The antibacterial activities of twelve species of anthozoans (4 gorgonians,
5 soft corals and 3 antipatharians) collected off the east coast of India
were assayed against four dominant marine fouling bacterial strains isolate
d from the biofilm of fouled aluminium panels. Of the 48 combinations (12 c
orals x 4 bacteria) eighteen interactions showed antibacterial activity (37
.5%). Such activity was most apparent in gorgonians, which inhibited bacter
ial growth in ten out of sixteen interactions (62.5%) compared with that of
five out of twenty interactions (25%) among soft corals and three out of t
welve interactions (25%) among antipatharians. The activity scores varied w
ith different extracts and test organisms used, and was highest in antipath
arians. Among the four bacterial strains Vibrio sp. was the least sensitive
(2/12) when compared with Flavobacterium sp. (6/12). This is the first rep
ort of antibacterial activities of antipatharian colonies against marine mi
crofoulers. The results imply that anthozoan corals harbour potent agents w
hich could be exploited for the development of antifouling technology.