Assessment of coral health status using two-dimensional Coral Health Index (2D-CHI): A preliminary study in Pulau Perhentian Marine Park, Malaysia

Identifying the key threats that influence coral reef ecosystems, one needs accurate information about coral health status to provide information for enhancing coral reef management. In this study, the health status of the coral reefs in the Pulau Perhentian Marine Park (PPMP) is characterized by using two ecological components, benthic (BI) and fish (FI) indexes, which were combined to form a two-dimensional Coral Health Index (2D-CHI). The BI was determined based on data collected using the Coral Video Transect (CVT) method, while the BI using the data collected using Underwater Visual Census (UVC). The findings showed that significant difference in percentage cover of biotic (live hard coral [HC], algae [ALG], and other invertebrates [OT]) and abiotic (dead coral [DC] and sand, silt, or rock [SR]) components between the islands largely was contributed by ALG, DC, and SR rather than HC. In total, 110 species were identified, with fish biomass ranging from 11.18 g m−2 to 193.62 g m−2. The total biomass among the site is mainly contributed by fish from the Pomacentridae family, comprised of small fish such as damselfish and clownfish. Based on the BI and FI values, the 2D-CHI in PPMP can be classified from “fair” to “very degraded”. The 2D-CHI revealed that 55.33% of the reefs were in a degraded state, and only one station was in fair condition. There were four survey stations recognized as being of a very degraded condition. The findings presented here suggest that local pressure such as sedimentation, nutrient enrichment, and heavy reliance on coral reefs (particularly due to tourism) are the potential threats to the reefs in PPMP. Therefore, strategic reef management is required to minimize impacts in order to improve the health of the fragile ecosystem.