Changes in the composition and structure of coral communities of Mju and Moon islands, Nha Trang Bay, South China Sea

Encrusting protected reef Hon Nai in Cam Ranh Bay in the South China Sea

“…Only representatives of the genus Acropora, there are 34 species, representing 80 percent of the total membership of these Scleractinian on reefs throughout Vietnam and a quarter of the total wealth of these corals on reefs Indo-Pacific [12]. The abundance of these corals showed favorable terms on the reef, as it is known that acroporids among the first negatively react to environmental changes, primarily to anthropogenic pollution and eutrophication of the surrounding waters and therefore the first to die, there is no or very few and far between in the contaminated areas [1,2,13,24]. The studied reef is characterized by distinct bionomical zonality, high species variety, and dense coral cover on the substrate, mass development of spherical and tabular forms of coral colonies, and continuous monosettlements of acroporids, which is typical for optimal climax conditions on the reef [9,18,[25][26][27].…”

“…The island is owned by the company "Sanest", there is a restricted if any at all access to the underwater resources. A visually coral ecosystem formed at the southwest of the island is distinguished by an amazing purity of the surrounding waters and a surpriseingly high species diversity of reef-building corals and other accompanying animals, which significantly distinguishes it from the adjacent Mainland and island reefs [1,2]. By the specificity of geomorphological and climate conditions, Vietnam's adjacent reefs are clearly distinguished into two types.…”

“…The abundance of these corals indicated favorable conditions on the reef. Acroporids belong to the first organisms that "acrophy to negatively" respond to environmental changes, primarily to anthropogenic pollution and increased eutrophication of the surrounding waters [1,2,13,14]. The species diversity of Hon Nai Island reef was comparable to that of reefs of large regions as the Gulf of Siam and the Bay of Tonkin (Figure 2), as well as Con Dao Islands [10].…”

“…Besides, coral reefs through their erosion serve as a main source of sand, replenishing critically eroded coasts. Results of hydrobiological studies on coastal Mainland and the island reefs of Vietnam in recent years clearly demonstrated their biodegradable, largely due to strong anthropogenic press [1,2,4]. Study of protected and best preserved reef is necessary to determine it's damage and to develop recommendations for the restoration and preservation of disturbed communities of reef.…”

“…Coral reefs of Vietnam are an integral part of IndoWest pacific tropic center of origin and diversity of corals [2]. They represent a very productive natural ecosystem with a variety of ecological niches and multiple inhabitants.…”