EFFECT OF SEDIMENTATION RATES AND CARNIVOROUS FISHES ON FOOD & HABITAT PREFERENCES OF CORALLIVOROUS FISH (CHAETODON OCTOFASCIATUS) IN THE SERIBU ISLANDS

Abstract

Sedimentation rates are a major stress factor for coral reefs. It also impacts the feeding behavior and habitat of corallivorous fishes. The presence of carnivorous fishes may also influence the feeding behavior of corallivorous fishes. This study aimed to assess the relationship between Chaetodon octofasciatus and hard coral (HC) cover. In addition, sedimentation rates and predator abundance were assessed as potential influence. Data were collected at 4 different sites in the Seribu Islands north of Jakarta/Indonesia, including the abundance of Chaetodontidae and carnivorous fishes, Chaetodon octofasciatus behavior, coral reef cover, and sedimentation rates. The abundance of fishes was assessed using 50-m length belt transects deployed at 3-m depth. Coral reef cover was assessed using the Point Intercept Transect (PIT) method with 100 points for each transect. Data on fish behavior was recorded using the Focal Animal method to assess feeding rates and prey selectivity. 10 sediment traps were mounted at each site and collected after 30 days of deployment to obtain sediment samples, which were analyzed for sediment dry weight, ash-free dry weight, and organic content in the laboratory. The study results showed that the condition of coral reefs at Panjang, Belanda, and Pelangi is currently fair in terms of hard coral cover (HC<50%), while Kelapa had poor reef conditions (HC<25%). The abundance of C. octofasciatus had a high relationship with HC cover and showed a weak relationship with predators. Sedimentation rates had the strongest relationship with the feeding rates of C. octofasciatus compared with predators and HC cover.