Plastic threats to coral reefs: A strategic management perspective from Bali’s marine protected areas
I. Gede Hendrawanabc*, Ade Riestiari Sudarmawanbc, Putra Bagus Panji Pamungkasb, Pande Gde Sasmita Julyantorod, I. Wayan Gede Astawa Karangab, Dwi Budi Wiyantoa,
I. Made Dharma Raharjaabc, I. Putu Ranu Fajar Mahartaabc, Cornelia Coraima Lazarenb, Alex S.J. Wyatte
aDepartment of Marine Science, Udayana University, Bali, Indonesia
bCenter for Remote Sensing and Ocean Sciences, Udayana University, Bali, Indonesia
cPlastic in Societies (PISCES) Living Lab, Udayana University, Bali, Indonesia
dDepartment of Aquatic Resource Management, Udayana University, Bali, Indonesia
eDepartment of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
Plastic pollution remains a significant threat to coral reef ecosystems, even within Marine Protected Areas (MPAs). This study assesses the levels and types of plastic debris, both macroplastics and microplastics, found in coral reef ecosystems at two MPAs in Bali: Karangasem and Nusa Penida. Coral health was evaluated using the Underwater Photo Transect (UPT) method, while plastic particles were identified through field sampling and laboratory analysis, including Raman spectroscopy. Macroplastic accumulation was higher in Karangasem, while microplastic concentrations were comparable between the two regions. Microplastics were detected in coral tissues, and Polyethylene (PET and LDPE) was the dominant polymer. Although Pollution Load Index (PLI) values indicate a low ecological risk, it is evident that both MPAs suffer from coral degradation. Notably, the data suggest that macroplastic may have a more direct impact on coral reefs through physical damage. Despite these threats, both MPAs exhibited high ecological resilience, suggesting strong recovery potential if waste inputs are reduced. The findings highlight the important of improving waste management, especially capacity building and increased funding allocation. Strengthening each strategic approach of the MPAs can reduce plastic leakage into the sea and support coral reef recovery.
