Researcher Neil Bruce of the Museum of Tropical Queensland studies specimens in lighted aquarium on Lizard Island Reef as part of the Census of Marine Life.
Credit: Gary Cranitch/Queensland Museum
SYDNEY: We are yet to discover 80% of the world’s marine species, scientists said after completing the first comprehensive inventory of our oceans.
A collection of papers published in the journal PLos One looks at 25 key ocean areas, including Australia, and will help to set a baseline for measuring future changes to our oceans, particularly from the threats of overfishing and pollution.
Scientists said they hope this research will help form better conservation and management policies.
Vertebrates make up just 2%
In each of the 25 ocean areas studied the recorded number of species varied from 2,600 to 33,000. Crustaceans make up around one fifth of these while vertebrates such as whales, seals and turtles comprised only 2% of all marine species.
Scientists estimated that for every one of these known species there are another four yet to be discovered.
“On the outer Australian shelf and on the slope beyond a lot of what we see is new” said marine ecologist Alan J Butler from CSIRO, and lead of author of the paper looking at the Australian waters.
Australian story
Butler and his colleagues concluded that 50,000 out of an estimated 250,000 total marine species have been identified in Australian waters. This includes 130 introduced species and 58 threatened species.
Conclusions were drawn from main databases and surveys of the Australian Exclusive Economic Zone.
Frequencies of finding new species - in this case, every one in five - and performing comparison surveys allow scientists to estimate how many species are yet to be discovered.
Estimating unknown species
Called ‘surrogate-based surveys’, they measure physical and chemical properties of a location, which scientists then compare to other ecosystems to extrapolate how many different species can be supported.
Worldwide, scientists reported that 230,000 species have been discovered but the total number of species could be up to 1.4 million. That leaves a possible 1.2 million species yet to be discovered.
“These are really just informed guesses, there are no analytical ways of getting to those estimates,” said marine biologist Gary Poore from Museum Victoria, who was not involved in the research.
“However, there are a lot of environments we haven’t explored. Over time, I think we will keep discovering more and more species.”
The collection of papers was part of the Census of Marine Life, a decade long initiative from scientists around the world to take stock of our oceans. The full results of the Census of Marine Life are expected to be released in early October 2010.
