Warmer seas create whale of time in NZ
Balmier sea temperatures are bringing marine mammals closer to New Zealand’s shores
Ryan Dunlop At least seven whales have been spotted around New Zealand in the past week and scientists expect public sightings of the great mammals to continue.
Higher than average sea temperatures are bringing them closer to our shores, experts say.
The humpback species is being reported more frequently as its population recovers. If that continues, in
20 years sighting the species on our coast will be a mundane affair, said University of Auckland associate professor Rochelle Constantine.
A rare white humpback whale was this week spotted tracing the North Island’s East Coast, heading north towards breeding grounds around New Caledonia.
It is believed to be either Migaloo, which hangs around Oceanic waters, or a new whale.
Migaloo is estimated to have been born in 1986 and was first spotted in
1991, passing through Australia’s Byron Bay.
Until a white whale calf emerged in September 2011, Migaloo was thought to be the only white whale in existence.
Last Friday members of the Houhora Big Game and Sports Fishing Club spotted a white humpback breaching off Mt Camel, about 50km north of Kaitaia, and managed to capture the spectacle on a cellphone.
A few days earlier commercial cray fisher Joshua Whitley was casting pots about 16km off the coast of Gisborne when he noticed the white whale near the boat.
Constantine says the humpback whale population that feeds south of New Zealand once stood at about
20,000.
But that number plummeted into the hundreds until whaling was banned in New Zealand waters in
1964. More than 50 years on from the ban, the population is on the rise and around 10,000.
The global population now is just over 80,000.
Constantine has been studying the marine mammals in the South Pacific since 1995.
“This is the time of the year when the humpback whales are moving to the winter breeding ground. It’s when we see most of the humpbacks passing New Zealand,” she says.
She was able to confirm the growing population thanks to recent scientific endeavours to tag the mammals to track their movements.
“As they recover in numbers we are seeing more humpbacks passing New Zealand. They go past our east and west coast.”
“I would like to go back and deploy some more satellite tags; perhaps the Oceanic whales are recovering slower because they migrate on a longer journey to their Australian cousins.”
Constantine will head to Antarctica in February with the National Institute of Water and Atmospheric Research to find feeding humpbacks as well and tag them to track their migration patterns.
“In the next 20 years, humpbacks will be a sight that is not remarked on. It’s everyone’s goal. When we stopped whaling we were at the forefront,” she says.
Meanwhile, a southern right whale made Wellington Harbour its home, in the process causing the Matariki fireworks display planned for last weekend to be delayed.
On Saturday, a 17m sperm whale, weighing more than 30 tonnes, washed up on Marfells Beach, near Seddon.
On Monday, two “superrare“pygmy right whales were found dead on Taupo¯ Bay in the Far North.
Department of Conservation marine ranger Cat Peters said the rare marine animals had only been sighted at sea 30 times.
Also on Monday, a pygmy sperm whale and its male calf stranded at Mahia beach. They both died. Peters, of Russell, said an unusually high number of whale sightings this year is due to warmer sea temperatures and easterly winds bringing the whale’s food closer to shore.
The sea temperatures also triggered a die-off of penguins this year. In March, Sir Peter Blake Trust environmental programme manager Bahkti Patel was involved in a project at the Kermadec Islands, one of the most densely populated meeting grounds for humpbacks in the Southern Hemisphere.
At the islands they were able to collect skin samples and carry out testing to determine the whales’ gender, health and relations to other whales.
Oceanic humpback populations are recovering, slowly but surely, she says.
“Certainly we can be confident numbers are recovering — there are two population of humpbacks in this area.
“The Oceania whales are recovering slower. Rochelle is looking if there a link to the longer migration of Oceania whales with the recovery rates we see.”
It wasn’t until 2015 the whales were tagged and they were able to trace their movements.
Orca Trust founder and marine biologist Ingrid Visser says she has had several reports of a white humpback whale travelling north on the east coast.
A white humpback has been recorded in the Atlantic Ocean but Visser is 99 per cent sure the sightings would not be of that whale.
It is possible the new whale could be the offspring of Migaloo.
Visser says the new whale is either albino or leucistic, meaning it has white pigmentation.
The difference between the two is that albino animals have pink eyes while leucistic animals have black eyes, Visser says.
It is not yet known whether Migaloo is albino or leucistic.
● Anyone sighting the white whale has been asked to report it to the Orca Research Trust on 0800 733 6722.