the coral community was co-dominated by Porites and Platygyra (Shelter Island),Porites and Goniopora (Tai She Wan), or
Porites and Montipora (Bluff Island). A total of 1837 D. setosum were found on the photoquadrats taken from the eight sites (total area for each site: 0.75 m 0.75 m 25 quadrats transect 13 transects site1
= 42.18 m
2
). Sea urchin
density varied dramatically among the sites, ranging between 0.1
individuals m
2
and 21.1 individuals m
2
. The low values occurred
at the three eastern sites: 0.1, 0.2, and 0.2 individuals m
2
at Tai
She Wan, Shelter Island and Bluff Island, respectively. The values
at northeastern sites varied by a factor of up to 19 times: 1.1