Abstract
The Manifa oilfield development involved the construction of a causeway to support 25 offshore drill site islands across the Manifa-Tanajib Bay System. As part of the environmental impact assessment of this project, a post-construction monitoring was performed between 2013 and 2015 to evaluate the artificial structure's effects on local marine communities. Benthic communities (fouling and sediment-dwelling organisms) were sampled two to three times per year at 10 to 16 stations along the causeway and islands. Seventeen epifaunal taxa were recorded from the fouling samples with mollusks (33%) and crustaceans (30%) dominating the community while 99 species were recorded from the sediment samples with polychaetes (69%) as the dominant taxon. As the causeway represents a no-entry area due to oil industry activities, the number of species utilizing it as a habitat will probably develop without significant disturbance in the coming years, highlighting its role as an artificial reef-like structure in the Saudi Arabian waters.