Marine life census shines light on biodiversity of the seas

Virginie Montet Yahoo News 3 Aug 10;

WASHINGTON (AFP) – Crabs, lobsters and other crustaceans represent the most common species in the world's seas, and the waters of Australia and Japan are the most diverse, according to a vast inventory of marine life published Monday.

"We have made discoveries. We have learned new things," Jesse Ausubel, co-founder of the Census of Marine Life project, which compiled the roll call of life in the sea, told AFP.

Australian and Japanese waters each feature almost 33,000 forms of life that have earned the status of "species."

The waters off China, the Mediterranean Sea and Gulf of Mexico also feature in the top five in terms of biodiversity, says the preliminary census published in the open-access Public Library of Science (PLoS ONE).

The roll call is the result of a 10-year project by 360 scientists at a cost of 650 million dollars.

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 inventory 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.

Even then, the inventory will be incomplete, said Nancy Knowlton of the Smithsonian Institution and leader of the census project on coral reefs.

"The ocean is simply so vast that after 10 years of hard work, we still have only snapshots, though sometimes detailed, of what the sea contains," Knowlton said.

So far, the study has found an average of 10,750 known, named species in a given region, and the census-takers believe that for every known species, there are at least four yet to be discovered.

And with the finding that crustaceans are the most numerous, it could change the way humans think of the sea.

"When people think of the ocean, they think of fish and whales," said Ausubel.

"But the big mammals are only two percent of diversity, and fish are 12 percent. We should think first of crustaceans and mollusks."

Around one-fifth of all marine life are crustaceans, followed closely by mollusks -- squid, octopi, clams, snails and slugs -- which make up 17 percent of species in the sea.

Next, at 12 percent, come members of the pisces, or fish, family, including sharks.

Single-cell microorganisms from the family of protozoa and algae and other plant-like organisms are tied for fourth place in the species inventory at 10 percent.

Among others are echinoderms, including starfish, sand dollars and sea cucumbers; porifera, which includes sponges; and cnidaria, including sea anemones, corals and jellyfish.

Popular marine mammals such as whales are included in the "other vertebrates" category and comprise only a tiny part of marine biodiversity.

Algae, protozoa, seabirds and marine mammals that continually cross the world's oceans are considered the most cosmopolitan species because they were found in more than one region.

The manylight viperfish -- Latin name 'Chauliodus sloani' -- earned itself the title of "Everyman of the deep ocean" after data showed that it has been recorded in more than a quarter of the world's seas.

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.

In contrast, the Mediterranean Sea had the most "alien" species: over 600 species, or four percent of those inventoried, were originally from elsewhere. Most had come from the Red Sea, via the Suez Canal.

The Mediterranean is also one of two regions most threatened by human activity including overfishing and pollution. The other is the Gulf of Mexico, which was inventoried just prior April's massive BP oil spill.

A key reason for compiling the inventory of marine life was to catalog species that are in danger of extinction.

"Marine species have suffered major declines -- in some cases 90 percent losses -- due to human activities and may be heading for extinction, as happened to many species on land," said Mark Costello of the University of Auckland in New Zealand, explaining why the "inventory was urgently needed."

Scientists plumb the depths to ask how many fish in the sea
First global census of marine life logs 230,000 species – but 10-year study by 360 scientists warns of mass extinctions
Alok Jha guardian.co.uk 2 Aug 10;

It has been the biggest and most comprehensive attempt ever to answer that age-old question – how many fish are there in the sea?

Published today, a 10-year study of the diversity, distribution and abundance of life in the world's oceans attempts just that. The Census of Marine Life, which hopes to paint a baseline of marine life, estimates there are more than 230,000 species in our oceans.

"From coast to the open ocean, from the shallows to the deep, from little things like microbes to large things such as fish and whales," said Patricia Miloslavich of Universidad Simón Bolívar, Venezuela and co-senior scientist of the COML. The study also covers crabs, plankton, birds, sponges, worms, squids, sharks and slugs.

A team of more than 360 scientists around the world have spent the past decade surveying 25 regions, from the Antarctic through the temperate and tropical seas to the Arctic to count the different types of plants and animals.

The results show that around a fifth of the world's marine species are crustaceans such as crabs, lobsters, krill and barnacles. Add in molluscs (squid and octopus) and fish (including sharks) and that accounts for up to half of the number of species in the world's seas. The charismatic species often used in conservation campaigning – whales, sea lions, turtles and sea birds – account for less than 2% of the species in the world's oceans.

The surveys have also highlighted major areas of concern for conservationists. "In every region, they've got the same story of a major collapse of what were usually very abundant fish stocks or crabs or crustaceans that are now only 5-10% of what they used to be," said Mark Costello of the Leigh Marine Laboratory, University of Auckland in New Zealand. "These are largely due to over-harvesting and poor management of those fisheries. That's probably the biggest and most consistent threat to marine biodiversity around the world."

The main threats to date include overfishing, degraded habitats, pollution and the arrival of invasive species. But more problems are around the corner: rising water temperatures and acidification thanks to climate change and the growth in areas of the ocean that are low in oxygen and, therefore, unable to support life.

The COML identified enclosed seas such as the Mediterranean, Gulf of Mexico, China's shelves, Baltic, and the Caribbean as having the most threatened biodiversity. "Enclosed seas have the risk that, when you impact it and throw chemicals or other garbage into it, it will not go away so easily as it will from the open ocean," said Miloslavich.

Dense coastal populations of humans also tend to be packed along enclosed seas, meaning increased pollution and extraction of more biodiversity from the water.

The Mediterranean, which contains almost 17,000 identified species, scored the maximum threat rating of five for four of the categories. Scientists studying the Mediterranean identified problems related to increased litter from shipping and munitions across the sea as well as bombs discharged during the Kosovo war.

The Mediterranean also faces problems because of invasive species displacing the creatures that already live there. This sea had the most alien species out of all the 25 regions surveyed by the COML, with more than 600 (4% of the all species present). Most had arrived from the Red Sea via the Suez Canal.

The most diverse regions identified by the COML are around Australia and south-east Asia. "It's also a hotspot for terrestrial biodiversity as well and this has been known for about 100 years," said Costello.

"It looks like that region with the coral reefs has always had a very high rate of speciation. It also has a very diverse range of habitats – from the deepest areas of the oceans to large areas of shallow seas, which can support coral reefs."

Both Australian and Japanese waters contain more than 30,000 species each and are among the most biologically diverse in the world. Next in line are the oceans off China, the Mediterranean Sea and the Gulf of Mexico.

Apart from algae and the seabirds and mammals that travel around the sea, the COML identified the manylight viperfish (Chauliodus sloani) as the most "cosmopolitan" marine creature. Its presence was recorded in around a quarter of the world's seas.

"This inventory was urgently needed for two reasons," said Costello. "First, dwindling expertise in taxonomy impairs society's ability to discover and describe new species. And secondly, marine species have suffered major declines – in some cases 90% losses – because of human activities and may be heading for extinction, as happened to many species on land."

Miloslavich said the COML data would "allow policy-makers to make better and more informed decisions on what areas should be protected for the better management of resources and the ecosystems as well, in order that they keep providing good services."

The results of the survey are published today online at the PLoS ONE journal. More detailed results will be published in October, at which time the COML will confirm how many species it estimates are in the world's oceans.

And for every marine species of all kinds known to science, COML scientists estimate that at least four have yet to be discovered. They said that around 70% of species of fish have been discovered, for example, but for most other groups likely less than one-third are known. As of February, the number of marine fish species known to science stood at 16,764, and was growing at around 100 a year.

Scientists estimate that there are almost 22,000 fish species in the world.

The most fruitful potential areas for discovery include the tropics, deep seas and southern hemisphere.

"At the end of the Census of Marine Life, most ocean organisms still remain nameless and their numbers unknown," said Nancy Knowlton, a biologist at the Smithsonian Institution, leader of the COML's coral reef project. "This is not an admission of failure. The ocean is simply so vast that, after 10 years of hard work, we still have only snapshots, though sometimes detailed, of what the sea contains. But it is an important and impressive start."

Marine census in Gulf of Mexico a pre-spill snapshot
Virginie Montet Yahoo News 3 Aug 10;

WASHINGTON (AFP) – A census of sea life in the Gulf of Mexico completed last year found it to be one of the most biodiverse bodies of water on the planet, a report published Monday as part of a massive inventory of marine life around the world shows.

But months after the census was completed, the scientists from Cuba, Mexico and the United States who worked on it could only watch, along with the rest of the world, as the biggest oil spill in US history unfolded in the sea after an explosion on the BP-leased Deepwater Horizon rig.

The roll call of sea life that scientists thought would be a tribute to the Gulf's biodiversity was now looking to be little more than a baseline to be used in future to show the damage done by the spill.

"The oil spill was a shock. The only good thing about it is that we have a baseline and we'll be able to assess the damage and monitor the changes that happen with the oil spill," said Patricia Miloslavich of Universidad Simon Bolivar in Venezuela, a senior scientist who worked on the Gulf census.

"We are very sad about the spill but we are happy that there is a good description of life in the region before the spill," Jesse Ausubel, co-founder of the Census of Marine Life program, which Monday published a preliminary inventory of the world's sea life and several accompanying reports, told AFP.

The inventory of marine life in the Gulf of Mexico was "the first authoritative listing and description of life" in the sea, including the spot around 50 miles off the coast of Louisiana where oil has been spewing since late April from a ruptured wellbore on the sunken Deepwater Horizon rig.

The scientists found more than 15,000 marine species in the Gulf, including 8,332 forms of marine life "that live right where the oil spill occurred in April," said Ausubel.

Even before the spill, the Gulf was one of the most at-risk regions from over-fishing, habitat loss and pollution, the Census of Marine Life found.

The millions of gallons of crude oil that have spilled into the Gulf since April have expanded the dangers facing sea life, especially for species that spawn in the Gulf.

"It's a breeding ground, a meeting area for blue fin tuna," said Ausubel.

"Blue fin tuna spawn in the Gulf in March and April ... in an area quite close to where the spill occurred.

"One of the concerns of the census scientists is that the fish eggs might become coated with oil and then have difficulty obtaining the necessary oxygen to grow," he said.

The Gulf of Mexico houses predominantly oyster reefs and salt marshes in the warm-temperate waters of the north and the tropical waters in the south.

The western Gulf houses one of only five hypersaline lagoons in the world, the Laguna Madre of Texas and Tamaulipas.

Coral reefs are common offshore, in the Florida Keys, in Cuba and off the Mexican state of Veracruz and Campeche.

As with the rest of the world's seas, the most common species in the Gulf are crustaceans, such as crabs and lobsters, followed by mollusks -- which includes octopi and squid, and fish.

Mediterranean most threatened sea on Earth
Marlowe Hood Yahoo News 3 Aug 10;

PARIS (AFP) – The Mediterranean Sea's exquisitely rich mix of flora and fauna is more threatened than marine life anywhere else on Earth, according to a landmark scientific survey released Monday.

In none of the other 20-odd ocean areas examined during the decade-long study does biodiversity face as bleak a future.

Habitat loss, pollution and overfishing have already take a heavy toll on the planet?s largest enclosed sea, and now climate change impacts have started to kick in as well, the study found.

The Mediterranean also has nearly three times as many invasive species when compared to the second-most infested region.

Drawing on the work of hundreds of scientists, the Census of Marine Life is the largest global research programme on marine diversity ever undertaken.

Results were rendered into more than a dozen studies published in the peer-reviewed journal PLoS ONE.

From Antarctica to the tropics, the Census uncovered thousands of previously unknown marine creatures across the planet, and confirmed that there are hundreds of thousands -- perhaps more than a million -- yet to be discovered.

The Mediterranean is among the five most generously endowed ocean zones, with an estimated 17,000 species ranging from microscopic, single-cell algae to loggerhead sea turtles and bluefin tuna.

Only oceans around Japan and Australia boast a greater variety of aquatic life.

But at the same time the Mediterranean -- encircled by dense concentrations of humanity and visited by 200 million tourists each year -- was shown to be suffering from decades, centuries and even millennia of exploitation.

Pollution along with rampant coastal development have decimated many habitats critical to marine diversity, including seagrass meadows and coral reefs.

Chemical runoff from industry and large-scale agriculture have starved some areas -- especially the Adriatic's sea-within-a-sea -- of oxygen, killing off many forms of wildlife and giving rise to toxic algae blooms known as red tides.

The 30-year crash of Atlantic bluefin tuna, which breeds in the Mediterranean, is only the most visible example of another serious strain on the sea's ecosystems: overfishing.

The depletion of tuna and other top ocean predators, for example, has helped drive a jellyfish explosion disruptive of aquatic food chains and the region's tourism.

Some of those unwelcome invertebrates -- such as the American comb-jelly -- have come from afar.

After hitching a ride in the ballast water of oil tankers in the early 1980s, the comb-jelly spread up into the Black and Caspian seas, outcompeting native species all along the way.

Some four percent of the Mediterranean's life forms are alien, far more than in any other region.

Not all invaders are destructive, and some have even become important commercial species, such as Erythrean prawns.

But the impact on delicately balanced ecosystems, experts agree, is unpredictable at best.

The most important threat looming on the horizon is increasing water temperatures and acidification brought on by global warming, the studies found.

At one end of the spectrum, cold- and deep-water species will likely find their habitats shrinking.

"Because they cannot move farther northward, they may dramatically decrease or even be at risk of extirpation," said Dalhousie University professor Marta Coll and colleagues in the report on biodiversity threats, citing diminishing stocks of deep-water white coral as an example.

Given than an estimated 75 percent of the region's deep-water species are unknown, it seems probable some will disappear before they can be identified, they said.

At the other end, non-native warm-water species have been moving into the Mediterranean for decades from the Red Sea through the Suez Canal, a process known as "tropicalisation."

"There is the need to develop comprehensive analysis of conservation and management initiatives to preserve Mediterranean biodiversity," the researchers conclude, adding that the Mediterranean can been seen, in terms of conservation efforts, as "a model for the world's oceans".

"Although much is known about individual threats, knowledge is very limited about how multiple impacts will interact," the added.

Australian, Japanese waters harbouring deep secrets: census
Amy Coopes Yahoo News 3 Aug 10;

SYDNEY (AFP) – Australia and Japan boast some of the planet's most diverse oceans but thousands of organisms remain unknown to science and global warming is a huge marine peril, a major new census says.

Both Australia and Japan have some 33,000 known species, according to the 10-year scientific survey of marine life called "What Lives in the Sea".

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 the icy southern pole, it said.

"This constitutes a vast array of highly diverse habitats and ocean features, but many have received limited if any exploration," wrote lead author Alan Butler from Australia's Commonwealth Scientific and Industrial Research Organisation.

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. Butler estimated that only 20 percent of Australia's total marine species had so far been found.

Life was most heavily concentrated in the northeast, which is home to the World Heritage-listed Great Barrier Reef and is filled with colourful corals as well as dolphins, turtles and dugongs.

"Australia is of tremendous ecological interest," said a spokeswoman for the marine census, Jessie Ausubel. "It is advanced in creating protected marine areas, around coral reefs but also around its deep-sea areas."

Katsunori Fujikura of Japan's Agency for Marine-Earth Science and Technology said about 155,000 species had been spotted in Japanese waters, accounting for a mere 30 percent of all estimated life, and only 33,000 officially registered.

"The reason why such high diversity occurs is undoubtedly the varied environments existing in Japanese waters," said Fujikura.

Roughly 11 times the size of its land mass, Japan's waters feature coral reefs, ice-bound seas and trenches 10 kilometres (six miles) deep. Strong ocean currents mean few -- just 5.6 percent -- of its species are unique to Japan.

By contrast, 19 percent of New Zealand's 17,000 marine species are found only around the isolated island state, and Antarctica's Southern Ocean also hosts many species not found anywhere else.

"Most species in the Southern Ocean are rare, with over half of the known benthic (sea-bed) species having only been found once or twice," said report author Huw Griffiths, from the British Antarctic Survey.

The remote and hostile Antarctic region is home to 8,800 recorded species, with moss animals, sponges and small crustaceans richly represented.

But more than 90 percent of its marine environment is more than a kilometre below the surface, and less than 11 percent of its total deep-sea area has been plumbed, "implying there are still a great many species yet to be described", Griffiths said.

He said charting Antarctica's marine life should be a "major priority" in the race against global warming, with its seas already "some of the fastest warming areas on Earth".

"Climate change is a significant potential threat to the long-term survival of Antarctic marine communities," he wrote.

Sea ice formation had slowed by 10 percent per decade and several floating ice shelves had collapsed, "dramatically altering" habitats, Griffiths said.

Growing acidification of the world's oceans was also predicted to hit the Southern Ocean first, threatening entire coral and mollusc species with extinction, he added.

Australia in some ways is a "beacon" of hope for marine life, said Ausubel, the census spokeswoman.

"Australia succeeded in protecting its biodiversity, it's very significant for the entire world," she said.

"At the same time the oceans are connected so one country alone cannot accomplish complete protection."

What Lives in the Sea? Census of Marine Life Publishes Historic Roll Call of Species in 25 Key World Areas
ScienceDaily 2 Aug 10;

Representing the most comprehensive and authoritative answer yet to one of humanity's most ancient questions -- "what lives in the sea?" -- Census of Marine Life scientists today released an inventory of species distribution and diversity in key global ocean areas.

Scientists combined information collected over centuries with data obtained during the decade-long Census to create a roll call of species in 25 biologically representative regions -- from the Antarctic through temperate and tropical seas to the Arctic.

Their papers help set a baseline for measuring changes that humanity and nature will cause.

Published by the open access journal PLoS ONE, the landmark collection of papers and overview synthesis will help guide future decisions on exploration of still poorly-explored waters, especially the abyssal depths, and provides a baseline for still thinly-studied forms, especially small animals.

Australian and Japanese waters, which each feature almost 33,000 forms of life that have earned the status of "species" (and thus a scientific name such as Carcharodon carcharias, a.k.a. the great white shark), are by far the most biodiverse. The oceans off China, the Mediterranean Sea and the Gulf of Mexico round out the top five areas most diverse in known species.

In a prelude to the ultimate summary of the landmark, decade-long marine census, to be released Oct. 4 in London, national and regional committees of the Census compiled the inventory of known and new species in the 25 key marine regions.

The 13 committees include over 360 scientists whose collective knowledge, including published and unpublished data, was assembled to create the initial profile of known marine biodiversity in Antarctica, Atlantic Europe, Australia, Baltic Sea, Brazil, Canada (East, West and Arctic), Caribbean Sea, China, Indian Ocean, Japan, Mediterranean Sea, New Zealand, South Africa, South America (Tropical East Pacific and Tropical West Atlantic), South Korea, the Humboldt Current, the Patagonian Shelf, and the USA (Northeast, Southeast, Hawaii, Gulf of Mexico, and California).

Major inventories continue in highly diverse areas such as Indonesia, Madagascar and the Arabian Sea, which have yet to report.

Scientists find that the number of known, named species contained in the 25 areas ranged from 2,600 to 33,000 and averaged about 10,750, which fall into a dozen groups. On average, about one-fifth of all species were crustaceans which, with mollusks and fish, make up half of all known species on average across the regions. The full breakdown follows:

* 19% Crustaceans (including crabs, lobsters, crayfish, shrimp, krill and barnacles),
* 17% Mollusca (including squid, octopus, clams, snails and slugs)
* 12% Pisces (fish, including sharks)
* 10% Protozoa (unicellular micro-organisms)
* 10% algae and other plant-like organisms
* 7% Annelida (segmented worms)
* 5% Cnidaria (including sea anemones, corals and jellyfish)
* 3% Platyhelminthes (including flatworms)
* 3% Echinodermata (including starfish, brittle stars, sea urchins, sand dollars and sea cucumbers)
* 3% Porifera (including sponges)
* 2% Bryozoa (mat or 'moss animals')
* 1% Tunicata (including sea squirts)

The rest are other invertebrates (5%) and other vertebrates (2%). The scarce 2% of species in the "other vertebrates" category includes whales, sea lions, seals, sea birds, turtles and walruses. Thus some of the best-known marine animals comprise a tiny part of marine biodiversity.

The authors note that their work constitutes a roll call of marine plant and animal species -- either present or unknown in 25 regions. It does not represent their abundance or biomass.

The most cosmopolitan species

Many species appear in more than one region. Current holders of the title "most cosmopolitan" marine species are two opposite kinds: microscopic plants (algae) and single-celled animals called protozoa and copepod in the plankton, and the seabirds and marine mammals that traverse the oceans throughout their lives.

Among fish, the manylight viperfish (Chauliodus sloani) can be considered the Everyman of the deep ocean. Census data shows the fish has been recorded in more than one-quarter of the world's marine waters.

How the microscopic species can be cosmopolitan is still a subject of research, and may be due to their ability to survive unsuitable environmental conditions and then reach enormous abundance in a suitable environment.

Says Patricia Miloslavich of Universidad Simón Bolívar, Venezuela, co-senior scientist of the Census and leader of the regional studies: "To create this baseline, the Census of Marine Life explored new areas and new ecosystems, discovering new species and records of species in new places.

"We reviewed what had been documented through the huge efforts of scientists in years past. However, most of this information was scattered or unavailable except at a very local level. The Census has made a tremendous contribution by bringing order to chaos. This previously scattered information is now all reviewed, analyzed and presented in a collection of papers at an open access journal."

Says lead author of the summary, Mark Costello of the Leigh Marine Laboratory, University of Auckland, New Zealand: "Sparse, uneven marine sampling in much of the world underlies this initial inventory, and future research will undoubtedly alter the profile presented today."

He adds that finding such great difference in the proportions of species across regions challenges assumptions that scientists can extrapolate knowledge of biodiversity from one location to another.

"This inventory was urgently needed for two reasons," says Dr. Costello. "First, dwindling expertise in taxonomy impairs society's ability to discover and describe new species. And secondly, marine species have suffered major declines -- in some cases 90% losses -- due to human activities and may be heading for extinction, as happened to many species on land."

Regional results (please see full details in the table appended below):

* Even less diverse regions such as the Baltic or Northeast USA still have about 4,000 known species.
* Relative to its volume of water, the Baltic, followed by China, has some of the highest known diversity.
* Relative to their seabed area, South Korea, China, South Africa and the Baltic, had most species.
* The relative contribution of different kinds of life to the species in each region varied greatly and enigmatically. While variation in research effort may be part of the explanation, it also seems that species have not flourished equally around the world.
* Crustaceans (including crabs, lobsters, crayfish, shrimp, krill and barnacles) contributed 22% to 35% of species for Alaska, Antarctica, Arctic, Brazil, California, Caribbean, and Humboldt regions, but only 10% for the Baltic.
* Mollusks (clams, snails, squid and slugs) contributed 26% of the species in Australia and Japan, but only 5% to 7% of the species in the Baltic, California, Arctic, and eastern and western Canada.
* Fish comprised 28% of species in the Tropical West Atlantic and Southeast USA, but only 3% to 6% for the Arctic, Antarctica, Baltic, and Mediterranean;
* Of the less species-rich groups, Annelida (worms) contributed 28% of the species for the Tropical Eastern Pacific, but only 3% for Japan.
* Plants and algae (mostly algae) contributed about one third of species in the Baltic, Arctic, Atlantic Europe, and Western Canada, but few in Antarctica, Caribbean, China, Humboldt, Tropical Eastern Pacific, and Tropical Western Atlantic.

Where to find unique, "endemic" or alien invasive species

* The number of unique "endemic" species seen nowhere else on Earth provides another measure of biodiversity. The relatively isolated regions Australia, New Zealand, Antarctica and South Africa have the most endemic species. They may have suffered fewer extinctions from climate cooling thousands of years ago during glaciation. Or, species from regions that escaped glaciers may have reached them more easily when the glaciers melted.
* Endemics comprise about half of New Zealand and Antarctic marine species and a quarter of those in Australian and South Africa. The waters of the Caribbean, China, Japan, and Mediterranean each have less than 2,000 endemic species, and the Baltic only 1 -- a seaweed (Fucus radicans).
* To encounter invasive species, visit the Mediterranean. It had the most alien species among the 25 regions with over 600 (4% of the all species inventoried), most of which arrived from the Red Sea via the Suez Canal.
* Many aliens have also invaded the European Atlantic, New Zealand, Australian Pacific, and Baltic waters. Mollusks, crustaceans, and fish were the most common invading aliens.

Says Dr. Ian Poiner, CEO of the Australian Institute for Marine Science and Chair of the Census Scientific Steering Committee: "Consider that a well-informed person walking along a familiar seashore might identify 20 species or so; a fish monger perhaps 100. Even in the world's least diverse marine regions, there are 50 to 100 times as many named species than an expert would know without resorting to field guides."

Many of the species records used for the report are part of the 10-year-old Ocean Biogeographic Information System (OBIS), a massive global database of what/where records and a major Census legacy. An interested person can find precise places on a world map where a marine organism has been reliably observed.

OBIS has consolidated almost 30 million records from the Census projects and more than 800 databases contributed by institutions around the world."

Says Edward Vanden Berghe, who leads development and management of the database: "A map of records in OBIS today underlines the uneven sampling of oceanic regions," he adds. "So even as records accumulate, the importance of orderly sampling grows."

Almost all the species in the key regional areas are included in the unprecedented list of 185,000 marine species created by the World Register of Marine Species (WoRMS), an affiliate of the Census of Marine Life.

How much is unknown?

In October, the Census will release its latest estimate of all marine species known to science, including those still to be added to WoRMS and OBIS. This is likely to exceed 230,000.

According to a recent open access Census of Marine Life paper in Zootaxa by US expert Bill Eschmeyer and colleagues, the number of marine fish species in mid-February stood at 16,764, and was growing at a rate of 100 to 150 per year. They estimate about 5,000 marine fish species have yet to be discovered and described -- twice the number described in the last 19 years -- for a projected total of approximately 21,800 marine fish species around the world.

And for every marine species of all kinds known to science, Census scientists estimate that at least four have yet to be discovered. In a few taxonomic groups, like fish, scientists believe more than 70% of species have been discovered, but for most other groups likely less than one-third are known. Scientists believe that the tropics, deep-seas and southern hemisphere hold the most undiscovered marine species.

The proportion of species not yet described is estimated at 39 to 58% in Antarctica, 38% for South Africa, 70% for Japan, 75% for the Mediterranean deep-sea, and more than 80% for Australia.

New Zealand has more than 4,100 undescribed species in its specimen collections, which would comprise 25% of the country's known marine species, but clearly is a minimum estimate because many species have not been collected and distinguished in collections.

Citizens of the Sea

"At the end of the Census of Marine Life, most ocean organisms still remain nameless and their numbers unknown," says renowned biologist Nancy Knowlton of the Smithsonian Institution, leader of the Census' coral reef project and author of a new book published by the National Geographic Society for release September 14. "Citizens of the Sea: Wondrous Creatures from the Census of Marine Life" is one of three books marking the Census' conclusion.

"This is not an admission of failure. The ocean is simply so vast that, after 10 years of hard work, we still have only snapshots, though sometimes detailed, of what the sea contains. But it is an important and impressive start."

Dr. Knowlton's book, written in everyday language and populated with scores of images, draws on discoveries of Census scientists and their colleagues, past and present. It chronicles "the variety, beauty, weirdness and wonder that characterizes life in the sea."

"The sea today is in trouble," says Dr. Knowlton. "Its citizens have no vote in any national or international body, but they are suffering and need to be heard. Much has changed just in the few decades that I have spent on and under the sea, but it remains a wondrous and enriching place, and with care it can become even more so."

Greatest threats

According to the Census studies published in PLoS ONE, the main threats to marine life to date have been overfishing, lost habitat, invasive species and pollution, although the relative importance of the threats varied among regions. Emerging threats include rising water temperature and acidification, and the enlargement of areas characterized by low oxygen content (called hypoxia) of seawater. These too will vary regionally (surface temperature, for example) whereas others are more global (such as acidification).

Overfishing not only depletes the exploited fish themselves but also depletes other species like turtles, albatrosses, sharks and mammals, caught unintentionally. It alters food webs within ecosystems.

Coastal urbanization, sediment runoff and nutrients in sewage and fertilizer washed from the land and causing eutrophication and hypoxia are destroying marine habitats.

The more enclosed seas -- Mediterranean, Gulf of Mexico, China's shelves, Baltic, and Caribbean -- were reported to have the most threatened biodiversity.

State-of-knowledge index

Census scientists created a relative "state-of-knowledge index," grading each region according to how well it was known, including the availability of guides to the identification of species and their number of taxonomic experts.

In a nutshell, the studies found that while the depth of knowledge varies across regions, knowledge in all regions is inadequate.

Australia, China and all three European regions scored the highest index results while the Tropical West Atlantic, Tropical East Pacific and Canadian Arctic were well below average. But, even in regions with the highest index scores, knowledge of marine biodiversity is poor. In Australia it is estimated that only about 10% of marine life in its Exclusive Economic Zone is known.

Scientists say the availability of comprehensive species identification guides strongly boost the discovery and management of marine biodiversity resources.

"We must increase our knowledge of unknown biodiversity more quickly, lest much of it is lost without even being discovered," says Dr. Miloslavich. "International sharing of data, expertise and resources, as has been accomplished through the Census of Marine Life, is the most cost-effective way of achieving this."

The Census papers collection, freely available Aug. 2 at PLoS ONE (www.coml.org/plos-one-collections), includes links to maps, databases and a suite of the first nine regional papers on which the summary drew, with several more to be added in weeks to come.

And there are Census reports on several more regions anticipated in years to come.

An exploration currently underway in the species-rich Timor and Arafura Seas, facilitated by Dr. Antonio (Tonny) Wagey, leader of the Census' National Committee in Indonesia, will enrich the Indonesian report.

Another this past spring, led by Philippe Bouchet of the Muséum National d'Histoire Naturelle, Paris, discovered a vast array of marine life in the Deep South of Madagascar.


More links
Census of Marine Life website