There are lessons to be learnt from whale strandings, marine expert says
New Zealand's waters are a hot-spot for whales, but we also have the highest rate of whale strandings in the world.
With 42 species and two subspecies in New Zealand waters, nearly half of the world's species of whales, dolphins and porpoises live off our coasts.
Despite this, less than one per cent of our oceans have 'no take' protection from fishing and extractive industries, which disrupt and harm marine animals, Forest & Bird marine mammal expert Anton Van Helden said.
Van Helden told Stuff what to do if you come across a beached whale, and why they end up there.
* Dozens of whales die on Stewart Island
* Past whale and dolphin strandings on our beaches
* Department of Conservation slammed over 'inhumane' handling of stranded whale
* Beached whale in Timaru dies despite multiple rescue attempts by locals
* Sperm whale stranded in Nelson's Rabbit Island will be buried and blessed
* Boat collision may have caused sperm whale beaching near Nelson
There are a number of factors, both natural and man-made that contribute to whales beaching themselves, Van Helden said.
Whales suffer from a lot of the same issues humans do - diseases, parasites and injuries or ailments that come with birth or old age.
But unlike humans, whales have to think about each breath they take. When they are sick or injured they come inshore where they can rest, without having to fight to stay at the surface.
Forest & Bird said that while people tend to associate whale strandings with whales dying, it can be a survival strategy.
Getting trapped in fishing gear or colliding with ships can injure and disorient whales, and extreme weather and getting trapped in low tides can also force them inshore.
Whales, dolphins and porpoises rely on sound for navigation, foraging, and communication, so military sonar and other human-made sounds can also cause whales to beach.
WHEN AND WHERE DO STRANDINGS OCCUR?
On average, Van Helden said, there are around 90 strandings per year in New Zealand, and most of these occur within the summer months.
Certain species, pilot whales and some beaked whales, tend to strand more in summer than any other time of year.
The Mahia Peninsula, Golden Bay, some of Northland's beaches, and the Chatham Islands are beaching hotspots.
WHY DO WHALES BEACH IN GROUPS?
Most of the strandings we have in New Zealand are just one whale at a time, or a mother stranding with a calf, Van Helden said.
But occasionally we see mass strandings, where large groups - some in their hundreds - beach together.
In 1918, 1000 pilot whales stranded themselves on the Chatham Islands, the worst mass stranding in New Zealand, and in 2015, nearly 200 pilot whales stranded themselves at Farewell Spit, in Golden Bay.
Social species, like pilot whales, work together. They often call out to one another in distress and more come to help, also getting themselves into trouble.
WHAT SHOULD YOU DO IF YOU SEE A STRANDED WHALE?
While your first instinct might be to check the whale out, you need to be careful, Van Helden said.
A small flick of a whale fin could injure or even kill a human - put your safety and the safety of those around you first, and then call the Department of Conservation.
Once help is on the way you could cordon off the animal, keep it shaded and keep it wet.
Be sure to keep water away from the whale's blowhole, as that is how they breathe.
Most importantly, stay calm.
A stranded whale will be stressed enough already, and stressed out people won't help, Van Helden said.