Paddlefish Movements and Habitat Use in Pool 13 of the Upper Mississippi River during Abnormally Low River Stages and Discharges

Abstract

Abstract We determined the movements and habitat use by adult paddlefish Polyodon spathula during unusually low water levels in Pool 13 of the upper Mississippi River. Thirty-two large fish (6.3–25.4-kg) implanted with radio transmitters were located an aggregate of 812 times during March-August 1988, and spring 1989. No relation could be discovered between changes in river stage or discharge and direction of movement. No tagged paddlefish moved upstream from Pool 13, but during 1988 six fish moved downstream into Pool 14. Rates of movement were not significantly different between sexes, but the linear range for females was twice that of males. The greatest linear distance a paddlefish moved was 92 km downstream, and the greatest cumulative movement – entirely within Pool 13 – was 435 km; both records were set by females. Nearly three-fourths of all contacts with paddlefish occurred in about 5% of available habitat in Pool 13. Paddlefish were located most frequently at the head of Pool 13 in the tailwater...