Species level identification of Antillogorgia spp. recruits identifies multiple pathways of octocoral success on Caribbean reefs

Successful recruitment is critical to the maintenance and resilience of populations and may be at the core of the transition from scleractinian- to octocoral-dominated faunas on some Caribbean reefs. For sessile invertebrates, recruitment incorporates the composite effects of larval supply, settlement and survival. The relative success of these processes differs between species, and successful recruitment may be achieved through different life history strategies. Recruitment of six abundant and widespread Antillogorgia spp. was assessed at six sites on Little Bahama Bank from 2009–2012. Identification of recruits to species level, based on microsatellite analyses, revealed differences in recruitment and survival between species, sites and years. The broadcast spawning species, A. americana and A. acerosa, had low rates of early recruitment and post-settlement survival. Higher levels of recruitment success were achieved among brooding and surface brooding species following somewhat different patterns of early recruitment and survival. The internal brooder A. hystrix had the highest recruitment at five of the sites, but low survival dramatically reduced its abundance and after a year it had similar densities as the surface brooding species, A. elisabethae and A. bipinnata. The brooders have smaller colonies and produce fewer larvae than the broadcast spawning species, but they release competent larvae, which may account for their higher recruitment rates. The Antillogorgia illustrate the diversity of successful reproductive strategies exhibited by octocorals, and differences in the life history strategies among these congeners are best characterized by their mode of larval development.