"Freshwater mussels are very sensitive to a variety of problems, including pollution, dams, water flows, loss of forests, and harvesting for their shells and as bait," said Dr. Danielle Kreeger, science director at the Partnership for the Delaware Estuary. "We have so few mussels left in almost all of our streams in the area, so to find seven species living together in dense communities right near Philadelphia was unexpected and cause for celebration."
Freshwater mussels are the most imperiled of all plants and animals in North America Nearly three-quarters of the continent's 300 species are in decline, and many are either extinct or headed toward extinction. In the Delaware River Basin, most of the one dozen native species are classified as reduced, threatened, or locally extinct. One of the basin's species is considered endangered at the federal level and others are listed as endangered at the state level. Water pollution and degraded habitats are the most common reasons for these declines. That is why scientists are so excited to find them in this stretch of the river.
One reason freshwater mussels may be doing better in the Delaware River compared to surrounding tributaries is the fact that the Delaware is the longest free-flowing river east of the Mississippi. Dams often block fish from swimming up the river, and this can interrupt the complicated breeding processes of freshwater mussels. Mussels rely upon fish to carry their babies, or larvae, around, including upstream. Whenever dams block these fish, they fail to deliver their payload of mussel larvae to new areas where they can grow and thrive. Pennsylvania has more dams than any other state, and many of these are located in streams throughout the Delaware Valley. The lone exception is the Delaware River.
"Until this discovery, our surveys for freshwater mussels in southeastern Pennsylvania during the past 10 years have painted a grim picture. Only one species seems to still be prevalent in the area's streams, and even that species is found in only a handful of locations anymore," said Roger Thomas, staff scientist at the Academy of Natural Sciences' Patrick Center for Environmental Research in Philadelphia. These recently discovered beds of mussels can be used to help support mussel reintroduction into other areas where they have been lost."
Dr. Kreeger and others are in the process of expanding a fledgling mussel-restoration effort with support from a number of funders. These include ConocoPhillips, the National Fish and Wildlife Foundation, and the Pennsylvania Coastal Resources Management Program. She believes it is now possible to increase mussel populations throughout the Delaware River Basin by either breeding them in a hatchery or relocating adults during breeding season by releasing them in targeted streams. She and her colleagues at the Academy of Natural Sciences have been working with Cheyney University, the U.S. Fish and Wildlife Service, and the U.S. Geological Survey to experiment with different methods since 2007. They call their effort the Freshwater Mussel Recovery Program.
The Partnership for the Delaware Estuary is restoring mussels for many reasons, not just the fact that these animals are rare and endangered.
"Dense beds of mussels filter pollutants and make conditions better for fish and other aquatic life, improving water quality downstream in the estuary," said Jennifer Adkins, executive director of the Partnership for the Delaware Estuary. "We may have these beds of mussels to thank for keeping certain types of pollution, like nutrients, low in this part of the river. This helps make our waters more inviting for everyone."
Restoring freshwater mussels won't be easy or fast, however. Although freshwater mussels can help to boost water quality, they are also some of the most sensitive animals to polluted water. Therefore, some area streams may not be able to sustain mussels until water quality is further improved or riverside woodlands are replanted. Also, freshwater mussels live to be up to 100 years old and are slow growing. But this does not concern Dr. Kreeger, who said, "We've made tremendous strides in improving some environmental conditions needed to support healthy ecosystems. That said, we know our job won't be complete until we see the return of these long-lived sentinels of healthy waterways."
Of the seven species of native freshwater mussels discovered this past summer,
Two species were thought to be extinct in Pennsylvania and New Jersey: the alewife floater, or Anodonta implicata, and the tidewater mucket, or Leptodea ochracea.
Two species are considered critically-imperiled: the pond mussel, or Ligumia nasuta, and yellow lampmussel, or Lampsilis cariosa.
Two species are considered vulnerable: the creeper, or Strophitus undulates, and the eastern floater, or Pyganodon cataracta
One species is listed as common: the eastern elliptio, or Elliptio complanata
The Partnership for the Delaware Estuary, a National Estuary Program based in Wilmington, leads collaborative and creative efforts to protect and enhance the Delaware Estuary, and its tributaries, for current and future generations. We envision everyone working together to make the Delaware Estuary the most inviting, prosperous and healthy natural resource of its kind in the nation.
The Academy of Natural Sciences, founded in 1812, is the oldest natural science research institution and museum in the Americas and a world leader in biodiversity and environmental research. The mission of the Academy is the encouragement and cultivation of the sciences.
Carolyn Belardo | EurekAlert!
Ambush in a petri dish
24.11.2017 | Friedrich-Schiller-Universität Jena
Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
24.11.2017 | Physics and Astronomy
24.11.2017 | Health and Medicine
24.11.2017 | Earth Sciences