Australian oceans are most biodiverse
AUSTRALIA AND JAPAN BOAST some of the planet’s most biodiverse oceans, but thousands of organisms remain unknown to science, according to a vast inventory of global marine life.
Both nations each have some 33,000 known species, according to the 10-year scientific survey published this week. But there could be as many as 250,000 species in Australia’s vast waters, which are bounded by three oceans and four seas and extend from the coral-rich tropics to Antarctica, it said.
“This constitutes a vast array of highly diverse habitats and ocean features, but many have received limited if any exploration,” says lead author Alan Butler from the CSIRO.
The survey is the result of a project of discovery involving 360 scientists at a cost of US$650 million (A$717 million). It was complied by the Census of Marine Life project (CML), which also published several accompanying reports on Monday.
Northeast concentration
Most of the 33,000 species recorded for Australia were animals, including fish, seabirds, and marine mammals, with a continuing high rate of discovery of new fish and shark species. Marine life is most heavily concentrated in the northeast, which is home to the Great Barrier Reef and is filled with colourful corals as well as dolphins, turtles and dugongs.
“Australia is of tremendous ecological interest,” says Jesse Ausubel, co-founder of the project. “It is advanced in creating protected marine areas around coral reefs but also around its deep-sea areas.”
The scientists combined information that had been collected over centuries with data obtained during the decade-long census to create a list of species in 25 regions, from the Antarctic to the Arctic via the world’s temperate and tropical seas.
The preliminary census, which was published in the journal PLoS ONE on Monday, will be complemented with information still being gathered in areas such as Indonesia, the Philippines, Madagascar and the Arabian Sea in an even larger work which will be released in October.
Crabs and lobsters
The survey found that crabs, lobsters and other crustaceans represent the most common species in the world’s seas, which could change the way humans think of the sea. “When people think of the ocean, they think of fish and whales,” says Jesse. “But the big mammals are only two per cent of diversity, and fish are 12 per cent. We should think first of crustaceans and molluscs.”
The relatively isolated waters of Australia, New Zealand, Antarctica and South Africa have the largest number of endemic species, or those unique to that region.
A key reason for compiling the inventory of marine life was to catalogue species that are in danger of extinction. “Marine species have suffered major declines – in some cases 90 per cent losses – due to human activities and may be heading for extinction, as happened to many species on land,” says Mark Costello of the University of Auckland in New Zealand, explaining why the “inventory was urgently needed.”
