Subtidal rocky reef and coral communities
Based on the results of preliminary surveys, locations in Section A were too shallow and sandy for conducting rocky subtidal survey, as a result, no sampling sites were chosen in Section A. For Sections B, C and D, three sites were chosen in each section, and the sampling was conducted twice in each season.
Samplings were conducted at depth level between 0 to -4 m C. D. of each site. Due to the greater water depths in the outer Tolo area (Section D), stratified sampling was conducted in Section D with two water depth levels (shallow: 0 to -4 m C.D. and deep: deeper than -4 m C.D.)
Within each study site, three 10 m transects were laid haphazardly along the depth contour. A belt area of 10 m × 2 m was surveyed for the presence of any mobile fauna. Two 2 m × 2 m areas were also designated at random within each belt to identify and count all mobile fauna encountered. The percentage cover of substrate types, sessile groups of plants and animals were also recorded by fixed number (10 for Section B; 15 for Sections C and D) of randomly placed photo-quadrats (0.5 m × 0.5 m), while the percentage cover of each group was estimated from the photos using CPCe.
Due to the difficulties in identifying some bivalves and epibionts using photo- quadrats, semi-destructive sampling was also conducted. During the sampling, three 0.5 m × 0.5 m quadrat areas were randomly designated on each transect, all epibionts and bivalves within the quadrat areas were collected and transferred to the Marine Science Laboratory of The Chinese University of Hong Kong for further identification.