Linking the feeding regime of Chaetodon octofasciatus to the coral health in Redang Island, Malaysia

Relationship between the feeding regime of the coral feeding butterflyfish, Chaetodon octofasciatus and the coral reef health were investigated across five reefs around Redang Island, Malaysia. Feeding and territorial behavior for a total of 15 pairs butterflyfishes were studied by using visual census observation approach. Ranging behavior, territories size, activity patterns, individual bite rates and types of food consumed were recorded. C. octofasciatus, the most common butterflyfish of Redang Island, feeds on different coral polyps, particularly on genus Acropora. The pairs of this species occupy feeding territory, of which they exclusively defended against conspecifics and congeneric intruders. A total number of 27 coral genera were identified within all study sites, of which coral community was typically dominated by genera Acropora and Porites. Percentages of live coral coverage among 5 sites were ranged from 48.87% to 63.21%, indicated that Redang Island's coral conditions were ordinarily "good". Our finding has shown the positive correlation between the abundance of C. octofasciatus with percentage live coral cover and Acropora cover. The feeding territories size, which ranged from 16.4 to 50.1m^2, showed no correlation with live coral cover. The feeding rates in all study sites varied from 6.0 to 9.9 bites min^<-1>, with an average of 7.9 bites min^<-1>, were not significantly related to either coral cover or the size of feeding territory. C. octofasciatus is diurnal and spends about 47% of the time budget in feeding activity. The remaining time is spent in other activities such as swimming, hanging, sheltering and territory defending