A rare and dangerous squid with eyes the size of dinner plates and scores of razor-sharp hooks to snag its prey has been caught by fishermen off Antarctica, New Zealand scientists say.


The half-grown female colossal squid is only the second intact example of the monster cephalopod known to have been found, said marine biologist Steve O'Shea of New Zealand's national museum.


"I've seen 105 giant squid, but seeing something like this is pretty sensational," O'Shea told Reuters on Thursday.


A trawler caught the 150-kg (330-lb) squid in the sub-Antarctic Ross Sea about 3,600 km (2,200 miles) south of Wellington.


The squid was eating Patagonian Toothfish, which grow to two metres in length, when it was caught. It was dead when it was hauled into the trawler and the remains are now in the New Zealand national museum.


The body of the colossal squid is much bigger than the giant squid, which can weigh up to 900 kg (2,000 lb) when fully grown. A giant squid's tentacles can be up to 13 metres (43 ft) long, compared with 5 metres (16 ft) on the recovered creature.


Comparisons are difficult because of the colossal squid's hostile environment and rarity. Five of the six previous discoveries have only been pieces inside sperm whale stomachs.


MORE DANGEROUS


American marine biologist Kat Bolstad said the colossal squid was a more dangerous animal than the giant squid, the mythical monster of the deep that attacked Captain Nemo's Nautilus in Jules Verne's "Twenty Thousand Leagues Under the Sea".


"This is a very aggressive animal and moves quickly. If you fell in the water next to it you would be in big trouble," said Bolstad.


The colossal squid finds food by literally glowing in the dark, deep waters to light up prey for its massive eyes -- the biggest of any animal.


But it is the colossal squid's weaponry that marks it out from its giant cousin.


Its eight arms and two tentacles have up to 25 teeth-like hooks -- deeply rooted into muscle and able to rotate 360 degrees -- as well as the usual suckers to ensure fish do not escape.


The hooks not only hold fish for the squid's two parrot-like beaks, but also are used to fend off attacks from hungry sperm whales, O'Shea said.


The species, whose scientific name is mesonychoteuthis hamiltoni, was previously thought to have lurked at least a kilometre (half a mile) down in the freezing waters near Antarctica, but the specimen found a fortnight ago was near the surface.


O'Shea said the discovery raised questions about what else was down deep in the ocean.


"We know so little about the marine environment in general. If animals like this are turning up, what's going to be at 3,000-metres (10,000-ft) depth. We don't know," O'Shea said.