Diversity of Benthic Organisms on Artificial Reef Structure

Abstract

One of the methods of a marine rehabilitation program to accelerate the recovery of damaged coral reefs is to make artificial reefs as a new coral growth substrate. Interestingly, many benthic invertebrates overgrowth the artificial reef structures. The purpose of this study was to investigate the benthic organisms encrusting the artificial reefs including the cement and iron substrates. In June 2018, 10 artificial reef structures were deployed in 7-8m depth around Putri Island, Belinyu, Bangka Regency. The artificial reef structures were made in the form of an iron frame with a cement concrete weight. Colonization of sessile benthic organisms is generally marine invertebrates; Scleractinia corals, sponges, bivalves, hydrozoa, bryozoa, soft corals, gastropoda, crinoid, ascidian, and gorgonian. Natural recruited coral Pocillopora sp. was found in all artificial reef structures with colony sizes 3-8cm and surprisingly only coral pocillopora found adhered in iron frames and sinkers. The other benthic organisms are sponge, crinoid, and bryozoa with the number of densities are 2 organism/m2. Meanwhile, the lowest benthic density are groups of Mollusc and Ascidian with organism/m2. The type of succession that occurs in this research was likely a primary succession. The preference of benthic organisms among reefs appeared to be related to the proximity of natural hard-bottom habitat and type of iron and coating materials.