A new eelway may save this endangered - and necessary - species in our river

image courtesy of USFWS monitoring American eels in Buffalo Creek, Pa. 33, chesapeake bay program flickr

Coming soon to a river near you: eels, and lots of them if everything goes according to plan.

Centuries ago the Potomac teemed with American eels (Anguilla rostrata), the only freshwater eel species in North America. They were a staple food source of George Washington and Abraham Lincoln’s armies.

But for the last 100 years or so, eels have been all but absent from the upstream waters of the Potomac River. According to the International Union for Consrevation in Nature (IUCN), the eel is at significant risk for extinction in the wild. The culprit? A hydroelectric dam originally constructed to divert water in the C&O Canal near Shepherdstown, West Virginia. The dam interrupts the eels’ lifecycle, making it extremely difficult for the species to thrive and survive in the Potomac.

Where did all the eels go?

American eels are born in the Atlantic Ocean and migrate into freshwater rivers to mature before returning to the ocean to spawn. Dams, like the one near Shepherdstown, prevent them from swimming upriver.

Interestingly, the eel’s migration pattern is the opposite of American Shad, a native fish that has been successfully restored to the Potomac River. Shad swim from the ocean into freshwater rivers to spawn (this makes shad anadromous species). Eels do the opposite (making them a catadromous species).

*Did you know? Until recently, freshwater eel spawning was one of the great unsolved biological mysteries! Scientists could not determine where within the vast ocean this slippery species went to mate and reproduce. However, in 2015, researchers were able to track a satellite-tagged female on her 1,500 mile journey from Nova Scotia to the Sargasso Sea.

Why do we need eels?

As creepy as they may seem, eels are actually a river’s best friend! Eels are an important and beneficial part of a healthy river ecosystem.

For starters, eels are an important food source to larger fish and fish-eating birds such as bald eagles. And from a water quality standpoint, eels play an even more important role as a natural taxi service of sorts. Eels transport freshwater mussels, which filter pollution from the water. Without eels, mussels can’t get around, which means dirtier water wherever they aren’t.

Restoring eels, and by extension mussels, could make the Potomac "crystal clear," David Sutherland, a biologist with the US Fish and Wildlife Service told WUSA 9.

An eelway on Dam 5 of the Potomac River.

How can we bring eels back to the Potomac?

In order to reconnect eels to their historic habitats, we need to provide them with safe passage back upstream. This means either destroying dams or…building “eelways”

A new project in Falling Waters, WV will help restore eels to the upstream waters of the Potomac River. To allow eels through the Shepherdstown dam (Dam 5), scientists from the US Fish and Wildlife Service are tracked their movements to determine where they try to pass. Once they figured out where the naturally swim, they constructed a special passage over the dam. The 65-foot aluminum eelway, completed in October 2019, is a covered ramp that allows American eels to swim safely to the top of the dam

So be on the lookout for eels, and if you spot one, don’t grimace. Remember, eels are a good thing!