Mothers matter: contribution to local replenishment is linked to female size, mate replacement and fecundity in a fish metapopulation

A major assumption of marine population ecology and marine fisheries management is that female size is related to the number of eggs they produced, and therefore, to the number of recruits they produce. Yet, this assumption has seldom been tested. In the past, the difficulties associated with following the fate of individual larvae through the pelagic phase have precluded such analyses. Here, we used field estimates of reproduction combined with DNA profiling of all members of a wild population of the panda anemonefish (Amphiprion polymnus) over two consecutive years to investigate (1) the predictors of egg production and (2) the predictors of the number of recruits produced. We found that across one and two life history transitions, female size was a significant predictor of egg production, and egg production was a significant predictor of the number of recruits produced (when controlling for farness) respectively. When looking across three life history transitions, we found that large females and couples where no male replacement occurred were more likely to produce at least one recruit that settled within the local population than small females or females where the original male died and was replaced. However, we found no evidence supporting the hypothesis that larger females contributed numerically more recruits than smaller ones to local replenishment. These findings provide the first support for the common assumption that egg production is correlated with recruit production. They also suggest that the duration of partnership in anemonefishes couples might be an important factor in their population dynamics.