ABSTRACT
Seaweeds are a vital part of coastal ecosystems, which offer indispensable ecosystem services as well as socio-economic value. Seaweeds are a rich source of vitamins, minerals and other bioactive compounds, which have great prospects for use as health supplements. Seaweeds are distributed in complex environmental gradients on a smaller spatial scale. The standing stock of about 844 seaweeds is found to be 58,715 tonnes wet weight in the Indian coast. The commercial seaweeds belong to agarophytes, carrageenophytes, alginophytes and edible seaweeds. Currently, K. alvarezii is the only commercially cultivated species, which accounts for 30%, and the rest are Gracilaria sp, Gelidiella sp and Sargassum sp. These seaweeds are mainly harvested from the naturally occurring coastal areas of Tamil Nadu and Gujarat states. The major seaweed culturing methods that are followed by the farmers in the coastal regions of Tamil Nadu and the other parts of India are (i) the single rope floating raft method, (ii) fixed bottom long line/monoline method, (iii) bamboo raft method and iv) net bag method. In India, there is a strong need to expand coastal seaweed cultivation to an offshore large-scale farming. Currently, the major problems associated with the seaweed industry are overexploitation of raw materials, low quality of stocks and lack of labours. Besides, most seaweeds are prone to epiphytism, and they are colonised by epibionts such as bacteria, protest, algae and invertebrates. High-resolution hydrodynamic modelling should be carried out before and after constructing farming structures for higher productivity. Furthermore, surveys need to be conducted to identify the seaweed cultivation zone to promote livelihood activities in coastal areas, with advanced seaweed mechanized vehicles within large spatial scales to identify proper localities for large-scale seaweed culture.
