Good News for Chesapeake Eels

CBS Balmer, American Eel Population Reaches Record High In The Susquehanna River

The American eel population in the Susquehanna River reached a record high this season.

The state’s Eel Migration Program recorded over half a million of these juvenile slippery creatures that pass through the Conowingo Dam — and experts say there’s no real reason behind a spike in population just luck.

A ramp is a key player in helping the eels migrate over the Conowingo Dam and these juvenile eels serve as a host fish for mussels. So more eels, means more mussels, resulting in cleaner water in the upcoming years for other native species like blue crabs and oysters.

An article from another TV station explains the ramp better: WBALTV,  Unique process to help eels migrate past the Conowingo Dam

They catch them with the eel-way. It is an 18-inch ramp that runs from the base of the river to a holding tank. A pipe pumping six gallons of water a minute is next to it which lures the eels onto the ramp.

"The eels think that it's a creek and there's a way around the dam. They climb up it," fisheries biologist Michael Martinek said.

The eels eventually fall into a holding tank.

So far this year, more than 621,000 eels have been collected at one location. The eels are trucked and let go in numerous freshwater locations miles above the dam. Back in their natural habitat, the eels act as a carrier for mussels.

Many species of freshwater mussels and clams rely on fish to move their larvae around. The larvae attach to the gills of fish, stay a while as parasites, then drop off to become free living bivalves on the bottom. It is thought that the precipitous decline of American Eels  has led to similar drops in mussel species that utilize it as a host. 

The Wombat has Rule 5 Sunday: Carol Cleveland ready for business at The Other McCain.

Can Mussels Save the Anacostia River?

Probably not, but at least they won't hurt anything: Can a few hundred mussels become millions in the Anacostia?

Last fall, Jorge Bogantes Montero of the Anacostia Watershed Society helped to transfer tiny, hatchery-raised mussels into protective baskets in the Anacostia River. At the time, Montero said, he “didn’t have any expectations” that they would survive. But, under the careful watch of the watershed group and local school children who helped monitor their growth, nearly 92% of them did.

Now, the pilot project that started with 9,000 quarter-size mussels placed in a river no one was sure could sustain them has graduated to a much bigger one. In late September, the surviving mussels — some of which grew as much as 2 inches over the last year — were disseminated to several other locations in the river, from the marshes around Kingman Island to the faster-flowing waters near Yards Park.

Projects to circulate mussels through more of the Chesapeake Bay’s freshwater systems have been picking up steam as more people recognize the bivalves’ powerful water-filtering capacity.

Although most of the species used for restoration projects won’t show up on a local menu, they function like the Bay’s beloved oysters by providing food and filtration to local ecosystems.

“Mussels filter the water. They take nutrients and bacteria and sediment out,” said Jim Foster, president and CEO of the Anacostia Watershed Society. “We see this as an opportunity to help naturally clean up the river.”

Researchers know of eight mussel species that are native to the Anacostia. So far, they’ve had success promulgating three of them: Alewife floaters — which grew the fastest this past year — Eastern pondmussels and Eastern lampmussels.

Montero, a natural resources specialist with the watershed society, estimates the mussels already filtered more than 32 million gallons of water in their first year and said that more reaches of the river stand to benefit from their presence.

In August, the District of Columbia’s Department of Energy & Environment gave the organization a $400,000 grant to distribute another 35,000 mussels in the river and involve 400 District students in the process. DC Water also is contributing to the project.

“Let me say that cleaning up an urban river like the Anacostia River takes a lot of hands, a lot of partnerships,”

Tommy Wells, director of DOEE, said on a boat near Kenilworth Marsh, where a few hundred mussels were released that day despite a steady rain. “You can just look out on the river today and see that this is a river worth turning back into an asset for the people who live here — and for the generations to come.”

Mussels were far from the minds of advocates determined to improve the health of the Anacostia River until Montero started finding them in and around grass beds that his organization was helping to restore in 2015. The next year, a biologist from Maryland’s Department of Natural Resources helped them conduct a survey for mussels.
They found a couple of dozen, enough to form a baseline of the river’s health and sow the seeds of a new project.

A collection at the Smithsonian Institution suggests how much of the river’s mussel population has been lost. On display are the shells of mussels that were once abundant in a stretch of the river near Benning Road around the turn of the 20th century and into the 1950s. Last year’s pilot project was a first stab at reintroducing some of those species, and it seemed to work.

Jim Foster, president and CEO of the Anacostia Watershed Society,
 prepares to toss a pair of mussels into the Anacostia River
 near Kingman Marsh. (Whitney Pipkin)

“In the back of our minds, we were expecting more mortality — because it’s the Anacostia River — but that wasn’t the case,” said Montero, who reported just 8% of the mussels dying in the first year. “The food available in the water column is great, apparently. They’re not dying but growing.”

Montero has worked closely on the project with fish biologist Rachel Mair from the Harrison Lake National Fish Hatchery, located along the James River south of Richmond. The facility and others like it are spawning the next generation of mussel researchers and hundreds of thousands of mussels for rivers like the James and Anacostia.

The hatchery produces thousands of baby mussels each year and grows them until they’re more likely to survive in the wild. All three species in the Anacostia project rely on a host fish to complete their life cycle, so the propagation process is delicate.

With the DOEE funding, the watershed group plans to add two more species to the mix: the Eastern floater and Eastern elliptio. The latter seems to rely on the American eel to reproduce, and the hatchery is experimenting with in vitro fertilization techniques to promulgate it.

The Virginia hatchery grows the mussels by collecting females that already have larvae in their gills. The staff then extracts the larvae with a needle (to mimic a fish rubbing against it) or allows the mussel to release them.

Placed into tanks with their host fish, the larvae will attach to the fish before dropping off two to four weeks later to continue feeding and growing in a series of tanks.

Now that the Anacostia mussels have grown successfully in their protective baskets at eight sites along the river, the organization will test their ability to survive in wetlands and on the river bottom. Volunteers on Sept. 30 tossed hundreds of the adolescent mussels into semi-protected portions of Kenilworth Marsh, where Montero said wild mussels have been found before, “so we know it’s good habitat.”

By the end of October, Montero said, about 8,700 mussels would be spread to new locations in the river.

My problem with "solutions" like this one is that if the mussels were capable of thriving and reproducing in the Anacostia, they'd already be there. They live in adjacent waters (I found a bunch in the C&O Canal once). There is something lacking in the Anacostia which will not let them succeed in good numbers, probably a lack of suitable host fish, since adult mussels . Until that problem is solved, planted mussels are not likely to play a huge role in cleaning the River. But I might be surprised.