Optimal temperature regimes for land‐based mariculture of tropical corals

Abstract

Thermal tolerances of ten coral taxa in relation to their survivorship, health status and growth performance were examined. These coral microcolonies were subjected to temperatures of 26°C, 28°C, 30°C and 32°C for 2 months in an indoor recirculating aquaculture system (RAS). Not unexpectedly, most coral species tested thrived well between 28°C and 30°C, except for Acropora valida which fared best at 26°C. However, subtle differences were apparent. Turbinaria mesenterina, Porites lobata/lutea, Pachyseris speciosa, Platygyra sinensis, Porites rus and Pavona frondifera thrived well at 28°C whilst Dipsastraea speciosa, Pocillopora acuta and Podabacia crustacea, together with Tur. mesenterina and Pla. sinensis, performed better at 30°C. Only Tur. mesenterina and Pod. crustacea survived at 32°C. Amongst the coral taxa tested, Pla. sinensis depicted the highest growth rate of 1.4 mm/month at 30°C, followed by Tur. mesenterina at 30°C and Pod. crustacea at 28°C where both grew at 1.0 mm/month. Dip. speciosa, Pla. sinensis and Pod. crustacea cultured at 30°C were the least bleached. In response to elevated temperatures, the survival of laminar corals outperformed massive and branching corals. This thermal study suggests that all species tested can be ex situ propagated in RAS and Tur. mesenterina and Pod. crustacea are also suitable for transplantation.