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April 30, 2021

Scientists from the U.S. Geological Survey will conduct a dye-trace assessment. For a few hours during this research, several miles of the Missouri river will appear reddish due to non-toxic dye. The red color will dissipate rapidly and will disappear after it travels several miles downstream. During the study, USGS will deploy several boats on the river to monitor how and where the dye moves

When: The research will be dependent upon weather and is expected to be one day during the week of May 3, 2021, from 10 a.m. to 5 p.m.

Where: The study will involve releasing a non-toxic fluorescent dye along the Missouri River near Huntsdale, Missouri. Scientists will monitor flow patterns for 2-10 miles downstream from the Interstate-70 bridge in Boone County, Missouri.

Why:  The assessment will help scientists understand how larvae from the critically endangered pallid sturgeon drift downstream after hatching and how they find supportive habitat in the complex Missouri River.

Image shows an aerial shot of the Missouri River with a boat traveling across the river, trailing bright pink dye
The photos illustrate previous dye assessment tracing on June 29, 2017 near Sidney, MT. (Public domain.)

This assessment follows successful experiments conducted by USGS on the Yellowstone and Upper Missouri Rivers in Montana in 2016 and 2017.

Rhodamine WT is commonly used for these types of assessments throughout the country and is considered completely safe. After releasing the dye into the river, scientists will measure dye concentrations using instruments placed in the river and by aircraft.

This study is in cooperation with the USGS, U.S. Army Corps of Engineers, and Missouri University of Science and Technology.

For questions, please contact: Robert Jacobson, 573-864-6183,

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