Date of this Version
Knowledge of the population structure of northern pike (Esox lucius), an important recreational and toplevel piscivore, is essential to Nebraska Sandhill lakes management. We collected a sample of adult northern pike from Hackberry Lake in June and July of 2004. Proportional stock density (PSD) was 98 (95% CI = ± 3) and relative stock density of preferredlength fish (RSD-P) was 40 (95% CI = ± 9). Northern pike were aged using sagittal otoliths, and fish from the 1993 to the 2002 year classes were present in our population sample. Age-frequency histograms revealed relatively consistent recruitment of northern pike, as no missing year classes were detected, but year-class strength was variable among years. Examination of mean length at age suggested that growth was rapid in the first two years and slowed thereafter but was faster than populations in other locations, perhaps because this population is near the edge of the geographical range for this species. Yearclass strength of northern pike was negatively related to spring wind speed and was curvilinearly related to spring air temperature. The strongest year classes occurred in years with relatively moderate air temperatures and lower wind speeds. This research provided useful information regarding northern pike population characteristics and recruitment in one Sandhill lake.