How many fish are there in the sea? Scientists would not dare guess, but they estimate, in the first-ever Census of Marine Life announced today, that there are at least 201,206 known species in the world's oceans, from the tiniest single-celled creatures to the most massive blue whales.
It took a decade of work, with 2,700 scientists from 80 countries spending 9,000 days at sea on 540 separate expeditions. Their work was financed by foundations, universities, and the governments of the researchers.
"We prevailed over early doubts that a census was possible, as well as daunting extremes of nature," said Ian Poiner, an Australian scientist who chaired the project, in a press statement. "This cooperative international 21st century voyage has systematically defined for the first time both the known and the vast unknown, unexplored ocean."
The purpose of the census was to establish a baseline -- a cross-section of marine life worldwide -- so that as things change, scientists will not have to speculate just how. Future scientists doing research on climate change, pollution, or shifts in the composition or acidity of sea water in particular parts of the world will have an idea of what lived there back in 2010.
This summer's massive oil spill in the Gulf of Mexico, said the project's organizers, was a prime example. Researchers and people in the spill zone believed the BP spill was doing harm -- but argued endlessly over just what it was. The Census of Marine Life, available to any researcher, should help give them a better idea.
On the way to assembling their database, the researchers came back with remarkable pictures of just a few of the 120,000 species they studied directly. Even after all the work that went into the census, the organizers say another 750,000 species may still be not be catalogued. Here is a sampling of what they saw: