Baby humpback whale spotted in Cook Strait

Baby humpback whale spotted in the Cook Strait. Photo / Supplied

A baby humpback whale spotted in the Cook Strait yesterday is only the second calf reported in New Zealand waters.

It came two days after whale watchers sighted a rare white humpback in the same stretch on Monday.

The baby humpback and its mother were seen by the Department of Conservation's whale research team, which described it as an "exciting encounter".

The first newborn humpback calf was seen in July 2010, also during the annual DoC Cook Strait Whale Survey, which is timed for humpback whales' migration from the Antarctic to South Pacific breeding grounds.

Seeing the newborn calf yesterday was a special treat for the survey team, whale survey leader, Nadine Bott, said.

"We marvelled at how lucky we were to witness such a miracle as a newborn whale. We hope it travels safely to warmer waters."

It came two days after the team had a "remarkable sighting" of a rare white humpback whale, which was identified as Migaloo, a well-known whale usually seen off Australia.

"The two calves we have seen were likely to have been born prematurely in our waters," Ms Bott said. "The former whalers who work with us on the whale survey assure me they never saw newborn calves in their day.

"The calf we saw yesterday still had faint foetal folds and was about 3-4 metres in length. It was probably several days to a week old, but it is hard to be sure. The mother was relatively small and the calf was possibly her first."

The calf is only the second reported in NZ waters. Photo / Supplied

The annual whale survey, a DoC partnership with OMV New Zealand, has so far spotted 136 humpback whales - the highest number in its 12 years, with three days of the four-week survey still to run.

The previous highest tally was 106 in 2012.

The research aims to assess humpback whale recovery since commercial whaling ended in New Zealand in 1964, and also aims to estimate the size of the humpback population in New Zealand waters.

The higher number of humpback whales being seen indicates their New Zealand population is "bouncing back", Ms Bott said.