Effect of interspecific competitive relationships involving Tubastraea spp. (Scleractinia, Dendrophyllidae) and Palythoa caribaeorum (Zoantharia, Sphenopidae)

The space is a limited resource for the establishment of benthic species on consolidated substrates.Considering the introduction of invasive species, the effects of the interspecific competitive interaction must be evaluated, once the prevalence of these organisms over native species depends upon a repertory of strategies not fully understanding.Tubastraea corals became overspread along the Atlantic Ocean, being majorly observed on artificial substrates.Palythoa caribaeorum is a native zoanthid with high growth rates, and colonies with short polyps embedded in the coenenchyma.To study the interaction between Tubastraea spp.and P. caribaeorum, a manipulative experiment was developed in situ in the Todos-os-Santos Bay (12ºS, Bahia State).Two species (and respective morphotypes), Tubastraea tagusensis (dendroid) and Tubastraea coccinea (plocoid), were tested.No tissue damage was detected in any Tubastraea sample during the interspecific experiment.P. caribaeorum underwent retraction, mucus deposition and overgrowth, but no statistical difference was recorded.The study of competition between native species and introduced organisms is fundamental to comprehend how local diversity will be affected.