Patterns of larval settlement preferences and post-settlement survival for seven Caribbean corals

Caribbean coral reefs continue to decline in coral cover; however, recruitment is a natural process that could increase coral abundance. Benthic habitats that increase coral recruitment are a key factor for coral persistence, but very little is known about habitat selectivity for larvae of most species of corals. The larval settlement preferences and post-settlement survival of 3 brooding and 4 broadcast spawning coral species were compared in this study. The crustose coralline algae Titanoderma prototypum and Hydrolithon boergesenii facilitated larval settlement more than the biofilm control for the broadcast spawning corals but not for the majority of the brooding corals. In paired choice experiments, the larvae of all 7 corals preferred T. prototypum over Paragoniolithon solubile, and 6 of them preferred H. boergesenii over Pa. solubile, the exception being larvae of Porites astreoides. All corals equally preferred T. prototypum and H. boergesenii, except Pseudodiploria strigosa, which preferred T. prototypum, and Acropora palmata, which preferred H. boergesenii. Some recruits from the 3 brooding corals survived longer than 1 yr in the field, but of the 4 spawning corals, only P. strigosa had 2 recruits that survived >1 yr. Corals that spawned their gametes had increased settlement in the presence of a few species of coralline algae, but corals that brooded their larvae settled on biofilms and had much greater post-settlement survival, suggesting that the recruitment of brooding corals will dominate on reefs without facilitating species of crustose coralline algae.