Ecological status of coral communities in the island area of the Nha Trang Bay (Vietnam)

The ecological status of coral communities in the island area of the Nha Trang Bay (Central Vietnam) has been evaluated in March to May 2013. The material has been sampled at five stations from depths of 3-6 m using the photoquadrat method. It has been shown that characteristics of these communities markedly change with distance from the Nha Trang City and the sources of eutrophication and sediment influx: the total coral cover and the proportion of acroporids increase from 5.3% to 82.6% and from 0 to 61% respectively, while the abundance of macroalgae decreases from 41.5% to 0; the species richness of corals also increases significantly, from 7 to 68 species per station. Possible causes of the long-term changes in the coral reef ecosystems of the Nha Trang Bay are discussed.