Thermal Stress, Depth Refugia, and Herbivorous Fish Biomass as Drivers of Post-Bleaching Coral Recovery in Raja Ampat, Indonesia

Abstract

Coral reef recovery following bleaching disturbances is influenced by environmental pressures, habitat characteristics, and biological interactions. This study aims to examine the individual and simultaneous relationships between thermal stress, depth refugia, herbivorous fish biomass, and post-bleaching coral recovery in Raja Ampat, Indonesia. A quantitative explanatory approach was employed involving 65 respondents selected through purposive sampling. Data were collected using a structured five-point Likert-scale questionnaire and analyzed through multiple linear regression using SPSS version 25. The results demonstrate that thermal stress has a negative and statistically significant relationship with coral recovery (β = −0.521, p < 0.001), while depth refugia (β = 0.329, p < 0.001) and herbivorous fish biomass (β = 0.323, p = 0.001) exhibit positive and significant relationships. The simultaneous regression model is statistically significant (F = 22.502, p < 0.001), with an R² value of 0.525, indicating that the three independent variables collectively explain 52.5% of the variation in coral recovery assessments. Thermal stress demonstrates the strongest statistical association among the examined predictors. These findings highlight the importance of integrating thermal disturbance monitoring, habitat protection, and herbivorous fish conservation into coral reef management strategies. The study contributes to understanding ecological resilience in Raja Ampat, although its questionnaire-based design limits conclusions to assessed ecological conditions rather than direct biophysical relationships.