How To Count Millions Of Fish In The Sea

It was decided we don't know enough about the sea. So 2,700 scientists started the Census of Marine Life, cooperating with museums, labs and aquariums across 80 countries to learn more. 10 years later, today, they're done.

The census used every conceivable kind of technology to get the job done, from Satellites, to manned and unmanned subs, to divers with cameras, to gyroscopic and GPS sensors slapped onto the backs of creatures. They observed a "riot of life" everywhere from beaches to the skies above the seas to the deep ocean where undersea volcanos and vents hot enough to melt lead still hosted ecosystems. They found 6,000 new species of life, many that are astoundingly odd. And even found some kinds of life that were thought to be extinct. But what's most interesting to me is how they managed to track large bodies of fish, sometimes in large schools, sometimes individually, across thousands of miles.

Census scientists at some point tried to measure the sea bed using sonar, only to find readings varying wildly. They realised that they were looking at a school of millions of Atlantic herring. Forming schools as large as Manhattan.

The scientists also used acoustic tags and seabed sensors scattered between Alaska and California to track the migrations of 18 species more than 3,000 kilometers in the pacific, noting the exact passages of individual trout, some as small as bananas.

These encounters were logged into a large database called OBIS, or, Ocean Biogeographic Information System, which has about 30 million entries on species and where they exist.

The rest is summarized in a 64 page PDF, which sounds long but considering the vast amounts of findings the Census has uncovered, it hardly seems to do the project justice.

But what's also notable is that even after 10 years of study, the Census estimates that there is still over 20% of the volume of the sea for which absolutely no data has been recorded. And that for all the fish we're counting, 90% of the world's biomass is microscopic.

[Census, OBIS, and a collection of the most interesting creatures discovered by the Census at Scuttlefish. ]