Analyzing Leap Characteristics and Water Escape Velocities of Silver Carp Using In Situ Video Analysis

Abstract

AbstractMeasuring the burst speeds of fish has long been problematic due to the lack of in situ measurements. Using boat‐mounted cameras, we recorded video of invasive Silver Carp Hypophthalmichthys molitrix in the field as they were leaping from the water and measured their leap height, horizontal distance, and angle of escape and estimated their escape velocity. Leap characteristics, fish morphometrics, and environmental data were measured from populations of carp in Mississippi, Missouri, and Illinois. The means for leap height and distance (±SE) across all of the study areas were 125 ± 5.54 and 209 ± 9.10 cm, respectively. The maximum leap height that was recorded was 276.08 cm (in Ramsey Creek, Missouri), and the maximum distance was 482.34 cm (in DeSoto Lake, Mississippi), both more than double the mean values. The majority of carp (66.1%) leaped at angles between 46° and 65°. The mean water escape velocities (WEV) varied across the three study sites. The velocities in Missouri, 628.4 ± 31.6 cm/s, were significantly higher than they were in Mississippi, 471.2 ± 16.9 cm/s or in Illinois, 551.7 ± 20.6 cm/s. The maximum measured escape velocity was 771 cm/s, but the maximum estimated WEV was substantially higher at 1,280 cm/s. Larger Silver Carp were captured at lower latitudes: 54.79 ± 0.74 cm in Illinois, 60.86 ± 0.75 cm in Missouri, and 73.09 ± 1.03 cm in Mississippi. A regression analysis indicated that leap distance and height were correlated with fish size, escape velocity, and angle of escape and that escape velocity was correlated with streamflow velocity, fish size, and water temperature. This study provides a first‐time quantification of the leap characteristics and escape velocities of Silver Carp, which we believe approximates their maximum burst swim speeds. Therefore, these data can be used to develop or refine effective vertical and hydraulic barriers to the dispersal of Silver Carp. The data also demonstrate that the leaping and high‐speed swimming capabilities of Silver Carp are greater than has been assumed previously.