USGS - science for a changing world

Upper Midwest Environmental Sciences Center

Paddlefish Study Project

Interesting Findings


Paddlefish Habitats

Paddlefish in the Upper Mississippi River often inhabit off-channel areas with deep water (more than 18 feet) and low current velocities. See paddlefish habitat (275k file download).

Paddlefish Movement

paddlefish movement 1995
paddlefish movement 1996
Arrows show the extent of paddlefish movement in 1995 and 1996.
During the study period, paddlefish were found to move as far as 230 miles in the Upper Mississippi River and tributaries.
In spring and fall, paddlefish moved longer distances at night than during the day. In summer, movements during night and day were similar. See paddlefish movement.(460k file download)

Movement Through Dams

Paddlefish were able to move both upstream and downstream through dams. The ability to move upstream through a dam appears to be determined by the difference in water elevation between the pool above the dam and the pool below. The larger the difference in elevation, the higher the current velocity through the dam gates that a paddlefish must swim against to pass upstream.
1995 dam flow chart
1996 dam flow chart
1995: The green window shows the period of time when paddlefish 49.190 was in the tailwaters below Navigation Dam 7. Dam head, which is the difference between water elevation above and below the dam, controls current velocity (flow) through the dam gates. In 1995, the dam gates were partially closed and dam head (difference between the red and blue lines) was high when the paddlefish was in the tailwaters. Consequently, the paddlefish probably could not swim upstream through the dam because of high flow through the dam gates. 1996: The green window shows the period of time when paddlefish 49.190 passed through Navigation Dam 7 in 1996. Dam head, which is the difference between water elevation above and below the dam, controls current velocity (flow) through the dam gates. In 1996, the dam gates were out of the water (open river conditions) during a strong spring flood and dam head (difference between the red and blue lines) was low during the time the paddlefish passed upstream. Consequently, this was an opportune time for paddlefish 49.190 to swim upstream because of lower flow in the dam gates.

One paddlefish was followed into a lock chamber and moved to the upstream pool with the barge that was locked through.
navigation button: main.html

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.umesc.usgs.gov/aquatic/fish/paddlefish/findings.html
Page Contact Information: Contacting the Upper Midwest Environmental Sciences Center
Page Last Modified: January 29, 2016