Scientists said on Sunday they found two types of shark, exotic "flasher" fish and corals among 52 new species in seas off Indonesia, confirming the western Pacific as the richest marine habitat on earth.
They urged more protection for seas around the Bird's Head peninsula at the western end of New Guinea island from threats including mining and dynamite fishing that can smash coral reefs.
"We feel very confident that this is the epicentre of marine biodiversity" in the world, said Mark Erdmann, a US scientist at Conservation International who led two surveys this year.
The scientists found 24 new species of fish, including two types of epaulette shark, slim and spotty growing up to about 1.2 metres long. Among other finds were 20 new species of coral and eight previously unknown types of shrimp.
"It's especially stunning to find sharks these are higher level creatures, not bacteria or worms," Erdmann told Reuters. The sharks get their name from markings on their sides like epaulettes decorations on the shoulders of military uniforms.
The researchers also found new species of "flasher" wrasse fish. The males, which keep harems of several females, suddenly "flash" bright yellows, blues, pinks or other colours on their bodies, apparently as part of a sex ritual.
Erdmann said the region, covering about 18,000 sq km, had a greater concentration of species than Australia's Great Barrier Reef.
He said a new type of fusilier fish, also known as yellowtail, was the only species that could be used for human food found in the two surveys, lasting a total of about six weeks.
"But there's a concern that some might become targets as aquarium fish," he said.
He said Indonesia's Fisheries Ministry wanted to increase the number of marine protected areas, currently covering only 11 per cent of the area around the peninsula.
"We are very concerned about the potential impact of planned commercial fisheries expansion in the region," said Paulus Boli, a State University of Papua researcher.
Threats include human migration to the little-developed region that could put pressure on the healthy reefs. Any logging or mining on the steep coastal hillsides might spur runoff of muddy sediments that can choke corals.
Erdmann said the area surveyed was the centre of a "Coral Triangle" between Indonesia, the Philippines, Papua New Guinea and the Solomon Islands.
Vast coral variety
Around the Bird's Head peninsula there were 1,223 species of fish and 600 types of corals.
The Great Barrier Reef covering an area 10 times bigger has slightly more types of fish 1,464 species but just 405 species of coral.
The Caribbean Sea has fewer than 1,000 species of fish and just 58 types of coral.