Sightings suggest whale numbers back on the rise
Ninety-two humpback whales were seen over a four-week period this year - the second highest sighting on record.
Figures from the latest Cook Strait Whale Project survey showed 33 more humpback whales were spotted this year than last year. The highest number sighted was in 2012, when 106 humpback whales were seen.
The annual survey has been carried out since 2004 to assess humpback whale recovery since commercial whaling was banned in 1964.
The four-week survey was completed on Friday and was timed to coincide with whales' annual northern migration from Antarctic waters to their South Pacific breeding grounds.
Former whaler turned conservationist and surveyor Joe Heberley, who lives with wife Heather on Arapawa Island, said despite bad weather they got "quite a few" DNA and skin samples.
"It's been a long month looking through those binoculars. Almost as hard as a day on the farm . . . [but] we enjoy it and it's all about the populations of humpback whales."
There was no proof yet that the population was increasing, but Heberley was hopeful, he said.
"I think it could be increasing. Ten years before the population was very, very low . . . but we are in hopes that population is on the increase."
One blue whale and several sperm whales and orca were also seen, but it was not unusual to spot a couple during the survey, Heberley said.
They knew there was a sperm whale hiding in Cook Strait and they were lucky enough to see it, though it wasn't counted in the official tally, he said.
Conservation Minister Dr Nick Smith said the 92 humpback sightings in Cook Strait this year was "good news".
"The findings, to date, indicate the New Zealand humpback population is increasing, but slowly."
The research team collected 41 skin samples using a biopsy dart tool and took 38 photos of individual whales, Smith said.
The skin samples were used to assess the humpback population and link to other humpback whales seen in the South Pacific, as well as providing genetic information.
The research team noted some unusual behaviour among humpbacks this year, including more sea surface activity and more milling around, he said.
"This might be due to the warmer-than-normal sea temperatures that have been reported this winter."
Whales were slaughtered in New Zealand waters throughout the 19th and 20th centuries, he said.
"[So] it is great news to see our conservation effort are paying off with these improved sightings, but with a slow breeding cycle we would expect it to take many decades for their populations to fully recover."
The humpback recovery will be assessed by comparing numbers seen in the survey with whaling station humpback records from the 1950s and early 1960s.
This year is the 11th annual survey.
BY THE NUMBERS
Whales spotted over a four-week period in the Cook Strait:
2008 – 40 humpback whales and four pygmy blue whales
2009 – 49 humpback whales and one sperm whale
2010 – 70 humpback whales, including a newborn, and two sperm whales and three minke whales
2011 – 73 humpback whales, blue whales, sperm whales and orca
2012 – 106 humpback whales 2013 – 59 humpback whales and blue whales
2014 – 92 humpback whales, one blue whale, several sperm whales and orca
The Marlborough Express