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Ecohydraulics in the Mississippi River: Freshwater Mussels Modeling

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Ecohydraulics in the Mississippi River: Freshwater Mussels Modeling

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    1. Ecohydraulics in the Mississippi River: Freshwater Mussels Modeling Joseph A. Daraio Larry J. Weber IIHR Hydroscience and Engineering Teresa Newton USGS Upper Midwest Environmental Sciences Center

    2. Freshwater Mussel Biology Most native mussels in the Mississippi are of the family Unioniidae They have an unique life cycle Larval Stage when they are parasitic on a host fish Attach to fish gills for several weeks Dependent on fish for survival and dispersal

    3. Mussels Role in Riverine Ecosystems Nutrient cycling: Interact with both sediment layer and water column Remove soluble nutrients from water column and deposit it in sediment through feces and psuedo-feces Uptake sediment nutrients and release them as soluble nutrients into the water column Bioperturbation of sediment Provide physical habitat for other organisms Stabilize the river bed Because of their importance to the ecosystem, mussels are an indicator species

    4. Mussels in the Mississippi River Early reports suggest mussel beds spanning the entire river width In the 1800s mussels were harvested to find pearls

    5. Button Harvesting Harvesting intensified with the rise of the pearl button industry, circa 1890 Machines developed to punch out buttons from mussel shells

    6. Impact of Lock and Dam system 29 Locks and Dams between St. Louis and Minneapolis-St. Paul Blocks migration of host fish vital to native mussel dispersion and survival Alters flow patterns and the hydraulics of the system Navigation system includes wingdams that direct the flow into the main channel and reduces flow into side channels (example next slide) This has a significant impact on conditions at the river bed where mussels make their home

    7. Wingdams in the river

    8. Current threats Water quality Chemical pollution (point and non-point source) Thermal pollution Excess nutrients (non-point source, e.g. agriculture, lawns) Sedimentation ZEBRA MUSSELS

    9. Zebra Mussels Native to Caspian Sea First introduced to the Great Lakes in the late 1980s in ships ballast First documented in the Mississippi River in 1991 Very efficient feeders and compete with native mussels for food Attach to substrate with byssal threads, and can attach directly to native mussels

    10. Imperiled Mussels As a result of over-harvesting, habitat alteration and loss, pollution, and the introduction of exotic species, mussels are a very imperiled group of organisms NO other group of animals in North America is in as much danger of extinction as freshwater mussels At least 1/3 (possibly as many as 43%) of the 300 known species of mussels in North America are imperiled, threatened, or endangered. Currently, 4 species in the Upper Mississippi River are federally protected under the Endangered Species act Higgins eye Fat pocketbook Scaleshell Winged mapleleaf

    11. Ecohydraulics Research Hydrodynamics modeling of pools of the Mississippi River Habitat Suitability Index model using physical flow characteristics and known mussel tolerances of physical conditions Population dynamics model of native and zebra mussels

    12. Questions or Comments?

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