Morphology Influences Climbing Ability of the Adult Tropical Gobiid Stiphodon elegans on Moorea, French Polynesia

Abstract

Amphidromy is a life history strategy that confers an adaptive edge to the extreme hydrological variability in tropical island streams, where organisms migrate between fresh and salt water. is allows for recolonization of stream habitats following large disturbances that carry juveniles to sea. Many members of the sh family Gobiidae are amphidromous and have evolved the ability to climb waterfalls in order to access upstream breeding habitats and evade low elevation predators. Two distinct climbing strategies have been observed across gobiids: powerburst climbers ascend barriers in a series of bursts and stops, while inching climbers move steadily with alternating head and body movements. Morphology has been shown to in uence inching gobiid climbing ability but has yet to be investigated in powerburst climbers. is study examines the relationship between morphology and climbing ability in the adult powerburst climber Stiphodon elegans on Moorea, French Polynesia, using an arti cial waterfall and morphological analysis. Climbing success was found to be signi cantly and positively associated with pelvic disk diameter, but not variation in head or body morphology. Reaching a better understanding of gobiid functional morphology is necessary for interpreting and predicting elevational distributions, which can inform tropical island stream management and gobiid conservation.