Marine & Environmental Sciences Faculty Articles
The removal of macroalgal biomass is critical to the health of coral reef ecosystems. Previous studies on relatively intact reefs with diverse and abundant fish communities have quantified rapid removal of macroalgae by herbivorous fishes, yet how these findings relate to degraded reef systems where fish diversity and abundance are markedly lower and algal biomass substantially higher, is unclear. We surveyed roving herbivorous fish communities and quantified their capacity to remove the dominant macroalga Sargassum ilicifolium on seven reefs in Singapore; a heavily degraded urbanized reef system. The diversity and abundance of herbivorous fishes was extremely low, with eight species and a mean abundance ~1.1 individuals 60 m−2 recorded across reefs. Consumption of S. ilicifolium varied with distance from Singapore’s main port with consumption being 3- to 17-fold higher on reefs furthest from the port (Pulau Satumu: 4.18 g h−1; Kusu Island: 2.38 g h−1) than reefs closer to the port (0.35–0.78 g h−1). Video observations revealed a single species, Siganus virgatus, was almost solely responsible for removing S. ilicifolium biomass, accounting for 83% of the mass-standardized bites. Despite low herbivore diversity and intense urbanization, macroalgal removal by fishes on some Singaporean reefs was directly comparable to rates reported for other inshore Indo-Pacific reefs.
his study was funded through the AXA Post-doctoral fellowship (Project No: 154-000-649-507) and the Singapore National Research Foundation (Project No: R-154-001-A25-281 MSRDP-P03). All research carried out abided by local laws and was done with permission of the Singapore government through the National Parks Board (Permit #NP/RP15-009c). We thank M. Lee and F. Yeo from Dolphin Explorer for boat and logistical support.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Andrew G. Bauman, Andrew S. Hoey, Glenn Dunshea, David A. Feary, Jeffrey Low, and Peter A. Todd. 2017. Macroalgal browsing on a heavily degraded, urbanized equatorial reef system .Scientific Reports , (8352) . https://nsuworks.nova.edu/occ_facarticles/1301.