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The dramatic decline of the American eel

Dr. Marc Gaden & Dr. John Dettmers
Great Lakes Fishery Commission

The American eel, a species native to the Great Lakes, is on the verge of collapse throughout much of its habitat. This collapse has occurred alarmingly fast and is especially strong at the far reaches of the eel’s range, which includes the Great Lakes. American eels are at or near the lowest recorded levels of abundance and scientists fear that the spawning stock has declined so dramatically that recovery at the edges of its range may not be possible.

The Great Lakes are in real danger of losing another native species, a result that the Great Lakes Fishery Commission, the Great Lakes jurisdictions, and people throughout the region agree should never occur. In response, numerous partners have embarked on an extensive effort to stop the decline of the American eel.

The Epic Journey of an American Eel

The life of an American eel is nothing short of remarkable. This highly migratory fish is seen in North America as far north as Labrador, as far south as the Caribbean Sea, as far west as the Missouri River, and as far east as the European coast. Lake Ontario represents a natural extremity of its native range, though some eels are now seen as far as Duluth and Thunder Bay.

The journey of the American eel begins in the Sargasso Sea — a region of the Atlantic Ocean off the south eastern coast of the United States — where the eels spawn. After the eggs hatch, American eel larvae drift from the Sargasso Sea to the North American coast. The larvae then transform into small, transparent eels, called “glass” eels, before becoming pigmented and transforming into what are called “elvers.” As the eels grow, they become “yellow” eels, living in the ocean, freshwater streams, or lakes from 3 to 20 years or more. Finally, American eels mature into “silver” eels, whose sole function is to migrate back to the Sargasso Sea to spawn and die. During its life, an American eel will travel thousands of miles, living in both salt and freshwater environments.

The American eel, unfortunately, is threatened during nearly every stage of its life. Glass eels and elvers are harvested for Asian aquaculture. Yellow eels are used for bait, and adult silver eels are harvested for food by thousands of large and small commercial fishing operations throughout its range. Elvers and yellow eels, navigating into and through stream systems, face dams or blockages, which inhibit their migration to suitable freshwater habitat. They must also contend with commercial fishers looking to harvest them. As silver eels migrate back to the Sargasso Sea to spawn, they must, again, run a gauntlet of commercial fishers and hydroelectric power turbines, such as those on the St. Lawrence River, which chew up thousands of eels every year.

Stopping the Decline

Protecting and restoring the American eel pose major conundrums for fishery managers. Competing sources of mortality — harvest at all life stages, hydropower — create tensions among users. Moreover, management is challenging because no fewer than twenty-five jurisdictions along the eastern seaboard are involved in eel management; any effort to stop the decline must include cooperation as broad as the eel’s range.

To address issues relating to the decline of the American eel, the Council of Lake Committees, an organization made up of senior managers from state, provincial, and tribal governments, established the American Eel Task Group. The task group was charged with developing a recovery framework for the American eel and reaching out to jurisdictions such as the federal governments, the Great Lakes and St. Lawrence River jurisdictions, the Atlantic provinces, and the Atlantic States Marine Fisheries Commission. The goals are to develop a coordinated range-wide approach to management of the American eel and to develop policies that all jurisdictions can adopt to immediately reduce human sources of American eel mortality. The Great Lakes Fishery Commission facilitates the task group’s work.

These steps must be taken. The American eel is on the verge of collapse, perhaps never to recover. It remains to be seen whether the political jurisdictions can take the necessary steps in time to prevent the loss of this native species.

For more information, see MacGregor et al, “Natural heritage, anthropogenic impacts and bio-political issues related to the status and sustainable management of American eel”, available online at www.glfc.org/eel.

© 2009 Great Lakes News.