A deep-sea search for giant squid has captured the world's first video footage of the mysterious creature in its habitat. The expedition that was a decade in the making involved two New Zealanders.
Auckland Museum's collection manager, Severine Hannam, was part of the expedition that caught the footage of a giant squid in seas off the Bonin Islands, about 1000km south of Tokyo.
The expedition, which involved more than 50 dives between June and July last year, involved scientists spending up to six hours a day in tiny submarines at depths of up to 1000m.
Ms Hannam, who acted as research assistant to another New Zealander, marine biologist Dr Steve O'Shea, said the expedition's aim was to capture footage of the giant squid for Japanese broadcaster NHK and the Discovery Channel.
A documentary on the expedition, narrated by David Attenborough, will feature on Sky TV's Animal Planet next week.
Ms Hannam didn't know what to expect when one of the expedition's scientists returned from a 600m dive with the footage of a 5m-long female giant squid.
"Like everyone else, all the giant squid I had seen were dark red or white but ... as the light went on it, it turned from a dark red to silver and then a gold colour.
"It looked amazing; it actually looked like it was made of gold."
Giant squid remain an enigma because most of the specimens that have been studied have been dead, or discovered in shallow water.
Scientists know what they look like and the sizes of specific animals but they don't know anything about how long they live, how they grow and reproduce or how they interact.
Despite the footage raising more questions than answers, Ms Hannam said the find would still be helpful.
"The way it was feeding was with its head down ... The squid had eight arms but it was missing tentacles so we know that giant squid can survive with missing tentacles and we know that light doesn't distract the giant squid too much."
The expedition was Ms Hannam's second giant squid-seeking venture in three years after spending a month on the Sea of Cortes (Mexico) in an unsuccessful search, also with Dr O'Shea.
She said the location was selected for its high number of giant squid caught by the local fishermen.
Ms Hannam blended 200kg of defrosted giant squid into a juice to use as a lure but admitted that once at sea, it felt like they were looking for a needle in a haystack.
Oceanographer Edith Widder said the scientists had more success with an optical lure that was designed to imitate the bioluminescent display of the common deepsea jellyfish, the Atolla. They also attached a light to a 1m-long diamond back squid that was used as bait.
How scientists found giant squid
*An optical lure attached to a drifting camera platform with over 600m of line with the only illumination coming from a red light invisible to most deep-sea animals
*The only light visible to deep-sea animals is the blue light of the lure, designed to imitate the bioluminescent display of the common deep-sea jellyfish, the Atolla.
*The jellyfish resorts to using this light when being chewed on by a predator as its only hope for escape may be to attract the attention of a larger predator that will attack its attacker.
*Scientists also attached a light, similar to a squid jig, to a one-metre long diamond back squid that giant squid feed on
Legends of the Deep: the Giant Squid, narrated by Sir David Attenborough, will screen on Animal Planet on September 2.