Joshua Lallaman (PhD) jjly87@mizzou.edu (573) 884-8534

Title: MOVEMENT, HABITAT USE, AND REPRODUCTION OF PADDLEFISH, Polyodon spathula, IN THE LOWER OSAGE RIVER, MO

Advisor: Dr David Galat

Paddlefish, Polyodon spathula, were once an abundant species throughout the major river systems of the Central United States. Dramatic declines in paddlefish populations during the 20^th century are primarily the result of large scale river modification. Paddlefish are currently extirpated, endangered, threatened, or of special concern in a large proportion of their range. An inadequate knowledge base on paddlefish ecology and population dynamics is one of the major limitations to rehabilitation. The objectives of my study are to 1) characterize paddlefish spawning migrations and habitat use, 2) determine under what stream conditions (temperature, velocity, discharge, and hydraulic head) paddlefish are able to pass through a low-head structure, Lock and Dam #1, 3) identify and characterize paddlefish spawning habitat, 4) document paddlefish reproductive success and characterize larval drift patterns in the lower Osage River, and 5) monitor seasonal movement and habitat use in the lower Osage and Missouri Rivers in 2007-2008. Paddlefish movement and habitat use will be determined by the use of Combined Acoustic and Radio Transmitters (CART) and monitored using stationary receivers and boat tracking. Paddlefish spawning movements will be modeled against changes in photoperiod, discharge, and temperature. Spawning habitat in the lower Osage River will be assessed using 2-D depth and flow models and verified by the presence of eggs captured with egg mats. Spatial and temporal patterns of larval paddlefish drift will be examined using larval drift nets placed below suspected spawning sites. Summer, fall, and winter movement and habitat use will be analyzed to better comprehend paddlefish habitat requirements. Understanding paddlefish movement and habitat use will allow for better management recommendations concerning regulated flow releases and habitat protection in Missouri.