Marine fouling on floating installations west of Dongsha Islands, the northern South China Sea

Abstract

Marine fouling on floating installations west of Dongsha Islands, the northern South China Sea, was investigated from August 1987 to October 1990. Two buoy stations were deployed at approximately 110 km and 115 km west of Dongshadao, Dongsha Islands, anchored in water at 325 and 345 m depths, and exposed for 8 and 12 months. The experimental panels were fixed on iron structure frames which were connected to the buoy and its mooring system immersed in water at different depths, and retrieved after 4, 8 and 12 months of exposure. Fouling organisms colonizing the buoys and their mooring systems were sampled after 8 and 12 months of deployment. A total of 86 species was collected and identified at these two stations and the fouling community showed a typical oceanic characteristics. Most of the species were mainly found in the top 50 m depth and a striking vertical zonation of species was also observed with depth. The distance from offshore is a major factor in determining the fouling community composition. In terms of biomass, the fouling community was dominated by pedunculate barnacles, hydroids, and algae, followed by common oysters, pearl oysters and acorn barnacles. Biomass of hard fouling organisms increased over time. Under the influence of hydrological currents propagules of communities around the Dongsha Islands may also affect the development of the fouling communities in the offshore waters.