Changing Planet

Let’s Not Shatter the Glass Eel

By Dr. John Waldman and Dr. Merry Camhi

With the exception of sushi aficionados devouring unagi in rolls of avocado, rice, and a dab of wasabi, American eels do not get a lot of love today. Once a dietary mainstay of native peoples and early colonists, these nutritious animals have been devastated over the centuries by growing fishing pressure and the construction of dams along rivers where they once swam in abundance.

Although a petition to add the American eel to the U.S. endangered species list was denied in 2007, a second petition will be considered in 2015. In the meantime, fishery managers can take critical steps to secure a better future for what many consider the most mysterious fish in the sea.


American eels lead a singular existence of sweeping geographies. Spawned deep in the Sargasso Sea—a two million-square mile becalmed region of the Atlantic between the Azores and West Indies—their larvae hitch a hemispheric ride for half a year on the Gulf Stream as they transform into ‘glass eels.’

By Julie Larsen Maher

Each spring, millions of these transparent, four-inch-long baby eels exit the Atlantic to enter estuaries and rivers from Greenland to northern South America. Once in fresh water they darken, drive upstream, and spend the next decade or two maturing, until the spawning imperative stirs them to migrate thousands of miles back to the Sargasso, where they reproduce just once and die.

For millions of years this unique life cycle was wildly successful. In the 1800’s, eels that had migrated  up the St. Lawrence River and into Lake Ontario aggregated at the foot of Niagara Falls. Nineteenth-century naturalists commented that “hundreds of wagonloads . . . would hardly be considered excessive by those who have visited the spot.”

Only a few decades ago Lake Ontario held five to ten million eels. Today some 84 percent of their historic habitat in East Coast watersheds and the Lake Ontario Basin is no longer accessible due to dam construction. Before the Conowingo Dam blocked almost the entire Susquehanna River, nearly 1 million pounds of eels were caught annually. By 2000, they fell to zero.

elvers in ME 6-13
Eels for sale in Maine

In recent years, glass eels have been undertaking a migration of another kind: Caught in nets as they enter East Coast tributaries, live eels are sold and shipped half way around the world to aquaculture pens in China, where they are fattened up for the Japanese sushi markets.

With relentless fishing, dams, habitat loss, and pollution American eels now find themselves “at or near historically low levels” according to a 2012 scientific assessment.

It’s as bad in Europe. By the end of the twentieth century, the number of glass eels entering rivers there declined to 1 percent of historical numbers. To fuel their recovery, the Convention on International Trade in Endangered Species (CITES) banned the export of all European eels – hence the Chinese imports of American glass eels for their aquaculture pens.

The Atlantic States Marine Fisheries Commission, charged with managing shared fishery resources in U.S. waters, will soon decide on new regulations for the American eel, including closure of all glass eel fisheries along the East Coast. They are currently legal only in South Carolina and Maine (other states closed their fisheries to spur recovery).

In the wake of European and Canadian glass eel fishery closures, the price per pound for American eels jumped ten-fold in the past decade, reaching as high as $2500 per pound. This has led to a veritable gold rush in Maine, with fistfights, thefts of catches, and considerable poaching in other states.

American eels need relief, not intense fishing of young eels that are the future of the species. In 2007, Ontario put the American eel on its Endangered Species List, and Canada declared it Threatened in 2012. The European eel is now Critically Endangered.  Just this February, Japan listed its own Japanese eel as Endangered. Eels worldwide need more friends.

It’s time for the Atlantic States Marine Fisheries Commission to step up to protect the American eel here in our own waters. At their August 7 meeting, rather than bow to pressure to open fisheries in other states, the Commission should vote to close all glass eel fisheries to give this once bountiful and still mysterious species relief before it’s too late.


Dr. John Waldman is Professor of Biology at Queens College  and the author, most recently, of Running Silver: Restoring Atlantic Rivers and Their Great Fish Migrations. Dr. Merry Camhi directs the New York Seascape Program at the Wildlife Conservation Society’s New York Aquarium.


WCS saves wildlife and wild places worldwide through science, conservation action, education, and inspiring people to value nature.
  • Walter Kumiega

    Interesting article. 2 decades to mature seems a bit of an exaggeration. Closing a fishery without addressing access issues does the species little good. Eels are no more endangered now than they were 5 years ago. They won’t be listed in 2015, and there are plenty of moderate conservation options short of closure that will help eel populations increase.

  • William Burgess Leavenworth

    Eels are very endangered, regardless of what folks in the eel fishery say. Commercial fishing in New England is steadily destroying the base on which a once-prosperous, sustainable and dependable near-shore fishery rested–as the eels, smelt, tomcod, cunner, alewife and shad go, so go the cod, hake, halibut, haddock, pollock, tuna, and swordfish. Those computer-dependent scientists who maintain otherwise are apparently unable to read, synthesize, and intuit pre-computer-era qualitative and quantitative data. That is, they are not scientists at all as the term was once used to describe Darwin, Newton, DesCartes, Humboldt, and others who laid the foundations of modern science. Two decades to mature may be an underestimation; I’ve seen eels in the lake at the head of the St. George River that were at least 1.5 meters long and 15 cm thick. Divers on a recovery mission in a Rockland quarry three decades ago saw eels as big as their thighs. They didn’t get that big in in just twenty years unless someone was feeding them regularly.

  • Martin

    I grew up in Neath, South Wales, during the very high tides the River Neath would back up into the freshwater streams (tributaries) I can recall many times during the mid to late 60’s where scores of youngsters (not even in our teens) could dip (just for a second) a jamjar into the freshwater stream at high tide and it would be crammed (like sardines) with elvers.

  • Daria

    I agree that this fishery needs to be managed. Maine has a highly sustainable lobster fishery – something similar should be done for elvers. Perhaps licensing structure and catch limits based on areas fished would help. You can judge New England fisheries for destruction of species, but really it is the technology and market destroying the fisheries. If there were no buyers, the fishermen would not make money, etc. For example, the urchin boom led to a complete habitat change and species reversals. Introduction of non-native green crabs has changed the underwater landscape. I think they should ban dragging the sea floor to catch every species (while destroying the groundfish habitat) in a boat’s wake. Using traditional nets and long lines would certainly be more difficult and reduce the ever important ROI, but my grandchildren might enjoy non-farmed fish as a result.

  • Emmanuel Hernandez

    I think the most destructive way of eliminating the species like eels and salmons to mention a few is to keep on building dams for renewable energy. We have in effect made that decision (to kill the species) early on. What we can do is let progress move on without necessary killing the species. In the case of elvers, we can build a spiral staircase for the levers which will simulate the same environment that elvers go through during elver migration up rivers. Same thing for salmon. This is one minuscule move to create one gigantic effort to save the species for our children to benefit from in generations to come.

  • Erno Bredenhann

    I am a chief engineer on a fishing trawler in south african waters. i have cought a glass eel in one of my strainers outside Houtbay. i have not seen someting like it before in our waters.

  • Erno Bredenhann

    found one in my cooling strainer. outside Houtbay ,South Africa

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