'Fossil fish' hits the web

The coelacanth, the extraordinary fish that has remained largely unchanged for 400 million years, has now become a star on the web.

Pictures of coelacanths (Latimeria chalumnae) swimming off the South African northeast coast are being streamed on the net.

The event is part of a scientific expedition that will help researchers determine the size and viability of the colony recently discovered in deep water in Sodwana Bay.

The coelacanth is sometimes referred to as "old four-legs" because of its distinctive and very large-lobed fins. It fascinates scientists because it is the modern representative of a group of fishes that swam in the seas before there were any back-boned animals on land.

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This is one of the reasons that the coelacanth has also been dubbed a "living fossil", and why the first sighting of a live specimen in 1938 was hailed as one of the major zoological discoveries of the 20th Century.

Coelacanth facts

Can be seen in the fossil record up to 400 million years ago

Over 120 species of extinct coelacanths are known

All coelacanths thought to have gone extinct about 70 million years ago

Live coelacanth caught near East London, South Africa, in 1938, causing huge excitement

Largest specimen ever recorded was 178 centimetres long and weighed 98 kilograms

Perhaps fewer than 1,000 live coelacanths worldwide

There have been relatively few observations since - near the Comoro Islands, off Africa's east coast, and more recently off Indonesia. The recent discovery of what appeared to be a whole colony in Sodwana Bay in October was a major breakthrough for researchers keen to learn more about these remarkable animals.

An expedition is now back among the fish to film them and study their habits. Video footage and still photographs of the coelacanths are also being displayed on a website for surfers to view moments after divers have delivered the images to the surface. The website is a subscription service charging a $10 entrance fee.

"We spotted an adult about 1.3 meters (over four feet) long and filmed it for five minutes,'' expedition head Pieter Venter said on Monday.

"It was fantastic as we were getting a bit nervous after four days of searching, three of them below 100 meters. The visibility and conditions were great and we'll go back Tuesday in the same area.''

This coelacanth was filmed at a depth of over 100 metres

Each coelacanth has a unique pattern of white markings, which enables scientists to identify individual fish.

The current expedition hopes to film more of the creatures so scientists can eventually determine if the Sodwana population is a viable and breeding one or is simply comprised of a few drifters from the Comoro Islands.

Divers can spend only 12 minutes at such depths and may take as long as two hours to go back up to the surface because they need to take decompression stops at different depths.

In November, one cameraman who filmed the fish died after surfacing without proper decompression - the second of three deaths that have been linked to the search for South Africa's coelacanths.