Laju Pertumbuhan Hasil Fragmentasi Karang Jenis Trachyphyllia geoffroyi di Fasilitas Ex Situ

Abstract

Ornamental corals have high economic value as aquarium trade commodities and play an important role in maintaining marine ecosystem balance. Indonesia is one of the main exporters, with 569 coral species, of which 55 are utilized for export under CITES regulations. Coral farming is carried out through transplantation using fragmentation techniques, either in-situ or ex-situ. Fragmentation allows coral fragments to grow into new colonies, but solitary species such as Trachyphyllia geoffroyi show low survival rates. This study aimed to determine the growth rate and survival of fragmented T. geoffroyi in an ex-situ facility. The research was conducted at PT. Tirta Samudra Bali, Klungkung, Bali, from April to June 2025. Nine parent colonies were fragmented into 18 samples with a gryphon tool. Observations were carried out for three months with weekly monitoring of survival and growth, using underwater photography and analysis with ImageJ. Data were processed with Microsoft Excel. Results showed that survival was only 39%, with 61% mortality. The average growth rate was 0.2 cm²/month, declining in the third month due to post-fragmentation stress. Water quality remained relatively stable, with alkalinity at 7 dKH, calcium 407 ppm, magnesium 1221 ppm, nitrate 15 ppm, phosphate 0.1 ppm, salinity 1.025 s.g, temperature 25°C, and pH 8.3. The low survival rate was attributed to the sensitivity of T. geoffroyi, its solitary morphology with a single mouth, small fragment size, and vulnerability to tissue damage from cutting. Overall, this study highlights the challenges of ex-situ cultivation of T. geoffroyi but provides important insights for developing sustainable coral farming techniques to support conservation and reduce reliance on wild harvests