Plastic threats to coral reefs: A strategic management perspective from Bali's marine protected areas

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.