Five of the 16 Higgins eye pearlymussels found during the survey at Central City. Photo by Tatsuaki Nakato

Scott Gritters, Iowa DNR, shows off a Higgins eye pearlymussel found 19 miles below the stocking site. Photo by Tatsuaki Nakato

In a 10-month time span, Iowa rivers have undergone two major flood events including the record setting flood of June 2008.  The effects of the floods on the inhabitants living along Iowa rivers were well documented by local and national news organizations, but what about the inhabitants that make their homes on the bottom of these rivers?  Biologists from Genoa National Fish Hatchery, Iowa Department of Natural Resources, and   Minnesota Department of Natural Resources set out to see how the freshwater mussels in the Wapsipinicon River, IA were doing after the floods.  The Wapsipinicon River is one of the sites where federal and state agencies have been working for the past seven years to reintroduce the federally endangered Higgins eye pearly mussel.  Surveys conducted around the Central City area in 2005 and 2006 produced a total of 10 Higgins eye indicating that the recovery effort was working.  A second recovery site on the Wapsipinicon River, located below the dam in Anamosa, had never been surveyed until this August when biologists converged on the site to determine the success at the Anamosa site.  Biologists were excited to find two young Higgins eye within the first two hours of searching, while third Higgins eye was found later that afternoon.  The second day of the survey took the biologists back to Central City, where an amazing 16 Higgins eye were found throughout a four mile stretch of river.  One of the 16 Higgins eye was recaptured from the 2006 survey as indicated by the number tag that was glued to the shell after its first collection.  The documentation of Higgins eye in this four mile stretch of river raised the question how far down stream from Central City have the Higgins eye gone?  Day three of the survey took biologists 19 miles further downstream to Stone City, located between Central City and Anamosa dam.  On this chilly, rainy day a single Higgins eye was found along a muddy bank of the Wapsipinicon River just upstream from Stone City, indicating that the Higgins eye recovery effort has produced sub-adult Higgins eye mussels in over 30 river miles of the Wapsipinicon River.  A total of 29 Higgins eye have been collected and tagged from the Wapsipinicon River, yet only a fraction of the river has been surveyed indicating that there could be thousands of Higgins eye now living in the Wapsipincon River.