Scleractinian recruits on natural and artificial substrates in temporary sediment-challenged coastal water of Bangkalan, Madura Island, Indonesia

Abstract

Recruitment of coral juveniles could serve as indicator for potential of coral reef recovery and is a critical process in supporting population as well as facilitating recovery after event of disturbance. However, sediments suspended in the water column and settling on to reef surface can negatively influence the distributions and abundances of reef-building corals, including altering the settlement patterns and survival of coral larvae and new recruits. In this study, we compared the density and diversity of Scleractinian recruits on natural substrate and artificial reef (made of concrete; 2 years after deployment) in the relatively turbid water of Sepulu coastal water, Bangkalan – Madura Island, East Java. Observation of stony coral recruits were conducted in-situ at depth of 3-4 meter in two locations. At the end of the study, we identified 18 species of Scleractinians from 10 genera and 7 families; dominated by Goniopora (F. Poritidae), Galaxea (F. Euphyllidae) and Goniastrea (F. Merulinidae). There was no difference in term of species richness and composition among locations and type of substrate. However, in both locations, more recruits grown in concrete artificial reef (15.2±2.61 - 18.3±2.91 unit/m2) compared to natural substrate (4±1.25 - 4.1±1.29 unit/m2), respectively. These findings suggest that concrete artificial reef is applicable for coral reef restoration and rehabilitation in temporary turbid coastal water by providing suitable substrate for larval recruitments.

Coral recruits on concrete hemispherical artificial reef (HSAR) with different composition in Pasir Putih, Situbondo, Indonesia

“…The hemispherical artificial reefs (HSAR, Figure 2) [13,14] were 50 cm in diameter and height, used as platform for coral settlement and recruitment process [15]. Three types or mixtures were selected: C1), conventional concrete which composed by a mixture of Portland cement, sand, and gravel (composition was 1:3:2); C2), a mixture of Portland cement, sand, and crushed bivalve's shells or CSW (composition was 1:3:2); and C3), a mixture of Portland cement, FABA, sand, and CSW (composition was 1:3:3:2), respectively.…”

Suitability Index of Snorkeling Tourism In Sepulu District, Bangkalan, Indonesia

“…In Sepulu District, many beach tourist destinations can be developed into snorkelling marine tourism, including Tabuhan Beach, Lembung Paseser Beach, Tengket Beach, and Maneron Beach. Coral cover in these four beaches is moderately good [3,4] and has several coral forms and species [5].…”

“…So far, the coastal area of Bangkalan, especially the north coast facing the Java Sea, has only been used for beach tourism [2]. The northern coastal area of Bangkalan, which has a stretch of coral reefs and is the primary capital for snorkelling tourism, is in the Sepuluh subdistrict area [3]. In Sepulu District, many beach tourist destinations can be developed into snorkelling marine tourism, including Tabuhan Beach, Lembung Paseser Beach, Tengket Beach, and Maneron Beach.…”