The Book of Eels, Patrik Svensson [bill gates best books .TXT] 📗

It seemed, they wrote, as though “eels follow olfactory cues originating in the spawning area or that eels navigate using oceanic cues imprinted or learned during the leptocephalus phase.”

Because what their study revealed more than anything was that the farther the eels got, the more they seemed to end up following a predetermined route. Simply put, they seemed to follow the Gulf Stream and the North Atlantic Drift, but in the opposite direction. As though a memory, a map, had been ingrained in them when they made the journey from the Sargasso Sea to Europe as tiny, transparent willow leaves, and as though that memory had survived in the eels, remaining constant through all their metamorphoses, for ten, twenty, thirty, or fifty years, until one day it was time to make that same journey in reverse, straight toward the mighty ocean current that had once carried them helplessly to Europe.

AND SO THE SILVER EEL FINALLY COMES HOME TO ITS BIRTHPLACE, its Sargasso Sea, and at the same time, it disappears out of sight and our realm of knowledge. No one has ever seen an eel in the Sargasso Sea.

Some have tried, however. After Johannes Schmidt’s years-long expeditions in the early twentieth century, it would be a while before anyone set off for the Sargasso Sea to look for the eel again, possibly because Schmidt’s work was so persuasive, but perhaps even more likely because it was so discouraging. But the past few decades have seen an increase in research traffic to the Sargasso Sea, expeditions manned by some of the most prominent eel experts in the world. They’ve gone to seek deeper knowledge of the eel’s migrations and reproduction, to test existing theories by verifying or disproving them, but also to find what no one has yet been able to: a living eel in the Sargasso Sea.

The German marine biologist Friedrich-Wilhelm Tesch went on a major expedition with two German ships in 1979, the eventual result of which was the much-cited article “The Sargasso Sea Expedition, 1979.” The expedition took place in the spring and roved across large parts of the eel’s supposed spawning area. Tesch was able to employ his nets and trawls in the exact location where breeding was thought to occur; like Schmidt, he caught large numbers of tiny leptocephalus larvae, but other than that, he found no sign of the presence of eels. For example, seven thousand fish eggs were collected, but closer examination revealed that not a single one came from an eel. It goes without saying that researchers didn’t see any mature breeding eels either.

The American marine biologist James McCleave, who for more than thirty years has been one of the world’s leading eel experts, went on his very first marine expedition together with none other than Friedrich-Wilhelm Tesch in 1974 and undertook his first journey to the Sargasso Sea in 1981. Since then, he and his team have returned seven more times, using a range of sophisticated methods to try to catch at least a glimpse of an eel. McCleave has posited a theory according to which areas where different bodies of water of different temperatures meet—so-called front regions—provide eels with exactly the right conditions for procreation. It is in such locations that he has caught the smallest specimens of leptocephalus larvae, and it is also where he has most zealously looked for adult eels. James McCleave has sailed back and forth across these regions, with ships equipped with advanced acoustic instruments designed to pick up echoes from breeding eels in the deep. And he has, in fact, recorded echoes very likely produced by living, breeding eels; each time he has tried to catch them, however, his nets have come up empty.

During one expedition, together with a fellow marine biologist, Gail Wippelhauser, McCleave employed almost malicious cunning to lure the shy eels out of the depths. Their team had caught a hundred fully grown female American eels and injected them with hormones to induce sexual maturity. The plan was to bring these females on their expedition and place them in cages fastened to floating buoys in the middle of a front region in the Sargasso Sea. The females were intended as bait, to attract males who had swum there to spawn, and thus force them out of hiding.

But the eels were reluctant participants. The scientists kept the mature females in a laboratory and were about to drive them down to the docks in Miami ahead of departure, but before the ship had even cast off, the majority of the eels had died. By the time the expedition arrived in the Sargasso Sea, only five of the one hundred female eels were still alive.

Regardless, the five surviving eels were placed in cages and tied to the buoys, and McCleave and Wippelhauser took turns monitoring the movements of the buoys around the clock with the help of radar. But inexplicably, they managed to lose them. Eels and cages and buoys disappeared without a trace and were never seen again.

During another expedition, which Gail Wippelhauser undertook without James McCleave, the acoustic instruments picked up echoes from what was believed to be a large group of breeding eels; the researchers threw at it everything they had, lowering no fewer than six nets into the water. And yet there was no sign of any eels.

Another strange detail is, of course, that it’s not only living eels that have proved elusive in the Sargasso Sea. No one has ever spotted a dead one either, whether in the form of a corpse or as the victim of a larger predator. Swordfish and sharks have been caught with silver eels in their stomachs, but never anywhere close to the Sargasso Sea. A sperm whale was once caught off the Azores with an eel in its stomach that was on its way to spawn, but the Azores are pretty far from the Sargasso Sea. Once eels reach their breeding ground, they universally manage to avoid human detection in both life and death.

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