Restoring Rivers with a Little Mussel Power

Freshwater mussels are one of nature’s greatest natural filtration systems. A healthy bed of mussels, in a reach of river just 2 football fields long, can filter over half a million gallons of water every day.

Freshwater mussels in the Allegheny River near Foxburg, PA are filtering millions of gallons of water a day. Credit: USFWS

Pocketbook (Lampsilis ovata) mantle display. Credit: USFWS

Many cities use rivers for their drinking water. And the river water must be treated to remove fine sediments and harmful bacteria and algae we don’t want in our water. It costs slightly more than $2/1000 gallons to deliver clean water to our homes, with treatment accounting for 15% of those costs (EPA). In 2005, Cincinnati, OH treated 136 million gallons per day; that’s over $17 million per year!

Rivers where freshwater mussel beds are intact could cost less to treat because mussels have been doing their job. “Filtering and recycling nutrients within food webs is an important job and these ecological engineers do it for free” says Dr. Danielle Kreeger, Science Director for the Partnership for the Delaware Estuary.

Tank with no mussels (on left) and tank with mussels (right) at time zero. Credit: Neves, VA Tech

Same tanks after 24 hours. Credit: Neves, VA Tech

Because mussels don’t move much (and certainly not quickly!), they are vulnerable to chronic pollution in the water and changes in habitat, including sediment buildup. Additionally, as rivers have been dammed and altered fish are harder to find above some barriers,

Woolen Mills Dam, Rivanna River, VA was removed in 2007. More freshwater mussels have been found below the dam than above. Credit: A.Weaver, VDGIF

Holtwood Dam, Susquehanna River Credit: USFWS

making mussel reproduction much harder. Over 70% of the 300 species of mussels in North America have been in decline for decades. Since the Clean Water Act, however, water quality has improved in many of our rivers. And through several other federal programs, we are restoring river habitats and removing barriers to fish passage.

The U.S. Fish and Wildlife Service began investing in freshwater mussel culture (and stocking) of freshwater mussels for recovering endangered species back in the late 1990s. We also have been collaborating with State agencies to culture species that formerly comprised a large portion of the biomass in rivers. Those methods are now helping restore these ecological engineers and recover endangered species.

Special tank systems maintain water quality and host fish health while awaiting metamorphosis of glochidia, Virginia Fisheries and Aquatic Wildlife Center. Credit: USFWS

One of the types of freshwater mussel culture systems used at the Virginia Fisheries and Aquatic Wildlife Center, Harrison Lake NFH. Credit: USFWS

In 2007, we partnered with the Virginia Department of Game and Inland Fisheries (DGIF) to restore freshwater mussels in Atlantic slope rivers of Virginia. The Virginia Fisheries and Aquatic Wildlife Center (VFAWC) at the Harrison Lake National Fish Hatchery (NFH) has been raising more than 12 different species, thanks in part to the work of biologist Rachel Mair, hatchery manager Michael Odom and Brian Watson from Virginia DGIF.

Rachel Mair, Harrison Lake NFH freshwater mussels are reared in floating baskets in these productive ponds. Credit: USFWS

The partnership has released over 185,000 mussels into Virginia rivers, including the Rappahannock, Appomattox, Mattaoponi, Pamunkey, Meherrin and Nottoway. They also are helping the Partnership for the Delaware Estuary restore mussels (and rivers) in the Delaware River basin.

Biologists head out to restore mussels in the Nottoway River, Virginia. Credit: C.Gatenby/USFWS

These tidewater muckets (Leptodea ochracea) are really important to water quality in Chesapeake Bay rivers. Credit: B. Watson, VDGIF

The eastern pond mussel (Ligumia nasuta) raised in floating baskets at the Virginia Fisheries and Aquatic Wildlife Center are ready to restore some rivers. Credit: B. Watson, VDGIF

The work hasn’t stopped there. The partnership is currently raising many at-risk mussel species including:

• Endangered James spinymussel: 1,000 being raised and PIT tagged for stocking in the James River this fall
• Atlantic pigtoe: petitioned for listing
• Green floater: petitioned for listing
• Brook floater: petitioned for listing
• Yellow lampmussel
• Triangle floater
• Notched rainbow

Juvenile James spiny mussels raised at the Virginia Fisheries and Aquatic Wildlife Center, Harrison Lake NFH. Credit: R. Mair, USFWS

Suspension-feeding yellow lampmussels, cultured at Harrison Lake NFH, will help restore a river’s health. Credit: R. Mair,USFWS

Indeed, the VFAWC will be raising many of the above species to restore ecosystem health back to the Dan River, Roanoke River basin. The Dan is a life source for residents in North Carolina and Virginia. The river provides drinking water, is used for recreational and subsistence fishing, for canoeing and kayaking, to irrigate crops and provide water to cattle. In 2014, however, a coal ash spill occurred near Eden, NC, that extended 70 miles downstream. The hatchery will be raising and stocking mussels, a critical step to restoring both species and ecosystem services mussels provide.

“If the causes for harm and degradation are removed, the environment can heal as long as the seeds for getting started are still there”, says Brian Watson. He adds “In the case of freshwater mussels with a complicated life cycle, it could take decades for a bed to rebuild itself. That’s why they need a little assistance to jump start the process and boost their numbers.”

Elyssa Mills, James River Association and Hanna Walker (right), student stock mussels at Presquile NWR. Credit: CBrame, USFWS

Lucky for us, we have dedicated biologists with the Service and the Virginia DGIF developing methods for restoring rivers using a little mussel power.

Virginia Department of Game and Inland Fisheries and Harrison Lake National Fish Hatchery staff support the Virginia Fisheries and Aquatic Wildlife Center. Credit: Gatenby, USFWS

 

Bringing back American eels in the Susquehanna River

In today’s post, Sheila Eyler, project leader for the Mid-Atlantic Fish and Wildlife Coordination Office, shares her success in working with American eel populations on the Susquehanna River.

When deciding to attend graduate school, I must admit that the American eel was not on the top of my list of fish to study. However, an opportunity to evaluate the impacts of hydroelectric dams on eel migration helped make the decision for me.

Seven years later, what I have learned about this unique and often misunderstood “snakelike” fish species has made me one of its biggest fans.

Historically, eels were abundant in estuaries and freshwater tributaries in much of the eastern U.S. and Canada. The construction of dams changed all this, drastically limiting eel migration routes from the ocean to upstream freshwater areas.

As a fisheries biologist, I continually look at the impacts that a species’ decline has on an entire ecosystem. In the case of the American eel, the population decline has an important – and fascinating – connection to certain native freshwater mussel species. Larval mussels need to attach to the gills of a fish in order to complete their life cycle. Some mussel species specifically need American eels to survive.

Elvers climbing to base of Conowingo Dam on the Susquehanna River. Elvers are juvenile eels that migrate to brackish waters and begin to develop gray to greenish-brown pigmentation. Credit: Maryland Fisheries Resources Office, USFWS

With fewer eels headed upstream, mussel larvae have fewer hosts to help them survive. In rivers where dams have excluded eels for decades or longer, some freshwater mussel populations have also declined. Fewer mussels means poorer water quality because mussels have the ability to filter gallons of water a day.

Working on the restoration program for American eels on the Susquehanna River is never dull and continues to bring daily adventures. Along with several partner agencies, my colleagues and I have been trapping young migrating eels at the Conowingo Dam and stocking them into the upper watershed for several years. In 2013, we collected nearly 300,000 elvers (baby eels) for the restoration program.

Stocking eels has been very successful in the Susquehanna River. And to our delight, we are now finding eels with larval mussels attached to the gills, which will promote the growth of the mussel population.  

Watch American eels swim upriver

For me, it has been very rewarding to be part of this successful restoration program. I am proud to share the story of the American eel – an underappreciated resident of much of our freshwater streams with an amazing life cycle and connection to our environment.

For more information on the Susquehanna River American eel stocking program, read more at: http://www.fws.gov/northeast/marylandfisheries/projects/Eel%20passage.html.