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. 

Quarry Curiosities, Part 5 - The American Eel

Or, "Life below the Surface "

 

An eel in the cattail roots, Halibut Point quarry

Occasionally during the summer an impressively large American eel Anguilla rostrata could be seen at the edge of the quarry, seemingly three inches thick and three feet long. It moved with the unhurried drift of a contented apex creature in its domain--well fed and unchallenged.

 

Minnows silhouetted against the eel

Interestingly the small fish in the neighborhood were at this moment at least unperturbed by its presence.
 

Eric Hutchins setting an eel trap

Eric Hutchins joined our quarry fish survey with a particular interest in eels. He has studied them extensively not only for their fascinating life story but as a bellwether of habitat health for the National Marine Fisheries Service.

And what do the landlocked waters of Halibut Point have to do with ocean species? Eels, like salmon and shad, spend part of their lives at sea and part in freshwater rivers and lakes. They depend on free movement through utterly different environments at different points in their lives. Waterway obstructions, pollution, and other significant alterations have decimated eel migrations in recent years.
 

Map of eel migration*

In a cycle opposite from salmon and shad, eels are born at sea but spend most of their lives maturing in fresh water. To accomplish this the larvae, which develop from eggs spawned only in the Sargasso Sea south of Bermuda, disperse by currents along the continental shelf through a series of metamorphoses that finally result in transparent glass eels swimming landward toward estuaries. There they take on pigment to match the mud and become 2.6-3.9 inch elvers determined to move upstream where they may spend twenty-five years or more reaching sexual maturity for the trip back to the Sargasso Sea to mate, spawn, and expire. That journey requires remarkable physical changes and stamina as well as uncanny navigational ability.
 

Looking up a damp swale toward the quarry.
Note the water-loving loosestrife blooming at the left.

During spring rains elvers can wriggle up damp swales and even across lawns in search of habitable water bodies. Presumably they reached the Halibut Point quarry in this manner, crossing under the perimeter road through seepage points in the grout that underlies the road in certain places and serves as a sluiceway for excess water flowing down to the sea.

 

Elvers moving upstream
Tim Watts photo

Because they inhabit both fresh and salt water environments American eels are a Trust Resource of the National Oceanic and Atmospheric Administration (NOAA) which incorporates the National Marine Fisheries Service (NMFS) where Eric is a Habitat Restoration Specialist.
 

Eric Hutchins netting an eel
Courtesy photo

Eric combines the personality, subject matter, and outdoor setting that appeal to environmental students. "Eels are also a really good species for education and stewardship. I can almost always find one between May and September and they are durable and safe to handle. Kids like to see them."
 

Rockport school student
Courtesy photo

Eric monitoring an elver trap at Millbrook Park with
the Marine Science and Aquaculture class from
Essex North Shore Agricultural & Technical School

The current tally at Millbrook Park, Rockport

Eric has a team of volunteers checking the elver trap daily. "I'm getting a lot of new people interested in the aquatic environment through catching this fish. Tomorrow I'm scheduled to give a program to the Pigeon Cove Sewing Circle. Who would have ever thought a sewing circle would care about eels? I'll see if I can get a live one to bring in."

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*Detail of the map shown in the brochure "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.

 

 

 

Quarry Curiosities, Part 4 - Science Convenes

Or, "Life below the Surface "

Looking into the quarry, June 2018

The birds had proven it, and I could see fish swimming in the quarry waters, but what were they and how did they get there?

Babson Farm Quarry, c. 1910
Photo from the Barbara Erkkila collection, Cape Ann Museum

The watery paradise had been a desolate open-pit mine a century ago.

Dr. Richard Webster stocking trout, c. 1958
Webster family photo.

After purchasing the abandoned water-filled quarry Dr. Richard Webster envisioned it as the centerpiece of recreational Pitcairn Park. He stocked it with trout, which may or may not have survived to sporting size.

Chris Leahy and Eric Hutchins

Cape Ann naturalist Chris Leahy warmed to the idea of making a fish survey of the quarry. He recruited to the project native Rockporter Eric Hutchins, a Habitat Restoration Specialist for the National Marine Fisheries Service.

The EPA New England Regional Dive Team

To get to the bottom of it - possibly sixty feet down in the cold waters where trout might live - he invited scuba divers from the Federal Environmental Protection Agency.

Chris angling

The survey utilized diverse tools of inquiry.

Phil Colarusso making his entry

The EPA divers came because of past ecological collaborations with a colleague of Chris in the Massachusetts Audubon Society. Team leader Phil Colarusso summarized their goals. "We try to give our team a wide range of experience. It's a great opportunity whether we see fish or not. It's different from what we normally do. I knew that it was a logistical challenge, good risk-management training. And it's for basic biological curiosity. So it checked all the boxes for us."

Eric and Chris inspecting the minnow catch

Probable Banded Killifish

The minnow trap brought in, not surprisingly, minnows. Almost all the diminutive fish that squeezed through the small trap opening proved to be Banded Killifish, an abundant native species. We relayed photos of the much larger fish speared by the Green Heron to Karsten Hartel*, co-author of Inland Fishes of Massachusetts, who identified it as a Golden Shiner, also classified as a minnow but one that commonly grows to five or six inches in the wild.
_____
* Karsten Hartel is the retired Curatorial Associate in Ichthyology at Harvard University's Museum of Comparative Zoology.

Golden Shiner

Karsten was not surprised that our collective efforts produced these two species of minnow. The escape or release of fishermen's bait may partially explain their dispersal to previously unpopulated water bodies. Furthermore, as Eric hypothesized, when Dr. Webster introduced the trout he likely also added minnows as a food source for them.

The scuba divers' visibility was greatly restricted by algae clouding the water. They did also observe minnows near the surface but could not confirm any species swimming at depth. Eric ventured that trout populations would have been unlikely to sustain themselves in the quarry for lack of the feeder streams critical to their reproduction needs. 


Aspiring biologists inspecting the minnows

The fish survey brought out the boyish enthusiasms of all us participants and gave Chris an educational opportunity that recalled his programs with Mass Audubon.

Kingfisher

From his perch on a quarry ledge a Kingfisher conducted his own survey of prospects beneath the surface.

We were all aware of one more quarry inhabitant that had not materialized this particular day.

Next week: The American Eel

Quarry Curiosities, Part 3 - The Green Heron

Or, "Life below the Surface"

Green Heron

From various vantage points around the quarry rim the green heron scans life below the water surface in search of his next meal.

The sight of a good prospect tautens its posture like an arrow in a drawn bow.

The heron springs on a tadpole surfacing to breathe, returns to the rock and swallows it headfirst.

 

In another corner of the main quarry it stalks through the cattails nabbing minnows in the shallows.

The bird developed a knack for fishing in deeper water. It maintained an observant vigil from a rock and launched forth on opportunity, sometimes spearing and sometimes snatching its prey.

 

 

Back on land it flipped the fish in the air to orient it for swallowing head first, spiny fins pointing harmlessly astern.

 

 

 Over the course of several days the heron demonstrated its prowess at catching what appeared to be a variety of fish species in the quarry.

 

 

This predatory pageant riveted me as only mortal intrigue can. It was a vignette in a far larger drama that ends and sustains life everywhere. Presumably that is why fish reproduce faster than herons and herons are relatively scarce.

 

The samples of fish retrieved by the heron extended my curiosity about life beneath the surface. What were they, and how did they get into the quarry?

Next week: "Science Convenes"