Population Demographics of Saugeye (Sander canadensis x S. vitreus) in Two Illinois Lakes [poster]

Saugeye are a popular sport fish that is commonly stocked throughout the Midwestern United States because of their fast growth and ability to control overpopulation of other sport fish, such as crappie. Despite their abundance, few studies have evaluated age-related metrics for development of informed management decisions, specifically in Illinois. We estimated the age of Saugeye to compare age and growth parameters between two lakes in central Illinois, Dawson Lake (148 acres) and Evergreen Lake (925 acres). A total of 224 fish (111 fish from Dawson and 113 fish from Evergreen) were sampled using fyke nets in the Spring of 2019. Fish were brought back to the laboratory and body measurements were collected, gender was determined, and calcified structures were extracted. Otoliths and dorsal fin rays provided similar age estimates for young Saugeye, but rays underestimated age of fish older than 5 years. Otoliths more often represent true age of fishes, therefore we used otoliths to generate age-related metrics. There was no difference in the age or size structure of female Saugeye between Dawson (age = 3.4 ± 0.3yrs; TL = 497.3 ± 11.0mm) and Evergreen Lake (age = 3.3 ± 0.2yrs; TL = 512.9 ± 11.6mm; P > 0.05). However, Evergreen Lake was comprised of older (age = 2.7 ± 0.1yrs), larger male fish (TL = 444.8 ± 8.9mm) compared to Dawson Lake (age = 2.1 ± 0.2yrs; TL = 393.3 ± 6.5mm; P < 0.05). Our findings emphasize the need for further evaluation to determine possible drivers for differences between lakes. Assessment of age-related metrics in specific waterbodies provides the information needed to develop informed management practices for a sustainable long-term sport fishing opportunity of this highly sought-after sport fish.