A new scientific study showing that dam removal is paying off for American eels in Virginia may hold lessons for restoring Pacific lamprey in the Columbia-Snake Basin here in the Northwest. We are overdue for action on lamprey; as of July 31 only two lamprey – two! – reached Idaho’s Snake River and the Nez Perce Tribe’s homelands from the ocean this year.
The new study, by the U.S. Geological Survey, U.S. Fish and Wildlife Service, and National Park Service, shows that removal of Embrey Dam on Virginia’s Rappahannock River has boosted American eel numbers in headwater streams nearly 100 miles inland from the dam – in contrast to decreasing numbers elsewhere in their range.
The study evaluated eel abundance in Shenandoah National Park streams before and after this large dam was removed in 2004. Researchers found significant increases in eel numbers in Shenandoah National Park, beginning in 2006 with continued increases nearly every year since. "Our study shows that the benefits of dam removal can extend far upstream," said Dr. Nathaniel Hitt, a USGS biologist and lead author of the study.
What do American eels on the east coast, and Pacific lamprey (often called lamprey eels) on the west coast have in common? Both are ancient native species; both migrate from freshwater to saltwater and back again to complete their life-cycle; both thrive best in free-flowing waters and have been badly damaged by dam-building; both are important parts of connected freshwater/salt water ecosystems; both are (in the case of American eels, were) vital parts of native Indian cultures. And both are declining towards extinction, though neither is yet an official endangered species.
The very positive response of American eels to dam removal on the Rappahannock does not prove Pacific lamprey will respond as well to dam removal on the Snake, but it is further strong evidence that such a positive response is likely. This new study adds to the mounting evidence that when dams go, migratory fish of all kinds – salmon, steelhead, shad, herring, eels, lamprey and others – come back.
We at SOS applaud the U.S. Fish and Wildlife Service for starting a collaborative effort to restore Pacific lamprey, especially in the Columbia-Snake Basin. Lamprey are a first food for the basin’s Indian Tribes, and an important contributor to food chains and ecosystems. But the species is in deep trouble, as this year’s return of just two lamprey to Nez Perce homelands shows.
It was 20 years ago this month that “Lonesome Larry” – the lone Snake River sockeye to return in 1992 – brought national attention to the dire condition of Columbia-Snake salmon. Now two lonesome lamprey are sending the same message: It’s time to act. Greater spill and lower Snake River dam removal are the two best actions that can be taken for lamprey and salmon in the Columbia Basin.