Porites sp. deposits pink pigmentation to limit the propagation of vermitid gastropods and rhodoliths at coral surface interfaces

Abstract

Pink pigmentation on massive corals is quite commonly observed in the global reefs, but its function on the surface area of corals is less understood. In the present study, the coral video transect method was employed to document the incidence of pink pigmentation on Porites colonies from 21 islands under the Gulf of Mannar Marine Biosphere Reserve (GoMMBR), India. Results revealed that 19% (n = 77 out of 517) of Porites sp. colonies displayed pink pigmentation as a stress indicator in response to the colonization of epibionts. Porites colonies exhibited pink pigmentation when infected with epibionts like a vermetid snail, Ceraesignum sp. (12%; n = 49), a rhodolith, Hydrolithon sp. (5%; n = 21), or both (2%; n = 7). This study indicates that Porites pink pigment deposition aids in minimizing surface tissue area damage by preventing further progression of infesting agents such as vermitid snails and rhodoliths on the surface areas of corals.