Larger female fish contribute disproportionately more to self-replenishment

Abstract

While chance events, oceanography and selective pressures inject stochasticity into the replenishment of marine populations with dispersing life stages, some determinism may arise as a result of characteristics of breeding individuals. It is well known that larger females have higher fecundity, and recent laboratory studies have shown that maternal traits such as age and size can be positively associated with offspring growth, size and survival. Whether such fecundity and maternal effects translate into higher recruitment in marine populations remains largely unanswered. We studied a population of Amphiprion chrysopterus (orange-fin anemonefish) in Moorea, French Polynesia, to test whether maternal size influenced the degree of self-recruitment on the island through body size–fecundity and/or additional size-related maternal effects of offspring. We non-lethally sampled 378 adult and young juveniles at Moorea, and, through parentage analysis, identified the mothers of 27 self-recruits (SRs) out of 101 recruits sampled. We also identified the sites occupied by each mother of an SR and, taking into account variation in maternal size among sites, we found that females that produced SRs were significantly larger than those that did not (approx. 7% greater total length, approx. 20% greater biomass). Our analyses further reveal that the contribution of larger females to self-recruitment was significantly greater than expected on the basis of the relationship between body size and fecundity, indicating that there were important maternal effects of female size on traits of their offspring. These results show, for the first time in a natural population, that larger female fish contribute more to local replenishment (self-recruitment) and, more importantly, that size-specific fecundity alone could not explain the disparity.