Recruitment, Lotteries, and Coexistence in Coral Reef Fish

The main goal of this analysis has been to evaluate Sale's (1982) suggestion that competitive exclusion was less likely in lottery competitive systems than in those having other mechanisms of competition. An analytical lottery model based on Sale's (1982) simulation was developed and used to show that the presence of totally intraspecific competition in the larval stages was responsible for the coexistence of the species in the model. This assumption could allow coexistence for any possible mechanism of adult competition. A model incorporating the more likely assumption of equal inter- and intraspecific larval competition allows at most two species to coexist in a constant-environment lottery model. Although some types of environmental variability promote coexistence in the lottery model (Chesson and Warner 1981), analogous types of variability promote coexistence in nonlottery models (Chesson 1983; Abrams 1984). Available evidence for territorial coral reef fish most strongly supports an explanation of coexistence based on resource partitioning over other possible explanations.