The removal of a large dam in Virginia has meant good news for the American eel population, according to a new study by the U.S. Geological Survey, U.S. Fish and Wildlife Service and National Park Service.Eels are a relatively rare catadromous fish; spawning in the deep ocean, and moving in to fresh water in both North America and Europe to grow to become adults. So, unlike many fish, dams don't prevent them from reaching their spawning grounds so much as substantially restrict the range for them to grow in.
The research, published this month in Transactions of the American Fisheries Society, shows that the removal of Embrey Dam on the Rappahannock River increased American eel numbers in headwater streams nearly 100 miles away.
American eels migrate from their spawning grounds in the Atlantic Ocean to freshwater streams along the coast. Dams were thought to slow or even stop the migration.
Researchers studied eel populations in in Shenandoah National Park streams before and after the removal of the large dam in 2004. The study shows significant eel numbers beginning two years after the dam removal and nearly every year since.
"Our study shows that the benefits of dam removal can extend far upstream," said Nathaniel Hitt, a USGS biologist and lead author of the study. "American eels have been in decline for decades and so we're delighted to see them begin to return in abundance to their native streams."
When I first moved to Maryland, eels were relatively common; you would often catch them on hook and line when fishing for bottom fish, and the Bay supported a substantial eel pot fishery (while not favorite food in the US, they are prized abroad). Smaller one were commonly used as bait for large Stripped Bass (and still are, sometimes). It's been many years since I have had to take one of the things off a hook; always a joy.
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