Study finds highest rate of feminized fish in Mississippi River in Minn.
Like this?
Log in to share your opinion with MPR News and add it to your profile.
Like this?
Thanks for liking this story! We have added it to a list of your favorite stories.
The Mississippi River in Minnesota has the highest rate of feminized fish found in a study conducted by the U.S. Geological Survey.
Scientists are concerned when they find male fish with female sex organs. In the Mississippi River, near Lake City Minnesota, 73 percent of the smallmouth bass had characteristics of both sexes.
The feminization is thought to be caused by hormone-disrupting chemicals in the environment. They can include pesticides, PCBs, heavy metals, household compounds such as laundry detergent and shampoo, and many pharmaceuticals.
Large and smallmouth bass seem to be particularly vulnerable to the chemicals.
The USGS study sampled fish in nine rivers around the country. The Yukon River basin in Alaska was the only one where researchers did not find at least one intersex fish.
Support the News you Need
Gifts from individuals keep MPR News accessible to all - free of paywalls and barriers.