo.

Department of Conservation The white humpback was spotted alongside a black humpback whale during the annual Cook Strait Whale Survey on Sunday.

"They include the dorsal fin's distinctive shape and also distinctive spiny protuberances behind the dorsal fin.

"Animals with these are commonly called 'razor backs'."

Migaloo, which is Aboriginal for "white fella", has been seen off eastern Australia almost every year since 1991.

An up-close look at the white humpback whale, thought to be known as Migaloo.

Bott said a skin sample, taken from the whale with a biopsy dart, would be compared with Migaloo's DNA to confirm whether it was the same whale.

"The analysis will also identify whether the whale is albino or whether its whiteness is due to colour variation," she said.

"White humpbacks are extremely rare and only four have been reported in the world."

Migaloo is the most famous and is believed to have fathered two white calves, Bott said.

Another white humpback whale was spotted in Norway this year.

The annual whale survey is a partnership between DOC and OMV New Zealand to assess humpback whale recovery since commercial whaling ended in Cook Strait 50 years ago.

The survey is timed for humpback whales' northern migration to South Pacific breeding grounds, and estimated the size of the humpback population.

This year's four-week survey, which ends on Friday, has counted 122 humpback whales, far more than the previous-highest tally of 106 humpbacks in 2012.

Bott said the survey showed a "promising" indication humpback whale numbers were on the rise in Cook Strait.

* The video was incorrectly captioned earlier. This is footage from Australia, not Cook Strait.