[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,From Ancient Greece to the 20th century, \NAristotle, Sigmund Freud,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and numerous other scholars were all \Nlooking for the same thing: eel testicles.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Freshwater eels, or Anguilla Anguilla,\Ncould be found in rivers across Europe,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,but no one had ever seen them mate.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And despite countless dissections,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,no researcher could find eel eggs\Nor identify their reproductive organs.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Devoid of data, naturalists proposed \Nvarious eel origin stories.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Aristotle suggested that eels spontaneously\Nemerged from mud.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Pliny the Elder argued eels rubbed \Nthemselves against rocks,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and the subsequent scrapings \Ncame to life.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Eels were said to hatch on rooftops,\Nmanifest from the gills of other fish,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and even emerge from the \Nbodies of beetles.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,But the true story of eel reproduction\Nis even more difficult to imagine.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And to solve this slippery mystery, \Nscholars
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,would have to rethink \Ncenturies of research.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Today, we know the freshwater eel \Nlifecycle has five distinct stages:
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,larval leptocepheli, miniscule glass \Neels, adolescent elvers,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,older yellow eels, and adult silver eels.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Given the radical physical differences \Nbetween these phases,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,you’d be forgiven for assuming these \Nare different animals.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,In fact, that’s exactly what European\Nnaturalists thought.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Researchers were aware of leptocepheli\Nand glass eels,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,but no one guessed they were related\Nto the elvers and yellow eels
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,living hundreds of kilometers upstream.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Confusing matters more, eels don’t \Ndevelop sex organs until late in life.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,And the entirety of their time in the\Nrivers of Europe
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,is essentially eel adolescence.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,So when do eels reproduce, \Nand where do they do it?
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Despite its name, the life of a freshwater\Neel actually begins
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in the salty waters of \Nthe Bermuda Triangle.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,At the height of the annual cyclone\Nseason,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,thousands of three-millimeter eel larvae
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,drift out of the Sargasso Sea.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,From here, they follow migration \Npaths to North America and Europe––
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,continents that were much \Ncloser when eels
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,established these routes \N40 million years ago.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Over the next 300 days, Anguilla Anguilla\Nlarvae ride the ocean currents
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,6,500 km to the coast of Europe––
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,making one of the longest \Nknown marine migrations.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,By the time they arrive, they’ve grown \Napproximately 45 mm,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and transformed into semi-transparent \Nglass eels.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,It’s not just their appearance \Nthat’s changed.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,If most marine fish entered brackish\Ncostal waters,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,their cells would swell with freshwater\Nin a lethal explosion.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,But when glass eels reach the coast,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,their kidneys shift to retain more salt
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and maintain their blood’s \Nsalinity levels.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Swarms of these newly freshwater \Nfish migrate up streams and rivers,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,sometimes piling on top of each other\Nto clear obstacles and predators.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Those that make it upstream develop\Ninto opaque elvers.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Having finally arrived in their hunting\Ngrounds,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,elvers begin to eat everything they \Ncan fit in their mouths.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,These omnivores grow in proportion\Nto their diets,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and over the next decade they develop\Ninto larger yellow eels.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,In this stage, they grow \Nto be roughly 80 cm,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and finally develop sexual organs.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,But the last phase of eel life–– \Nand the secret of their reproduction––
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,remains mysterious.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,In 1896, researchers identified \Nleptocepheli as larval eels,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,and deduced that they had come to\NEurope from somewhere in the Atlantic.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,However, to find this mysterious breeding\Nground,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,someone would have to perform an \Nunthinkable survey of the ocean
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,for larvae no larger than 30mm.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Enter Johannes Schmidt.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,For the next 18 years, this Danish \Noceanographer
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,trawled the coasts of four continents,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,hunting down increasingly \Ntiny leptocepheli.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Finally, in 1921, he found the smallest\Nlarvae yet,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,on the southern edge \Nof the Sargasso Sea.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Despite knowledge of their round trip\Nmigration,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,scientists still haven’t observed \Nmating in the wild,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,or found a single eel egg.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Leading theories suggest that eels\Nreproduce
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in a flurry of external fertilization,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,in which clouds of sperm fertilize\Nfree-floating eggs.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,But the powerful currents and \Ntangling seaweed of the Sargasso Sea
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,have made this theory \Ndifficult to confirm.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Researchers don’t even know where to look,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,since they’ve yet to successfully track \Nan eel
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,over the course of its return migration.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,Until these challenges can be met,
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,the eel’s ancient secret will continue\Nslip through our fingers.
Dialogue: 0,9:59:59.99,9:59:59.99,Default,,0000,0000,0000,,