A major goal in marine ecology is to understand patterns of larval dispersal and population connectivity. Dispersal plasticity allows for adaptive variation in dispersal phenotypes in response to variation in environmental conditions and may help to explain intraspecific variation in dispersal distances. However, this phenomenon has not yet been investigated in marine fishes. Here, we test the hypothesis that parents produce larvae with different dispersal-related traits in response to variation in environmental quality using the orange anemonefish, Amphiprion percula. By experimentally manipulating food rations, we show that parents produce larger offspring on low-food rations than on high-food rations. However, there was no effect of parental diet on larval critical swimming speed. We also found an effect on larval otolith core size which, in combination with parentage analyses, may provide a way to test the dispersal plasticity hypothesis in the field. This study shows that parents can produce different larval phenotypes in response to variation in environmental conditions, demonstrating plasticity in a dispersal-related trait which may help to explain observed variation in A. percula larval dispersal distances. Incorporating dispersal plasticity into our understanding of marine dispersal patterns may enhance our understanding of marine metapopulation ecology, fisheries management, and conservation.

Dispersal, the movement of individuals away from their natal location to another location, is a basic driver of ecological and evolutionary processes. Direct measures of marine fish larval dispersal have shown that individual dispersal distances can vary over several orders of magnitude within a species. We currently do not know the causes of this variation. One plausible explanation for the cause of intraspecific variation in individual dispersal distances is dispersal plasticity. Dispersal plasticity, especially as an adaptive parental effect where parents can alter the dispersal phenotype of their offspring in response to an environmental cue, is widespread in terrestrial systems, but has yet to be described in marine fishes. In this study, we address a key, although often untested, condition for the evolution of dispersal plasticity as an adaptive parental effect: whether parents have information that would enable them to reliably predict the environmental conditions that their offspring will encounter. Using a wild population of orange anemonefish, Amphiprion percula, we investigate habitat quality predictability by testing for spatial autocorrelation in three habitat quality indicators: anemone size, female size, and egg clutch size. We found strong, positive spatial autocorrelation for all three habitat quality indicators from 50 to about 500 meters. This suggests that selection might favor parents that increase allocation to offspring that stay within 500 m if they are in good habitat and increase allocation to offspring that travel farther than this if they are in poor habitat. Results from this study lay solid foundations for further investigation of dispersal plasticity in A. percula and other marine fishes, providing testable hypotheses for probable causes of individual dispersal distance variation. Incorporating dispersal plasticity in our investigations of marine fish larval dispersal potentially could contribute to a greater understanding of marine fish metapopulation dynamics, and therefore fisheries recovery and reserve management.