Habitat variation of wild clownfish population shapes self-recruitment more than genetic effects

Self-recruitment, the return of individuals to their natal area to reproduce, is widely recognized as a driver of the local population replenishment. Yet, approaches measuring its environmental and genetic variation in wild populations are extremely rare, especially for marine species. Building upon the recent resolution of a multi-generational pedigree in a wild orange clownfish population, we quantified the contribution of individuals to the local population replenishment. Adults currently contributing the most are located in shallow waters, where the anemone micro-habitat is most vulnerable to climate change. We then quantified the additive genetic, maternal and environmental components of self-recruitment variation by using a quantitative genetic linear mixed model approach. Our results showed extremely low to negligible contributions of genetic and maternal effects. In contrast, we found that habitat variation explained self-recruitment variation to a very large extent. These findings have implications for the potential response of the clownfish population to environmental drivers and selection.