Strong habitat and weak genetic effects shape the lifetime reproductive success in a wild clownfish population

Lifetime reproductive success (LRS), the number of offspring an individual contributes to the next generation, is of fundamental importance in ecology and evolutionary biology. LRS may be influenced by environmental, maternal and additive genetic factors, and the relative contributions of each are critical in determining whether species can adapt to rapid environmental change. However, studies quantifying LRS across multiple generations in wild populations are extremely rare, and to date, non-existent for marine species. Here we use pedigrees of up to 5 generations resolved from a 10-year data-set for a wild orange clownfish population from Kimbe Island (PNG) to assess the contribution of every breeder to the local population. We quantified the additive genetic, maternal and environmental contributions to variation in LRS for the self-recruiting portion of the population using a genetic linear mixed model approach. We found that the habitat of the breeder, including the anemone species and geographic location, made the greatest contribution to LRS, explaining ~97% of the variation. There were low to negligible contributions of genetic (1.3%) and maternal factors (1.9%) equating with low heritability and evolvability. Our findings imply our population will be extremely susceptible to short-term, small-scale changes in habitat structure and may have limited capacity to adapt to these changes.