Anguilla and Elliptio – stimulus and symbiosis

If Democrats and Republicans could work as well together as Anguilla rostrata and Elliptio complanata do, we'd probably have a better country. They don't have to like each other much — Anguilla and Elliptio aren't especially fond of each other, either — but if the leaders of the two major parties could at least strive toward the kind of symbiosis found in nature, we might see some progress on all sorts of issues confronting the nation.

Consider what goes on between the American eel (Anguilla rostrata) and a certain Eastern fresh-water mussel, Elliptio complanata.


According to the intrepid marine biologists who have studied the relationship — Steve Minkkinen of the U.S. Fish and Wildlife Service in Maryland is one — it goes something like this:

When it's feeling particularly reproductive, Elliptio spreads its larvae, called glochidia, into the water. Fish swim through the glochidia, and they end up carrying it with them as they migrate. (I know what you're saying that this point: "Ew, gross!" But wait, there's more, and it's all good.)


Of all the fish in the rivers, the American eel seems to be the one that gets the most glochidia. In fact, it's believed that the American eel is the primary host of the hitchhiking E. complanata.

The eels swim here and there and they spread the glochidia, and pretty soon more mussels are growing up and thriving in various river beds, where they can live for decades.

And they don't just lie around.

They work. They filter gunk out of the water.

Various scientists have looked at the filtering power of Elliptio and found that they're really good at removing suspended solids and nutrients, and controlling algal growth. They play a vital part in making rivers healthy. An adult mussel can filter up to a gallon of water per hour.

A few years ago, William Lellis of the U.S. Geological Survey told the Chesapeake Bay Journal that the Delaware River has about 2 million mussels per mile, and that translates to the natural filtering of between 2 billion and 4 billion gallons of water per day.

So the Elliptio clean up rivers.

Therefore, the further Rostrata can travel while hosting the glochidia, the better. That would mean more miles of river being filtered and cleaned, and if you clean the rivers that feed the Chesapeake — the Susquehanna or the Patapsco, to name just two — you'll have a cleaner bay.


This gets me to the 2009 American Recovery and Reinvestment Act, the so-called stimulus package that Republicans and their tea party allies like to dismiss as a colossal waste of taxpayer money, when clearly the economy would have been even slower to recover from the Great Recession without it.

A bit more than $4 million of the $787 billion in the stimulus went to a restoration project on the Patapsco River. American Rivers, a conservation organization that has been trying to make waterways healthier since the 1970s, got the funds to take down three of the old dams that block the passage of the American eel on the Patapsco. Crews completed removal of the Union Dam last month, and the breach of the Simkins Dam is expected to come in November. Removal of the Bloede Dam is still on the drawing board.

These dams go back to the 19th century, when they were used to power mills along the river in Baltimore and Howard counties. They're not needed anymore — the Union Dam was breached during Tropical Storm Agnes in 1972 — and keeping them only creates places for sediment to build up while reducing the amount of oxygen in the water. They also present hazards for swimmers and paddlers, and they block the passage of fish, like the American eel.

American Rivers collaborated on the Patapsco dam removals with the National Oceanic and Atmospheric Administration, the Maryland Department of Natural Resources and the Friends of Patapsco Valley State Park.

In addition to keeping a few dozen people employed during the course of the project, what we'll get as a result of this relatively modest investment is a free-flowing river with gravelly spawning beds and new habitat for fish. If the Anguilla rostrata continues to collaborate with Elliptio complanata as it migrates, we'll get more miles of cleaner water, and a much prettier and healthier Patapsco feeding the Chesapeake.

Even Republicans, the party of no, and their tea party allies would agree that's a good thing — right?


Dan Rodricks' column appears Tuesdays, Thursdays and Sundays. He is the host of Midday on WYPR, 88.1 FM. His e-mail is