Humpback whales spotted in record numbers

By Erica Mather 17/07/2015

Delighted researchers and volunteers counted a record 137 whales during the Cook Strait Whale Survey completed this week.  This is the highest tally since the survey began in 2004 and suggests that their numbers are increasing in New Zealand waters.

The annual four-week survey, run by DOC research in partnership with oil and gas company OMV New Zealand, is timed to coincide with the northern migration of humpback whales from Antarctica to the warmer South Pacific to breed.

Researchers aim to estimate the population size of the humpback whale and determine whether they are recovering since the cessation of commercial whaling in 1964.  This will be ascertained by comparing their survey data to the records of whalers that hunted humpbacks in Cook Strait during the 1950s and early 1960s.

“The higher number of humpback whales being seen indicates the New Zealand population is recovering but we are not yet seeing the extraordinary rates of increase they have in Australia of around 11% a year. Perhaps that is something we will enjoy in our waters in the future,” survey leader Nadine Bott said.

Humpback whale slapping its tail
Humpback whale slapping its tail

Six former whalers provided invaluable assistance to the researchers by spotting whales from a rise on Arapawa Island, a superb location overlooking Cook Strait.  The whales spotted from the island were approached by boat to be photographed and precisely identified using a biopsy dart tool that collects skin samples for genetic analysis.

This technique enables researchers to learn more about the genetic diversity of New Zealand humpback whales.  Skin samples are matched with those collected across the South Pacific, thereby mapping the whales’ path.  Humpback whales identified in New Zealand have also travelled around the east coast of Australia and around New Caledonia.

Two surprise sightings made this year’s survey particularly special.  The characteristic dorsal fin of the famous ‘Migaloo’ – a rare, white humpback whale that usually migrates past Australia, was seen on July 5.  The survey team also spotted a newborn humpback whale calf, the second to ever be reported in New Zealand.