Sea anemone, Stichodactyla haddoni (10 individuals)
was procured from a fish trader, Chennai, Tamilnadu,
India. Animals were acclimatized at the Marine Ornamental
Fish Hatchery, Centre of Advanced study in Marine
Biology, Annamalai University. Representative anemones
(n = 5) were placed without substrate in individual experiment
tanks (300 L capacity), one per tank, and (n = 5) were
allowed with substrate (small rocks), and marked Sh 1–Sh
10 (Sh 1–Sh 5 without and Sh 6–Sh 10 with substrate). The
water quality parameters were maintained as temperature
28
±
1◦ C, salinity 26
±
1 psu, Dissolved oxygen 4–5 ppm
and pH 7.7 and light intensity was 12L:12D. S. haddoni was
circled around the pedal disk using a waterproof felt-tip
pen and each position (per 24 h) was sketched to permit
reorientation of the overlay map. The distances traveled
by each anemone were calculated using a measuring scale
during the study period (July–September 2011). Net distance
traveled in gross by representative anemones was
calculated using the formula