Coastal Urbanization Impacts on Biodiversity the Case of Marinas in Singapore

Most of Singapore’s coastline has been modified by coastal development with variable influences on marine biodiversity. Marinas are typically designed as a semienclosed environment with a complex mix of structures that provide ecological niches throughout the water body. Water flow is inevitably reduced with a possible decline of water quality. This investigation was conducted to determine how marinas affect marine biodiversity. The three marinas studied Marina at Keppel Bay (MKB), One Degree 15 Marina (ODF), Raffles Marina (RM) all supported rich biodiversity. The combined 71 faunal taxa (two Classes, 10 Orders and 59 Families) from the soft bottom of all three marinas surveyed using the Ekman grab, were dominated by polychaetes (71.4%) and arthropods (16.7%; mainly crustaceans). The total fish species surveyed using customised traps was 49 from 31 Families, ranging from the very common and abundant fan-bellied filefish (Monacanthus chinensis) and eeltail catfish (Plotosus spp.), to the less commonly seen fishes such as the starry triggerfish (Abalistes stellatus) and estuarine stonefish (Synanceja horrida). Reef-associated fish species were more abundant at MKB and ODF, while estuarine species dominated at RM. Epibiotic diversity was evident on the artificial structures in all marinas. The submerged sides of berthing pontoons supported up to 107 taxa, dominated by ascidians, macroalgae and sponges. Corals also recruited naturally with 10 and 22 scleractinian genera established on pontoons at MKB and on seawalls at ODF, respectively. In general, fish and soft bottom macrobenthic abundance and diversity were comparable or higher within the marina compared to the adjacent open water. The findings indicate that modified coastal environments such as marinas can support diverse biological communities.