Combined mean densities of zebra mussels recorded from 24 November 2019 – 26 September 2020 on settlement plates deployed at depths of 1.0, 4.7, 8.4, and 11–12 m on 2 September 2019 in Belton (yellow) and Stillhouse Hollow Lakes (red) when mussels had settled on plates at all four depths. Vertical lines above bars indicate standard deviations of the mean. Red asterisks above paired bars indicate significant difference in mean mussel density determined by a t-test assuming unequal variances (p ≤ 0.05). P values for each paired set of mussel densities at the two lakes are indicated above the yellow Belton Lake density bars.