Species diversity and distribution of seagrasses from the South Andaman, Andaman and Nicobar Islands, India

A survey was conducted with the objective to study seagrass distribution, bed size and shoot density in different substrata of the South Andaman Islands. A total of 231 seagrass sites were observed during the study, in which a total of eight species were found. The South Andaman region exhibited the highest species diversity followed by Havelock, Little Andaman and Neil Islands. Eleven continuous seagrass bed were noted during the study which were confined to three different types of substrata: sand only; sand mixed with coral sand and coral rubble; sand mixed with mud. Thalassia hemprichii and Cymodocea rotundata were found in dense canopies and covered large areas associated with sand and coral rubble. Halophila beccarii showed moderate abundance in muddy substrata and Halodule spp. grew in fine sand. The highest shoot density was recorded at Haddo, followed by Vijaya Nagar and Chidyatapu, contributed mostly by Halodule spp. In general, seagrass diversity and distribution were mainly influenced by the percentage composition of sand. The authors recommend that the seagrass meadow of Haddo should be considered for conservation priority because of multiple anthropogenic pressures, such as sewage input, dumping of solid wastes on the shoreline and anchoring of boats.