Comparison of Diel Sampling Data for Sauger Collected by Electrofishing

ABSTRACT Using a stratified-random sampling design, we sampled sauger (Stizostedion canadense) by day and night electrofishing during the spring from Lewis and Clark Reservoir, South Dakota-Nebraska. Catch per unit effort (number of stock-length (≥20 cm) sauger caught per hour of electrofishing) did not vary among three sites (lake, transition area, and river; P=0.64) nor between diel periods (P=0.91). Size structure of samples, indexed using stock density indices, was consistently higher during the day than at night; sauger ≥51 cm were only collected during the day. Differential size structure for samples collected during diel periods should be considered when biologists design sampling programs or assess population size structure.