Survey of the deep water area from Kilakkarai (Appa Tivu to Rameswaram Island
(Dhanushkodi) was undertaken from December 1990 to January 1991 in the IV Sector survey
of Deep water Seaweed Resources off Tamil Nadu coast, which formed the last phase of the
survey from Rameswaram to Kanyakumari carried out during 1986-91. An area of 417 .5 sq.km.
was surveyed yielding a total biomass of 18,162.5 tons (wet) seaweeds. Out of 167 stations
surveyed in 13 transects, vegetation occurred only in 12 stations. Of the 29 species of marine
algae recorded 8 belonged to Chlorophyta, 8 to Phaeophyta, 12 to Rhodophyta, and I to
Cyanophyta, One species of seagrass Cymodocea serrulata was also recorded. Twenty species
were found in estimable quantities, of which the following 8 species were abundant: Halimeda
macr%ba, Spatog/ossum asperum, Zonaria crenata, Sargassum ilicijolium, Amphiroa
jragilissima, Hypnea muscijormis, Botryocladia /eplOpoda and Lyngbya majuscula with a biomass
of 1325, 9775, 650, 1550, 1925,300,862.5 and 1012.5 tons (wet) respectively. The species of
Hypnea and Sargassum could be exploited for the manufacture of phytochemicals