FACTORS INFLUENCING GROWTHS OF CULTURED JUVENILE CORALS IN A NURSERY SYSTEM

Abstract

In 2010, the hard coral mortality ranged between 32% to 78.8% of populations and other reef organisms, including sea anemones and giant clams were also affected by the bleaching at Samae san Island, Chon Buri Province, Thailand. After the bleaching events, there was an attempt to rehabilitate coral reefs in certain areas. In this study, the influence of physical factors (temperature, salinity, light intensity, and photoperiod) and food factors (capture rates, digestibility, feeding preferences, and feeding efficiency) on growth, survival, and photosynthetic efficiency of four coral species (staghorn corals, Acropora millepora and Acropora nobilis; cauliflower coral, Pocillopora damicornis; and brain coral, Platygyra sinensis) were used as an experimented corals. All corals used in the experiment were cultivated via sexual propagation. The results showed that temperature significantly affected growth, survival, and photosynthetic efficiency (p < 0.05) compared to salinity. For the light intensity experiment, P. sinensis seemed to have more tolerance to wider ranges of light intensities and photoperiods than other coral species. When feeding preference experiments of corals were conducted, the results showed that the capture rates on Artemia salina nauplii of corals ranged between 0.44 to 2.39 individuals per polyp and 2 hours to 2.5 hours to complete the prey digestion. Moreover, the feeding preferences and feeding efficiency showed that the protein concentrations were higher in A. millepora fed on Artemia salina. In conclusion, both physical (temperature, salinity, light intensity, and photoperiod) and food factors can have an influence on growth, survival, and photosynthetic rates of corals. The results of this study can be used for achievement of coral culturing technique for restoration of coral reefs