One Ocean, Many Worlds of Life - Convention on Biological Diversity

Blue-footed booby (Sula nebouxii), Galápagos Islands Coral reef, Belize
Dan Oflynn/Hemera/Thinkstock flickr/Lauretta Burke/World Resources Institute
By the time the Census ended, it had added 1,200 species to the known
roster <strong>of</strong> life in the sea; another 5,000, assumed to be previously unrecorded,
await <strong>of</strong>ficial categorization. Excluding the likes <strong>of</strong> bacteria, viruses and the
peculiar life forms known as Archaea, Census scientists concluded that the
most diverse group <strong>of</strong> marine life is the crustaceans, such as crabs, lobsters,
barnacles and krill, which comprise slightly less than 20 percent <strong>of</strong> all species
in the ocean. By way <strong>of</strong> comparison, fish comprise approximately 12 percent
<strong>of</strong> marine species, and a mere 2 percent are other vertebrates such as marine
mammals and seabirds.
As for how many species there are in total—that’s a question that still hasn’t
been fully answered, despite the magnificent achievements <strong>of</strong> the Census
<strong>of</strong> Marine <strong>Life</strong>.7 As Nancy Knowlton <strong>of</strong> the Smithsonian Institution, the
leader <strong>of</strong> the Census’s coral reef studies, put it: “At the end <strong>of</strong> the Census
<strong>of</strong> Marine <strong>Life</strong>, most ocean organisms still remain nameless and their
numbers unknown. This is not an admission <strong>of</strong> failure. The ocean is simply
so vast that, after 10 years <strong>of</strong> hard work, we still have only snapshots, though
sometimes detailed, <strong>of</strong> what the sea contains. But it is an important and
impressive start.”8
The estimated number <strong>of</strong> known marine species—the species that have been
identified and the ones that have been documented but await classification—
has increased as a direct result <strong>of</strong> the Census’s efforts, and is now around
250,000. In its final report, the Census team suggested it could be at least a
million9. Some think the figure could be much higher.
<strong>One</strong> <strong>Ocean</strong>, <strong>Many</strong> WOrlds Of life
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