Effects of Environmental Factors on Sucker Catch Rate, Size Structure, Species Composition, and Precision from Boat Electrofishing

Catostomidae (catostomids) are suckers of the order Cyprinifores and the majority of species are native to North America; however, species in this group are understudied and rarely managed. The popularity in bowfishing and gigging for suckers in the United States has increased concerns related to overfishing. Little information exists about the relative gear effectiveness for sampling catostomids. Our study objective was to evaluate the relative effectiveness of boat electrofishing for sampling Black Redhorse Moxostoma duquesnei, Golden Redhorse M. erythrurum, Northern Hogsucker Hypentelium nigricans, White Sucker, and Spotted Sucker populations in Lake Eucha, OK. We used an information theoretic approach to determine the abiotic variables related to sucker catch per effort (C/f). Our analysis indicated that sucker C/f was highest during night and decreased with increasing water temperature. Sucker size structure was significantly different between daytime and nighttime samples; however, effect size estimates for size structure comparisons indicated size distributions exhibited moderate overlap. Distributional comparisons indicated daytime and nighttime samples were similar for fish >180 mm total length (TL). Effect size estimates also indicated little association between the proportion of each species captured and time of day or water temperature. Night electrofishing in reservoirs at water temperatures from 16-25 ⁰C yielded the most precise C/f estimates, with the highest numbers of suckers collected at water temperatures from 6-15⁰C. Further study of the relationship between abiotic variables and catostomid catchability using various gears would be beneficial to agencies interested in these populations.