Ontogeny of larval swimming abilities in three species of coral reef fishes and a hypothesis for their impact on the spatial scale of dispersal

The late-stage larvae of many reef fishes possess strong swimming abilities that may allow them to influence their dispersal. However, due to the challenges associated with directly measuring patterns of larval dispersal, determining how swimming abilities relate to dispersal outcomes remains a critical gap in our knowledge of the mechanisms that shape dispersal patterns. In this study, we first investigated the ontogeny of swimming speed and endurance in lab-reared larvae of the clown anemonefish (Amphiprion percula), and neon gobies (Elacatinus lori and E. colini). In general, the swimming speed and endurance of larvae improved with age. The congeners, E. lori and E. colini, possessed similar swimming speed and endurance, while A. percula was capable of swimming nearly twice as fast and 322 times longer than either Elacatinus. Second, to relate swimming abilities and other larval traits with patterns of dispersal, we searched the literature for all species in which the dispersal kernel, swimming speed, larval body size and pelagic larval duration have been measured. We found complete datasets for three species: A. percula, E. lori and Plectropomus leopardus. For these species, maximum swimming speed was a better predictor of long-distance dispersal than other larval traits. Thus, we propose the testable hypothesis that swimming abilities may play an important role in determining the extent of long-distance dispersal. Testing this hypothesis, and the alternatives, will require measuring the dispersal kernel, swimming speed, and other dispersal-related larval traits of multiple species in the same seascape.