Freshwater mussels discovery in Delaware river, USA


This video from the USA is called Freshwater Mussel TV – Wavy-rayed Lampmussel (Lampsilis fasciola) mantle lure display.

From the Academy of Natural Sciences in the USA:

Freshwater mussels discovered in urban Delaware river

November 30, 2010

Scientists working with the Partnership for the Delaware Estuary and The Academy of Natural Sciences have made an important discovery in the Delaware River between Chester, Pennsylvania, and Trenton, New Jersey: beds of freshwater mussels. This includes several uncommon species, two of which were previously believed to no longer exist in both Pennsylvania and New Jersey.

“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. …

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

In February 2018 the Texas hornshell mussel, Popenaias popeii, became the first among 15 state-threatened freshwater species to receive federal protection under the U.S. Endangered Species Act: here.

Galician researchers have studied the evolution in the introduction of non-native fresh water species in Galicia over the past century, and have compared this with the rest of the Iberian Peninsula. The results show that 31 exotic aquatic species out of the 88 recorded for the entire Iberian Peninsula have become established in the region: here.

4 thoughts on “Freshwater mussels discovery in Delaware river, USA

  1. Researchers discover freshwater mussel species thought to be extinct

    August 15, 2011 By: AgriLife Today

    COLLEGE STATION — Researchers from the Texas A&M Institute of Renewable Natural Resources have discovered fresh remains of a freshwater mussel species thought to be extinct in Texas, according to a research associate with the institute.

    Dr. Charles Randklev said his research team found a single individual of false spike “Quadrula mitchelli” with tissue still in the shell — which indicates that the individual was recently alive — in the San Saba River in Central Texas.

    Mussel thought to be extinct found in Texas river

    “Based on this finding, it is likely that the false spike may not be extinct and small populations may exist in the San Saba River,” said Randklev, who holds a joint appointment with Texas AgriLife Research.

    Randklev said this is the first hard evidence of the false spike found in the last 30 years. The only other recent evidence was in 2000 when two specimens without soft tissue were collected in the San Marcos River.

    Historically, false spike inhabited the Rio Grande, Guadalupe, San Antonio, Colorado and Brazos river basins, according to Randklev.

    The researchers also found significant populations of three threatened Texas freshwater mussel species — Texas pimpleback “Quadrula petrina,” smooth pimpleback “Quadrula houstonensis” and Texas fawnsfoot “Truncilla macrodon” — in the San Saba River.

    “We documented the largest known population for Texas pimpleback and the second largest population for Texas fawnsfoot in Texas,” Randklev said. “We collected juveniles for all three species, indicating recent recruitment or reproduction.”

    All four species are on the Texas Parks and Wildlife Department’s state-threatened list. Of the 15 on the state list, 11 are being considered for protection under the federal Endangered Species Act.

    The researchers began surveying the San Saba after reports that populations of the Texas pimpleback, smooth pimpleback and Texas fawnsfoot had been seen in the river. Finding the remains of the false spike was an added surprise, Randklev said.

    Identifying populations of rare mussel species is important for their long-term conservation, Randklev said.

    “We have a good idea of where they occurred historically, but our knowledge of their distribution within a given river drainage and, in some cases, the status of existing populations, is lacking,” he said.

    Randklev said that in general mussels are good indicators of water quality and stream health because they are sensitive to changes in the environment.

    “In Texas, many streams and rivers are unable to support mussel populations at levels that existed in the past because of changes to their habitats and declining water quality,” he said.
    false spike freshwater mussel, a species previously thought to be extinct.

    This recently discovered fresh remains is of a false spike freshwater mussel, a species previously thought to be extinct. (Photo courtesy of Texas AgriLife Research)

    Declining populations of mussels can have a huge impact on stream ecosystems, Randklev said.

    “Freshwater mussels are a source of food for some fishes, birds and small mammals,” he said. “Their wastes are important for algal and macroinvertebrate production, and their shells can provide habitat for benthic (bottom dwelling) invertebrates. So when mussels start declining in a river or stream, it’s going to impact other species that depend on them, whether it be for food or for habitat.”

    Julie Groce, Texas AgriLife Extension Service program specialist with the institute, said the surveys on the San Saba River are part of a larger project the institute is working on for the Texas Department of Transportation. The department wants to know more about the current distribution, basic biology and habitat requirements of the 15 state-listed species. The researchers have conducted previous surveys in the Brazos and Colorado rivers and their tributaries.

    “Now that the species are state-listed, the Texas Department of Transportation needs to take these species into consideration when it does any construction or development that might affect these species and their habitats,” said Groce, who manages the mussel project.

    If any state-listed species live within planned construction or maintenance, the department must come up with a plan to avoid, minimize or compensate for any loss of the species or its habitat, she said.

    Prior to the surveys, the institute created a database of all mussel specimens collected in museums in Texas and other parts of the country in the last 150 years. From the database, a digitized map of where the mussels occurred historically was produced.

    The next step, Randklev and Groce said, is working with The University of Texas at Tyler to develop a model that will predict the probability of the 15 species occurring across the state.

    Not only will that involve collecting mussel location information during the field surveys, but the researchers will gather information on mussel habitat use, water quality, land use, river morphology and discharge of the surveyed areas to input into the statewide model, Groce said.

    “What the transportation department would like is a model that will allow it to focus its mussel survey efforts in areas where there is a high probability for these species to occur,” Randklev said.

    “Observations made in the field regarding mussel behavior and habitat preferences will provide a foundation for drafting recovery plans and help in the development of proper management strategies for populations of threatened mussel species,” said Dr. Neal Wilkins, the institute’s director.

    Research on freshwater mussels in Texas is also being encouraged by the Interagency Task Force on Economic Growth and Endangered Species, established by Senate Bill 2534, which was passed by the 81st Texas Legislature.

    The task force provides policy and technical assistance regarding compliance with endangered species laws and regulations to local and regional governmental entities and their communities engaged in economic development activities.

    For more information, visit the institute’s website at http://irnr.tamu.edu
    -30-

    Contacts

    Dr. Charles Randklev, 817-966-3235, crandklev@tamu.edu
    Julie Groce, 210-222-0763, jegroce@ag.tamu.edu
    Dr. Neal Wilkins, 979-845-7726, nwilkins@tamu.edu
    Kathy Wythe, 979-845-1862, kwythe@tamu.edu

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