Meeting Abstract
Effective locomotion is an essential component of animal survival and fitness. The demands placed on locomotor systems change markedly with respect to habitat. Habitat related differences in the physical environment, food types and locations, and exposure to predation risk potentially shift the relationship between locomotor performance and organismal fitness. Some species also show parallel variation in phenotype that may be adaptive in differentially enhancing particular aspects of performance associated with fitness within a given habitat type. For example, bluegill sunfish from open water habitats are more economical steady-state swimmers than those from the weedy, littoral, whereas littoral fish are more maneuverable than those from open water. Potential links between this performance variation and fitness can only be assessed if they are informed by locomotor performance data from the field. We have used underwater video camera arrays to quantify swimming behavior and performance of bluegill sunfish in both habitat types. When compared across similar fish size classes, times of day and season, and water temperatures there were marked habitat differences in swimming behavior. Littoral fish spent the majority of their time engaged in station holding or low-speed maneuvering controlled by the pectoral fins. In contrast, open water fish spent more time engaged in higher-speed body caudal fin (BCF) powered swimming. In both locations BCF propulsion was intermittent when present, and interspersed with periods of gliding. Open water trajectories were also associated with lower path curvature and lower turning rates. These performance analyses suggest that the performance variation quantified within this species parallels the variation in swimming behavior exhibited in the field.
