202-208-5657

THEIR NICHE IN THE ECOSYSTEM IS AS SLIPPERY AS THEIR NAME, BUT PERSISTENCE MAY BE NUDGING A COMEBACK FOR THE EEL

Biologists believe that eels begin and end their life in the waters of the Sargasso Sea, in the middle of the Atlantic Ocean, but questions about their reproduction, migration and life cycle remain as slippery as their skin.

That’s why it’s important for U.S. Fish and Wildlife fishery biologists like David Sutherland, of the Chesapeake Bay Field office, to keep working with the Maryland Department of Natural Resources and other partners to learn how the species has slid into decline.

Sutherland can cite the obvious and traditional reasons – overfishing, habitat degradation, contaminants and poor water quality – but that doesn’t tell the whole story. Amid those obstacles, the eels have managed to do what few other species have done: they are still making it upstream on the Maryland side of Great Falls, and that’s unusual. Some eels are even managing to find their way around the next dam or through the National Park Service’s C&O National historic Park canal to get upstream to old rearing habitats.

This summer, Sutherland and Keith Whiteford of the Maryland Department of Natural Resources, found 7 untagged eels. Sutherland considered that “significant” because it means that new eels are making it up Great Falls during the late summer months, well beyond what was understood to be just a spring migration period.

“It can mean that the eels have a bright future,” said Sutherland. “Any species that can find its way this far upstream and can find a way around a dam is a very hardy species.” The next step: eelways are being built at other dams to enhance fish passage to cut delays and injury. Allegheny Energy Supply built the first eelway in the Chesapeake Bay Watershed, at the first dam on the Shenandoah River. Allegheny is planning to build six more eelways in the Potomac River Watershed over the next several years.

Eels still face daunting obstacles. They remain a major commercial fishery, have some appeal to recreational anglers and there is the much-touted appeal to sushi afficianadoes. Five years ago, law enforcement agents from the Service and several states put an end to a coastal poaching business that was bringing in $5,000 for five gallons of eels, on the overseas market. That type of activity keeps big pressures on the eel population.

Even though researchers have studied eels for years, none have ever found their exact spawning area. In one of the more curious adaptations, eels change into males if the population density is high and food competition strong. They change into females if densities are low and competition is minimal. The species remains on the research scope of the Service, and of biologists like Sutherland. “The study of eels is still in its infancy. That’s part of the fascination. When we finally unlock its ecological niche and fully understand its life cycle, we’ll really have something that can assist fishery managers,” Sutherland said.

Others are helping. Jon Siemien of the District of Columbia Fisheries office is tagging eels in the tidal Potomac River, downstream from Great Falls, with the expectation that some will migrate upstream to the Shenandoah River where Stuart Welsh, of the U.S. Geological Survey Cooperative Research Unit, is studying eels at the new eelway.

-FWS-

For more information about the U.S. Fish and Wildlife Service, visit our home page at http://www.fws.gov

Click Here To Return To The Previous Page