Functional diversity in extreme environments: effects of locomotor style and substrate texture on the waterfall‐climbing performance of Hawaiian gobiid fishes

• DOI: 10.1111/j.1469-7998.2005.00034.x
• Publication Date: 2006-02-21T10:46:51Z
• Authors: R. W. Blob; R. Rai; M. L. Julius; H. L. Schoenfuss
• Keywords: Climbing; Climb

Abstract Juveniles of three species Hawaiian gobiid fishes climb waterfalls during migration to adult habitats using two kinematically distinct patterns: Awaous guamensis and Lentipes concolor use rapid, intermittent bouts axial undulation (‘powerbursts’), whereas Sicyopterus stimpsoni inches up by alternately attaching oral pelvic suckers the substrate. Despite differing kinematics speed these behaviors, extreme demands locomotion might require similar levels performance from all climbing goby species. However, roughness surfaces affect differently between styles, with rough decreasing inching impairing grip sucking discs on substrate, but improving powerburst allowing pectoral fins better purchase as they push against substrate start bouts. To test whether gobies differ in performance, we filmed multiple individuals each ascended distances several body lengths over substrates different degrees roughness. Substantial differences among were independent style. For example, climber L. always had a faster net (speed 20 cm, including rests bouts) than S. ; however, A. was , or, smooth substrates, climbed more slowly. Yet, some did emerge styles. Substrate not but, predicted, both climbers rougher surfaces. In addition, motion rest periods for seem appropriate durations facilitate an increase distance that travel before fatigue, spent time either climber, relative its less likely convey any advantages. These results indicate considerable functional diversity beyond varieties show wide range capabilities can persist members fauna even under environmental conditions.