Many sessile organisms rely on the transport of one or both types of gametes for reproductive success. While sperm limitation has been reported in some species, high fertilization success has been observed in others including the branching octocoral Pseudopterogorgia elisabethae. In such cases, males may compete for eggs to fertilize and the local dispersion of sperm will be an important component of male success. Individual reproductive success of 91 male P. elisabethae colonies found within a 400 m 2 area on San Salvador Island, Bahamas was examined based on microsatellite analysis of planulae collected from female colonies. Larvae which were brooded on the surface of 4 different females were collected during 2 separate spawning events. Males in the study area were sampled, and parentage was assessed using 5 microsatellite loci and the paternity assignment program CERVUS 3.0. Twenty-five percent of the larvae were assigned sires with ≥80% likelihood and 87% of the planulae could have been sired by males within the study area. The success of males was not related to either distance to the female or to male colony size. On average, successful sperm only travelled 5.2 m and the success of individual males within the 400 m 2 study site was not significantly different from random expectations. Male P. elisabethae may follow spawning strategies that increase the likelihood of siring some planulae, spread success across multiple females and reduce variance in reproductive success.KEY WORDS: Gorgonian coral · Microsatellites · Paternity · Sperm · Dispersal · Male reproductive success Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 367: [153][154][155][156][157][158][159][160][161] 2008 studies have typically been based on paternity analysis of embryos produced in controlled matings involving only a few individuals (Yund & McCartney 1994, Yund 1995. The only study examining paternity in a natural spawning event (Coffroth & Lasker 1998) examined a population of the octocoral Plexaura kuna, in which there were only a few potential sires. Although these studies provide insights into the factors controlling mating patterns, they do not address sperm dispersal and reproductive success in most natural populations in which numerous males are present.The development of highly polymorphic DNA genetic markers such as microsatellites, has increased the possibility of assessing paternity within local populations containing multiple males. For instance, a large number of investigations in plants have used microsatellites to estimate the contribution of pollen dispersal to gene flow, and to assess mating patterns and male reproductive success in natural plant populations (Dow & Ashley 1998, Streiff et al. 1999, Konuma et al. 2000, Lian et al. 2001. In this study, we used microsatellites to assess male reproductive success and sperm dispersal in a population of the branching octocoral Pseudopterogorgia elisabethae.Pseudopterogorgia elisabethae is a gorgoniid alcyonacean wit...