Meeting Abstract
The Northern Snakehead (Channa argus) is an ecologically-harmful invasive species to the United States, known for air-breathing capabilities and amphibious behaviors. However, previous descriptions of these behaviors are inconsistent and lack important details. The goals of this study were to quantify the terrestrial locomotion of C. argus, compare their locomotor behaviors to other amphibious fishes’, determine environmental conditions for emersion, and assess the potential of this species to disperse overland. We quantified kinematics from videos of C. argus (TL = 5-70 cm) moving on five terrestrial substrates and recorded electromyograms from axial and appendicular muscles as C. argus moved over turf. While C. argus perform better on rougher substrates, they always use their pectoral fins and body for axial-appendage-based terrestrial locomotion, with axial kinematics similar to Tidepool Sculpins (Oligocottus maculosus), but use both pectoral fins simultaneously rather than alternatingly. However, C. argus juveniles <5 cm use tail-flip jumps to move on land, suggesting an ontogenetic shift in terrestrial behaviors. We also exposed individuals to a variety of environmental conditions, such as hypoxia, to determine conditions that promote C. argus emersion from the water. In these experiments, C. argus fry voluntarily emerged when exposed to extreme environmental conditions, including low pH (pH = 4.8) and hypercapnia. Their functional terrestrial locomotor behaviors, combined with their emersion behavior and efficient air-breathing capabilities, suggests that C. argus may be able to colonize new bodies of water via temporary overland movements.
