Abstract
The symbiotic community associated with a scleractinian coral Pocillopora verrucosa has been studied along the Red Sea coast of Saudi Arabia from Al Wajh to the entrance of the Gulf of Aqaba. Forty colonies have been sampled from 2- to 15-m depth in 2 areas, southern and northern. Thirty-six associated species were found, including 15 symbionts and 21 species with uncertain status (SUS). The number of recorded symbiotic species was close to the statistically expected value, while SUS were rare and did not reach the value expected from the Chao 2 model. Species number and abundance positively correlated with the colony volume. Mean abundance of all species and symbionts and the number of SUS per covariate colony volume were higher in the northern area than in the southern area. This may be related to a higher habitat diversity of the surrounding reefs and to the presence of colonies with partially dead tissues in the north. These two factors have a weak impact on symbionts, but strongly affect SUS. The diversity of the pocilloporid-associated communities range from 36 to 127 species along the Indo-Pacific and Tropical East Pacific, with 9 to 19 of them being symbionts. The total species diversity varies owing to the SUS number, while the core of true symbionts includes much fewer species and is less variable. The diversity of Pocillopora symbionts in the Saudi Arabian coast (15 species) is among the highest for the studied areas in the Indo-Pacific.