Mussel species thought extinct found in Delaware River

    Scientists have discovered large colonies of freshwater mussels in the Delaware River between Trenton and Philadelphia.  Two of the mussel species found were thought to have been extinct in Pennsylvania and New Jersey.


    Danielle Kreeger, science director at the Partnership for the Delaware Estuary, was on the research vessel that discovered the beds. She said she couldn’t believe her eyes when she donned a wetsuit and discovered mussel beds the size of pingpong tables in the Delaware River.

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    The two species previously believed to be extinct in Pennsylvania and New Jersey are the alewife floater, or Anodonta implicata, and the tidewater mucket, or Leptodea ochracea.


    Kreeger has been on the hunt for mussels such as these in the area for 15 years and hasn’t been able to find them. She says the size and diversity of the beds means the water quality is better in the area than many people thought.

    “The health and fitness of populations of freshwater mussels are probably one of our best indicators of the health of the system,” Kreeger said. “The fact that these animals are still there, both species and populations, it’s a good sign.  I mean it’s a very, very good sign.”

    Roger Thomas, with the Academy of Natural Sciences, was also surprised to find such large beds in an urban area.

    “Being in an urban setting on the Delaware between Trenton and Philadelphia, to see the mussel varieties and densities that were discovered, that’s what makes it so exciting,” he said.

    Kreeger and her team with the Freshwater Mussel Recovery Program hope to breed the newly discovered mussels, then use their descendants to repopulate waters throughout the Delaware River Basin where mussel beds have been wiped out. Mussels filter impurities out of water at the rate of 5 to 50 gallons a day, according to Kreeger, so they are important in improving water quality.

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