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When Galileo trained his homemade telescope on the night sky, it transformed from a black
pool populated by a few thousand stars into a sparkling sea filled with ten times the
number. And today, with the help of bigger and better telescopes, we know that our home
galaxy - the Milky Way - is an ocean of as many as 400 billion stars.
However, telescopes can’t help us peer into the watery oceans here on Earth, so to count
their inhabitants, we've used fish trawls to drag them up into the light - and then
- more often than not - onto our plates. But now we don't have to fish fish in order
to count fish. In 2010, Spanish researchers sailed around the world with an ultra high-powered
SONAR, shooting sound waves into the depths and using the reflected signals to spot inhabitants.
While previous net counts had given us a global estimate of about 300 trillion fish, the fish-o-scope
method revealed that our oceans are home to roughly ten times that number.
One reason previous counts were so much lower seems to be that fish actively hide from approaching
trawls. In one study, scientists took a SONAR scan while dragging an open net through the
water behind them, and check this out: so many fish got out of the way that their relative
absence highlights the whole path of the trawl. We don’t know exactly how they manage to
avoid the nets, but deep-ocean dwellers like the fangtooth, lantern fish, and stoplight
loosejaw, all of which were especially undercounted by fish trawls, may take warning cues from
their neighbors flashing bioluminescent spots. Another deep water fish, the finger-sized
bristlemouth, turns out to be the most populous vertebrate on our planet. There are an estimated
quadrillion bristlemouths swimming the world’s oceans. That’s a few thousand fish for every
star in the Milky Way. Hi, Emily here. I'd like to thank Audible.com
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Why We Sucked At Counting Fish (Until Now)

384 タグ追加 保存
Mises 2016 年 6 月 12 日 に公開
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