Dozens of exotic new fish and corals have been discovered in a spectacular Indonesian seascape which scientists have hailed as a "species factory" - possibly the richest marine environment in the world.
The barely-explored Bird's Head Seascape, off the province of Papua, is "mind-blowing" and "unparalleled" in terms of the number and variety of species that have been logged there, scientists say. Further expeditions are expected to discover dozens more fish and corals.
Among more than 50 creatures discovered in two recent explorations by scientists from Conservation International (CI) are two new epaulette sharks, one of which appears to "walk" on its fins, several types of "flasher' wrasse and many other multicoloured reef fish, new types of mantis shrimp and around 20 new reef-building corals. A total of more than 1,200 species of fish and almost 600 species of coral were recorded, three quarters of the world's total.
Although investigated in the 1880s by explorers including the great Victorian naturalist Alfred Russel Wallace - who described it as "one of the most singular and picturesque landscapes I've ever seen'' - the Bird's Head area was largely ignored by modern scientific expeditions until this century.
Dr Mark Erdmann, who led the two expeditions, said: "These reefs are species factories. This region is simply mind-blowing in terms of its diversity. For our surveys to uncover over 50 new species of coral, fish, and mantis shrimp in less than six weeks is unheard of in this day and age. From the perspective of marine - and especially coral reef - bio-diversity, it is unparalleled for an area of this size.''
"Compared to the Great Barrier Reef, the Bird's Head has roughly 50 per cent more reef-building coral species - 600 as opposed to 405 - in an area with approximately one-tenth the size," Dr Erdmann said. "Although the GBR has slightly more recorded species of reef fish, 1,464 compared with 1,233 in the Bird's Head, it is important to note that the Bird's Head has received a fraction of the scientific attention as the GBR, and there are undoubtedly many more discoveries to be made there.''
The Bird's Head had 10 times the number of reef building coral species as the Caribbean Sea, which is 20 times bigger, he said. During the expeditions, scientists twice broke world records for the number of species found at single sites - 330 species of reef fish from an area called Fak-Fak.
The area also includes the largest nesting area for Pacific leatherback turtles and migratory populations of sperm and Bryde's whales, orcas and several dolphin species.
CI is calling for urgent action to preserve the area from destructive activities such as bomb and cyanide fishing as well as the intensification of commercial fisheries. The seascape is also under threat from mining and timber operations in coastal areas which could result sediments being washed into the sea. Only a tenth of the area is currently protected. Fortunately, strong currents and cool water, among other factors, will, scientists believe, help the reefs resist the "coral bleaching", caused by climate change, which has damaged many other reefs around the world.
The Bird's Head peninsular and its 2,500 offshore islands and submerged reefs lie off the western half of New Guinea. The coastline is extraordinarily diverse, with deeply forested steep inclines and mangrove swamps. Some shallow reefs are inland, bathed in river waters while others are exposed to Pacific waves.
The area lies at the centre of the "Coral Triangle" of the Pacific, which encompasses the Philippines, Indonesia, Papua New Guinea and the Solomon Islands and which scientists believe functions as a "centre of origin" for much of the species diversity of that region of the world, actively exporting species outwards.
The discoveries of the Bird's Head Seascape come in the wake of an expedition last year to Papua's isolated Foja Mountains, several hundred kilometres to the south, where scientists found what they described as a "lost world" containing new species of birds, butterflies, frogs and other wildlife and confirm the international importance of the region.
Scientists are still debating the reasons behind the region's biodiversity. Dr Erdmann said one reason was that, over time, some deep sea basins - such as Cenderwasih Bay, a large lagoon-like area in the north of the region - had been closed by geological movements, which allowed new species to develop through natural selection and genetic drift. When the bays were reopened by rising sea levels or further geological movements, the species dispersed.