"We are sure there are populations off Tanzania. And I expect them to be very common off the Mozambique coast as well," he told Reuters on Thursday on the sidelines of a scientific conference on the coelacanth.

Ribbink said raised public awareness seemed to be behind the surge of Tanzanian fishermen coming forward to report coelacanth catches -- though the trend could also point to more offshore fishing in response to depleted inshore stocks.

He said he also expected fishermen were netting them off Mozambique but not reporting the catches.

Scientists say coelacanths, which live in underwater caves and canyons at depths of between 100 and 300 metres, may provide clues to life's distant past, while the search for them deepens our understanding of the western Indian Ocean.

The ultimate survivor, the coelacanth was around long before the dinosaurs and was long thought to have died out with the massive beasts over 65 million years ago.

Then one was netted by a fishing trawler off South Africa in 1938 -- a catch that shook the scientific world and was widely regarded as the zoological find of the 20th century.

They were subsequently found to be near the Comoros Islands off Africa's east coast and were first observed there in their natural habitat from a submersible vessel.

In 2000, scuba divers stumbled across South Africa's coelacanths in Sodwana Bay off the country's northeast coast.

But while they have been netted in other places and been found off Indonesia, they have not been observed elsewhere.

Dr. Ron Uken of the University of KwaZulu-Natal said mapping of the canyons along Africa's east coast -- the favoured home of the coelacanth -- had hardly begun.

"Only Sodwana off South Africa has been mapped. The underwater canyons of Tanzania, Mozambique, Kenya and Madagascar all have to be mapped," he said. A sophisticated ship-based sonar system is used for such mapping.

The conference also heard that the 1938 specimen, long believed to have been a "stray" dragged down to South Africa's southern coastline by currents, may in fact have been on the edge of its range.

Oceanographer Mike Roberts said recent research showed the popular belief that there was a westward moving current off Mozambique was simply not true.

"The Mozambique current does not exist and so coelacanths could not have been washed down to East London from the Comoros. The currents off Mozambique move in big swirls," he said.