Some Intimacies about Eels

The serpentine eel celebrated in my last episode of Quarry Curiosities stirred more than the usual reflexes among readers. I too must own up to flashpoints of internal chemistry at the sight of one, somewhat as if a shark had appeared in the quarry. My startle response eases to fascination once I understand that personal safety is not at stake. But I'm not sure I want to touch one.

Childhood memories good and bad wriggle forward in my mind to commingle with amazing facts about eels. The miniatures we found under rocks in the Lanesville creek running past Grandpa's house to the ocean livened up our coffee-can aquariums of crabs and snails.

On the other hand, on a barefoot day at East Moriches, Long Island, my other grandpa took us to the pier to fish for snappers. Suddenly the bobber disappeared and the bamboo pole bent double. "Lordy, Lordy, must be an eel," exclaimed a big black woman sympathetically. She advised handfuls of sand to help grab that slippery thrashing fiend while Grandpa set about extracting the hook. I don't think the dilemma went particularly well for any of us.

All those eels, the little puddle ones and the monsters in the Bay, had come from one spawning place over a thousand miles away in the middle of the ocean on the other side of Bermuda. As larvae (leptocephali) they are shaped like sails to catch the drift of the Gulf Stream northward until they develop tails and begin swimming landward. They spend many years maturing in brackish estuaries or far upstream in freshwater ponds. Then comes the irresistible urge to return to their birthplace in the Sargasso Sea.

Life phases of the American eel ¹

 The maturing fish that we see locally are called yellow eels because of the cream-colored sides and underbellies contrasting with mud-brown tops. Their coloration makes them generally invisible on pond and river bottoms, but more noticeable against the granite ledges of the Halibut Point quarry when they emerge from cattail stands.

The call to return to the sea may come after ten to thirty years of contentment with continental life. Heading downstream it begins its transformation to a silver eel. It takes on the protective coloration of an ocean species. Its eye expands and adapts to low visibility in deep water. Its skin thickens. Its body fat increases to supply energy for migrating and spawning. Its pectoral fins and swim bladder enlarge to improve propulsion.  Its digestive tract degenerates during this metamorphosis, evidence that the seaward migration is a one-way trip. It ceases eating as a new complex of hormones guides its purpose.

No mature eel has ever been seen in the open ocean to verify the route to nor the precise location of the homecoming. However it results in the replenishment of all the eel population in the Americas. Such a mystery aches at the heart of science. Several years ago Canadian researchers harnessed with radio telemetry large females migrating from the St. Lawrence River.

The journey of Eel No. 28 ²

Perhaps handicapped by their radio attachments most of the tagged eels seem to have fallen prey to sharks and tuna. Only No. 28 reached the open Atlantic after its eastward traverse of the continental shelf. Suddenly she turned straight south, crossed the Gulf Stream, and continued a 1,400-mile marathon to the edge of the Sargasso Sea where her tag popped off prematurely and began streaming data to an overhead satellite. The recording showed that while the sun was up she dove to depths of more than 2,000 feet to avoid predators.

Hopefully at a latitude unknown our Champion No. 28 united with others of the eel odyssey in a final bliss of mating and a release of her millions of fertilized eggs to the northwesterly currents, to the elements of chance and design, to the intimacies of treasure and waste that perpetuate her race. She had finished her own life journey.

Her spawn floated off to unknowable estuaries. A few of them would be able to work their way upstream to prosperity with flagellations of their snakelike tails. Like serpents of maritime and Biblical lore, they would unnerve speculators on murky mysteries.

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¹ Illustration and life history details from "American Eels: Restoring a Vanishing Resource in the Gulf of Maine" produced by the  Gulf of Maine Council on the Marine Environment, 2007. It is available online at  www.gulfofmaine.org.

² Dr. Julian J. Dobson et al, "Direct Observations of American Eels Migrating across the Continental Shelf to the Sargasso Sea," Nature Communications, October 2015.