EVALUATION OF THE SUCCESS OF CORAL REEF RESTORATION BASED ON CORAL NUMBER, SIZE, AND RECRUITMENT AT MENGIAT BEACH, NUSA DUA, BALI

• Main Author: Tazkia Ghiffari, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/72190
• Institution: Institut Teknologi Bandung

Coral reefs are marine ecosystems consisting of clusters of corals, i.e., marine animals that form a mutualistic symbiosis with Zooxanthellae, algae that provide a food source for corals. Coral reefs are very important for humans and underwater life as they are a habitat for various types of fish. Damage to coral reefs can be triggered by destructive fishing, boat anchors, as well as climate change which causes coral bleaching and coral death. Rehabilitation/restoration aims to restore the structure and function of damaged coral reef ecosystems. This study aims to evaluate the resilience of coral reefs by comparing the number, size, and recruitment of corals in artificial reef clusters of different ages. The study was conducted at Mengiat Beach, Nusa Dua, Bali at the restoration site managed by Nusa Dua Reef Foundation (NDRF) since 2016 using the Mars-Assisted Reef Restoration System (MARRS) and reef star structures as artificial reef. Comparisons were made among the number of corals per structure, the size of Acropora spp. corals, and the number of coral recruitments in clusters of structures with restoration age of 2, 4 and 6 years. The method used was stratified random sampling with the visual census method and direct count with 20% data sampling from the total number of structures in each cluster. Survivorship is calculated based on the difference between the number of corals per structure and the initial number of corals. The results show that as cluster age increases, survivorship decreases. Coral survivorship from low to high were 36.1 ± 1.25% at the 6 year-old cluster, 41.64 ± 1.94% at the 4 year-old cluster, and 51.38 ± 2.43% at the 2 year-old cluster. There is a significant difference between survivorship at clusters aged 2 and 4 years with the 6 year-old cluster. As the cluster ages, the average coral size increases; at the age of 2 years cluster 17.58 ± 6.69 cm, at the age of 4 years 23.92 ± 8.04 cm and at the age of 6 years 42.1 ± 12.68 cm. There is a significant difference in the average size of Acropora spp. at each cluster age. Overall, as the cluster age increases, the number of coral recruits per structure increases. In the 2 year old cluster there were 0.25 juveniles per structure, at 4 years old there were 0.35 juveniles per structure and at 4 years old there were 0.47 juveniles per structure. This study showed that the number of corals per structure decreased, the average size of Acropora spp. increased, and the number of coral recruitments per structure increased with increasing age of the cluster. The observed trends in coral size and number of juvenile coral recruits per structure indicate that recovery has been quite successful.