Crayfish

Between 1991 and 2011 Flambeau Mining Company (FMC) was required to test crayfish in the Flambeau River for heavy metal accumulation, both upstream and downstream of the Flambeau Mine site.

Dr. Ken Parejko, Professor Emeritus, Department of Biology, University of Wisconsin-Stout, did an independent analysis of FMC’s crayfish data for the Wisconsin Resources Protection Council (WRPC) in April 2009. At that time he concluded:

“Crayfish whole-body copper appears to have been consistently higher at both downstream locations even prior to mining and to have risen at all three locations (including the upstream sampling site) during the mine operation. … [However, a statistical analysis of the data] indicates that the gap between upstream and downstream copper concentrations [in crayfish] appears to have increased during operation of the mine, and has been sustained in the post-mining years with significantly higher copper levels reported in the downstream crayfish. This suggests a possible mining effect. … [Because] metals are expected to continue moving from the mine pit to the river, and because metals can build up in sediments over time and bioaccumulate in organisms (with potential for moving up the food chain), continued monitoring could yield important information.”

What the future holds for the crayfish in the Flambeau River is unknown. Polluted groundwater from the Flambeau Mine site continues to enter the river through fractured bedrock, but, with the end of mandatory crayfish testing in 2011, FMC is now “off the hook.”

To see the crayfish data submitted by Flambeau Mining Company to the Wisconsin Department of Natural Resources and various reports evaluating the data, click on the below links:

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