The permanent darkness of the ocean depths is home to a far greater range of animals than previously thought, scientists said on Sunday. (REUTERS/Larry Madin/Handout)

From a translucent jumbo octopus to a fish bearing barbed fangs, scientists say they have discovered hundreds of new species living several kilometres beneath the ocean surface and in total darkness.

Researchers probing pitch-black waters from the Antarctic to deep seas off Iceland say they have cataloged about 5,700 marine life forms that have never seen light, with some being new to science.

The data, part of the ongoing Census of Marine Life project, stunned some of the international scientists who say the unexpected finds show how poorly understood the deep seas are and how much more there could be out there.

“It really illustrates just how little we know about the deep ocean and how species-rich it is,” Paul Snelgrove, a marine biologist at Memorial University in St. John’s, N.L., said before the release of the findings Sunday.

“The fact that they’re so pervasive is really the exciting thing.”

Scientists plumbed waters from the continental margins to a spine-like ridge running down the mid-Atlantic, taking in huge mountain chains comparable to the Alps and shallow plains that support several fisheries.

Odd Aksel Bergstad of the Institute of Marine Research in Norway said they discovered 1,000 species in an area between Iceland and the Azores and suspects at least 40 are new to science.

“We were surprised to find so many big animals,” he said from Oslo, referring to large squid and fish species.

“That’s not so common anymore. We thought we were getting to the level of knowledge that we wouldn’t find so many.”

Of the close to 700 crustaceans found to the southeastern Atlantic, 99 per cent are thought to be new discoveries.

At up to 3,000 meters down, researchers found nine species of a slimey, gelatinous octopod commonly referred to Dumbo because of its large ear-like fins. One measured two meters, while another may never have been seen before.

They also found a new species of sea cucumber around the Crozet Islands, a sub-Antarctic archipelago of small islands in the southern Indian Ocean.

“We have a more complete picture now of the deep-water habitats,” Bergeron said.

Some of the species lived in frigid waters of 2 degrees C and fed on meagre droppings from the water’s surface far above, bacteria and the bones of dead whales.

At such depths and being so remote, Snelgrove assumed they would find little evidence of human impacts on habitat and ecology. But even at 4,000 meters he said they detected the effects of climate change through warming temperatures and a depletion of food sources.

“I always tended to think of the deep sea as being invulnerable to human activity,” he said. “And we’re starting to see more and more evidence now that in fact there is significant impact of deep-water fishing and ocean acidification.”

Bergeron said the growing understanding of what exists in the world’s deep seas should inform governments and marine “managers“ of what needs to be done to protect the areas.

Some regions with fragile corals and seamounts in the North Atlantic have been closed to bottom fisheries, but he says more should be deemed off limits to destructive fishing and oil industry practices.

The 10-year census is cataloguing the ocean’s marine species, diversity and distribution, and plans to wrap up in October 2010. Using deep-towed cameras, it has so far documented 17,600 species known to live in darker waters.