I've heard that Zebra mussels are out-competing indiginous Unionids
rather badly, leading to local extinctions, expecially in the
Mississippi system.  Can anybody tell the list which species have been
hit the hardest, and where, and does anyone know of a speicies that has
actually gone extinct, or is immanant danger of doing so, because of
zebra-mussel competion?

A foot of snow enough for you?  (it's plenty for me!!).
-Ross.

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