A large giant squid has fascinated visitors after washing ashore at Farewell Spit at the top of the South Island.
Farewell Spit Tours guide Anton Donaldson came across the cephalopod while taking a group to the lighthouse last Friday.
"We found a large white object at the top of the beach, which I presumed at the time was a large woolsack. But it turned out as we got closer, we could see it had tentacles and it turns out it was a giant squid."
He stopped the bus so passengers could disembark to view the squid up close.
Donaldson said there was excitement among the visitors as it was a really special find, a once-in-a-lifetime opportunity to see a creature that lives hundreds of metres below the ocean's surface.
The mantle to the end of its head measured about 4m long, not including its tentacles.
"The tentacles had been gnawed at the end, so they didn't taper to a point - it looked a little like they'd been perhaps eaten by creatures in the sea, small sharks or other fish perhaps."
Donaldson said the squid was otherwise in good condition and there were no clues as to why it might have washed up on the beach.
In the past 30 years or so, about six or seven giant squid have washed up on Farewell Spit.
AUT marine biologist Dr Kat Bolstad runs the lab for cephalopod ecology and systematics - the Squid Squad - and said there were several reasons a giant squid, which usually lives at depths of about 500m, may wash up on the shore.
"We hear about this maybe once a year, every couple of years, perhaps. We've had some in the last few years in Wellington, there was one in Kaikōura a few years ago. It's not unknown, but it's always exciting when it happens."
Dr Bolstad said it was possible that when an entire giant squid washed up it had been caught in a fishing trawl and put back into the ocean, while bits of giant squid washing up were likely the remnants of a sperm whale's meal.
"There don't seem to be too many animals that really like the taste of giant squid, they have a high concentration of ammonium in their tissues, which makes them pretty unpalatable to a lot of animals, they probably taste something like bleach.
"Sperm whales seem to either really like the taste of them or can't taste them. We are not sure which one it is."
She said it appeared the giant squid on Farewell Spit was in good condition which indicated it had died recently.
"People do get very excited about it and rightly so, I mean, how often do you get to see a giant squid specimen in any kind of shape?"
Scientists had been building a picture of giant squid biology for over 100 years but there was lots to learn about them, she said.
It was not known how long they live, what their egg masses look like, and where they lived as young individuals (babies live at the surface, adults in the deep sea).
Bolstad said little was known about their diet, other than they ate small fish and squid.
Later this week, Bolstad and her team will be examining the stomach contents of a giant squid that was frozen earlier in the year.
"A lot of squid seem to digest their food very, very quickly, especially the ones where the bodies are quite transparent, because having any kind of opaque stomach contents probably compromises their camouflage in the deep sea so we think that they have very acidic stomach conditions.
"If you don't get to the stomach contents right away, or freeze them, at least, decomposition happens very quickly and it's quite hard to tell, even if there was something in there, what that had been."
AUT squid scientists, which are called teuthologists, have examined more than 50 giant squid in the past 20 years. These have usually been caught by accident in commercial fishing or research trawls, or washed up on beaches.
Giant squid grow up to 13m long and weigh up to 300kg. The females are larger than males at maturity, with males reaching about 10m and weighing about 200kg.
RNZ
