Age of Awareness
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Age of Awareness

Counting Eels Is Hard

Cyprus Akamas — European eel (Anguilla anguilla) at Aphrodite’s Bath by muffinn.

Like Hansel and Gretel, Danish biologist Johannes Schmidt followed the crumbs. But they weren’t crumbs; they were eel larvae, strung in a meandering but generally westward trail across the Atlantic Ocean. And he hadn’t laid them. And he wasn’t feeling his way out of the forest. He was, writes Swedish culture reporter Patrik Svensson in his new book The Book of Eels, instead searching for the mysterious breeding ground of the European eel, Anguilla anguilla.

This creature had perplexed researchers and intellectuals going back at least to Aristotle (as does virtually everything else). The eel’s life cycle was for centuries a black box so elusive that we didn’t know about it. One might have seen a larva and the next day a full-grown eel and the following day one animal each of the two intervening stages and thought they were four distinct species.

The eel’s life cycle is a catadromous one, the opposite of the salmon, an anadromous fish. This means that whereas the salmon is born in freshwater, lives in saltwater, and fights to spawn and die at its birthplace, the eel does precisely the opposite. The eel’s larva, which experiences two substages, comes first in the shape of the willow leaf: a slender body tapers to a smaller head. Over about a year, it grows to become a “glass eel,” a translucent creature that slices east from the west half of the Atlantic Ocean. Having found one of various European deltas and penetrated the continent, it becomes an elver, which, over the course of between half a decade and two, slowly morphs into a “yellow eel,” with vibrant yellow patches on its underbelly and sides. Finally, it matures into a silver eel, the adult stage where hormones prompt the growth of sex organs. Equipped with these devices and up to 5 feet of slimy, muscular length, the European eel slides down the watersheds of the entire European continent and North Africa into the Atlantic. It travels back west and expires in sex, closer to the Americas than the Old World.

We know all this now, but for centuries no one had observed the metamorphoses. Thinkers puzzled over the origin of the silver eel. Aristotle postulated the European eel alchemized from dust. In keeping with his later passions, a young Sigmund Freud spent his free time dissecting hundreds of eels in a mad quest for the animal’s testicles. After months, he turned up a gonad, upsetting a two-millennia myth.

Yet even after it was discovered that each of these stages represented an eel in a different life stage, the animal remained an enigma. It is a secretive creature, hiding in every marine habitat imaginable. The frustrated International Union for the Conservation of Nature (IUCN) writes: “Anguillids are often referred to as ‘freshwater eels’, however it is known that they can exhibit inter-habitat migration and that a proportion may stay in estuaries, lagoons and coastal waters, rarely, if ever, entering freshwater: this element of the population is particularly poorly understood.”

WHERE DO EELS COME FROM?

Schmidt, a more dogged investigator endowed with better tools than his predecessors, came along at the beginning of the twentieth century. For years, he tried to answer this question about one of the most mysterious creatures in the world. He trawled the ocean near Europe from 1904 to 1911, turning up some larva that were too large to be close to their birthplace. It wasn’t working, and he realized he needed help. He enlisted 23 cargo ships to help him from 1911 to 1914. Schmidt himself borrowed a schooner and followed the smaller larvae, the 2.5 inch, the 1.3, the 0.7, the 0.33, diminishing like some mineral with a half-life.

That final year, the crumb trail had led Schmidt to the Sargasso Sea, a gigantic oval gyre between Miami and Halifax. It has no knowable borders, only ethereal ocean currents. Evoking more mystery, Svensson compares the Sargasso to a dream: “you can rarely pinpoint the moment you enter or exit; all you know is that you’ve been there.”

Schmidt’s schooner ran aground and sank, and current events curtailed his collaborators’ progress. During World War I, Svensson writes, “Submarines patrolled the sea, threatening any and all who dared to venture out; several of the trading ships participating in Schmidt’s search were sunk.”

He was forced to suspend the effort until the curtain was drawn on the “irrelevant skirmish,” Svensson writes. In 1920 and ’21, Schmidt took another schooner to the west Atlantic where he discovered so many minuscule European eel larvae that he felt confident enough to write “that there can be no question … where the eggs were spawned,” according to Svensson.

KILLING EELS

In 2014, the eel gained an unenviable spot on the IUCN’s Red List of threatened species as “critically endangered,” the station on the continuum just before “extinct in the wild.” Its report on the eel — which has only sparse and inconsistently collected data to rely on — says eels leaving the European continent and North Africa have declined 50 to 60 percent in the four and half decades before the designation. About 95 percent of the world’s known eel stocks have disappeared.

The IUCN lists several reasons for the eel’s decline: “[B]arriers to migration — including damage by hydropower turbines; poor body condition; climate change and/or changes in oceanic currents; disease and parasites … exploitation and trade of glass, yellow and silver eels; changing hydrology; habitat loss; pollutants; and predation.”

The organization goes on to note the Atlantic currents that carry the eel on its way to Europe are crucial to its survival. Climate change threatens these currents — part of the “global conveyor belt” that helps regulate the Earth’s temperatures — by melting glacier ice into the Atlantic, slowing or stopping the current.

The National Oceanic and Atmospheric Administration writes:

If global warming results in increased rainfall in the North Atlantic, and the melting of glaciers and sea ice, the influx of warm freshwater onto the sea surface could block the formation of sea ice, disrupting the sinking of cold, salty water. This sequence of events could slow or even stop the conveyor belt, which could result in potentially drastic temperature changes in Europe.”

It’s easy to imagine horror stories about this process also holding up the migration of many species, including A. anguilla.

But part of the story is more intimate than global trends, dealing specifically with our relationship to eels as food. Svensson spends parts of The Book of Eels remembering the eel fishing he did with his father as a child. One night, he writes, he observed his dad trying to wrestle a hook from the mouth of an eel that was too small for eating. The slimy creature twisted and bit. It was no use.

EELS at RIGA’S CENTRAL MARKET, LATVIA 2009 by EuroVizion.

“And I handed him the knife,” Svensson writes, “the long fishing knife whose blade had been whetted so many times it was thin as a reed, and he squatted, held the eel against the ground, and firmly pushed the point of the knife through its head.”

I remember similar experiences with animals — wild and domesticated — when I was a kid. When I was probably 7 or 8, I used a machete to dispatch a snake I thought was dying because a nasty-looking protrusion hung from its abdomen. It was clearly mortally wounded, and I didn’t want it to suffer. Having learned many then-unknowable things about the world, I now think the snake had an erection, which reptiles sometimes deploy as a defensive measure — whatever the purity of my motive, I probably killed this snake because it was trying to fend me off.

Later, I put a bullet through the head of a bull elk, too small to keep like the eel, that was limping around the hills of Northwest Colorado with a gangrenous hind leg. This one I’m confident I saved from suffering. But the reason its hind leg was injured was likely because it had been shot by groups of hunters who chased it and its brethren down with pickup trucks in the sagebrush. Herds would be corralled in arroyos and shot at from both sides. Five or six would fall, most would escape, and uncounted others made off with bullet wounds that would later spell an excruciatingly prolonged death. The bull was probably separated from its herd in the chaos and was lost. I had hunted this way. How many of my own bullets had put other animals in the same condition?

My dad breeds dogs, purebred golden retrievers and goldendoodles (a golden retriever-poodle mix). He sometimes lacks the funds to euthanize the occasional puppy that, in this industry, needs to be killed so it doesn’t suffer an excruciating death from a deformity or illness. Several times, dad was forced to shoot a pup with a cleft pallet in the head with his .357 magnum revolver that he keeps loaded atop his gun cabinet. This took an incredible toll — dad would return from the dubious task shaken and weeping. I had enormous respect for dad’s perseverance until I realized that killing the puppies — at a time when discarded canines around the country needed homes — was of the exploitative trade he had chosen to practice. Those puppies would not have to die if there was not an industry that demanded their presence.

These instances stoke a deep sense of species guilt in me and an awareness that nothing I do can be trusted. It’s a lonely feeling. I don’t know whether most people experience this. But Svensson seemed to.

There’s a small passage in The Book of Eels, recalling Svensson’s childhood fishing for eels, about a mink:

Dad told me about the mink that lived by the stream. A small, slender, almost entirely black creature crept along the water’s edge at night. At least that’s what he said. I’d never seen it and wasn’t sure Dad had either. But sometimes we would find half-eaten fish in the grass. “Must be the mink,” Dad would offer.

He said they were lovely animals, but also crafty and dangerous, maybe not to us, but to the stream and the reason we visited it — the fish and the eel. “It kills for sport,” he told me. He said the mink goes for mice and frogs and fish, definitely, and it doesn’t stop until it kills everything in its path. Every time it runs into another life form, it has to kill it. It’s in its nature. It was an intruder, not just by our stream, but in the very ecosystem. It would be capable of emptying the stream of eels pretty much single-handedly. It fell to us to put things right.

They tried and failed to trap the mink. Svensson was glad. He didn’t want to kill a mammal. It seems there are degrees of separation between humans and other species. The Svenssons baited the trap with a cockroach and didn’t think much of it. They made part of their living killing eels, an alien-seeming life form that looks at you with dead-seeming eyes. Svensson describes this look: “The eel’s tiny button eyes, which seemed to stare at me but never returned my gaze.”

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Aaron Hedge

Aaron Hedge

I like to write about human-wildlife relationships, mostly.