Multiple paternity and maintenance of genetic diversity in the live-bearing rockfishes Sebastes spp.

Abstract

The understanding of mating systems is key to the proper management of exploited spe- cies, particularly highly fecund, r-selected fishes, which often show strong discrepancies between census and effective population sizes. The development of polymorphic genetic markers, such as codominant nuclear microsatellites, has made it possible to study the paternity of individuals within a brood, helping to elucidate the species' mating system. In the present study, paternity analysis was performed on 35 broods, representing 17 species of the live-bearing scorpaenid genus Sebastes. We report on the finding of multiple paternity from several species of Sebastes and show that at least 3 sires can contribute paternity to a single brood. A phylogenetically and ecologically diverse sample of Sebastes species was examined, with multiple paternity found in 14 of the 35 broods and 10 of the 17 examined species, we suggest that this behavior is not a rare event within a single species and is likely common throughout the genus. Despite high variance in reproductive success, Sebastes spp., in general, show moderate to high levels of genetic diversity. We suggest that multiple paternity may be a form of bet hedging that serves to maximize genetic diversity within broods and that, regardless of the selective value at the level of individual fitness, the net effect at the population level may be a genetic buffer to the consequences of severe overexploitation.